JP6666662B2 - Carbon catalyst, electrode and battery using the same - Google Patents

Description

The present invention relates to a carbon catalyst and an electrode and a battery using the same. More specifically, the present invention relates to a carbon catalyst which can be suitably used as a catalyst for an electrode of a battery such as a fuel cell, and an electrode and a battery using the same.

In recent years, energy sources have been changing from oil and coal to electricity in various industrial fields against the background of growing interest in environmental issues, and not only electronic devices such as mobile phones and notebook computers, but also automobiles and aircraft The use of batteries has been expanding in various fields, including the fields such as.
Batteries are broadly classified into primary batteries, secondary batteries, and fuel cells. Among them, fuel cells are characterized in that discharge can be continued by replenishing a material serving as a positive electrode and a negative electrode active material. 2. Description of the Related Art In recent years, attention has been paid to fuel cells, such as the release of an automobile using a fuel cell using oxygen and hydrogen as a power source.

Currently, a Pt / C catalyst is used as an electrode catalyst for a fuel cell (particularly, a positive electrode). However, since Pt, which is a noble metal, is expensive, development of a cheaper electrode catalyst is required. As an electrode catalyst not using a noble metal, a carbon alloy catalyst containing carbon, nitrogen, and Fe and Co as components has been studied. For example, in a catalyst carrier containing carbon as a main component and having at least a nitrogen atom and other hetero atoms on its surface, the content ratio of carbon atoms to nitrogen atoms and hetero atoms, and the ratio of nitrogen atoms to other hetero atoms A catalyst carrier having a specified abundance ratio (see Patent Document 1), a wholly aromatic polyimide composition comprising a wholly aromatic polyimide composed of a repeating unit having a specific structure and a metal phthalocyanine having a specific structure are subjected to an inert gas atmosphere. A carbon material obtained by firing at a predetermined temperature (see Patent Document 2) and a nitrogen-containing carbon alloy obtained by firing an organic material containing a nitrogen-containing crystalline organic compound having a specific molecular weight (see Patent Document 3). ) Is disclosed.

JP 2009-277360 A JP 2010-275116 A JP 2011-225431 A

In order to spread fuel cells, which are expected to spread in various fields of society in the future, one of the important factors is to make fuel cells cheaper. In order to realize a cheaper fuel cell, there is a great need for an inexpensive electrocatalyst that does not use a noble metal, and an electrocatalyst that meets such needs is demanded.

The present invention has been made in view of the above situation, and has as its object to provide an inexpensive catalyst having good catalytic activity as an electrode catalyst for a fuel cell.

The present inventors have conducted various studies on inexpensive catalysts that can be used as electrode catalysts for fuel cells, and found that a carbon catalyst containing carbon as a main component and containing nitrogen and halogen atoms in a specific ratio to the entire catalyst, respectively, is a fuel. It has been found that it has good catalytic activity as an electrode catalyst for batteries and the like. Since this catalyst can be produced without using expensive materials, the present inventors have conceived that this can solve the above-mentioned problem brilliantly, and have reached the present invention.

That is, the present invention relates to a carbon catalyst containing carbon as a main component and containing 0.1 to 20% by mass of nitrogen with respect to the whole catalyst. It is a carbon catalyst characterized by containing 20% by mass.
Hereinafter, the present invention will be described in detail.
A combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

The carbon catalyst of the present invention contains carbon as a main component. Mainly containing carbon means that the mass ratio of carbon atoms to the entire carbon catalyst is 50% by mass or more. The ratio of carbon atoms to the entire carbon catalyst is more preferably 60 to 99% by mass, still more preferably 70 to 98% by mass, and particularly preferably 80 to 97% by mass.
The carbon catalyst of the present invention contains 0.1 to 20% by mass of nitrogen based on the whole catalyst, and the mass ratio of nitrogen atoms to the whole catalyst is preferably 0.2 to 15% by mass. It is more preferably from 0.3 to 10% by mass, further preferably from 0.5 to 8% by mass, and particularly preferably from 1 to 6% by mass.
Further, the carbon catalyst of the present invention contains 0.1 to 20% by mass of a halogen atom with respect to the whole catalyst, and the mass ratio of the halogen atom to the whole catalyst is preferably 0.2 to 15% by mass. It is more preferably from 0.3 to 10% by mass, further preferably from 0.5 to 8% by mass, and particularly preferably from 1 to 6% by mass.

The halogen atom contained in the carbon catalyst of the present invention may be any halogen atom such as fluorine, chlorine, bromine and iodine, but is preferably fluorine. By including a fluorine atom, the carbon catalyst has higher activity as an electrode catalyst for a fuel cell or the like.

The carbon catalyst of the present invention preferably further contains at least one transition metal atom selected from transition metal atoms of Groups 5 to 11 of the periodic table with respect to the entire catalyst. By including a transition metal atom, the carbon catalyst has higher activity as an electrode catalyst of a fuel cell.
The transition metal atom is not particularly limited as long as it is a transition metal atom belonging to Groups 5 to 11 of the periodic table. At least one transition metal atom selected from the group consisting of vanadium, chromium, manganese, iron, cobalt, nickel and copper It is preferred that By including any of these atoms among the transition metal atoms of Groups 5 to 11 of the periodic table, the carbon catalyst has higher activity as an electrode catalyst for a fuel cell or the like. The transition metal atom is more preferably at least one selected from the group consisting of manganese, iron, cobalt, nickel and copper, and still more preferably at least one selected from the group consisting of iron, cobalt and copper. .

When the carbon catalyst of the present invention contains at least one transition metal atom selected from transition metal atoms belonging to Groups 5 to 11 of the periodic table, the content is 0.05 to 20 mass% based on the entire carbon catalyst. %. More preferably, it is 0.1 to 10% by mass, still more preferably 0.1 to 6% by mass.

The carbon catalyst of the present invention may contain carbon, nitrogen, a halogen atom, and other atoms other than at least one transition metal atom selected from transition metal atoms of Groups 5 to 11 of the periodic table. The content of other atoms is preferably 20% by mass or less based on the entire carbon catalyst. More preferably, it is 10% by mass or less, and still more preferably 5% by mass or less.

The production method of the carbon catalyst of the present invention is not particularly limited as long as it contains carbon as a main component and contains nitrogen and a halogen atom in the above-described predetermined ratio. It is preferably obtained by the above.
Since the carbon catalyst of the present invention contains carbon, nitrogen and halogen atoms as essential constituent atoms, it is necessary that the organic compound as a raw material contains nitrogen and halogen atoms in addition to carbon. As an organic compound serving as a raw material, an organic compound containing all of carbon, nitrogen, and a halogen atom may be used, or an organic compound containing carbon and nitrogen and an organic compound containing carbon and a halogen atom may be used.
That is, the carbon catalyst of the present invention is obtained by calcining a raw material containing an organic compound, and the organic compound is a nitrogen-containing organic compound and a halogen atom-containing organic compound, or an organic compound containing nitrogen and a halogen atom. Including is one of the preferred embodiments of the present invention.
In this case, the raw material of the carbon catalyst may contain another organic compound as long as it contains a nitrogen-containing organic compound and a halogen atom-containing organic compound, or an organic compound containing nitrogen and a halogen atom. When the raw material contains two or more kinds of organic compounds, the compounding ratio of these organic compounds is adjusted so that the ratio of carbon, nitrogen and halogen atoms in the carbon catalyst obtained by calcining satisfies the ratio of the carbon catalyst of the present invention. Can be appropriately adjusted and used.
Here, the nitrogen-containing organic compound means a compound containing nitrogen and no halogen atom, and the halogen-containing organic compound means a compound containing a halogen atom and not containing nitrogen.

The nitrogen-containing organic compound is not particularly limited as long as it is a compound containing a nitrogen atom as an atom constituting the compound. Preferred are azo compounds, azoxy compounds, nitro compounds, nitroso compounds and the like. More preferred are polyimide, polyamic acid, polyamideimide, amino group-containing polymer, polynitrile and the like. Examples of the polyimide or polyamic acid include non-fluorinated fluorinated polyimide and / or fluorinated polyamic acid described below. Specific examples of the polyimide include those having a structure in which a fluorine atom of a fluorinated polyimide represented by the following formulas (6-1) and (6-2) is replaced with hydrogen, and a polyimide represented by (6-3). Polyimide.

The halogen atom-containing organic compound is not particularly limited as long as it is a compound containing a halogen atom as an atom constituting the compound, but a compound containing a fluorine atom is preferable. More preferred are fluorine-containing polymers such as fluorinated polyetherketone, fluorinated polyaryletherketone, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, and polyvinyl fluoride.

The organic compound containing nitrogen and a halogen atom is not particularly limited as long as it is a compound containing a nitrogen atom and a halogen atom as atoms constituting the compound, and may be a compound containing a nitrogen atom and a fluorine atom. preferable. More preferably, it is a polymer containing a nitrogen atom and a fluorine atom, and even more preferably, it is a fluorinated polyimide or fluorinated polyamic acid.
That is, the organic compound contained in the raw material of the carbon catalyst preferably contains fluorinated polyimide and / or fluorinated polyamic acid. By using a raw material containing these, the obtained carbon catalyst has higher activity as an electrode catalyst for a fuel cell or the like.
In addition, the fluorinated polyamic acid may be one in which a part of the amide acid structure is imidized.

The weight average molecular weight of the fluorinated polyimide is preferably from 50,000 to 2,000,000, more preferably from 60,000 to 1,500,000, even more preferably from 70,000 to 1,200,000. The weight average molecular weight of the fluorinated polyamic acid is such that the fluorinated polyimide obtained when the fluorinated polyamic acid is imidized (preferably imidized so that the imidization ratio becomes 100%) is the weight average molecular weight. It is preferable that the weight average molecular weight is in the molecular weight range.
The weight average molecular weight can be measured by gel permeation chromatography (GPC) under the conditions described in Examples described later, using a calibration curve of standard polystyrene.

The fluorinated polyamic acid is a precursor of a fluorinated polyimide.
The fluorinated polyamic acid has the following general formula (1);

(In the general formula (1), X represents a divalent organic group. Y represents a tetravalent organic group. At least one of X and Y is an organic group containing a fluorine atom.) It is preferable to have a structural unit represented by the formula:

In the above general formula (1), the divalent organic group represented by X and the tetravalent organic group represented by Y may have any of a linear, branched or cyclic structure. Alternatively, a structure combining these may be used.
Examples of the divalent organic group represented by X include divalent aliphatic organic groups derived from cyclic alkyl, chain alkyl, cyclic alkene, chain alkene, glycol, and the like; benzene, biphenyl, biphenyl ether, bisphenylbenzene , A divalent aromatic organic group derived from bisphenoxybenzene, and the like; a divalent organic group in which at least one divalent aliphatic organic group and at least one divalent aromatic organic group are bonded to each other. Further, these structures may be further substituted with a hetero atom or a functional group containing a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom.

In the general formula (1), as the divalent organic group represented by X, those having an aromatic ring in the structure are preferable among the above-mentioned ones, and the following general formulas (2-1) to (2-8) );

(In the formula, Z is the same or different and represents a hydrogen atom, an alkyl group, an aryl group, or a halogen atom. The alkyl group or the aryl group may be substituted with a substituent such as a halogen atom. Z may be the same or different in each organic group and each benzene ring, R may be the same or different and represent a halogen atom or a hydrogen atom, and X 'may be the same or different. , An oxygen atom, a nitrogen atom, a carbon atom, -S-, or -S (= O) _2- . The * portion is bonded to the N atom in the general formula (1).) Any of the divalent organic groups is more preferred.
When Z or R in the general formulas (2-1) to (2-8) has a halogen atom, the halogen atom is preferably a fluorine atom. Incidentally, notation and Z ₄ represents the atoms represented by Z is attached four to a benzene ring. Similarly, A ₃ in the general formula (3-1) described later, and A ₄ and A _{5 in} the general formulas (5-1) to (5-4) also have the plurality of atoms bonded to the benzene ring. It represents that.

The fluorinated polyamic acid having the structural unit represented by the general formula (1) preferably has an ether bond in the structure. More preferably, each structural unit represented by the general formula (1) has two or more ether bonds.
Further, in the general formula (1), the tetravalent organic group represented by Y preferably has an aromatic ring. Among them, Y in the general formula (1) is the following general formula (3-1) or (3-2);

(In the general formulas (3-1) and (3-2), A represents the same or different and represents a hydrogen atom or a fluorine atom. R ¹ represents the following general formula (4-1) or (4-2) Wherein each * part is bonded to a carbon atom in the above general formula (1).) It is more preferable that the organic group is a tetravalent organic group represented by the above general formula (1).

In the above general formula (4-1), the divalent organic group represented by Q may have any of a straight-chain, branched-chain, or cyclic structure, and a combination thereof. You may.
Examples of the divalent organic group include divalent aliphatic organic groups derived from cyclic alkyl, chain alkyl, cyclic alkene, chain alkene, glycol and the like; benzene, biphenyl, biphenyl ether, bisphenylbenzene, bis A divalent aromatic organic group derived from phenoxybenzene or the like; an organic group formed by bonding one or more aliphatic organic groups and one or more aromatic organic groups. Further, these structures may be further substituted with a hetero atom or a functional group containing a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom.
Among the above, as the divalent organic group represented by Q, those having an aromatic organic group are preferable, and the following general formulas (5-1) to (5-4);

(In the formula, each * portion is bonded to an oxygen atom of an ether bond in the general formula (4-1). In the formula, A is the same or different and represents a hydrogen atom or a fluorine atom.) The divalent organic groups represented are more preferred.

By the imidization reaction of the fluorinated polyamic acid, a fluorinated polyimide is obtained. Preferred fluorinated polyimides in the present invention include 10FEDA / 4FMPD represented by the following formula (6-1), 6FDA / TPEQ represented by the formula (6-2), and formula (6-3) Examples include those having a structure in which part or all of the hydrogen atoms of the aromatic ring of PMDA / ODA represented by the above are partially or entirely substituted with fluorine atoms.

When the raw material of the carbon catalyst of the present invention contains fluorinated polyamic acid, it may contain one kind of fluorinated polyamic acid or may contain two or more kinds of fluorinated polyamic acid.
The fluorinated polyamic acid can be obtained by reacting a mixture of an acid dianhydride described below and a diamine by a usual method. In addition, the raw material of the carbon catalyst may further contain an acid dianhydride, a diamine which is a raw material of the polyamic acid, and other components.

As the acid dianhydride, a compound represented by the following general formula (7) is preferable. Note that Y in the formula is the same as Y in the general formula (1).

Further, as the diamine, the following general formula (8);

The compound represented by is preferred. Note that X in the formula is the same as X in the general formula (1).
The reaction between the acid dianhydride and the diamine can be performed with reference to WO 2010/150908 and the like.

The raw material of the carbon catalyst of the present invention may contain other components such as a compound containing a transition metal atom as described below. The content of the organic compound containing a nitrogen atom or a halogen atom in the raw material (when two or more organic compounds containing a nitrogen atom or a halogen atom are contained, the total amount thereof) is determined by the nitrogen content in the carbon catalyst obtained by firing. The content of the organic compound containing a nitrogen atom or a halogen atom with respect to the entire solid content of the raw material of the carbon catalyst is 5 to 90% by mass. Is preferred. More preferably, the content is 10 to 80% by mass.
Note that the following compounds containing a transition metal atom may contain a nitrogen atom or a halogen atom, but the organic compound containing a nitrogen atom or a halogen atom here does not include a compound containing a transition metal atom.

When producing the above-mentioned carbon catalyst containing a transition metal atom, it is preferable to add the compound containing a transition metal atom to a raw material in addition to the above-mentioned organic compound, and calcinate.
In this case, as the compound containing a transition metal atom, a transition metal complex or a transition metal salt can be used.
Examples of the transition metal complex include a transition metal phthalocyanine complex, a tris (pentanedisionate) complex, a porphyrin complex, a salen complex, and a cyclopentadienyl complex.
Examples of the transition metal salt include chloride, sulfide, oxide, hydroxide, carbonate, sulfate, nitrate, acetate, phosphate, citrate and the like.

When the raw material of the carbon catalyst of the present invention contains a transition metal complex or a transition metal salt, the content thereof may be adjusted so that the amount of transition metal atoms in the fired carbon catalyst is in the above-described preferred range. It is preferably 0.5 to 50% by mass based on the entire solid content of the raw material of the carbon catalyst. More preferably, it is 1 to 40% by mass, still more preferably 2 to 30% by mass.

The raw material of the carbon catalyst of the present invention may contain a solvent. As the solvent, one or more of water, methanol, ethanol, isopropanol, acetone, ethyl acetate, dimethylacetamide, N, N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, hexane, toluene and the like can be used. .
The content of the solvent is not particularly limited, but is preferably 30 to 95% by mass of the entire raw material of the carbon catalyst.

The temperature at which the raw material of the carbon catalyst of the present invention is calcined is preferably 500 to 1500 ° C. By firing at such a temperature, the resulting carbon catalyst has higher activity as an electrode catalyst for a battery. The firing temperature is more preferably from 700 to 1300 ° C, and still more preferably from 800 to 1100 ° C. Especially preferably, it is 800-1000 degreeC.
The firing step may be performed at a fixed temperature, may be performed while changing the temperature, or may be performed in combination. Preferably, it includes firing while raising the temperature. When baking is performed while raising the temperature, the initial temperature is preferably 0 to 100 ° C. More preferably, it is 10 to 50 ° C. The final temperature after the completion of the temperature rise is preferably from 700 to 1300 ° C. More preferably, it is 800 to 1100 ° C. Further, the heating rate is preferably 0.5 to 20 ° C./min. More preferably, it is 1 to 10 ° C / min.
The time for the entire firing step is preferably 30 to 1200 minutes. More preferably, it is 60 to 600 minutes, and still more preferably, it is 100 to 500 minutes.

When the raw material of the carbon catalyst of the present invention contains a fluorinated polyamic acid, it is preferable to include a step of thermally imidizing the polyamic acid before the above-mentioned calcination. The thermal imidization step is preferably performed at 200 to 400 ° C. More preferably, it is 250-380 degreeC, Still more preferably, it is 270-340 degreeC.
The thermal imidization step may be performed at a fixed temperature, may be performed while changing the temperature, or may be performed in combination. It is preferable to include thermal imidization while raising the temperature. When performing thermal imidization while raising the temperature, the initial temperature is preferably 0 to 100 ° C. More preferably, it is 10 to 50 ° C. The final temperature after the completion of the temperature rise is preferably from 250 to 350 ° C. More preferably, it is 270-330 ° C. Further, the heating rate is preferably 1 to 50 ° C./min. More preferably, it is 2 to 30 ° C./min.
The total time of the thermal imidization step is preferably 10 to 600 minutes. More preferably, it is 20 to 400 minutes, and still more preferably, it is 30 to 300 minutes.

The baking step and the thermal imidization step are preferably performed in an inert gas atmosphere. As the inert gas, any inert gas such as helium, nitrogen, and argon may be used.

The carbon catalyst of the present invention can be suitably used as a catalyst for an electrode of a battery such as a fuel cell. Such an electrode including the carbon catalyst of the present invention is also one of the present invention.
Since the carbon catalyst of the present invention has high activity as an oxygen reduction catalyst, the electrode of the present invention is preferably used as an air electrode of a fuel cell.

The electrode of the present invention preferably includes the carbon catalyst of the present invention and a current collector supporting the carbon catalyst.
As the current collector, carbon paper, metal foil, metal mesh, or the like can be used.
Further, forming the carbon catalyst of the present invention into a sheet shape and having a function as a current collector is also one of the preferable embodiments of the electrode of the present invention.

The electrode of the present invention may contain other components other than the carbon catalyst of the present invention and a current collector supporting the carbon catalyst. Other components include a binder, a conductive auxiliary, an ionomer, and the like.
When other components are included, when preparing a dispersion of the following carbon catalyst, other components are mixed with a binder together with the carbon catalyst, and the obtained dispersion is applied on a current collector, dried, and dried. It is preferable to create

When the electrode of the present invention contains the carbon catalyst of the present invention and other components other than the current collector supporting the carbon catalyst, the content of the other components is 5 to 1000 mass% with respect to 100 mass% of the carbon catalyst. %. More preferably, it is 10 to 500% by mass, still more preferably 20 to 300% by mass.

Although the method for producing the electrode of the present invention is not particularly limited, it can be obtained by applying a dispersion of the carbon catalyst of the present invention on a current collector and drying.
The binder used to prepare the dispersion of the carbon catalyst includes poly (meth) acrylic acid-containing polymer, poly (meth) acrylate-containing polymer, polyacrylonitrile-containing polymer, polyacrylamide-containing polymer, polyvinyl alcohol-containing polymer, Ethylene oxide containing polymer, polypropylene oxide containing polymer, polybutene oxide containing polymer, polyethylene containing polymer, polypropylene containing polymer, polybutene containing polymer, polyhexene containing polymer, polyoctene containing polymer, polybutadiene containing polymer, polyisoprene containing polymer, halogen containing polymer, analgen, benzene , Trihydroxybenzene, toluene, piperonaldehyde, carbowax, carbazole, cellulose, acetate cell , Hydroxyalkylcellulose, carboxymethylcellulose, dextrin, polyacetylene-containing polymer, polyethyleneimine-containing polymer, polyamide-containing polymer, polystyrene-containing polymer, poly (anhydride) -maleic acid-containing polymer, polymaleate-containing polymer, poly (anhydride) itaconic acid -Containing polymer, polyitaconate-containing polymer, polytetrafluoroethylene, polyvinylidene fluoride, ion-exchange polymer used for cation / anion exchange membrane, etc., cyclized polymer, sulfonate, sulfonate-containing polymer Sulfonic acid group-containing polymers, quaternary ammonium salts, quaternary ammonium salt-containing polymers, quaternary phosphonium salts, quaternary phosphonium salt ammonium polymers, and the like. It is possible to have.

Further, a solvent may be used to prepare a dispersion of the carbon catalyst, and water, ethanol, acetone, isopropyl alcohol, butanol, butyl acetate, N-methylpyrrolidone, dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide , Toluene, xylene and the like, and one or more of these can be used.

The present invention is also a battery including the electrode of the present invention and an electrolyte.
The electrolyte included in the battery of the present invention is not particularly limited, and examples of the organic solvent-based electrolyte include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, and 1,2-dimethoxyethane. 2-diethoxyethane, dimethoxymethane, diethoxymethane, acetonitrile, dimethylsulfoxide, sulfolane, fluorine-containing carbonate, fluorine-containing ether, ionic liquid, gel compound-containing electrolyte, polymer-containing electrolyte, and the like are preferable. Examples of the liquid include an aqueous solution of potassium hydroxide, an aqueous solution of sodium hydroxide, and an aqueous solution of lithium hydroxide. The electrolyte may be used alone or in combination of two or more. Further, a solid polymer electrolyte such as a sulfonic acid group-containing polymer or an inorganic solid electrolyte may be used as the electrolyte.

The battery of the present invention may be configured to include a separator.
As the separator, polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, cellulose, cellulose acetate, hydroxyalkyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, cellophane, polystyrene, polyacrylonitrile, polyacrylamide, polyvinyl chloride, polyamide, vinylon, High molecular weight polymers having micropores such as poly (meth) acrylic acid, their copolymers, gel compounds, ion exchange membrane polymers and their copolymers, cyclized polymers and their copolymers, poly (meth) Use acrylate-containing polymers and their copolymers, sulfonate-containing polymers and their copolymers, quaternary ammonium salt-containing polymers and their copolymers, quaternary phosphonium salt-containing polymers and their copolymers, etc. Rukoto can.

As described above, since the carbon catalyst of the present invention is suitable as an electrode catalyst of a fuel cell, the cell of the present invention is preferably a fuel cell. When the battery of the present invention is a fuel cell, the fuel supplied to the fuel electrode is not particularly limited, and various fuels such as hydrogen, carbon monoxide, methanol, ethanol, liquefied petroleum gas, methane, ethane, propane, and natural gas can be used. Can be used.

The carbon catalyst of the present invention has the above-described structure and has good catalytic activity as an electrode catalyst of a battery if it is inexpensive, and can be suitably used particularly as an electrode catalyst of a fuel cell.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “parts” means “parts by weight” and “%” means “% by mass”.

The weight average molecular weight of the fluorinated polyamic acid synthesized in Synthesis Example 1 was measured under the following conditions.
<Weight average molecular weight measurement (GPC measurement)>
Equipment: Tosoh Corporation HCL-8220GPC
Column: TSKgel Super AWM-H
Eluent (LiBr · H ₂ O, NMP containing phosphoric acid): 0.01 mol / L

Synthesis Example 1 (Synthesis of fluorinated polyamic acid)
In a 100 ml three-necked flask, 1,4-bis (3,4-dicarboxytrifluorophenoxy) tetrafluorobenzene dianhydride (10FEDAN) (also known as: 4,4 '-[(2,3,5,6) -Tetrafluoro-1,4-phenylene) bis (oxy)] bis (3,5,6-trifluorophthalic anhydride) 14.51 g, 1,3-diamino-2,4,5,6-tetrafluoro 4.489 g of benzene (4FMPD) and 31.0 g of N, N-dimethylacetamide were charged and stirred for 5 days at room temperature under a nitrogen atmosphere to obtain 30 g of a fluoropolyamic acid (10FEDA / 4FMPD) resin composition. (Solid content of polyamic acid: 38%), and the weight average molecular weight of the polyamic acid was measured by GPC to be 80,000. .

Preparation Examples 1 to 7 (Preparation of raw materials for carbon catalyst)
10 g of N, N-dimethylacetamide (DMAc) was added to 10 g of an N, N-dimethylacetamide solution of 10FEDA / 4FMPD obtained in Synthesis Example 1, and further, in Preparation Examples 2 to 7, metal complexes described in Table 1 below were added. Was added to prepare raw materials 1 to 7 of the carbon catalyst.

The metal complexes described in Table 1 are as follows. These were all used as reagents sold by Tokyo Chemical Industry.
FePc: iron (II) phthalocyanine complex (Mw: 568.38)
FeAA: tris (pentanedionate) iron (III) complex (Mw: 353.17)
CoPc: cobalt (II) phthalocyanine complex (Mw: 571.47)
CoAA: tris (pentanedionate) cobalt (III) complex (Mw: 356.26)

Examples 1 to 11, Comparative Examples 1 to 7
Raw materials 1 to 7 of the carbon catalyst were stirred for 5 minutes with foam and Rintaro (manufactured by Shinky Corporation). Thereafter, the solid was precipitated in ultrapure water. The obtained solid content was heated at 70 ° C. for 2 hours, and then at 5 ° C./min. When the temperature reached 300 ° C., the temperature was stopped and heating was performed at 300 ° C. for 1 hour. By returning, thermal imidization was performed. The thermal imidization was performed under a nitrogen atmosphere.
Thereafter, firing was performed under a nitrogen atmosphere under the conditions shown in Table 2, respectively. The firing was performed by raising the temperature from room temperature to the firing (carbonization) temperature shown in Table 2 at a rate of 5 ° C./min, and then maintaining the temperature at the firing (carbonization) temperature for one hour. The nitrogen content (N content) in the obtained carbon material (carbon catalyst) was determined by CHN elemental analysis. Regarding the fluorine amount (F amount), the sample was heated to 950 ° C. in humidified (steam-introduced) helium gas and oxygen gas using a sample combustion apparatus (QF-02, manufactured by Mitsubishi Chemical Corporation) to generate. The gas was absorbed in ultrapure water, and the absorption liquid was analyzed and determined by ion chromatography. Further, the amount of transition metal in the obtained carbon material (carbon catalyst) was determined by calculating from the residue weight when the sample was heated to 1000 ° C. in air and burned. Table 2 shows the measurement results of the nitrogen amount (N amount), fluorine amount (F amount), and transition metal amount of each carbon material (carbon catalyst).
5 mg of the obtained carbon material (carbon catalyst), 15 mg of Vulcan XC72 (manufactured by Cabot) as a conductive assistant, and 0.2 ml of a 5% Nafion (registered trademark) solution were dispersed by ultrasonic dispersion in 5 ml of 2-propanol. Then, a dispersion (slurry) was prepared. This dispersion was applied to a rotating disk attached to a rotating electrode device (HR-201, manufactured by Hokuto Denko) in an amount of 10 μL and dried to prepare an electrode with carbon catalyst (working electrode). Using this, linear sweep voltammetry measurement was performed with a rotating electrode in a 0.1 M sulfuric acid aqueous solution in which oxygen was bubbled (counter electrode Pt line, reference electrode Ag / AgCl, sweep speed 10 mV / s, rotation speed 500 rpm, scanning potential range). 1 V to -0.1 V [LSV, negative scan]). The current value at a voltage of 0.3 V in the linear sweep voltammetry measurement was defined as oxygen reduction ability (ORR performance). The results are shown in Table 2.
For comparison, various materials of Comparative Examples 1 to 7 shown in Table 2 were also fired under a nitrogen atmosphere under the conditions shown in Table 2, and the obtained materials were subjected to linear sweep in the same manner as in the examples. The current value at a voltage of 0.3 V in the voltammetry measurement was defined as the oxygen reducing ability (ORR performance). The results are shown in Table 2.
As a result of the measurement, it was confirmed that the material obtained by calcining the carbon catalyst raw materials 1 to 5 had excellent catalytic activity for the oxygen reduction reaction.

In addition, the amount of the added metal complex in Table 2 is a mass ratio of the added metal complex to the entire solid content of the carbon catalyst raw material.
In Table 2, 6FDA / 4FMPD is a polymer having a structural unit represented by the following formula (9).

Claims (4)

A method for producing a carbon catalyst for an oxygen reduction reaction containing carbon as a main component and containing 0.1 to 20% by mass of nitrogen based on the entire catalyst,
The carbon catalyst for oxygen reduction reaction further contains 0.1 to 20% by mass of a fluorine atom with respect to the whole catalyst, and at least one transition metal atom selected from transition metal atoms of Groups 5 to 11 of the periodic table. the unrealized 0.05 to 10% by weight,
The production method includes the following general formula (1);

(In the general formula (1), X represents a divalent organic group. Y represents a tetravalent organic group. At least one of X and Y is an organic group containing a fluorine atom. X, Y At least one of which contains an aromatic ring in its structure), and / or an organic compound containing a fluorinated polyimide having a structural unit represented by the following formula: A compound containing at least one transition metal atom selected from the group 5 to 11 transition metal atoms is selected so that the amounts of nitrogen atoms, fluorine atoms and transition metal atoms in the obtained carbon catalyst are in the desired proportions. A method for producing a carbon catalyst for an oxygen reduction reaction , comprising a step of calcining a raw material of a catalyst that is adjusted and contained . The carbon for oxygen reduction reaction according to claim 1, wherein the transition metal atom is at least one transition metal atom selected from the group consisting of vanadium, chromium, manganese, iron, cobalt, nickel, and copper. Method for producing catalyst. A step of producing a carbon catalyst for oxygen reduction reaction by the method for producing a carbon catalyst for oxygen reduction reaction according to claim 1 or 2 ,
The resulting oxygen reduction dispersion of reaction carbon catalyst was coated onto a current collector, the production method of an electrode which comprises a step of drying. A step of producing an electrode by the method for producing an electrode according to claim 3 ;
Method for producing a battery, which comprises the step of combining the resulting electrode and an electrolyte.