JP2021130062A - Carbon catalyst carrying polyazine, and catalyst electrode therewith - Google Patents

Abstract

To provide highly active proton reducing electrode catalyst constituted only from non-metal elements with energy saving low environmental load.SOLUTION: A carbon catalyst carrying, on carbon, a polyazine compound having arylene group represented by a general formula (1) (in the formula, X represents a nitrogen atom or C-H), and a triazine ring as a repeating unit, having a nitrogen-containing aromatic hydrocarbon group of a single ring of hydrogen atom at a molecular terminal or of 4 to 18 carbon atoms, and a linkage ring, or a condensed ring. Carbon catalysts of which the nitrogen-containing aromatic hydrocarbon group is pyridyl group, bipyridyl group, pyrimidyl group, pyridyl group, quinolinyl group, phenanthroline group, cyanopyridyl group, dicyanopyridyl group, carbazolyl group, or diphenyl amino group. Carbon catalyst, the pyrolysis point of the polyazine compound is in the range of 350 to 700°C. Catalyst electrode containing carbon catalyst. A method of producing hydrogen using a catalyst electrode as a proton reducing electrode. Fuel cell comprising catalytic electrode.SELECTED DRAWING: None

Description

The present invention relates to a carbon catalyst carrying a polyazine compound, which is useful as an electrode material for reducing the overvoltage of an electrochemical proton reduction reaction.

A polyazine compound, which is a polymer containing a triazine ring as a repeating unit, has a semiconductor-like electronic structure derived from a two-dimensional conjugated system and an azine ring that functions as a catalytically active point, and is useful as an electrode catalyst. Is.
Patent Document 1 discloses a method for producing a hybrid material similar to the carbon catalyst of the present invention in which a polyazine compound and conductive carbon are combined, and a method for applying the hybrid material as an electrode catalyst material. In order for the material to function as an electrode catalyst, it is necessary to add a metal element, and there is no description regarding the electrode catalyst activity of a material consisting only of a polyazine compound and conductive carbon. Further, Non-Patent Document 1 describes the application of the polyazine ring compound as an oxygen reduction electrode catalyst, but does not mention the application as a proton reduction electrode catalyst.

WO2016035321A1 JP2017160144 WO2017050689A1

Polymer, 2017, Vol. 126, pp. 283-290 Angewante Chemie International Edition, 2008, Vol. 47, pp. 3450-3453. Inorganic Chemistry, 2008, Vol. 47, pp. 4481-4489

An object of the present invention is to provide a highly active proton-reducing electrode catalyst composed of only non-metal elements that are resource-saving and have a low environmental load.

As a result of diligent studies to solve the above problems, the present inventors have found that a carbon catalyst carrying a polyazine compound obtained by a reaction between a nitrile compound and a base has good electrochemical proton reduction activity as a non-metal catalyst. The present invention has been completed.

That is, the present invention
(I) General formula (1)

（式中、Ｘは窒素原子又はＣ−Ｈを表す。）で示されるアリーレン基、及び一般式（２）

(In the formula, X represents a nitrogen atom or CH.) An arylene group represented by the general formula (2).

で示されるトリアジン環を繰り返し単位として有し、分子末端に一般式（３）

It has a triazine ring represented by, as a repeating unit, and has a general formula (3) at the end of the molecule.

（式中、Ａｒは、水素原子又は炭素数４から１８の単環、連結環、若しくは縮合環の含窒素芳香族炭化水素基を表す。該含窒素芳香族炭化水素基は、炭素数１から６のアルキル基若しくはシアノ基で修飾されていてもよい。）で示される末端基を有するポリアジン化合物をカーボンに担持した、カーボン触媒。
（ｉｉ）含窒素芳香族炭化水素基がピリジル基、ビピリジル基、ピリミジル基、ピラジル基、キノリニル基、フェナントロリニル基、シアノピリジル基、ジシアノピリジル基、カルバゾリル基、ジフェニルアミノ基である前記（ｉ）に記載のカーボン触媒。
（ｉｉｉ）Ａｒがシアノピリジル基である前記（ｉ）又は（ｉｉ）に記載のカーボン触媒。
（ｉｖ）Ａｒが水素原子である前記（ｉ）又は（ｉｉ）に記載のカーボン触媒。
（ｖ）ポリアジン化合物の熱分解点が３５０℃から７００℃の範囲にある、前記（ｉ）から（ｉｖ）のいずれか１項に記載のカーボン触媒 。
（ｖｉ）下記式（Ｉ）又は（ＩＩ）に記載の分子構造を有するポリアジン化合物を担持した、前記（ｉ）又は（ｉｉ）に記載のカーボン触媒。

(In the formula, Ar represents a nitrogen-containing aromatic hydrocarbon group of a hydrogen atom or a monocyclic, connecting ring, or condensed ring having 4 to 18 carbon atoms. The nitrogen-containing aromatic hydrocarbon group has 1 to 18 carbon atoms. A carbon catalyst in which a polyazine compound having a terminal group represented by (6), which may be modified with an alkyl group or a cyano group, is supported on carbon.
(Ii) The nitrogen-containing aromatic hydrocarbon group is a pyridyl group, a bipyridyl group, a pyrimidyl group, a pyrazil group, a quinolinyl group, a phenanthrolinyl group, a cyanopyridyl group, a dicyanopyridyl group, a carbazolyl group, or a diphenylamino group. The carbon catalyst according to i).
(Iii) The carbon catalyst according to (i) or (ii) above, wherein Ar is a cyanopyridyl group.
(Iv) The carbon catalyst according to (i) or (ii) above, wherein Ar is a hydrogen atom.
(V) The carbon catalyst according to any one of (i) to (iv) above, wherein the pyrolysis point of the polyazine compound is in the range of 350 ° C. to 700 ° C.
(Vi) The carbon catalyst according to (i) or (ii) above, which carries a polyazine compound having a molecular structure according to the following formula (I) or (II).

（ｖｉｉ）ポリアジン化合物が、ニトリル化合物と金属水酸化物塩とを混合加熱することにより製造されることを特徴とする、前記（ｉ）から（ｖｉ）のいずれか１項に記載のカーボン触媒。
（ｖｉｉｉ）ポリアジン化合物の含有量が、カーボンに対して０．０１から５０重量％の範囲にある前記（ｉ）から（ｖｉｉ）のいずれか１項に記載のカーボン触媒。
（ｉｘ）カーボンが、アセチレンブラック、ファーネスブラック、カーボンブラック、活性炭、カーボンナノチューブ及び黒鉛からなる群から選ばれる少なくとも１種類である前記（ｉ）から（ｖｉｉｉ）のいずれか１項に記載のカーボン触媒。
に関するものである。

(Vii) The carbon catalyst according to any one of (i) to (vi) above, wherein the polyazine compound is produced by mixing and heating a nitrile compound and a metal hydroxide salt.
(Vii) The carbon catalyst according to any one of (i) to (vii), wherein the content of the polyazine compound is in the range of 0.01 to 50% by weight with respect to carbon.
(Ix) The carbon catalyst according to any one of (i) to (viii) above, wherein the carbon is at least one selected from the group consisting of acetylene black, furnace black, carbon black, activated carbon, carbon nanotubes and graphite. ..
It is about.

Further, the present invention
(X) A catalyst electrode containing the carbon catalyst according to any one of (i) to (ix) above.
(Xi) The method for producing a catalyst electrode according to (x), wherein the catalyst electrode is manufactured through the following three steps.
Step 1: A step of supporting a polyazine compound on carbon to produce a carbon catalyst.
Step 2: A step of preparing a catalyst ink composed of a carbon catalyst, a binder and a dispersion medium.
Step 3: A step of applying the catalyst ink prepared in Step 2 onto the current collector and heating and curing the ink.
(Xii) A method for producing hydrogen using the catalyst electrode according to (x) as a proton reducing electrode.
(Xiii) A fuel cell including the catalyst electrode according to (x) above.
It is about.

By using the carbon catalyst of the present invention carrying a polyazine compound as a material constituting an electrode, the energy efficiency of electrochemical reduction of protons can be improved.

The present invention will be described in more detail below.

X in the arylene group (1) contained as a repeating unit in the polyazine compound supported on the carbon catalyst of the present invention represents a nitrogen atom or CH, and X is CH in that synthesis is easy. Is preferable. Specifically, the arylene group (1) includes a 2,3-pyridylene group, a 2,4-pyridylene group, a 2,5-pyridylene group, a 2,6-pyridylene group, a 3,4-pyridylene group, and 3, A 5-pyridylene group, a 2,4-pyrimidylene group, a 2,5-pyrimidylene group, a 4,5-pyrimidylene group or a 4,6-pyrimidylene group can be exemplified, and 2,4-pyridylene is easy to synthesize. A group, a 2,5-pyridylene group, a 2,6-pyridylene group or a 3,5-pyridylene group is preferable, and a 2,4-pyridylene group or a 2,6-pyridylene group is more preferable in terms of excellent catalytic activity.

The terminal group (3) contained in the polyazine compound supported by the carbon catalyst of the present invention represents a nitrogen-containing aromatic hydrocarbon group having a monocyclic ring, a linking ring, or a fused ring having 4 to 18 carbon atoms. Pyrrolyl group, pyridyl group, turpyridinyl group, bipyridyl group, pyrimidyl group, pyrazil group, quinolinyl group, isoquinolinyl group, phenanthrolinyl group, indolinyl group, carbazolyl group, phthalazinyl group, naphthyldinyl group, quinoxalinyl group, quinazolinyl group, An acridinyl group and the like can be exemplified.

The nitrogen-containing aromatic hydrocarbon group may be substituted with an alkyl group having 1 to 6 carbon atoms. The alkyl group may be a linear, branched or cyclic alkyl group, and specifically, a methyl group, a cyclohexylmethyl group, an ethyl group, a 2-cyclopentylethyl group, a propyl group or a 2,2-dimethylpropyl group. , 3-Cyclopropylpropyl group, 1-methylethyl group, cyclopropyl group, butyl group, 2-methylbutyl group, 3-methylbutyl group, 2-butyl group, 3-methylbutane-2-yl group, tert-butyl group, Cyclobutyl group, pentyl group, 2-methylpentyl group, 2-pentyl group, 2-methylpentane-2-yl group, 3-pentyl group, cyclopentyl group, 2-methylcyclopentyl group, 3-methylcyclopentyl group, hexyl group, Examples thereof include 2-hexyl group, 3-hexyl group, cyclohexyl group and the like.

As the terminal group (3), a nitrogen-containing aromatic hydrocarbon group having a cyano group and having 5 to 10 carbon atoms is preferable, and a cyanopyridyl group or a dicyanopyridyl group is more preferable, because it is easy to synthesize a high molecular weight molecule. ..

A hydrogen atom is preferable as the terminal group (3).

The polyazine compound supported on the carbon catalyst of the present invention preferably has a thermal decomposition point in the range of 200 ° C. to 700 ° C., and has a thermal decomposition point in the range of 300 ° C. to 700 ° C. in terms of excellent thermal stability. It is even more preferable to have a thermal decomposition point in the range of 300 ° C. to 600 ° C.

The polyazine compound supported on the carbon catalyst of the present invention preferably has a structure represented by the following formula (I) or (II).

本発明のカーボン触媒に担持されるポリアジン化合物の具体例としては、化合物（Ｉ）〜（ＩＩ）および以下の（Ａ−１）から（Ａ−３６）を例示できるが、本発明はこれらに限定されるものではない。

Specific examples of the polyazine compound supported on the carbon catalyst of the present invention include compounds (I) to (II) and the following (A-1) to (A-36), but the present invention is limited thereto. It is not something that is done.

本発明のカーボン触媒に担持されるポリアジン化合物としては触媒活性が良い点で、（Ｉ），（ＩＩ），（Ａ−３），（Ａ−４），（Ａ−２８）で表される化合物が好ましい。

The polyazine compound supported on the carbon catalyst of the present invention has good catalytic activity, and is represented by (I), (II), (A-3), (A-4), and (A-28). Is preferable.

The polyazine compound supported by the carbon catalyst of the present invention is disclosed in a nucleophilic substitution reaction (for example, a reaction disclosed in Patent Document 2) and a cross-coupling reaction (for example, Non-Patent Document 1) using a Grignard reagent. The reaction can be produced by a triazine ring formation reaction by quantifying a nitrile compound or the like, but the triazine ring formation reaction is preferable because the reaction operation is simple. As a triazine ring forming reaction, a method of mixing and heating a nitrile compound with a zinc chloride melt (for example, a method disclosed in Non-Patent Document 2) and a method of mixing and heating with a strong acid (for example, disclosed in Non-Patent Document 1). (Method), a method of mixing and heating with a base (for example, a method disclosed in Non-Patent Document 3), etc., but a method of mixing and heating a nitrile compound and a base in terms of high yield Is preferable. At this time, the nitrile compound used can be produced by a method familiar to those skilled in the art. Moreover, you may use a commercially available product.

The base used in the method of mixing and heating the nitrile compound and the base may be either an inorganic base or an organic base, for example, sodium hydroxide, potassium hydroxide, cesium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide. Metal hydroxides such as sodium carbonate, potassium carbonate, lithium carbonate, cesium carbonate and other metal carbonates, potassium acetate, sodium acetate and other metal acetates, potassium phosphate, sodium phosphate and other metal phosphates, bases, etc. Metal fluoride salts such as sodium, potassium fluoride, cesium fluoride, metal amides such as sodium methoxydo, potassium methoxydo, sodium ethoxydo, potassium isopropyl oxide, potassium tert-butoxide, trilyethylamine, diisopropylethylamine, tributylamine , N-methylpyrrolidin, N-methylpiperidine, N, N'-dimethylpiperazin, N-methylmorpholin, 1,4-diazabicyclo [2.2.2] octane, 1,8-diazabicyclo [5.4.0] -7-Undecene, N, N-dimethylaniline, N, N-diethylaniline, N, N-diethyltoluidine, pyridine, amines such as picolin, lithium amide, sodium amide, potassium amide, lithium diisopropyl amide, sodium diisopropyl amide, Examples thereof include metal amides such as lithium bis (trimethylsilyl) amide, sodium bis (trimethylsilyl) amide, and potassium bis (trimethylsilyl) amide. Of these, inorganic bases are preferable in terms of ease of purification, metal hydroxides are more preferable in terms of good yield, and sodium hydroxide is particularly preferable in terms of low cost.

In the method of mixing and heating a nitrile compound and a base, the equivalent of the base used with respect to the nitrile compound is preferably in the range of 0.001 to 0.8 molar equivalents, and 0.02 to 0.20 in terms of good yield. It is more preferably in the range of molar equivalents.
In the method of mixing and heating a nitrile compound and a base, crown ether may be added for the purpose of improving the reaction yield. Crown ethers include 1,4,7-trioxacyclonan, 1,4,7,10-tetraoxacyclododecane, 1,4,7,10,13-pentaoxacyclopentadecane, 1,4,7, Examples thereof include 10,13,16-hexaoxacyclooctadecane, 1,4,7,10,13,16,19,22-octaoxacyclotetracosan, and when the base is a metal hydroxide. May be used by appropriately selecting a crown ether that matches the ionic radius of the metal ion. The crown ether used is preferably in the range of 1-2 equivalents with respect to the base.

In the method of mixing and heating a nitrile compound and a base, the heating temperature is preferably a temperature appropriately selected from the range of 100 to 400 ° C., more preferably 150 to 300 ° C., in terms of good yield.

Next, a method for producing the carbon catalyst of the present invention and a catalyst electrode containing the carbon catalyst of the present invention (hereinafter, may be referred to as an electrode of the present invention) will be described.

The carbon catalyst of the present invention and the electrode of the present invention can be obtained through the following three steps.
Step 1: A step of supporting a polyazine compound on carbon to produce a carbon catalyst.
Step 2: A step of preparing a catalyst ink composed of a carbon catalyst, a binder and a dispersion medium.
Step 3: A step of applying the catalyst ink prepared in Step 2 onto the current collector and heating and curing the ink.

Step 1 is a step of producing the carbon catalyst of the present invention by dispersing or dissolving the polyazine compound and carbon in an organic solvent and then removing the organic solvent.

Examples of the carbon used in step 1 include acetylene black, furnace black, carbon black, activated carbon, carbon nanotubes, graphite, and the like, and two or more types of carbon can be used in combination. Carbon is more preferably acetylene black because of its high catalytic activity.
The polyazine compound used in step 1 is preferably in the range of 0.005% by weight to 99% by weight in terms of high conductivity of the material with respect to carbon, and 0.01% by weight to 50% in terms of high catalytic activity. It is more preferably in the weight% weight range.

The organic solvent used in step 1 is not particularly limited, and monoalcohols such as methanol, ethanol, propanol, butanol, hexanol, and cyclohexanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, diethylene glycol monomethyl ether, and diethylene glycol mono Ethers such as ethyl ether, diethyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether (CPME), tetrahydrofuran (THF), 2-methyl tetrahydrofuran, 1,4-dioxane, dimethoxyethane, benzene, toluene, xylene, mesitylene, nitrobenzene Aromatic hydrocarbons such as tetralin and anisole, halogenated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, dichlorobenzene, chlorobenzene, trichlorobenzene and 1-chloronaphthalene. , Ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, carbonate such as 4-fluoroethylene carbonate, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, propion Ethers such as ethyl acid, methyl butyrate and γ-lactone, and amides such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc) and N-methylpyrrolidone (NMP) can be exemplified. These may be mixed and used in arbitrary ratios. Toluene, chloroform, DMF, and NMP are preferable in terms of good solubility or dispersibility of the polyazine compound, and chloroform or DMF is more preferable in terms of easy removal. The amount of the organic solvent used is not particularly limited, and the content of the polyazine compound in the dispersion is preferably 0.01 to 90% by weight, more preferably 0.1 to 50% by weight. Amount can be used.

In step 1, an additive may be added for the purpose of improving the activity of the catalyst. This additive is a complex or salt containing Group 3 to Group 12 elements, specifically manganese, iron, cobalt, nickel, copper, zinc, molybdenum, ruthenium, rhodium, palladium, silver, platinum, etc. A complex or salt such as gold can be exemplified.

In step 1, there is no limitation on the method of dissolving or dispersing the polyazine compound or the like in an organic solvent, and methods familiar to those skilled in the art such as heating and stirring, shaking, ball milling, and ultrasonic irradiation can be used. Heat stirring or ultrasonic irradiation is preferable because the dispersibility of the polyazine compound and the like is good.

The carbon catalyst of the present invention can be obtained by removing the organic solvent by filtration, centrifugation or the like after the dissolution or dispersion operation is completed. The obtained carbon catalyst may be heat-dried at a temperature appropriately selected from the range of 60 ° C. to 450 ° C., if necessary, and heat-treated at 200 to 400 ° C. in terms of improving the catalytic activity. Is preferable.

Step 2 is a step of dispersing the carbon catalyst and the binder of the present invention in a dispersion medium and adjusting the catalyst ink (hereinafter, may be referred to as the catalyst ink of the present invention) used for producing the electrode of the present invention. Yes, for example, the method disclosed in Patent Document 2 can be used.

The binder used in step 2 may have a function of binding the carbon catalyst and the current collector, and for example, a hydrophobic resin such as polytetrafluoroethylene or polyvinylidene fluoride, cellulose fiber, or polyvinyl alcohol. , Hydrophilic resins such as polyethylene glycol, cation exchange resins such as Amberlite (manufactured by Organo), Nafion (manufactured by DuPont), and Levacit (manufactured by Lanxess) can be exemplified, and they are excellent in proton conductivity. Therefore, a cation exchange resin is preferable, and Nafion is more preferable. The amount of the binder used is not particularly limited, and the content of the binder in the catalyst ink is preferably selected from 0.01 to 20% by weight, more preferably 0.01 to 10% by weight. Can be used.

As the dispersion medium used in the step 2, water, an organic solvent, a polymer dispersion medium and the like can be used, and an organic solvent is preferable in terms of good dispersibility. Specific examples of the organic solvent include monoalcohols such as methanol, ethanol, propanol, butanol, hexanol, and cyclohexanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether. , Diethyl ether, diisopropyl ether, dibutyl ether, cyclopentyl methyl ether (CPME), tetrahydrofuran (THF), 2-methyl tetrahydrofuran, 1,4-dioxane, dimethoxyethane and other ethers, benzene, toluene, xylene, mesityrene, nitrobenzene, tetraline. , Aromatic hydrocarbons such as anisole, dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, dichlorobenzene, chlorobenzene, trichlorobenzene, halogenated hydrocarbons such as 1-chloronaphthalene, ethylene Carbonates such as carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 4-fluoroethylene carbonate, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate , Ethers such as methyl butyrate and γ-lactone, and amides such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc) and N-methylpyrrolidone (NMP) can be exemplified. It may be mixed and used at an arbitrary ratio. Water and monoalcohol are preferable in terms of good dispersibility of the binder, water, methanol, ethanol, propanol, butanol, or a mixed solvent thereof is more preferable, and methanol or ethanol is particularly preferable in terms of easy removal. The amount of the dispersion medium used is not particularly limited, and the content of the polyazine compound in the dispersion is preferably 0.01 to 90% by weight, more preferably 0.1 to 50% by weight. Amount can be used.

In step 2, as a method for dispersing the carbon catalyst or the like of the present invention in a dispersion medium, the same method as that exemplified in step 1 can be exemplified, and ultrasonic irradiation is preferable in terms of good dispersibility. The dispersion liquid obtained after the dispersion operation can be used as a catalyst ink in the next step.

Step 3 is a step of applying the catalyst ink of the present invention to the current collector and then heat-curing to obtain the electrode of the present invention.
Examples of the current collector used in step 3 include precious metals such as platinum, gold, silver, rhodium, and ruthenium, base metals such as stainless steel, iron, aluminum, copper, and titanium, and carbon materials such as glassy carbon and carbon non-woven fabrics. Of these, precious metals or carbon materials are preferable, and glassy carbon is more preferable, because they are inexpensive and have high acid resistance.

As a method of applying the catalyst ink of the present invention to the current collector in step 3, a general method can be used in the thin film forming process by the wet method. Specifically, cast coating method, spin coating method, dip coating method, spray coating method, flow coating method, roll coating method, curtain coating method, bar coating method, ultrasonic coating method, screen printing method, brush coating method, sponge Painting and the like can be exemplified. The cast coating method, spin coating method, dip coating method, and spray coating method are preferable in that they are inexpensive and a smooth film can be produced, and the cast coating method is more preferable in that they are simple.

The temperature of heat curing in step 3 may be any temperature as long as the dispersion medium volatilizes from the coating film of the catalyst ink of the present invention to form a catalyst layer made of a dispersoid, preferably 40 to 400 ° C., and the heat of the catalyst. In terms of suppressing decomposition, it is preferable to heat at a temperature appropriately selected from the range of 50 to 250 ° C.

The heat curing time in step 3 may be any time as long as the dispersion medium volatilizes from the coating film of the catalyst ink of the present invention and a catalyst layer made of a dispersoid is formed, preferably 1 minute to 5 hours, more preferably. Is preferably fired for a time appropriately selected from the range of 5 to 30 minutes.

After the completion of step 3, steps 2 and 3 may be repeated in order to obtain a catalyst membrane having a desired film thickness.
Since the carbon catalyst of the present invention has a small proton reduction overvoltage as a non-metal material, it can be used as a resource-saving proton reduction catalyst electrode. Since the carbon catalyst of the present invention can efficiently electrolyze water with resource saving, it may be applied to the field of energy conversion.

When the carbon catalyst of the present invention is used as an electrode catalyst for a hydrogen production apparatus, the current collector, the conductive auxiliary agent, and the binder in the electrode are selected according to the type of electrolytic solution used and the electrolytic conditions. Materials known in the field can be used. Further, as a method for producing the electrode, a method practiced in the art can be used.

When the carbon catalyst of the present invention is used as a hydrogen electrode of a fuel cell, the current collector, the conductive auxiliary agent, and the binder at the electrode are known in the art depending on the type of electrolyte used and the operating conditions. Materials can be used. Further, as a method for producing the electrode, a method practiced in the art can be used.

Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples and Reference Examples, but the present invention is not construed as being limited thereto.
[ ^{1 1} H-NMR measurement]
¹ Bruker ASCEND HD (400 MHz; manufactured by BRUKER) was used for 1 H-NMR measurement. ^{1 1} H-NMR was _{measured using deuterated chloroform (CDCl 3} ) as a measurement solvent and tetramethylsilane (TMS) as an internal standard substance. In addition, commercially available reagents were used.
[Infrared spectroscopy]
Measurement of the infrared spectrum, using a powdery compound, carried out by ATR method using a Fourier transform infrared spectrometer (HORIBA, FT-720), spectrum in the range from 600 cm ^-1 to 4000 cm ^-1 Was measured.
[TG / DTA measurement]
The thermal decomposition temperature was measured by thermogravimetric analysis in a dry air atmosphere using a thermogravimetric analyzer (Hitachi High-Technologies Corporation, TG / DTA-6200). Measurements were carried out using a powdery compound (about 5 mg) in a temperature range of 30 ° C. to 800 ° C. and a heating rate of 10 ° C. min- ^1.
[Evaluation of proton reduction activity]
The activity of the proton reduction reaction was evaluated by linear sweep voltammetry using a potentiostat (Hokuto Denko, HSV-100). The working electrode is a glassy carbon electrode (GC electrode) with an electrode catalyst layer formed on the surface, the reference electrode is a silver-silver chloride electrode with a saturated potassium chloride solution as the internal solution, the counter electrode is a Pt wire, and the electrolytic solution is 0. A 5 molcm- ³ sulfuric acid solution was used. The sweep range was 0 V to −1.2 V (vs. Ag / AgCl), and the potential sweep rate was 50 mVsec ^-1 .
From the obtained potential and proton reduction current plots, -0.2 mAcm ^-2 reach potential (Onset, [Vvs. SHE]), -5 ^{mA cm -2} reach potential (E _{5 mA} , [V vs. SHE]), Tafel slope ( TS, [mVdecade ^-1 ]) was calculated.
Reference example-1

２−シアノピリミジン（２００ｍｇ，１．６ｍｍｏｌ）と水酸化ナトリウム（７．８ｍｇ， ０．２０ｍｍｏｌ）とを粉砕混合した。アルゴン雰囲気下、この混合物を２２０℃で４時間加熱攪拌した。反応終了後、生成物を水およびメタノールで洗浄した後、シリカゲルクロマトグラフィーにより精製することで、目的の２，４，６−トリ（２−ピリミジル）−１，３，５−トリアジン（Ａ−４）を得た（１２０ｍｇ，０．３８ｍｍｏｌ，１１％）。
^１ＨＮＭＲ（ＣＤＣｌ３）：δ７．５４（ｔ，Ｊ＝４．９Ｈｚ，３Ｈ），９．１３（ｄｄ，Ｊ＝４．９Ｈｚ，０．７Ｈｚ，６Ｈ）．
参考例−２

2-Cyanopyrimidine (200 mg, 1.6 mmol) and sodium hydroxide (7.8 mg, 0.20 mmol) were pulverized and mixed. The mixture was heated and stirred at 220 ° C. for 4 hours under an argon atmosphere. After completion of the reaction, the product was washed with water and methanol and then purified by silica gel chromatography to obtain the desired 2,4,6-tri (2-pyrimidyl) -1,3,5-triazine (A-4). ) Was obtained (120 mg, 0.38 mmol, 11%).
^{1 1} HNMR (CDCl3): δ7.54 (t, J = 4.9Hz, 3H), 9.13 (dd, J = 4.9Hz, 0.7Hz, 6H).
Reference example-2

６−シアノ−２，２’−ビピリジル（５０ｍｇ，０．２８ｍｍｏｌ）と水酸化ナトリウム（２．３ｍｇ，０．０６ｍｍｏｌ）とを粉砕混合した。アルゴン雰囲気下、この混合物を２２０℃で４時間加熱攪拌した。反応終了後、生成物を水およびメタノールで洗浄することで、目的の２，４，６−トリ（２−ピリミジル）−１，３，５−トリアジン（Ａ−２８）を得た（３３ｍｇ， ０．０６ｍｍｏｌ， ６６％）。
^１ＨＮＭＲ（ＣＤＣｌ３）：δ７．３７（ｍ，３Ｈ），７．８６（ｍ，３Ｈ），８．０１ （ｔ，３Ｈ），８．２５（ｄｄ，Ｊ＝７．７，１．１Ｈｚ，３Ｈ），８．４０（ｍ，３Ｈ），８．６２ （ｄｄ，Ｊ＝７．７，１．１Ｈｚ，３Ｈ），８．７０（ｍ，３Ｈ）．
参考例−３

6-Cyano-2,2'-bipyridyl (50 mg, 0.28 mmol) and sodium hydroxide (2.3 mg, 0.06 mmol) were pulverized and mixed. The mixture was heated and stirred at 220 ° C. for 4 hours under an argon atmosphere. After completion of the reaction, the product was washed with water and methanol to obtain the desired 2,4,6-tri (2-pyrimidyl) -1,3,5-triazine (A-28) (33 mg, 0). .06 mmol, 66%).
^{1 1} HNMR (CDCl3): δ7.37 (m, 3H), 7.86 (m, 3H), 8.01 (t, 3H), 8.25 (dd, J = 7.7, 1.1Hz, 3H) ), 8.40 (m, 3H), 8.62 (dd, J = 7.7, 1.1Hz, 3H), 8.70 (m, 3H).
Reference example-3

水酸化カリウム（１ｍｇ，０．０２ｍｍｏｌ）、１，４，７，１０，１３，１６−へキサオキサシクロオクタデカン（５．３ｍｇ，０．０２ｍｍｏｌ）、およびエタノール（１ｍＬ）を反応容器に入れ、室温で２０分間撹拌し均一溶液とした後、エタノールを減圧留去した。反応容器に２，４−ジシアノピリジン（２００ｍｇ，０．１５ｍｍｏｌ）を加え、アルゴン雰囲気下３００℃で４時間加熱攪拌した。反応終了後、生成物をクロロホルム及び純水で洗浄することで、白色固体の生成物を得た（８２ｍｇ）。
この生成物を粉砕した後、赤外分光スペクトルを測定したところ（図１）、波数１５８０ｃｍ^−１付近にトリアジン環に由来する吸収ピーク［ａ１］が現れたことから、目的のポリアジン化合物（Ｉ）であることを確かめた。

Potassium hydroxide (1 mg, 0.02 mmol), 1,4,7,10,13,16-hexaoxacyclooctadecane (5.3 mg, 0.02 mmol), and ethanol (1 mL) were placed in a reaction vessel at room temperature. After stirring for 20 minutes to make a uniform solution, ethanol was distilled off under reduced pressure. 2,4-Dicyanopyridine (200 mg, 0.15 mmol) was added to the reaction vessel, and the mixture was heated and stirred at 300 ° C. for 4 hours under an argon atmosphere. After completion of the reaction, the product was washed with chloroform and pure water to obtain a white solid product (82 mg).
After pulverizing this product, the infrared spectroscopic spectrum was measured (FIG. 1). As a result, an absorption peak [a1] derived from the triazine ring appeared near ^{the wave number of 1580 cm -1, and thus the target polyazine compound (I) was found.} I confirmed that.

The thermal decomposition temperature of compound (I) was about 400 ° C. (FIG. 3).
Reference example-4

２，４−ジシアノピリジン（２００ｍｇ，１．５５ｍｍｏｌ）と水酸化ナトリウム（１３ｍｇ，０．３２ｍｍｏｌ）とを粉砕混合した。アルゴン雰囲気下、この混合物を２２０℃で４時間加熱攪拌した。反応終了後、生成物をクロロホルム及び純水で洗浄することで、褐色固体の生成物を得た（１５２ｍｇ，７６％）。
この生成物を粉砕した後、赤外分光スペクトルを測定したところ（図３）、波数１５８０ｃｍ^−１付近にトリアジン環に由来する吸収ピーク［ａ１］が現れたことから、目的のポリアジン化合物（ＩＩ）であることを確かめた。

2,4-Dicyanopyridine (200 mg, 1.55 mmol) and sodium hydroxide (13 mg, 0.32 mmol) were pulverized and mixed. The mixture was heated and stirred at 220 ° C. for 4 hours under an argon atmosphere. After completion of the reaction, the product was washed with chloroform and pure water to obtain a brown solid product (152 mg, 76%).
After pulverizing this product, the infrared spectroscopic spectrum was measured (Fig. 3). As a result, an absorption peak [a1] derived from the triazine ring appeared near ^{the wave number of 1580 cm -1, and thus the target polyazine compound (II) was obtained.} I confirmed that.

The thermal decomposition temperature of compound (II) was about 600 ° C. (Fig. 4).
Example-1
Production of carbon catalyst Compound (A-3) (1 mg) and acetylene black (Denka, Li-100, 5 mg) were added to chloroform (1 mL) and then ultrasonically dispersed. The dispersoid was collected by filtration and then vacuum dried to obtain a carbon catalyst carrying compound (A-3) (5 mg).
Preparation of catalyst ink A catalyst ink was prepared by suspending a carbon catalyst (5 mg) carrying a compound (A-3) and a Nafion dispersion (50 μL) in ethanol (950 μL) and ultrasonically dispersing them.
Preparation of Electrode Containing Carbon Catalyst This catalyst ink (6 μL) was cast on a GC electrode and then dried at 60 ° C. to form an electrode catalyst layer on the GC electrode.
Evaluation of Proton Reduction Activity The proton reduction catalytic activity is shown in Table 1 from the linear sweep voltammetry (FIG. 7) of the GC pole on which the electrode catalyst layer was formed.
Example-2
A carbon catalyst was produced using compound (A-4) instead of compound (A-3) according to the method described in Example-1. The proton reduction catalytic activity is shown in Table 1 and FIG.
Example-3
A carbon catalyst was produced using compound (A-28) instead of compound (A-3) according to the method described in Example-1. The proton reduction catalytic activity is shown in Table 1 and FIG.
Example-4
A carbon catalyst was produced using compound (I) instead of compound (A-3) according to the method described in Example-1. When the infrared spectroscopic spectrum was measured, the support of the polyazine compound was confirmed (Fig. 5). The proton reduction catalytic activity is shown in Table 1 and FIG.
Example-5
A carbon catalyst was produced using compound (II) instead of compound (A-3) according to the method described in Example-1. When the infrared spectroscopic spectrum was measured, it was confirmed that the polyazine compound was supported (Fig. 6). The proton reduction catalytic activity is shown in Table 1 and FIG.
Comparative Example-1
According to the method described in Example 1, acetylene black (Denka, Li-100) was used instead of the carbon catalyst. The proton reduction catalytic activity is shown in Table 1 and FIG.
Comparative Example-2
After producing the carbon catalyst according to the method described in Example 1, annealing was performed at 200 ° C. for 4 hours. The proton reduction catalytic activity is shown in Table 1.
Comparative Example-3
Comparison with precedents

アルゴン雰囲気下、反応容器にトリフルオロメタンスルホン酸（１．７０ｇ，１１．３ｍｍｏｌ）を加えた後、１００℃に加熱した。加熱撹拌しながら、１，４−ジシアノベンゼン（２００ｍｇ，０．１５ｍｍｏｌ）のジクロロメタン溶液（２０ｍＬ）を２時間かけて滴下した。滴下終了後、１００℃で４時間加熱撹拌した後、反応容器にエタノール（１００ｍＬ）を加えた。生じた析出物をろ取し、エタノール及びＤＭＦで洗浄することで、化合物（Ｃ）を得た（１２４ｍｇ，６２％）。
実施例１に記載の方法に則り、化合物（Ａ−３）の代わりに化合物（Ｃ）を用いてカーボン触媒を製造した。プロトン還元触媒活性を表１および図８に示した。

Trifluoromethanesulfonic acid (1.70 g, 11.3 mmol) was added to the reaction vessel under an argon atmosphere, and then the mixture was heated to 100 ° C. A solution of 1,4-dicyanobenzene (200 mg, 0.15 mmol) in dichloromethane (20 mL) was added dropwise over 2 hours with heating and stirring. After completion of the dropping, the mixture was heated and stirred at 100 ° C. for 4 hours, and then ethanol (100 mL) was added to the reaction vessel. The resulting precipitate was collected by filtration and washed with ethanol and DMF to give compound (C) (124 mg, 62%).
A carbon catalyst was produced using compound (C) instead of compound (A-3) according to the method described in Example 1. The proton reduction catalytic activity is shown in Table 1 and FIG.

実施例１〜５と比較例１より、種種のポリアジン化合物を担持したカーボン触媒のプロトン還元活性と、未担持のカーボンの触媒活性を比較した。Ｏｎｓｅｔ、Ｅ_５ｍＡが上昇したことから、ポリアジン化合物を担持したカーボン触媒（実施例１〜５）は、プロトン還元反応の触媒活性を有することがわかった。また、Ｅ_５ｍＡ が上昇したことから、ポリアジン化合物（ＩＩ）を担持したカーボン触媒（実施例５）は高電流域でもプロトン還元反応の触媒活性を有することがわかった。
実施例１と比較例２より、化合物（Ａ−３）を担持したカーボン触媒について、加熱処理の有無を比較した。カーボン触媒の加熱処理によって、Ｏｎｓｅｔが上昇した。加熱処理によって、プロトン還元活性が向上することがわかった。高温長時間でのアニーリングの効果により、カーボン担体とポリアジン化合物間の界面抵抗が減少したことに因ると考えられる。
実施例５と比較例３より、非特許文献１で報告されたポリアジン化合物（Ｃ）を担持したカーボン触媒と、本発明のカーボン触媒とを比較した。ポリアジン化合物（ＩＩ）を担持したカーボン触媒の方が、Ｏｎｓｅｔ、Ｅ_５ｍＡともに高いことから、本発明のカーボン触媒を担持した電極は、既知の含トリアジンポリマー材料よりも良好なプロトン還元触媒活性を有することがわかった。

From Examples 1 to 5 and Comparative Example 1, the proton reduction activity of the carbon catalyst supporting various kinds of polyazine compounds and the catalytic activity of the carbon catalyst not supported were compared. From the increase in Onset and E _{5 mA} , it was found that the carbon catalysts carrying the polyazine compounds (Examples 1 to 5) had catalytic activity for the proton reduction reaction. Also, E _5mA It was found that the carbon catalyst carrying the polyazine compound (II) (Example 5) had the catalytic activity of the proton reduction reaction even in the high current range.
From Example 1 and Comparative Example 2, the presence or absence of heat treatment was compared with respect to the carbon catalyst carrying the compound (A-3). Heat treatment of the carbon catalyst increased Onset. It was found that the heat treatment improved the proton reduction activity. It is considered that the interfacial resistance between the carbon carrier and the polyazine compound was reduced due to the effect of annealing at high temperature for a long time.
From Example 5 and Comparative Example 3, the carbon catalyst carrying the polyazine compound (C) reported in Non-Patent Document 1 was compared with the carbon catalyst of the present invention. Polyazines compound (II) is more of carrying carbon catalyst and, Onset, since E _{5 mA} both high, carrying an electrode carbon catalyst of the present invention has good proton reduction catalytic activity than the known containing triazine polymeric material I understand.

It is an infrared spectroscopic spectrum of a polyazine compound (I). It is a thermogravimetric curve of the polyazine compound (I) in an air atmosphere. It is an infrared spectroscopic spectrum of a polyazine compound (II). It is a thermogravimetric curve of the polyazine compound (II) in an air atmosphere. It is an infrared spectroscopic spectrum of a carbon catalyst carrying a carbon carrier, a polyazine compound (I) and a polyazine compound (I). It is an infrared spectroscopic spectrum of a carbon catalyst carrying a carbon carrier, a polyazine compound (II) and a polyazine compound (II). It is a linear sweep voltammogram corresponding to a proton reduction reaction of the catalyst electrode described in Example 1, Example 2, Example 3 and Comparative Example 1. It is a linear sweep voltammogram corresponding to a proton reduction reaction of the catalyst electrode described in Example 4, Example 5, Comparative Example 1 and Comparative Example 3.

Claims (13)

General formula (1)

(In the formula, X represents a nitrogen atom or CH.) An arylene group represented by the general formula (2).

It has a triazine ring represented by, as a repeating unit, and has a general formula (3) at the end of the molecule.

(In the formula, Ar represents a nitrogen-containing aromatic hydrocarbon group of a hydrogen atom or a monocyclic, connecting ring, or condensed ring having 4 to 18 carbon atoms. The nitrogen-containing aromatic hydrocarbon group has 1 to 18 carbon atoms. A carbon catalyst in which a polyazine compound having a terminal group represented by (6), which may be modified with an alkyl group or a cyano group, is supported on carbon. 15. The carbon catalyst described. The carbon catalyst according to claim 1 or 2, wherein Ar is a cyanopyridyl group. The carbon catalyst according to claim 1 or 2, wherein Ar is a hydrogen atom. The carbon catalyst according to any one of claims 1 to 4, wherein the pyrolysis point of the polyazine compound is in the range of 350 ° C. to 700 ° C. The carbon catalyst according to claim 1 or 2, which carries a polyazine compound having a molecular structure according to the following formula (I) or (II).

The carbon catalyst according to any one of claims 1 to 6, wherein the polyazine compound is produced by mixing and heating a nitrile compound and a metal hydroxide salt. The carbon catalyst according to any one of claims 1 to 7, wherein the content of the polyazine compound is in the range of 0.01 to 50% by weight with respect to carbon. The carbon catalyst according to any one of claims 1 to 8, wherein the carbon is at least one selected from the group consisting of acetylene black, furnace black, carbon black, activated carbon, carbon nanotubes and graphite. A catalyst electrode containing the carbon catalyst according to any one of claims 1 to 9. The method for manufacturing a catalyst electrode according to claim 10, wherein the catalyst electrode is manufactured through the following three steps.
Step 1: A step of supporting a polyazine compound on carbon to produce a carbon catalyst.
Step 2: A step of preparing a catalyst ink composed of a carbon catalyst, a binder and a dispersion medium.
Step 3: A step of applying the catalyst ink prepared in Step 2 onto the current collector and heating and curing the ink. The method for producing hydrogen using the catalyst electrode according to claim 10 as a proton reducing electrode. A fuel cell comprising the catalyst electrode according to claim 10.

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