JP6320078B2 - Nitrogen-containing carbon material, method for producing the same, and electrode for fuel cell - Google Patents

Description

  The present invention relates to a nitrogen-containing carbon material, a method for producing the same, and an electrode for a fuel cell.

  The polymer electrolyte fuel cell has advantages such as high power generation efficiency, high output density, rapid start / stop, small size and light weight, portable power, mobile power, small stationary It is expected to be applied to power generators.

  In a polymer electrolyte fuel cell, platinum or a platinum alloy is generally used as a catalyst in order to promote the oxygen reduction reaction occurring at the positive electrode. However, since the amount of platinum resources is extremely small and expensive, it is put to practical use. It has become a big barrier. Therefore, as an electrode catalyst for a fuel cell that does not require a noble metal such as platinum, a carbon material that expresses oxygen reduction activity by containing a transition metal and nitrogen (hereinafter also referred to as “carbon catalyst”) attracts attention. Yes.

  For example, it is known that a nitrogen-containing carbon material containing a large amount of nitrogen can be obtained by paying attention to azurmic acid which is a cyanide polymer and carbonizing the same (see Patent Document 1). Further, it is known that carbon materials useful as an electrode catalyst can be synthesized by carbonizing a precursor obtained by adding a transition metal or a salt thereof (see Patent Documents 2, 3, and 4). .

International Publication No. 2007/043311 Pamphlet International Publication No. 2008/123380 Pamphlet JP 2011-256093 A JP2013-043821A

  The oxygen reduction active site of the carbon catalyst containing transition metal and nitrogen is a structure in which the end of the graphene skeleton and defects are doped with nitrogen, or its transition metal complexed with nitrogen, although the details are not clear it is conceivable that. Basically, the transition metal added to azulmic acid functions as a carbonization catalyst, but may also contribute as a reaction active site. In any case, it is important that the transition metal is highly dispersed in the precursor.

  However, there is no solvent that well dissolves both azulmic acid and transition metal salt, and there is a problem that it is difficult to mix them highly. As a result, the carbon material obtained by carbonizing the precursor, which is a mixture of azulmic acid and transition metal, does not have sufficient oxygen reduction activity as an electrode catalyst for a polymer electrolyte fuel cell, and has superior oxygen reduction activity. There is a demand for the development of an electrode catalyst.

  It is also conceivable to use diaminomaleonitrile instead of azulmic acid. However, the nitrogen-containing carbon material derived from diaminomaleonitrile obtained by carbonizing at a high temperature has a problem that the yield in the process is low. Further, diaminomaleonitrile is a relatively expensive compound, and countermeasures such as reducing the amount of use and greatly improving the yield are required.

  Therefore, the present invention has been made in view of the above circumstances, a nitrogen-containing carbon material having high oxygen reduction activity, a method for producing a nitrogen-containing carbon material for producing the nitrogen-containing carbon material in high yield, and this It aims at providing the electrode for fuel cells using this.

  As a result of intensive studies to solve the above problems, the present inventors have surprisingly found that a precursor prepared by mixing diaminomaleonitrile, which is a tetramer of hydrocyanic acid, and an easily carbonized polymer such as a phenol resin. It was found that the above problems can be solved by using the body as a starting material, and the present invention has been achieved.

That is, the present invention is as follows.
[1]
A first step of obtaining a precursor by mixing diaminomaleonitrile, an easily carbonized polymer material, and a transition metal salt;
And a second step of obtaining the nitrogen-containing carbon material by heat-treating the obtained precursor.
[2]
A nitrogen-containing carbon material produced by the production method described in [1] above.
[3]
A fuel cell electrode comprising the nitrogen-containing carbon material according to the item [2].

  According to the present invention, there are provided a nitrogen-containing carbon material having high oxygen reduction activity, a method for producing a nitrogen-containing carbon material for producing the nitrogen-containing carbon material in high yield, and a fuel cell electrode using the same. be able to.

Example 1, Example 2, Example 3, Example 4, Example 1, Comparative Example 1 and Comparative Example 2 were obtained by firing the nitrogen-containing carbon material and the oxygen reduction starting potential obtained by electrochemical measurement. The correlation with the mixing ratio of diaminomaleonitrile and a phenol resin is shown.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. The present embodiment is an example for explaining the present invention, and the present invention is not limited only to the embodiment. That is, the present invention can be variously modified without departing from the gist thereof.

[Method for producing nitrogen-containing carbon material]
The method for producing a nitrogen-containing carbon material of the present embodiment includes a first step of obtaining a precursor by mixing diaminomaleonitrile, an easily carbonized polymer material, and a transition metal salt, and the obtained precursor. Heat-treating the body to obtain a nitrogen-containing carbon material.

(Diaminomaleonitrile)
Diaminomaleonitrile is a tetramer of hydrocyanic acid and is known to have a carbon double bond, an amino group, and a nitrile group in the structure. Here, diaminomaleonitrile may be a commercially available product, or may be produced based on a known method (for example, see JP-A-49-126619, JP-A-60-651158, etc.). . Further, diaminomaleonitrile may be purified by a method such as recrystallization to increase the purity, or an unpurified one may be used.

(Easily carbonized polymer material)
The carbonized polymer material is not particularly limited, and examples thereof include polyaniline, polyvinyl pyridine, polyimide, melamine resin, phenol resin, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, aromatic polyamide, and polyvinyl pyrrolidone. Among these, from the viewpoint of easy carbonization in the heat treatment step, a resin having an aromatic group or a heterocyclic group is preferable, and a phenol resin is more preferable.

The ratio (x) of the mass of diaminomaleonitrile to the mass of the easily carbonized polymer material is preferably 0.01 to 0.99, more preferably 0.10 to 0.90, and even more preferably 0. .15 to 0.75. When this ratio is 0.01 or more, the oxygen reduction activity tends to be more excellent when a nitrogen-containing carbon material is used. Moreover, when this ratio is 0.99 or less, the yield when the precursor is heat-treated tends to be more excellent. The ratio (x) can be calculated by the following formula (I).
Ratio (x) = diaminomaleonitrile mass / (diaminomaleonitrile mass + easily carbonized polymer material mass) (I)

(Transition metal salt)
The transition metal salt is not particularly limited, and examples thereof include transition metal cyano complexes, hydroxy complexes, chloro complexes, acetylacetonate complexes, nitrates, sulfates, acetates, carbonates, oxalates, nitrites, Examples include chloride, bromide, iodide, and various organometallic compounds. Of these, cyano complexes, chloro complexes, acetylacetonate complexes, nitrates, chlorides and bromides are preferable, and nitrates, chlorides and bromides are more preferable. Among these, those that are soluble in polar solvents such as water and lower alcohols are more preferable.

  Further, the transition metal is not particularly limited, but for example, Fe, Co, Ni, Cu, Mn, or Cr is preferable, Fe, Co, or Cu is more preferable, Fe or Co is further preferable, and particularly preferable Fe. By using such a transition metal, the oxygen reduction activity of the nitrogen-containing carbon material tends to be further improved.

  The reason why the nitrogen-containing carbon material obtained by the production method of the present embodiment exhibits high oxygen reduction activity is not clear, but diaminomaleonitrile, which is a tetramer of hydrocyanic acid, has high solubility in a solvent. This height is advantageous for complex formation with the transition metal, and as a result, a nitrogen-containing carbon material in which the transition metal is more evenly dispersed is obtained.

  Specific iron salts are not particularly limited. For example, iron (II) chloride, iron (II) chloride tetrahydrate, iron (III) chloride, iron (III) chloride hexahydrate, iron bromide (II), iron (II) bromide hexahydrate, iron (III) bromide, iron (III) bromide hexahydrate, ammonium hexacyanoferrate (II) trihydrate, iron hexacyanoferrate (II) Potassium acid trihydrate, ammonium hexacyanoferrate (III), potassium hexacyanoiron (III), sodium hexacyanoferrate (II) decahydrate, sodium hexacyanoferrate (III) monohydrate, iron nitrate (II ) Hexahydrate, iron (III) nitrate nonahydrate, iron (III) thiocyanate, iron (II) carbonate, iron (II) carbonate monohydrate, methylammonium hexachloroferrate (III), tetrachloro Tetramethy iron (II) acid Ammonium, potassium pentacyanonitrosyl iron (III) dihydrate, potassium iron (III) hexacyanoferrate (II), sodium pentacyanonitrosyl iron (III) dihydrate, ammine pentacyanoiron ( II) Sodium acid trihydrate, aquapentacyanoiron iron (II) sodium heptahydrate, iron (II) thiocyanate trihydrate, iron acetate, iron (III) oxalate pentahydrate, oxalic acid Iron (II) dihydrate, iron (III) citrate trihydrate, iron (II) iodide, iron (II) iodide tetrahydrate, iron (III) sulfate, iron (III) sulfate nine Hydrates, ammonium tetrachloroferrate (II), iron (II) perchlorate hexahydrate, iron (III) perchlorate hexahydrate, potassium aquapentafluoroiron (III), potassium iron sulfate (III) Twelve water Bis (sulfato) iron (II) diammonium hexahydrate, tris (sulfate) iron (III) sodium trihydrate, iron (III) phosphate dihydrate, iron (II) phosphate eight Hydrates, iron (II) sulfate heptahydrate and the like can be mentioned. Preferably, iron (II) chloride, iron (III) chloride, iron (II) bromide, iron (III) bromide, and iron (III) nitrate nonahydrate are used.

  Specific cobalt salts are not particularly limited, and examples thereof include potassium hexacyanocobalt (III), cobalt nitrate (II) hexahydrate, cobalt (II) fluoride, cobalt (II) bromide, and cobalt bromide. (II) hexahydrate, cobalt carbonate (II), cobalt thiocyanate (II) trihydrate, cobalt acetate (II) tetrahydrate, cobalt acetate (III), cobalt chloride (II), cobalt chloride ( II) Hexahydrate, cesium tetrachlorocobalt (II), potassium hexafluorocobalt (III), cobalt (II) iodide, cobalt (II) iodide hexahydrate, hexanitrocobalt (III) acid Examples include potassium, cobalt (II) phosphate, cobalt (II) phosphate octahydrate, cobalt (II) sulfate, and cobalt (II) sulfate heptahydrate. It is. Preferably, cobalt (II) chloride, cobalt (II) bromide, and cobalt (II) nitrate hexahydrate are used.

The ratio (y) of the mass of the transition metal element in the transition metal salt to the total mass of the diaminomaleonitrile and the easily carbonized polymer material is preferably 0.0001 to 0.20, more preferably 0.0005. It is -0.05, More preferably, it is 0.001-0.03. When this ratio is 0.0001 or more, the yield when the precursor is heat-treated tends to be more excellent. Moreover, when this ratio is 0.20 or less, the oxygen reduction activity tends to be more excellent when a nitrogen-containing carbon material is used. The ratio (y) can be calculated by the following formula (II).
Ratio (y) = transition metal element mass / (diaminomaleonitrile mass + easily carbonized polymer material mass) (II)

  The mixing method of the diaminomaleonitrile, the easily carbonized polymer material and the transition metal salt is not particularly limited. For example, the diaminomaleonitrile, the transition metal salt and the easily carbonized polymer material are dissolved in a solvent, A method of evaporating the solvent to dryness is preferred. The mixing method is not particularly limited. For example, all the raw materials may be dissolved in one solvent, or the respective solvents may be mixed after dissolving the respective raw materials in different solvents.

  Although it does not specifically limit as a solvent, For example, water, alcohols (methanol, ethanol, propanol, butanol, etc.), ketones (acetone, diethyl ketone, etc.), ethers (diethyl ether, tetrahydrofuran, etc.), chlorinated hydrocarbons (Dichloromethane, chloroform, dichloroethylene, trichloroethylene, carbon tetrachloride, etc.), glycols (ethylene glycol, propylene glycol, etc.), nitriles (acetonitrile, propionitrile, benzonitrile, etc.), amides (N, N-dimethylformamide) , Dimethylacetamide, etc.), lactams (N-methyl-2-pyrrolidone, etc.), dimethyl sulfoxide, aliphatic hydrocarbons (n-pentane, n-hexane, cyclohexane, n-heptane, n-octane, etc.), aroma Hydrocarbons (benzene, toluene, xylene, ethylbenzene, etc.) and the like. Among these, preferred are polar solvents, and more preferred are lower alcohols such as methanol and ethanol, acetonitrile, N, N-dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide and the like. As the solvent, one type of solution may be used alone, or two or more types of solutions may be used in combination. In particular, methanol and acetonitrile are preferred from the viewpoint of high solubility of diaminomaleonitrile or ease of evaporation and drying described below.

  The temperature at the time of mixing diaminomaleonitrile, the easily carbonized polymer material, and the transition metal salt is preferably 0 to 200 ° C, more preferably 10 to 100 ° C, and further preferably 20 to 50 ° C. is there. When the temperature is 0 ° C. or higher, the solubility of diaminomaleonitrile and the transition metal salt tends to be further improved. Moreover, when the temperature is 200 ° C. or lower, the stability of diaminomaleonitrile and the transition metal salt tends to be further improved.

  The pressure when mixing diaminomaleonitrile, the easily carbonized polymer material, and the transition metal salt is preferably 0.05 to 2.0 MPa, more preferably 0.08 to 1.5 MPa, and still more preferably. Is 0.1 to 1.0 MPa. When the pressure is 0.05 MPa or more, the oxygen reduction activity when the nitrogen-containing carbon material is used tends to be further improved. Moreover, when the pressure is 2.0 MPa or less, the runaway reaction can be further suppressed, and the safety during the preparation of the precursor tends to be further improved.

  The time for mixing diaminomaleonitrile, the easily carbonized polymer material, and the transition metal salt is preferably 1 minute to 240 hours, preferably 10 minutes to 120 hours, and more preferably 30 minutes to 60 hours. It's time. When the time is 1 minute or longer, the oxygen reduction activity of the nitrogen-containing carbon material tends to be further improved. Moreover, when time is 240 hours or less, it exists in the tendency for oxygen reduction activity when it is set as a nitrogen containing carbon material to improve more.

  When mixing the diaminomaleonitrile, the easily carbonized polymer material, and the transition metal salt, a batch reactor or a flow reactor may be used. The flow reactor may be a complete mixing tank, a tubular reactor, or a combination of a complete mixing tank and a tubular reactor.

  The atmosphere in the reactor may be air, but may be an inert gas such as nitrogen, helium, or argon.

  The method for evaporating and drying is not particularly limited. For example, the solvent may be removed under reduced pressure using a rotary evaporator or the like, or the solvent may be volatilized using a spray dryer or the like. Among these, a method using a spray dryer is preferable from the viewpoint of maintaining a uniform composite state and from the viewpoint of granulation.

[Second step]
In the second step, the precursor obtained in the first step is heat-treated to obtain a nitrogen-containing carbon material. The second step may be a one-step heat treatment, but may be a two-step or more heat treatment. Among these, in the second step, it is preferable to perform both the heat treatment in an inert gas atmosphere and the heat treatment in an ammonia-containing gas atmosphere in this order. The heat treatment in an inert gas atmosphere is mainly for the purpose of carbonization, and the heat treatment in an ammonia-containing gas atmosphere is mainly for the purpose of activation, and such a second step is performed. Thus, there is a tendency to obtain a nitrogen-containing carbon material that is superior in oxygen reduction activity.

  Although it does not specifically limit as said inert gas, For example, nitrogen, a noble gas, a vacuum etc. can be used. The heat treatment temperature in an inert gas atmosphere is preferably 600 to 1100 ° C, more preferably 700 to 1000 ° C, and still more preferably 800 to 950 ° C. When the heat treatment temperature is 600 ° C. or higher, the carbonization of the precursor tends to proceed sufficiently. Moreover, when the heat treatment temperature is 1100 ° C. or lower, a sufficient yield tends to be obtained.

  The heat treatment time in an inert gas atmosphere is preferably 5 minutes to 50 hours, more preferably 10 minutes to 20 hours, and further preferably 20 minutes to 10 hours. When the heat treatment time is 5 minutes or longer, carbonization of the precursor tends to proceed sufficiently. Moreover, it exists in the tendency for sufficient yield to be acquired because heat processing time is 50 hours or less.

  The appropriate heat treatment temperature and / or heat treatment time varies depending on the type and amount of the transition metal salt used.

  The ammonia-containing gas is not particularly limited. For example, it is preferable to use only ammonia or a gas obtained by diluting ammonia with nitrogen or a rare gas. The heat treatment temperature in the ammonia-containing gas atmosphere is preferably 600 to 1200 ° C, more preferably 700 to 1100 ° C, and further preferably 800 to 1000 ° C.

  The heat treatment time in an ammonia-containing gas atmosphere is preferably 5 minutes to 5 hours, more preferably 10 minutes to 3 hours, and even more preferably 15 minutes to 2 hours. When the heat treatment time is 5 minutes or longer, activation of the precursor is sufficiently advanced, and a nitrogen-containing carbon material excellent in oxygen reduction activity tends to be obtained. Moreover, it exists in the tendency for sufficient yield to be acquired because heat processing time is 5 hours or less.

  Before and after the heat treatment in an inert gas gas atmosphere and / or the heat treatment in an ammonia-containing gas gas atmosphere, a part of the transition metal may be removed using hydrochloric acid, sulfuric acid, or the like. In particular, when transition metal particles are generated by heat treatment, it is preferable to remove the transition metal particles from the viewpoint of suppressing an increase in crystallinity in a subsequent heat treatment step (heat treatment in an ammonia-containing gas atmosphere). The ease with which transition metal particles can be produced varies depending on the type, concentration, dispersibility, or heat treatment temperature of the transition metal. Further, in order to increase the removal rate of the transition metal particles, it is preferable to divide the heat treatment step in an inert gas gas atmosphere and / or the heat treatment step in an ammonia-containing gas gas atmosphere into a plurality of steps and repeatedly remove the transition metal. .

[Nitrogen-containing carbon material]
The nitrogen-containing carbon material of the present embodiment is manufactured by the above manufacturing method. The nitrogen-containing carbon material according to the present embodiment can be suitably used for fuel cell electrodes and the like. A fuel cell electrode containing a nitrogen-containing carbon material has high oxygen reducing ability. A method for obtaining an oxygen reduction electrode, a fuel cell and the like from the oxygen reduction catalyst is not particularly limited, and a general method for producing a polymer electrolyte fuel cell can be used.

Hereinafter, although an example etc. are given and the present invention is explained still in detail, these are illustrations and the present invention is not limited to these. Accordingly, those skilled in the art can implement the present invention by making various modifications to the examples described below.
First, the measurement method performed in this example will be described.

<Electrochemical measurement>
The measurement method of linear sweep voltammetry by the electrode manufacturing method and the rotating electrode method (using a rotating ring disk electrode device “RRDE-1” manufactured by Nisshi Kogyo) is shown below. First, 5 mg of nitrogen-containing carbon material is weighed into a vial, and about 50 mg of glass beads, 50 μL of 5% by mass Nafion (trade name) dispersion (manufactured by Sigma Aldrich Japan), ion-exchanged water and ethanol 150 μL of each was added, and the mixture was irradiated with ultrasonic waves for 20 minutes to prepare a slurry. 4 μL of this slurry was weighed, applied onto glassy carbon (0.2828 cm ² ) of the rotating electrode, and dried under saturated steam. The dried rotating electrode was the working electrode, the reversible hydrogen electrode (RHE) was the reference electrode, and the carbon electrode was the counter electrode. 0.5M sulfuric acid was used as an electrolyte, and oxygen was bubbled through the electrolyte for 30 minutes, and then the electrochemical measurement was performed by sweeping from 1.1 V to 0 V at a sweep speed of 5 mV / s and a rotation speed of 1500 rpm. Further, the oxygen reduction start potential E ₀ was defined as a potential giving a current of −10 μA / cm ² . Higher E ₀ means higher oxygen reduction activity. In addition, in FIG. 1, it obtained by the baking yield and electrochemical measurement of the nitrogen-containing carbon material obtained in Example 1, Example 2, Example 3, Example 4, Comparative Example 1, and Comparative Example 2. The correlation between the oxygen reduction initiation potential and the mixing ratio of diaminomaleonitrile and phenol resin is shown.

[Example 1]
<Preparation of precursor>
In a 0.5 L eggplant-shaped flask, 2.0 g of diaminomaleonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.), 4.0 g of phenol resin (manufactured by Gunei Chemical Industry Co., Ltd., Registop PSK-2320), 0.041 g of iron (II) chloride and methanol 200 g was added and stirred at room temperature for 12 hours. Then, the solvent was removed using a rotary evaporator in a 50 ° C. water bath, and dried at 80 ° C. for 2 hours using a vacuum dryer. The sample was pulverized in an agate mortar to obtain a powdery precursor.

<Synthesis of nitrogen-containing carbon materials>
Of the prepared precursor, 2.0 g was placed on a quartz boat, which was placed in a quartz tube furnace having an inner diameter of 36 mm, and the inside of the furnace was heated from room temperature to 800 ° C. over 60 minutes under nitrogen flow at atmospheric pressure and 1 NL / min. The temperature was raised to 0 ° C. and kept at 800 ° C. for 1 hour. After cooling to room temperature, this was pulverized and classified with a planetary ball mill (manufactured by Fritsch, trade name “Pulverisete-7”) to adjust the average particle size to about 2 μm. Further, the entire amount of the precursor after the pulverization treatment was placed on a quartz boat, accommodated in a quartz tube furnace having an inner diameter of 36 mm, and the inside of the furnace was heated from room temperature to 900 ° C. over 20 minutes under a flow of ammonia gas at atmospheric pressure and 1 NL / min. The temperature was raised to 0 ° C., kept at 900 ° C. for 1 hour, and then cooled to room temperature. Finally, 0.48 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction starting potential E ₀ was 0.92V.

[Example 2]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1, except that 2.0 g of diaminomaleonitrile was changed to 4.0 g and 0.041 g of iron (II) chloride was changed to 0.054 g of iron (II) chloride.

<Synthesis of nitrogen-containing carbon materials>
Using 2.0 g of the prepared precursor, a nitrogen-containing carbon material was synthesized in the same manner as in Example 1. Finally, 0.50 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction starting potential E ₀ was 0.91V.

[Example 3]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1 except that 2.0 g of diaminomaleonitrile was changed to 1.0 g and 0.041 g of iron (II) chloride was changed to 0.034 g of iron (II) chloride.

<Synthesis of nitrogen-containing carbon materials>
Using 2.0 g of the prepared precursor, a nitrogen-containing carbon material was synthesized in the same manner as in Example 1. Finally, 0.38 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction starting potential E ₀ was 0.90V.

[Example 4]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1 except that 2.0 g of diaminomaleonitrile was changed to 8.0 g and 0.041 g of iron (II) chloride was changed to 0.082 g of iron (II) chloride.

<Synthesis of nitrogen-containing carbon materials>
Using 2.0 g of the prepared precursor, a nitrogen-containing carbon material was synthesized in the same manner as in Example 1. Finally, 0.30 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction starting potential E ₀ was 0.90V.

[Example 5]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1 except that 0.041 g of iron (II) chloride was changed to 0.014 g of iron (II) chloride.

<Synthesis of nitrogen-containing carbon materials>
Using 2.0 g of the prepared precursor, a nitrogen-containing carbon material was synthesized in the same manner as in Example 1. Finally, 0.26 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction starting potential E ₀ was 0.91V.

[Example 6]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1 except that 200 g of methanol was changed to 200 g of acetonitrile.

<Synthesis of nitrogen-containing carbon materials>
Using 2.0 g of the prepared precursor, a nitrogen-containing carbon material was synthesized in the same manner as in Example 1. Finally, 0.46 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction starting potential E ₀ was 0.92V.

[Example 7]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1.

<Synthesis of nitrogen-containing carbon materials>
A nitrogen-containing carbon material was synthesized in the same manner as in Example 1 except that 2.0 g of the prepared precursor was used and the temperature under the circulation of ammonia gas was changed to 1000 ° C. Finally, 0.37 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction starting potential E ₀ was 0.91V.

[Example 8]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1.

<Synthesis of nitrogen-containing carbon materials>
A nitrogen-containing carbon material was synthesized in the same manner as in Example 1 except that 2.0 g of the prepared precursor was used and the temperature under nitrogen flow was changed to 900 ° C. Finally, 0.56 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction starting potential E ₀ was 0.91V.

[Example 9]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1 except that 0.041 g of iron (II) chloride was changed to 0.042 g of cobalt (II) chloride.

<Synthesis of nitrogen-containing carbon materials>
Using 2.0 g of the prepared precursor, a nitrogen-containing carbon material was synthesized in the same manner as in Example 1. Finally, 0.28 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction starting potential E ₀ was 0.86V.

[Comparative Example 1]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1 except that 2.0 g of diaminomaleonitrile was not mixed and 0.041 g of iron (II) chloride was changed to 0.027 g of iron (II) chloride.

<Synthesis of nitrogen-containing carbon materials>
Using 2.0 g of the prepared precursor, a nitrogen-containing carbon material was synthesized in the same manner as in Example 1. Finally, 0.24 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction start potential E ₀ was 0.67V.

[Comparative Example 2]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1 except that 4.0 g of phenol resin was not mixed and 0.041 g of iron (II) chloride was changed to 0.014 g of iron (II) chloride.

<Synthesis of nitrogen-containing carbon materials>
Using 2.0 g of the prepared precursor, a nitrogen-containing carbon material was synthesized in the same manner as in Example 1. Finally, 0.06 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction start potential E ₀ was 0.89V.

[Comparative Example 3]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1 except that 4.0 g of phenol resin was not mixed and 0.041 g of iron (II) chloride was changed to 0.005 g of iron (II) chloride.

<Synthesis of nitrogen-containing carbon materials>
Using 2.0 g of the prepared precursor, a nitrogen-containing carbon material was synthesized in the same manner as in Example 1. Finally, 0.05 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction starting potential E ₀ was 0.90V.

[Comparative Example 4]
<Preparation of precursor>
A precursor was prepared in the same manner as in Example 1 except that 4.0 g of phenol resin was not mixed and 0.041 g of iron (II) chloride was changed to 0.014 g of cobalt (II) chloride.

<Synthesis of nitrogen-containing carbon materials>
Using 2.0 g of the prepared precursor, a nitrogen-containing carbon material was synthesized in the same manner as in Example 1. Finally, 0.04 g of a nitrogen-containing carbon material was obtained.

<Electrochemical measurement>
The electrochemical measurement was performed on the obtained nitrogen-containing carbon material. The oxygen reduction starting potential E ₀ was 0.84V.

Table 1 shows the oxygen reduction starting potential E ₀ obtained from the experimental conditions, firing yield, and electrochemical evaluation results in Examples 1 to 9 and Comparative Examples 1 to 4.

* DAMN: diaminomaleonitrile, PhRs: phenol resin, FeCl ₂ : iron chloride (II), CoCl ₂ : cobalt chloride (II), MeOH: methanol, MeCN: acetonitrile ratio (x) = diaminomaleonitrile / (diaminomaleonitrile + Easily carbonized polymer material)
Ratio (y) = transition metal amount in transition metal salt / (diaminomaleonitrile + easily carbonized polymer material)

  The nitrogen-containing carbon material obtained by the production method of the present invention has industrial applicability as an electrode material application for fuel cells and the like.

Claims (2)

A first step of obtaining a precursor by mixing diaminomaleonitrile, an easily carbonized polymer material, a transition metal salt, and a solvent ;
Obtained by heat-treating the precursor, possess a second step of obtaining a nitrogen-containing carbon material, a
The method for producing a nitrogen-containing carbon material, wherein the easily carbonized polymer material is polyaniline, polyvinyl pyridine, polyimide, melamine resin, phenol resin, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, aromatic polyamide, or polyvinyl pyrrolidone . A method for producing a fuel cell electrode comprising a nitrogen-containing carbon material,
The manufacturing method of the electrode for fuel cells including the process of manufacturing the said nitrogen-containing carbon material, and the said process is performed by the manufacturing method of the nitrogen-containing carbon material of Claim 1.