WO2006003831A1

WO2006003831A1 - Electrode catalyst for fuel cell, process for producing the same and fuel cell utilizing the catalyst

Info

Publication number: WO2006003831A1
Application number: PCT/JP2005/011512
Authority: WO
Inventors: Jun-Ichi Ozaki; Asao Oya; Tomonori Anahara
Original assignee: National University Corporation Gunma University
Priority date: 2004-07-05
Filing date: 2005-06-23
Publication date: 2006-01-12
Also published as: JP2007311026A

Abstract

[PROBLEMS] To enhance the activation of platinum supported on a carbon base material by causing a dopant to control the crystal growth of the carbon base material and to modify the electronic state thereof, thereby obtaining a high current density. [MEANS FOR SOLVING PROBLEMS] There is provided an electrode catalyst for fuel cell, comprising a carbon base material composed of carbon alloy microparticles doped with either nitrogen atoms or boron atoms or both and, supported on the carbon base material, platinum or a platinum alloy. Carbon alloy microparticles doped with nitrogen atoms are obtained by subjecting a nitrogenous compound and a precursor of thermosetting resin to thermal reaction and polymerization, heating the thus obtained nitrogen compound-containing thermosetting resin at 400˚ to 1500˚C so as to carbonize the same, and micropulverizing the carbonized nitrogen compound-containing thermosetting resin. The electrode catalyst for fuel cell can be produced by causing the carbon alloy microparticles to support platinum.

Description

Specification

ELECTRODE CATALYST FOR FUEL CELL, PROCESS FOR PRODUCING THE SAME, AND FUEL CELL USING THE CATALYST

Technical field

[0001] The present invention relates to an electrode catalyst for a fuel cell having a small amount of platinum or a platinum alloy supported thereon, a production method thereof, and a fuel cell using the catalyst. More specifically, the present invention relates to an electrode catalyst for a polymer electrolyte fuel cell suitable for a force sword having a highly active oxygen reduction catalytic ability, a method for producing the same, and a fuel cell using the catalyst.

Background art

[0002] Practical use of high-efficiency, pollution-free fuel cells is an important countermeasure against global warming and environmental pollution problems. In particular, solid polymer fuel cells used in fuel cell vehicles (FCVs) and household cogeneration power sources have recently been widely researched and developed for competition because of their high potential for cost reduction. ing.

In such a polymer electrolyte fuel cell, the reaction occurs in the porous gas diffusion electrode. In order to obtain a sufficient current density I (AZ projected electrode area), an electrode having a large specific surface area and conductive carbon black as a porous structure / catalyst support is generally used as the electrode. Yes. In addition, platinum (Pt) or platinum alloy-based catalysts (Pt—Fe, Pt—Cr, Pt—Ru) are used as the catalyst, and these noble metal catalysts are supported in a highly dispersed state (particle size 2 to several tens of nm). It has been.

[0003] In the polymer electrolyte fuel cell, since the oxygen reduction reaction that occurs at the force sword electrode is very unlikely to occur, platinum, which is a catalyst, is used on a certain brand of carbon support as a standard support material. However, for example, a large amount of lmgZcm ² has been introduced. That is, the standard carrier materials for gold include (1) carbon black, such as Carbon Black, Bl Degussa-Huels (Frankfurt), and (2) furnace black, such as Vulcan XC-72 Cabot. (Massachusetts), (3) acetylene black, such as Shawinigan Black and Chevron Chemicals (Houston, Texas). Carbon black B1 as a standard support material for platinum For example, Patent Document 1 describes Vulcan XC-72 and Shawi-Gan Black, for example, Patent Document 2.

[0004] However, as to how platinum is supported on carbon black, furnace black, and acetylene black, which are conventional standard support materials, much effort has been put into fine dispersion of platinum as much as possible. In this case, a standard support material such as carbon black merely facilitates the dispersion of platinum, and the support itself is merely a medium that imparts conductivity, so that the activity of the supported platinum can be sufficiently achieved. It was a powerful force.

[0005] In order to improve this point, a group power consisting of B, N and P is used for a fuel cell in which a particle-like or fiber-like carbon support containing at least one selected element contains platinum particles or the like. A catalyst is disclosed. In this fuel cell catalyst, a compound containing at least one element selected from the group consisting of B, N, and P is converted into a gas state and introduced into a furnace containing a carbon support, where 600 to 900 ° C. At least one kind selected from the group consisting of B, N and P together with a carrier gas is generated by discharging in a vacuum chamber where a carbon carrier is installed and generating a plasma. It is produced by introducing a compound containing an element in a gas state and reacting for a certain time (for example, Patent Document 3).

Patent Document 1: Japanese Patent Laid-Open No. 2001-85020 (Claim 1, [0041])

Patent Document 2: US Pat. No. 5,759,944 (Example 1, Example 2)

Patent Document 3: Japanese Patent Laid-Open No. 2004-79244 ([0010], [0025] to [0027])

Disclosure of the invention

Problems to be solved by the invention

[0006] Since the carbon support before containing B, N, etc. described in Patent Document 3 uses a conventional standard carrier material, a compound containing B or N is made into a gas state and this carbon support is used. Even if the support is heat-treated or plasma-treated, the edge surface, which is the active site of the carbon substrate, cannot be introduced, and a catalyst in which the platinum catalyst is activated exclusively by the electronic interaction of nitrogen and boron is prepared. However, there was a problem that cannot be said to be maximizing the characteristics of carbon materials.

[0007] An object of the present invention is to control the crystal growth of a carbon substrate by a dopant and to perform an electronic state. By modifying the catalyst, the activity of platinum supported thereon can be further improved, and a fuel cell electrode catalyst capable of obtaining a high current density, a method for producing the same, and a fuel cell using the catalyst are provided. It is in.

Means for solving the problem

[0008] As a result of diligent studies to solve the above-mentioned problems, the present inventors have demonstrated that the carbon material itself that has been used as a catalyst carrier for supporting platinum in a highly dispersed state has an oxygen reduction catalytic ability under predetermined conditions. As a result, the inventors have found that the above object can be achieved, and have completed the present invention.

[0009] The invention according to claim 1 is an electrode catalyst for a fuel cell in which platinum or a platinum alloy is supported on a carbon base material, and the carbon base material is a carbon alloy fine particle doped with nitrogen atoms. This carbon substrate heat-reacts the nitrogen-containing compound and the thermosetting resin precursor, and superimposes, and the resulting nitrogen compound-containing thermosetting resin is heat treated and carbonized to carbonize. An electrode catalyst for a fuel cell, which is a carbon alloy fine particle obtained by finely pulverizing a nitrogen compound-containing thermosetting resin.

[0010] The invention according to claim 2 includes a polymerization step of obtaining a nitrogen compound-containing thermosetting resin by heating and polymerizing a nitrogen-containing compound and a thermosetting resin precursor. A carbonization step in which the nitrogen compound-containing thermosetting resin is carbonized by heat treatment, and the carbonized nitrogen compound-containing thermosetting resin is pulverized to obtain carbon-aromatic particles doped with nitrogen atoms. A method for producing an electrode catalyst for a fuel cell, comprising a pulverization step and a step of obtaining a carbon substrate by supporting platinum on the carbon alloy fine particles.

[0011] The invention according to claim 4 is an electrode catalyst for a fuel cell in which platinum or a platinum alloy is supported on a carbon base material, and the carbon base material is a carbon alloy fine particle doped with boron atoms. This carbon substrate was polymerized by heating and reacting a boron-containing compound and a precursor of thermosetting resin, and the resulting boron compound-containing thermosetting resin was heat treated and carbonized to be carbonized. An electrode catalyst for a fuel cell, which is a carbon alloy fine particle obtained by finely pulverizing a boron compound-containing thermosetting resin.

The invention according to claim 5 includes a polymerization step of obtaining a boron compound-containing thermosetting resin by heating and polymerizing a boron-containing compound and a thermosetting resin precursor. The A carbonization step in which the boron compound-containing thermosetting resin is carbonized by heat treatment, and the carbonized boron compound-containing thermosetting resin is pulverized to obtain carbon alloy particles doped with boron atoms. It is a method for producing an electrode catalyst for a fuel cell, comprising a powder frame step and a step of obtaining a carbon substrate by supporting platinum on the carbon alloy fine particles.

[0013] The invention according to claim 7 is an electrode catalyst for a fuel cell in which platinum or a platinum alloy is supported on a carbon base material, wherein the carbon base material is doped with nitrogen atoms and boron atoms. The carbon substrate is polymerized by dissolving a nitrogen-containing compound and a boron-containing compound in a methanol solution of furfuryl alcohol or resol-type phenol resin, and performing a polymerization reaction under methanol subcritical or supercritical conditions. An electrode catalyst for a fuel cell, characterized in that it is a carbon alloy fine particle obtained by carbonizing a polymer fine particle obtained by heat treatment after obtaining the product fine particle.

[0014] The invention according to claim 8 is a solution in which a nitrogen-containing compound and a boron-containing compound are dissolved in a methanol solution of furfuryl alcohol or resol type phenol resin, and polymerized under methanol subcritical or supercritical conditions. A polymerization step for obtaining polymer fine particles by carrying out a reaction, a carbonization step for obtaining carbon alloy fine particles doped with nitrogen atoms and boron atoms by heat-treating the obtained polymer fine particles, and platinum on the carbon alloy fine particles A method for producing an electrode catalyst for a fuel cell, comprising a step of obtaining a carbon base material by supporting a catalyst.

[0015] In the invention according to claim 10, in the fuel cell electrode catalyst in which platinum or a platinum alloy is supported on a carbon base material, the carbon base material contains an aqueous solution containing phenol, formaldehyde, and a base catalyst. An electrode catalyst for a fuel cell, characterized in that it is carbon ultrafine particles obtained by carbonizing by heating high molecular ultrafine particles recovered from a solution that has been kept at a predetermined time and reacted and dried.

[0016] The invention according to claim 11 includes a step of obtaining a reaction solution by holding an aqueous solution containing phenol, formaldehyde, and a base catalyst at a predetermined temperature for a predetermined time, and freeze-drying the reaction solution to obtain a polymer superpolymer. A step of collecting the fine particles, a carbonization step of carbonizing the polymer ultrafine particles by heating to obtain carbon ultrafine particles, and a step of obtaining a carbon base material by supporting platinum on the carbon ultrafine particles. A method for producing an electrode catalyst for a fuel cell. The invention's effect

[0017] In the invention according to claim 1, 4 or 7, when one or both of nitrogen and boron is introduced into carbon, the introduced element hinders the development of the carbon structure. When examined by X-ray diffraction, the development of X-ray diffraction lines in the basal plane direction of the carbon structure is suppressed, and along with this, the ratio of the edge surface in the direction perpendicular to the basal plane increases. The edge surface is more electronically and chemically active than the basal surface, so that platinum in contact with it is activated. At the same time, electrons increase in the electrode catalyst, and when boron atoms are doped in the carbon substrate, electrons decrease in the electrode catalyst. As a result, compared with the case where nitrogen atoms or boron atoms are not doped, the carbon base material doped with nitrogen atoms or boron atoms is added with a function of oxygen reduction in addition to the function as a conductive material. The activation of is higher. Furthermore, when both a nitrogen atom and a boron atom are doped in the carbon substrate, the activity of the supported platinum is caused by the interaction between the electrically negative nitrogen atom and the electrically positive boron atom. Is further increased. As a result, a high current density can be obtained with a small amount of platinum. In particular, in Patent Document 3, the surface of a carbon substrate that has already been prepared is modified with one or both of nitrogen and boron to achieve activation, whereas in the invention according to claim 1, 4 or 7, Since either or both of nitrogen and boron are added at the time of carbon preparation, the edge surface can be formed on the carbon surface by controlling the development of the carbon structure, and is expected in Patent Document 3. It also has an effect. For this reason, the present invention is more excellent in the activation of platinum than the invention of Patent Document 3.

[0018] In the invention according to claim 2 or 5, a carbon alloy doped with nitrogen atoms or boron atoms by carbonizing and pulverizing the nitrogen compound-containing thermosetting resin or boron compound-containing thermosetting resin. Fine particles are obtained. By changing the compounding ratio of the nitrogen-containing compound or boron-containing compound and the precursor of the thermosetting resin, the amount of nitrogen atom or boron atom can be easily adjusted.

[0019] In the invention according to claim 8, fine particles can be obtained by conducting a polymerization reaction of a furfuryl alcohol or a resol type phenol resin dissolved in nitrogen-containing compound and boron-containing compound under a subcritical or supercritical condition. A polymer can be obtained in the form of carbon alloy, and by carbonizing this polymer, carbon alloy fine particles doped with nitrogen and boron atoms can be obtained. Particles are obtained. By changing the amount of the nitrogen-containing compound and boron-containing compound dissolved, the doping amount of nitrogen atoms or boron atoms can be easily adjusted.

[0020] In the invention according to claim 10, since the carbon base material is ultrafine carbon particles, the ratio of the edge surface exposed by introducing defects on the carbon surface increases. This adds the function of oxygen reduction and further increases the activation of platinum carried by electronic and chemical interactions with such active surfaces.

In the invention according to claim 11, ultrafine polymer particles are obtained in the reaction solution by holding an aqueous solution containing phenol, formaldehyde, and a base catalyst at a predetermined temperature for a predetermined time.

Brief Description of Drawings

FIG. 1 is a graph showing the relationship between the X-ray incident angle and diffraction X-ray intensity of N, B-carbon alloy fine particles F to J of Examples 9 to 13 and carbon fine particles 1 of Comparative Example 1.

FIG. 2 is a graph showing the relationship between the potential and current density of N-carbon alloy fine particles 1 and 2 of Examples 1 and 2 and carbon fine particles 1 of Comparative Example 1.

FIG. 3 is a graph showing the relationship between the potential and current density of B-carbon alloy fine particles of Example 3 and carbon fine particles 1 of Comparative Example 1.

FIG. 4 is a graph showing the relationship between the N and B-carbon alloy fine particles A, B and E of Examples 4, 5, and 8 and the carbon fine particle 1 of Comparative Example 1 and the current density.

[FIG. 5] (a) to (c) are the oxygen reduction initiation potentials of the N, B-carbon alloy fine particles A to E of Examples 4 to 8 and the carbon fine particles of Comparative Example 2, and the boron atoms and nitrogen atoms, respectively. It is a graph which shows the relationship with content.

FIG. 6 is a graph showing NlsX-ray photoelectron spectra of N, B-carbon alloy fine particles A to E of Examples 4 to 8.

FIG. 7 is a graph showing Bls X-ray photoelectron spectra of N, B-carbon alloy fine particles A to E in Examples 4 to 8.

FIG. 8 is a photographic diagram of a field emission high resolution scanning electron microscope showing carbon ultrafine particles of Example 14.

[Fig. 9] Carbon base oxygen-reduced voltammo of Example 15 and Comparative Example 3 each carrying platinum. It is a figure which shows a gram.

FIG. 10 is a diagram showing cyclic voltammograms of carbon substrates of Example 15 and Comparative Example 3 each carrying platinum.

FIG. 11 is a schematic diagram of a three-pole rotating electrode cell.

Explanation of symbols

[0023] 1 3-pole rotating electrode cell

2 Working electrode (carbon sample)

3 Reference electrode (AgZAgCl)

4 Counter electrode (Pt)

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be specifically described.

[1] The first form of the carbon base material in the fuel cell electrode catalyst according to the present invention is carbon alloy fine particles. This carbon alloy fine particle is a carbon alloy fine particle in which one or both of a boron atom and a nitrogen atom located on both sides of a group 14 carbon atom and a carbon atom. The average particle size of the carbon alloy fine particles is 0.05 μm force or less than 45 μm. Preferably 0.05.0 .: m.

With such carbon alloy fine particles, the carbon material itself that has been used as a catalyst carrier for supporting platinum in a highly dispersed state has an oxygen reduction catalytic ability, and can be suitably used as an electrode catalyst for a fuel cell.

[0025] In the carbon alloy fine particles according to the present invention, when the doping amount of nitrogen atom or boron atom is 0.1 to 40 atom%, preferably 4 to 20 atom%, good electrode activity with respect to oxygen reduction. Indicates. In addition, when nitrogen and boron atoms are doped at the same time, higher electrode activity is exhibited due to the interaction between the two. In addition, when both nitrogen (N) and boron (B) atoms are doped, the atomic ratio (BZN) is from 0.06 to L5, preferably from 0.2 to 0.4. The atomic ratio ((B + N) ZC) is preferably 0.03-0.4. Within the range of these atomic ratios, both atoms interact well, and highly active force-bonded particles can be obtained.

[0026] (a) Method for producing carbon alloy fine particles doped with nitrogen atoms In order to produce carbon alloy fine particles doped with nitrogen atoms, first, nitrogen sources such as phthalocyanine, acrylonitrile, EDTA (ethylene diamine tetraacetic acid), melamine and the like, as well as furan coconut resin and phenol resin. A precursor of thermosetting resin is mixed and reacted by heating to obtain a nitrogen compound-containing thermosetting resin. For example, when phthalocyanine is used as the nitrogen-containing compound and furfuryl alcohol is used as the precursor of the thermosetting resin, an acid such as hydrochloric acid is added to the mixture, preferably 80 to 200 ° C. A phthalocyanine-containing furan resin can be obtained by heating at a temperature within the range of 1 to cause a polymerization reaction. In order to make the nitrogen atom doping amount 0.1 to 40 atomic%, the compounding ratio of furfuryl alcohol and melamine or phthalocyanine is 1: (0.07-3), preferably C: N. ίMA 1: Set to (0. 1 to 0.5).

[0027] The obtained phthalocyanine-containing furan resin is carbonized by heat treatment at a predetermined temperature in an inert atmosphere such as nitrogen or helium. The heat treatment temperature is not particularly limited as long as it is a carbonizable temperature, but a preferable temperature is 400 to 1500 ° C, and a more preferable temperature is 500 to 1200 ° C. Next, the average particle diameter doped with nitrogen atoms is preferably 0.05 μm or less, preferably 45 μm or less, preferably from 0.05 μm to 0.1 by finely pulverizing with a ball mill such as a planetary ball mill. Carbon alloy fine particles of μm or less can be obtained. The fine particles obtained as described above are loaded with 0.5 to 60% by weight, preferably 10 to 50% by weight, more preferably 20 to 50% by weight of platinum or a platinum alloy, whereby the fuel cell of the present invention is supported. An electrode catalyst is obtained. Here, examples of the platinum alloy include Pt—Fe, Pt—Cr, Pt—Ru, Pt—Ni, and Pt—Cu.

[0028] The method for supporting platinum is not particularly limited, and a known method can be employed. For example, there is a method in which carbon alloy fine particles are dispersed in a platinum colloid solution, platinum is reduced, and then solid-liquid separation and drying are performed. According to this method, the amount of platinum supported can be easily adjusted by changing the amount of carbon alloy fine particles dispersed in the colloidal gold solution.

[0029] (b) Method for producing carbon alloy fine particles doped with boron atoms

To produce carbon alloy fine particles doped with boron atoms, first, boron-containing compounds such as BF methanol complex or BF tetrahydrofuran (THF) complex as a boron source. And a thermosetting resin precursor such as furan resin and phenol resin are mixed and reacted by heating to obtain a boron compound-containing thermosetting resin. For example, BF

3 When using a methanol complex and using furfuryl alcohol as a precursor of thermosetting resin, it is preferably heated at a temperature in the range of 80 to 200 ° C. to cause a polymerization reaction, thereby producing a BF-containing furan. A rosin can be obtained. The boron atom doping amount described above is 0.1 to

Three

In order to achieve 40 atomic%, the compounding ratio of furfuryl alcohol and BF should be C: B.

Three

1: (0.1-1), preferably 1: (0.15-0.6).

[0030] The obtained BF-containing furan resin is described in (a) above under an inert atmosphere such as nitrogen or helium.

Three

It is carbonized by heat treatment at a predetermined temperature. Next, the average particle diameter doped with boron atoms is preferably 0.05 μm or less, preferably not more than 45 μm, preferably 0.05 μm to 0.1 μm, by pulverizing with a ball mill such as a planetary ball mill. The following carbon alloy fine particles can be obtained. The fine particles thus obtained are loaded with 0.5 to 60% by weight of platinum or a platinum alloy, preferably 10 to 50% by weight, more preferably 20 to 50% by weight. A battery electrode catalyst is obtained. Here, examples of the platinum alloy include Pt—Fe, Pt—Cr, Pt—Ru, Pt—Ni, and Pt Cu. The method for supporting platinum is not limited to the force generally used in the method described in (a) above.

[0031] (c) Method for producing carbon alloy fine particles doped with nitrogen atom and boron atom (thermal polymerization method)

In order to produce carbon alloy fine particles doped with nitrogen atoms and boron atoms, first, a boron-containing compound and a nitrogen-containing compound similar to the above, and a precursor of a thermosetting resin such as furan resin and phenol resin. The body is mixed and reacted by heating to obtain a boron nitrogen compound-containing thermosetting resin. For example, BF methanol complex as boron-containing compound, nitrogen-containing

Three

When melamine is used as a compound and furfuryl alcohol is used as a precursor of thermosetting resin, it is preferably heated at a temperature in the range of 80 to 200 ° C. to cause a polymerization reaction. A BF-containing furan resin can be obtained. Nitrogen atoms and boron mentioned above

Three

In order to make the doping amount of elementary atoms 0.1 to 40 atom% and BZN atomic ratio 0.2 to 0.4, respectively, the mixing ratio of furfuryl alcohol, melamine and BF methanol complex should be changed.

Three

The atomic ratio of C: N: B is 1: (0. 04-2): (0.02-: 0, preferably 1: (0.3-0.7): (0. 4 ~ 1.5).

The obtained polymer fine particles are carbonized at a predetermined temperature described in the above (a) under an inert atmosphere such as nitrogen or helium, thereby obtaining carbon alloy fine particles doped with nitrogen atoms and boron atoms. be able to. The fine particles thus obtained are supported by 0.5 to 60% by weight, preferably 10 to 50% by weight, more preferably 20 to 40% by weight of platinum or platinum alloy. A battery electrode catalyst is obtained. The kind of platinum alloy and the method for supporting platinum are the same as the supporting method in the method for producing carbon alloy fine particles doped with nitrogen atoms described in (a) above.

[0033] (d) Method for producing carbon alloy fine particles doped with nitrogen atom and boron atom (subcritical method)

Another method for producing carbon alloy fine particles doped with nitrogen and boron atoms is the following subcritical method. In this method, first, in a methanol solution of furfuryl alcohol or resole phenol resin, a nitrogen-containing compound similar to the above and a boron-containing compound such as BF methanol complex or BF tetrahydrofuran (THF) complex as a boron source. Conversion

3 3

The compound is dissolved and a polymerization reaction is performed. For example, furfuryl alcohol in methanol

Melamine as a nitrogen-containing compound and BF methanol complex as a boron-containing compound

Three

When used, the polymerization reaction of furfuryl alcohol is carried out under methanol subcritical or supercritical conditions at 200 to 350 ° C. In order to make the doping amount of each of the nitrogen atom and boron atom 0.1 to 40% by atom, furfuryl alcohol, melamine and BF

3 The compounding ratio of the nor complex is 1: (0.2 to 0.8): (0.1 to 0.4), preferably 1: (0.3 to 0.7) in terms of the C: N: B atomic ratio. ): Set to (0.15 to 0.4).

[0034] The obtained polymer fine particles are carbonized at a predetermined temperature described in the above (a) under an inert atmosphere such as nitrogen or helium to obtain carbon alloy fine particles doped with nitrogen atoms and boron atoms. be able to. Carbon alloy fine particles doped with nitrogen atoms and boron atoms can be obtained. The fine particles thus obtained are supported by 0.5 to 60% by weight, preferably 10 to 50% by weight, more preferably 20 to 40% by weight of platinum or platinum alloy. A battery electrode catalyst is obtained. The type of platinum alloy and the method for supporting platinum are described in the above (a). This is the same as the loading method in the child manufacturing method.

[0035] [2] The second form of the carbon substrate in the fuel cell electrode catalyst according to the present invention is ultrafine carbon particles produced by a sol-gel method. The average particle size of ultrafine carbon particles produced by this method is 10 to 1 OOnm.

The carbon ultrafine particles are produced as follows. First, an aqueous solution containing a base catalyst such as phenol, formaldehyde, and sodium carbonate is prepared. By holding this aqueous solution at a predetermined temperature for a predetermined time, phenol and formaldehyde are reacted. Polymer ultrafine particles are generated in the reaction solution. The predetermined temperature is preferably 60 to 90 ° C, more preferably 80 to 90 ° C. Also, the predetermined time is preferably 1-20 hours, more preferably 8-18 hours. Next, the reaction solution is cooled to liquid nitrogen temperature, frozen and dried to collect ultrafine polymer particles. Further, the collected ultrafine polymer particles are then heat-cured at 100 to 250 ° C. for 0.5 to 10 hours, preferably at 200 to 230 ° C. for 3 to 6 hours. By heating the cured ultrafine polymer particles under the carbonization heat treatment conditions described in (a) above, carbon ultrafine particles having an average particle size of 10 to 100 nm, preferably 10 to 30 nm can be obtained. . In order to obtain such ultrafine particles, the mixing weight ratio of phenol, formaldehyde and sodium carbonate (phenol: formaldehyde: sodium carbonate) is 1: (1-2): (0. 05-0.2), preferably 1: (1. 4 to 1.6): Set to (0. 05 to 0.1).

[0036] The ultrafine particles thus obtained are loaded with 0.5 to 60% by weight, preferably 10 to 50% by weight, more preferably 20 to 40% by weight of platinum or a platinum alloy. A fuel cell electrode catalyst is obtained. The kind of platinum alloy and the method for supporting platinum are the same as the method for supporting the carbon alloy fine particles doped with nitrogen atoms described in (a) above.

[0037] [3] The solid fuel cell according to the present invention is manufactured using the fuel cell electrode catalyst described in [1] and [2] above.

[0038] A solid polymer fuel cell is composed of an anode (fuel electrode) and a force sword (acid additive electrode), which are arranged so that cells built in a battery module are sandwiched between sheet-like solid polymer electrolyte membranes. They are organized. As this solid polymer electrolyte membrane, a fluorine-based ion exchange typified by a perfluorosulfonic acid rosin membrane (for example, a naphthoion membrane manufactured by DuPont). A replaceable oil membrane is used. On one or both surfaces of the solid polymer electrolyte membrane, an electrode reaction layer containing the fuel cell electrode catalyst described in [1] and [2] above is formed in layers. That is, the anode and the force sword (hereinafter abbreviated as “electrode”) are configured to include the electrode reaction layer including the electrode catalyst for fuel cells described in [1] and [2] above and the electrode substrate. Both electrodes are bonded together as a MEA (Membrane Electrode Assembly) by hot-pressing them to the main surfaces of the polymer electrolyte membrane on the electrode reaction layer side.

[0039] The electrode base material supports a catalyst layer and supplies and discharges reaction gases (fuel gas and oxidant gas), and also has a porous sheet (for example, carbon base) that also functions as a current collector. 1 par) is used. When a reactive gas is supplied to each of the electrodes, a gas phase (reactive gas), a liquid phase is formed at the boundary between the catalyst layer supporting the platinum-based noble metal provided on both electrodes and the solid polymer electrolyte membrane. A three-phase interface (solid polymer electrolyte membrane) and solid phase (catalyst possessed by both electrodes) is formed, and direct current power is generated by causing an electrochemical reaction.

[0040] In the electrochemical reaction,

The anode side: H → 2H ^{+ +} 2e "

2

Force sword side: (1/2) 0 + 2H ⁺ + 2e "→ HO

twenty two

H + ions generated on the anode side move toward the cathode side in the polymer electrolyte membrane, and e "(electrons) move to the force sword side through an external load. On the other hand, on the power sword side, oxygen contained in the oxidant gas reacts with H + ions and e- that have moved from the anode side to produce water. Will generate direct current power from hydrogen and oxygen to produce water.

Example

Hereinafter, examples of the present invention will be described together with comparative examples.

Mahaku, the carbon alloy fine particles that have been collected.

Add phthalocyanine (13 lg), a nitrogen-containing compound, to 10 g of furfuryl alcohol (furan rosin precursor), add an appropriate amount of hydrochloric acid, and heat the mixture in an oven at 80 ° C to contain phthalocyanine. Obtained furan rosin. This was heated in a nitrogen atmosphere at a rate of 10 ° CZ from room temperature and kept at 1000 ° C for 1 hour. This As a result, the phthalocyanine-containing furan resin was carbonized. This carbonized product was pulverized with a planetary ball mill to obtain carbon alloy fine particles (hereinafter referred to as “N-carbon alloy fine particles 1” t) having an average particle diameter of 0.1 doped with 13.4 atomic% of nitrogen atoms. .

[0042] Platinum was supported on the obtained N-carbon alloy fine particles by the following method. In order to reduce the supported platinum in advance, a reducing agent consisting of a mixed solution of 3.5 ml of 2-propanol and 40 mg of sodium borohydride was prepared. Then, add 20 ml of distilled water to 53 mg of chloroplatinic acid hexahydrate, then add 0.21 ml of hydrogen peroxide solution to this solution, and irradiate with ultrasonic waves for 10 minutes to prepare a platinum colloid solution. did. This platinum colloid solution was dropped into 0.2 g of the above N-force single Bonalloy fine particles, and the N-carbon alloy fine particles were uniformly dispersed in the platinum colloidal solution by ultrasonic irradiation for 20 minutes. Next, the reducing agent was added dropwise to the dispersion over 20 minutes, followed by stirring for 12 hours. Thereafter, the obtained liquid was filtered through a membrane filter made of hydrophilic polytetrafluoroethylene (PTFE) having an opening diameter of 1.0 μm and separated into solid and liquid. The solid content on the membrane filter was collected and dried at 80 ° C to obtain N-carbon alloy fine particles carrying 10% by weight of platinum.

Saya Yasuhara's e ^ line of doped carbon alloy fine particles (Part 2)

A nitrogen-containing compound, melamine (1.4 g), was mixed with furanyl alcohol (furanyl alcohol precursor, 10 g), and this mixture was heated in an oven at 80 ° C. to obtain a phthalocyanine-containing furan resin. This was heated at a rate of 10 ° CZ from room temperature in a nitrogen atmosphere and kept at 1000 ° C for 1 hour. This carbonized the melamine-containing furan resin. The carbonized product is pulverized with a planetary ball mill to obtain carbon alloy fine particles (hereinafter referred to as “carbon alloy fine particles 2”) having an average particle diameter of 0.1 μm doped with 13.4 atomic% of nitrogen atoms. It was. In the same manner as in Example 1, 10% by weight of platinum was supported on the soot-carbon alloy fine particles 2.

Production example of carbon alloy fine particles doped with boron atoms

Boron trifluoride-methanol complex (204 g), a boron-containing compound, is mixed with furfuryl alcohol (10 g), a furan resin precursor, and the mixture is heated in an oven at 80 ° C. By doing so, a phthalocyanine-containing furan rosin was obtained. This was heated at a rate of 10 ° CZ from room temperature in a nitrogen atmosphere and kept at 1000 ° C for 1 hour. This carbonized the phthalocyanine-containing furan resin. The carbonized product was pulverized with a planetary ball mill to obtain carbon alloy fine particles (hereinafter referred to as “B-carbon alloy fine particles”) having an average particle diameter of 0.1 doped with 14.4 atomic% of boron atoms. In the same manner as in Example 1, 10% by weight of platinum was supported on the B-carbon alloy fine particles.

[0045] <Comparative Example 1>

Comparative carbon fine particles 1 made of furan rosin were obtained in the same manner as in Example 1 except that phthalocyanine as a nitrogen source was not added. The comparative carbon fine particles 1 were loaded with 10% by weight of platinum in the same manner as in Example 1.

ffi Notification of carbon alloy fine particles that have been maharahaya and houmaharahaku by the boundary method

Ά

In 150 ml of methanol solution in which 6 g of furfuryl alcohol is dissolved, 1.5 g of melamine as a nitrogen source and 24 g of BF methanol complex as a boron source are dissolved and stirred for about 10 minutes.

Three

did. Next, this was placed in a stainless steel pressure-resistant container with a PTFE liner, and the container was allowed to stand in an oven maintained at 200 ° C. for 1 hour to polymerize furfuryl alcohol in subcritical methanol.

[0047] The obtained contents were filtered on a hydrophilic PTFE membrane filter having an opening diameter of 1.0 m, and the solvent was distilled off from the passing material to obtain a membrane filter having an opening diameter of 0.45 m. Fine particles were obtained by washing on top. The obtained polymer fine particles were heated from a room temperature at a rate of 10 ° C. Z under a nitrogen atmosphere and kept at a temperature of 1000 ° C. for 1 hour for heat treatment. As a result, polymer fine particles are carbonized, and carbon alloy fine particles (hereinafter referred to as “N, B-carbon alloy fine particles A”) having a submicron particle diameter doped with 4 atomic% nitrogen atoms and 1.2 atomic% boron atoms, respectively. ) In the same manner as in Example 1, 10% by weight of platinum was supported on the N, B-carbon alloy fine particles A.

<Example 5> Example 4 except that 2.3 g of melamine as a nitrogen source and 36 g of BF methanol complex as a boron source were dissolved in 150 ml of a methanol solution in which 6 g of furfuryl alcohol was dissolved.

Three

Similarly, N, B-carbon alloy fine particles B having a particle size of submicron doped with 4 atom% nitrogen atoms and 1.7 atom% boron atoms were obtained. This N, B-carbon alloy fine particle B was loaded with 10% by weight of platinum in the same manner as in Example 1.

The same as Example 4 except that 3 g of melamine as a nitrogen source and 48 g of BF methanol complex as a boron source were dissolved in 150 ml of a methanol solution containing 6 g of furfuryl alcohol.

Three

In this way, N, B-carbon alloy fine particles C having a particle size of submicron doped with 5 atom% nitrogen atoms and 1.4 atom% boron atoms were obtained. The N, B-carbon alloy fine particles C were loaded with 10% by weight of platinum in the same manner as in Example 1.

[0050] <Example 7>

Example 4 is the same as Example 4 except that 4.5 g of melamine as a nitrogen source and 72 g of BF methanol complex as a boron source were dissolved in 150 ml of a methanol solution in which 6 g of furfuryl alcohol was dissolved.

Three

Similarly, N, B-carbon alloy fine particles D having a particle size of submicron doped with 5.4 atomic% nitrogen atoms and 1.4 atomic% boron atoms were obtained. In the same manner as in Example 1, 10% by weight of platinum was supported on the N, B-carbon alloy fine particles D.

Example 4 except that 7.5 g of melamine as a nitrogen source and 121 g of BF methanol complex as a boron source were dissolved in 150 ml of a methanol solution in which 6 g of furfuryl alcohol was dissolved.

Three

In the same manner as above, N, B-carbon alloy fine particles E having a particle size of submicron doped with 12.8 atomic% nitrogen atoms and 2.6 atomic% boron atoms were obtained. In the same manner as in Example 1, 10% by weight of platinum was supported on this N, B-force single Bonalloy fine particle E.

[0052] <Comparative Example 2>

Without adding melamine as a nitrogen source and BF methanol complex as a boron source,

Three

Instead, comparative carbon fine particles 2 made of furan rosin were obtained in the same manner as in Example 4 except that an appropriate amount of hydrochloric acid was added. The comparative carbon fine particles 2 were loaded with 10% by weight of platinum in the same manner as in Example 1. <Example 9>

Example of production of carbon alloy fine particles doped with atoms and boron atoms by thermal synthesis method

Melt 0.8 g of melamine, a nitrogen-containing compound, 13 g of boron trifluoride-methanol complex, a boron-containing compound, and 10 g of furfuryl alcohol, a precursor of furan resin, in lOOg of methanol. By heating in an oven at 80 ° C., phthalocyanine-containing furan sesame was obtained. This was heat-treated by raising the temperature from room temperature at a rate of 10 ° CZ in a nitrogen atmosphere and holding at 1 000 ° C for 1 hour. This carbonized the melamine boron trifluoride-containing furan resin. This carbonized product is pulverized with a planetary ball mill, and carbon alloy fine particles with an average particle size of 0 (hereinafter referred to as “B, N-carbon alloy” doped with 2.7 atomic% of nitrogen atoms and 0.2 atomic% of boron atoms). Fine particles F ”). This N, B-carbon alloy fine particle F was loaded with 10% by weight of platinum in the same manner as in Example 1.

Example 9 except that melamine 2.lg as a nitrogen source and 34g of BF methanol complex as a boron source were dissolved in 100ml of a methanol solution in which 10g of furfuryl alcohol was dissolved.

Three

In the same manner as above, B-carbon alloy fine particles G having an average particle size of 0.1111 doped with 3 atom% nitrogen atoms and 0.6 atom% boron atoms were obtained. In the same manner as in Example 1, 10% by weight of platinum was supported on the N, B-carbon alloy fine particles G.

[Example 11]

Example 9 except that 4.7 g of melamine as a nitrogen source and 76 g of BF methanol complex as a boron source were dissolved in 100 ml of a methanol solution in which 10 g of furfuryl alcohol was dissolved.

Three

In the same way, the average particle diameter of 0.1 111 is doped with 3.2 atomic% of nitrogen atoms and 0.5 atomic% of boron atoms, respectively. ^ B—carbon alloy fine particles H were obtained. In the same manner as in Example 1, 10% by weight of platinum was supported on the N, B-carbon alloy fine particles H.

Except for dissolving 12.7 g of melamine as a nitrogen source and 204 g of BF methanol complex as a boron source in 100 ml of a methanol solution containing 10 g of furfuryl alcohol.

Three

As in Example 9, 9.4 atomic percent nitrogen and 7.4 atomic percent boron Average particle size of 0.1 1 111? ^ B—carbon alloy fine particles I were obtained. The N, B-carbon alloy fine particles I were loaded with 10% by weight of platinum in the same manner as in Example 1.

Example 9 except that 29 g of melamine as a nitrogen source and 460 g of BF methanol complex as a boron source were dissolved in 100 ml of a methanol solution in which 10 g of furfuryl alcohol was dissolved.

Three

In the same way, the average particle size of 0.1 111 is doped with 7.7 atomic% of nitrogen atoms and 10.6 atomic% of boron atoms, respectively. ^ B—carbon alloy fine particles J were obtained. In the same manner as in Example 1, 10% by weight of platinum was supported on the N, B-force single Bonalloy fine particles J.

[0058] <Comparison evaluation 1>

N-carbon alloy particles 1 of Example 1 before carrying platinum, N-carbon alloy particles 2 of Example 2, B-carbon alloy particles of Example 3, N, B-carbon alloy particles A to 4 of Examples 4 to 13, respectively. Elemental ratio and carbonization yield of J, Comparative Carbon Fine Particle 1 of Comparative Example 1 and Comparative Carbon Fine Particle 2 of Comparative Example 2 were determined by X-ray photoelectron spectroscopy (XPS) method. The results are shown in Table 1. The charged atomic ratio indicates the amount of N and B dopants at the time of preparation.

Further, X-ray diffraction was performed on the N, B-carbon alloy fine particles F to J of Examples 9 to 13 and the carbon fine particles 1 of Comparative Example 1. The results are shown in Fig. 1.

[0059] [Table 1]

Charged atomic ratio

Carbonization yield B / N (B + N) / C

C: N: B (%) Example 1 (N-force-horn Py ¾ίΐ1) 13: 2: 0-― 0.16 Example 2 (Ν-force-hona 2) 16: 2: 0 ― 0 0.16 Example 3 (Β-force-honah πi difficulty) 2.7: 0: 1 ― ― ― Example 4 (Ν, Β-kar-honalloy ¾ particle Α) 5.2: 2 : 1 48 0.32 0.060 Example 5 (Ν, Β-Carton Honalloy Fine Particles Β) 9.3: 2: 1 41 0.42 0.066 Example 6 (Ν, Β-Force-Hon Nyung Lung C) 6.5: 2: 1 39 0.28 0.076 Example Ί (Ν, Β-Car-Ho-Han Nya D fine particle) 3.8: 2: 1 39 0.26 0.081 Example 8 (Ν, Β-Car-Ha-Hon han 了難) 2.7: 2: 1 8 0.20 0.220 Example 9 (Ν, Β-Carho ', Nalloy F) 28: 2: 1 ― 0.07 0.033 Example 10 (Ν, Β-Carho, Nya. Fine i-G) 11: 2: 1 ― 0.21 0.041 Example 11 (Ν, Β-Caho'n alloy fine particle Η) 5.4: 2: 1 ― 0.16 0.044 Example 12 (^ _ 8-Car ¾ Particle 1) 2.7: 2: 1 ― 0.79 0.25 Example 13 (Ν, Β-Kaho Naro) J) 1.7: 2: 1 1.38 0.38 Comparative Example 1 (Comparative Car; Fine Particle 1) 1: 0: 0 ― ― Comparative Example 2 (Comparative Coffee ¾ Grain Finish-2) 1: 0: 0 43 As is apparent from Table 1, as a result of X-ray photoelectron spectroscopy (XPS), the N-carbon alloy fine particles obtained in Examples 1 and 2 both contain about 14% nitrogen in consideration of the presence of oxygen. The N, B-carbon alloy fine particles obtained in Examples 4 to 13 were fixed at V: 2 and the atomic ratio of nitrogen and boron in the raw material was fixed at 2: 1. The total dope amount of these N, B carbon alloy fine particles (B + N) ZC varied depending on the charged atomic ratio. The BZN ratio at this time varied depending on the charging ratio. This Thus, it was found that the doping level in the prepared carbon alloy fine particles can be changed by changing the charged atomic ratio.

Also, as shown in Fig. 1, as the content of nitrogen and boron atoms increases, the development of X-ray diffraction lines in the direction of the basal plane of the carbon structure is suppressed, and the introduced elements can interfere with the development of the carbon structure. I was divided.

[0061] <Comparison evaluation 2>

Thunder pole activity test, experiment to oxygen return

N-carbon alloy fine particles 1 of Example 1, N-carbon alloy fine particles 2 of Example 2, B-carbon alloy fine particles of Example 3, and N, B-carbon alloy fine particles A to 4 of Examples 4 to 13 after carrying platinum, respectively. Using J, Comparative Carbon Fine Particle 1 of Comparative Example 1 and Comparative Carbon Fine Particle 2 of Comparative Example 2, an electrode activity test was conducted on these electrode catalysts in order to investigate the redox function.

The electrode activity related to this oxygen reduction was measured using a tripolar rotating electrode cell 1 schematically shown in FIG. Specifically, the working electrode (rotating electrode) 2 in the central part has a polymer insulator around it and an electrode part made of glassy carbon at the central part. A catalyst ink prepared as follows was applied to each of the electrode parts to obtain a working electrode. Reference numeral 3 is a reference electrode (AgZAgCl), and reference numeral 4 is a counter electrode (Pt).

[0062] First, the N-carbon alloy fine particles 1 of Example 1, the N-carbon alloy fine particles 2 of Example 2, the B-carbon alloy fine particles of Example 3, and the N, B of Examples 4 to 13 after carrying platinum, respectively. —Weigh 5 mg each of carbon alloy fine particles A to J, comparative carbon fine particle 1 of comparative example 1 and comparative carbon fine particle 2 of comparative example 2, and add binder (trade name: Nafion, DuPont) solution, water and ethanol to this. Appropriate amounts were added to prepare each catalyst ink. Next, the obtained catalyst ink was sucked with a small amount of pipette, applied to the glassy carbon part (diameter 5 mm) of the rotating electrode device, and dried to prepare a working electrode.

[0063] As the electrolyte solution, a 1M sulfuric acid aqueous solution in which oxygen was dissolved at room temperature was used. The electrode was rotated at a rotational speed 1500 rpm, by sweeping the potential at a sweep rate 0. 5mVs ^_1, Currents were recorded at that time as a function of potential. The results are shown in Figs. Figure 2 shows the current from the N-carbon alloy fine particle 1 of Example 1 and the N-carbon alloy fine particle 2 of Example 2. Each potential curve is shown. Fig. 3 shows the current-potential curves of the B-carbon alloy fine particles of Example 3. FIG. 4 shows the current-potential curves of Examples 4, 5, and 8 with N, B-carbon alloy fine particles A, B, and E, respectively. 2 and FIG. 3 show the current-potential curve of Comparative Carbon Fine Particle 1 of Comparative Example 1 and FIG. 4 shows the current-potential curve of Comparative Carbon Fine Particle 2 of Comparative Example 2 for comparison.

From the results shown in Figs. 2 to 4, it can be seen that in any of the carbon alloy fine particles, the oxygen reduction current starts to flow from a higher potential than that of the comparative carbon alloy fine particles 1 and 2, and when compared at the same potential, a large current density is exhibited. I was divided.

[0064] Fig. 5 shows the element ratio and oxygen reduction obtained from XPS for N, B-carbon alloy fine particles A to E of Examples 4 to 8 and Comparative carbon fine particle 2 of Comparative Example 2 after carrying platinum, respectively. The relationship with the starting potential is shown.

From the results shown in FIG. 5, the N, B-carbon alloy fine particles of Examples 4 to 8 have higher oxygen reduction activity than the comparative carbon fine particles of Comparative Example 2 in which nitrogen atoms and boron atoms are not doped. In addition, among the N, B-carbon alloy fine particles of Examples 4 to 8, it was found that the oxygen reduction activity tends to increase as the doping amount of nitrogen atoms and boron atoms (B + N) ZC increases. In addition, by comparing with NZC and BZC, it was examined which of nitrogen atom and boron atom is involved in oxygen reduction. As shown in Fig. 5 (b) and (c), both elements were compared. The same tendency was observed, and it was found that nitrogen and boron interacted to bring about activity.

[0065] N 1 sX-ray photoelectron spectra and B 1 sX-ray photoelectron spectra of N, B-carbon alloy fine particles A to G of Examples 4 to 10 after carrying platinum are shown in Figs. 6 and 7, respectively. Show. From Fig. 6, each N and B carbon alloy fine particle has two states. When the doping amount of boron and nitrogen atoms is small, the peak on the high bond energy side is dominant, but as the doping amount increases, Nls It was found that the low energy peak of became dominant. In contrast, Fig. 7 shows that all N and B carbon alloy fine particles show a single spectrum, and the binding energy tends to shift to higher side as the doping amount of boron atom and nitrogen atom increases. In other words, it was found that electrons increased in nitrogen atoms and decreased in boron atoms. From this, charcoal It can be said that an active carbon material is given by generating an electrically negative nitrogen atom and an electrically positive boron atom by interaction of a nitrogen atom and a boron atom in an elementary atom.

Production example of ultrafine carbon particles by sol-gel method

First, 2.96 g (29 mmol) of phenol was charged with 4.75 g (57 mmol) of formaldehyde and 0.212 g (2 mmol) of sodium carbonate as a base catalyst, and distilled water was added so that the amount of these substances was 5% by weight. Was added to prepare a 100 ml aqueous solution. The aqueous solution was stirred and then transferred to a screw vial and held at 85 ° C. for 18 hours. As a result, phenol and formaldehyde reacted to form ultrafine polymer particles in the reaction solution. Next, the reaction solution was cooled to liquid nitrogen temperature, frozen and dried to recover ultrafine polymer particles. Further, the polymer ultrafine particles recovered were cured by heating at 200 ° C for 5 hours. The cured ultrafine polymer particles were heated from room temperature at a rate of 10 ° CZ in a nitrogen atmosphere, and carbonized by holding at 1000 ° C for 1 hour to obtain ultrafine carbon particles having an average particle size of 30 nm. . Figure 8 shows a field emission high-resolution scanning electron microscope (FE—SEM) image of these ultrafine carbon particles. In the same manner as in Example 1, 10% by weight of platinum was supported on the ultrafine carbon particles.

Sodium remains in the ultrafine carbon particles obtained in Example 14. In order to remove this, stirring was performed in 6M sulfuric acid. Figure 6 shows a field emission high-resolution scanning electron microscope (FE—SEM) image of this ultrafine carbon particle. The ultrafine carbon particles were loaded with 10% by weight of platinum in the same manner as in Example 1.

[0068] <Comparative Example 3>

Comparative Example 3 was a commercially available platinum-supported catalyst (trade name ETC-10) purchased from ElectroChem, USA. This catalyst is a furnace black made of Vulcan XC-72 Cabot with a carbon substrate carrying 10% by weight of platinum.

[0069] <Comparison evaluation 3>

Carbon ultrafine particles carrying platinum of Example 15, commercially available platinum-supported catalyst of Comparative Example 3 Figure 9 shows the oxygen reduction voltammogram and Fig. 10 shows the cyclic voltammogram. The voltammogram of FIG. 9 was obtained by measuring the carbon substrate carrying platinum of Example 15 and Comparative Example 3 in the same manner as in Comparative Evaluation No. 2. From FIG. 9, the tendency is more pronounced as the oxygen reduction current density increases as a whole, especially as the potential decreases, compared to that in Comparative Example 3 where the carbon substrate carrying the white metal of Example 15 is a commercially available catalyst. There was something to do

[0070] The cyclic voltammogram of Fig. 10 is obtained by applying the carbon substrate carrying platinum of Example 15 and Comparative Example 3 onto a glassy carbon electrode in the same manner as in Comparative Evaluation No. 2, and acting this. The electrode was obtained by measurement under the following conditions. The electrode was immersed in 1M sulfuric acid from which dissolved oxygen had been removed by publishing nitrogen in advance, and a potential scan of 0.2 to 1.3V vs AgZAgCl was performed at a sweep rate of 50mVZs without rotation. The current-potential relationship is plotted. From FIG. 10, it was found that the carbon base material carrying platinum of Example 15 did not show a clear H2 desorption wave than that of Comparative Example 3. That is, it was presumed that Example 15 had a different platinum loading state than that of Comparative Example 3, which caused a difference in the activity of the white metal.

[0071] <Comparison Evaluation 4>

Example 1 of carbon alloy particles doped with nitrogen atoms and 10% by weight of platinum loaded, Example 1 of carbon alloy particles doped with nitrogen atoms and boron atoms and loaded with 10% by weight of platinum Example 12 of platinum alloy particles with platinum loaded Force by 10% by weight supported sol-gel method Comparative Example 1 of carbon substrate supporting 10% by weight of platinum not doped with nitrogen atoms of Example 14 and Example 1 of ultra-one-bonn fine particles, and 10% of platinum A commercial force loaded on a weight percent, and the current density at a potential of 0.6 V vs. AgZAgCl were measured for Comparative Example 3 of one bon black. The results are shown in Table 2.

[0072] [Table 2] Current density (μ A / cm ² -Pt) Example 1 5 7

Example 1 2 1 0 7

Example 1 4 1 9 1 Comparative Example 1 2 0

Comparative Example 3 1 7

As is clear from Table 2, the current density per unit surface area of Example 1, Example 12 and Example 14 was higher than that of Comparative Examples 1 and 3. In particular, the current density of Example 12 doped with both nitrogen and boron atoms was about twice as high as that of Example 1 doped with only nitrogen atoms. Further, when platinum was supported on the ultrafine carbon particles by the sol-gel method of Example 14, a higher current density was obtained.

Industrial applicability

[0074] The polymer electrolyte fuel cell electrode catalyst of the present invention has a highly active oxygen reduction catalytic ability and is used on the power sword side of a fuel cell.

Claims

The scope of the claims

[1] In an electrode catalyst for a fuel cell in which platinum or a platinum alloy is supported on a carbon substrate,

The carbon substrate is a carbon alloy fine particle doped with nitrogen atoms, and the carbon substrate is polymerized by heating and reacting a nitrogen-containing compound and a thermosetting resin precursor, and the nitrogen compound obtained thereby An electrode catalyst for a fuel cell, comprising carbon alloy fine particles obtained by heat-treating and carbonizing a containing thermosetting resin, and finely pulverizing the carbonized thermosetting resin containing a nitrogen compound.

[2] A polymerization step for obtaining a nitrogen compound-containing thermosetting resin by heating and polymerizing a nitrogen-containing compound and a thermosetting resin precursor,

A carbonization step in which the obtained nitrogen compound-containing thermosetting resin is heat treated and carbonized, and the carbonized nitrogen compound-containing thermosetting resin is pulverized to obtain carbon alloy fine particles doped with nitrogen atoms. Obtaining a grinding step;

A method for producing a fuel cell electrode catalyst, comprising: obtaining a carbon substrate by supporting platinum on the carbon alloy fine particles.

[3] It is a nitrogen-containing compound curamine or phthalocyanine, the thermosetting rosin precursor is furfuryl alcohol, and the ratio of the thermosetting rosin precursor to the nitrogen-containing compound is C 3. The fuel cell electrode catalyst according to claim 2, wherein (thermosetting resin precursor (C): nitrogen-containing compound (N)) is 1: (0.0 7-3) at an atomic ratio of: N. Production method.

[4] In a fuel cell electrode catalyst having platinum or a platinum alloy supported on a carbon substrate,

The carbon base material is a carbon alloy fine particle doped with boron atoms, and the carbon base material heat-reacts a boron-containing compound and a thermosetting resin precursor, and boron obtained thereby An electrode catalyst for a fuel cell, comprising carbon alloy fine particles obtained by heat-treating and carbonizing a compound-containing thermosetting resin and finely pulverizing the carbonized boron compound-containing thermosetting resin.

[5] A polymerization step of obtaining a fluorine compound-containing thermosetting resin by heating and polymerizing a boron-containing compound and a thermosetting resin precursor;

A carbonization step of heat-treating and carbonizing the obtained boron compound-containing thermosetting resin, and pulverizing the carbonized boron compound-containing thermosetting resin to dope boron atoms Pulverizing step for obtaining carbon alloy fine particles,

[6] The boron-containing compound is a BF methanol complex or a BF tetrahydrofuran complex, and thermosetting

3 3

The precursor of the curable resin is furan resin or phenol resin, and the compounding ratio of the precursor of the thermosetting resin and the boron-containing compound is C: B (ratio of thermosetting resin) 6. The method for producing an electrode catalyst for a fuel cell according to claim 5, wherein the precursor (C): the boron-containing compound (B) is 1: (0.1-1).

[7] In an electrode catalyst for a fuel cell in which platinum or a platinum alloy is supported on a carbon substrate,

The carbon substrate is a carbon alloy fine particle doped with nitrogen atoms and boron atoms,

Polymer fine particles are obtained by dissolving a nitrogen-containing compound and a boron-containing compound in a methanol solution of furfuryl alcohol or resol-type phenol resin, and performing a polymerization reaction under methanol subcritical or supercritical conditions. After that, an electrode catalyst for a fuel cell, which is a carbon alloy fine particle obtained by heat-treating the obtained polymer fine particle and carbonizing it.

[8] Polymer fine particles are obtained by dissolving a nitrogen-containing compound and a boron-containing compound in a methanol solution of furfuryl alcohol or resol-type phenol resin, and performing a polymerization reaction under methanol subcritical or supercritical conditions. A polymerization step to obtain;

Carbonization step of heat-treating the resulting polymer fine particles to obtain force-bonded alloy fine particles doped with nitrogen atoms and boron atoms;

[9] Nitrogen-containing compound power S-melamine, boron-containing compound is BF methanol complex, and

Three

Furfuryl alcohol or resol-type phenol rosin, melamine and BF methanol complex

Three

The mixing ratio of C: N: B (furfuryl alcohol or resol type phenol resin (C): melamine (N): BF methanol complex (B)) is 1: (0. 04

The method for producing an electrode catalyst for a fuel cell according to claim 8, wherein 3 to 2): (0.02 to 1).

[10] In a fuel cell electrode catalyst in which platinum or a platinum alloy is supported on a carbon base material, the carbon base material reacts by holding an aqueous solution containing phenol, formaldehyde, and a base catalyst at a predetermined temperature for a predetermined time. Solution power Electrocatalyst for fuel cell, characterized in that it is carbon ultrafine particles obtained by carbonizing by heating the recovered and dried polymer ultrafine particles

[11] obtaining a reaction solution by holding an aqueous solution containing phenol, formaldehyde, and a base catalyst at a predetermined temperature for a predetermined time;

Lyophilizing the reaction solution to recover the ultrafine polymer particles;

A carbonization step of carbonizing the polymer ultrafine particles by heating to obtain carbon ultrafine particles;

A process for producing a carbon base material by supporting platinum on the carbon ultrafine particles.

[12] The base catalyst is sodium carbonate, and the weight ratio of phenol, formaldehyde and sodium carbonate (phenol: formaldehyde: sodium carbonate) is 1: (1-2): (0.05-0.2) 12. The method for producing an electrode catalyst for a fuel cell according to claim 11.

[13] A fuel cell having an electrode reaction layer in which the electrode catalyst for a fuel cell according to any one of claims 1, 4, 7, or 10 is formed in layers on one or both surfaces of a solid polymer electrolyte membrane .