JP2006209999A - Electrode for polymer electrolyte fuel cell and its manufacturing method - Google Patents

Electrode for polymer electrolyte fuel cell and its manufacturing method Download PDF

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JP2006209999A
JP2006209999A JP2005016940A JP2005016940A JP2006209999A JP 2006209999 A JP2006209999 A JP 2006209999A JP 2005016940 A JP2005016940 A JP 2005016940A JP 2005016940 A JP2005016940 A JP 2005016940A JP 2006209999 A JP2006209999 A JP 2006209999A
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electrode
carbon material
catalyst metal
cation exchange
exchange resin
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Hiroki Sawada
裕樹 澤田
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GS Yuasa Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultramicro catalyst metal carrying electrode for a polymer electrolyte fuel cell having excellent output characteristics by forming a uniform cation exchange resin film on the surface of a carbon material and to provide its manufacturing method. <P>SOLUTION: In the electrode for the polymer electrolyte fuel cell, a functional group containing oxygen atoms or nitrogen atoms in a range of 0.1-10.0 meq/g is made present on the surface of the carbon material, and catalyst metal is mainly carried on the contact surface between the surface of the carbon material and a proton conducting passage of the cation exchange resin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、固体高分子形燃料電池用電極およびその製造方法に関するものである。   The present invention relates to an electrode for a polymer electrolyte fuel cell and a method for producing the same.

固体高分子形燃料電池（ＰＥＦＣ）は、エネルギー変換効率が高いことおよび環境負荷が低いこととによって、電気自動車用または家庭用コージェネレーションシステム用電源として有力な候補の一つである。ＰＥＦＣに用いられる膜／電極接合体は、アノード、カソードおよびそれらの電極を隔てる陽イオン交換膜で構成され、電極と陽イオン交換膜とを加熱圧着で接合することによって製造される。この接合体を備えた固体高分子形燃料電池は、たとえば、アノ−ドに燃料として水素、カソ−ドに酸化剤として酸素を供給することによって、電力を発生させることができる。   The polymer electrolyte fuel cell (PEFC) is one of the promising candidates as a power source for electric vehicles or household cogeneration systems because of its high energy conversion efficiency and low environmental load. The membrane / electrode assembly used in PEFC is composed of an anode, a cathode, and a cation exchange membrane that separates the electrodes, and is manufactured by joining the electrode and the cation exchange membrane by thermocompression bonding. The polymer electrolyte fuel cell provided with this assembly can generate electric power, for example, by supplying hydrogen as fuel to the anode and oxygen as oxidant to the cathode.

特許文献１には、固体高分子形燃料電池用電極の例として、触媒金属が炭素材料と陽イオン交換樹脂のプロトン伝導経路との接面に選択的に担持された電極が開示されている。この触媒を用いた電極は、超少量触媒金属担持電極といわれており、この電極はつぎの手順で製造する。最初に、炭素材料と高分子電解質の溶液とを混合する。その混合物を電極基材に塗布した後、乾燥して、触媒金属未担持電極を形成する。つぎに、触媒金属未担持電極を触媒金属の陽イオンを含んだ溶液に浸漬し、触媒金属未担持電極に含まれる陽イオン交換樹脂のプロトン伝導経路に陽イオンを吸着させる。最後に、吸着した陽イオンを化学的に還元することによって、触媒金属が陽イオン交換樹脂のプロトン伝導経路と炭素材料の表面との接面に選択的に担持される。   Patent Document 1 discloses an electrode in which a catalytic metal is selectively supported on a contact surface between a carbon material and a proton conduction path of a cation exchange resin as an example of an electrode for a polymer electrolyte fuel cell. An electrode using this catalyst is said to be an ultra-small amount of catalyst metal-supporting electrode, and this electrode is produced by the following procedure. First, a carbon material and a polymer electrolyte solution are mixed. The mixture is applied to an electrode substrate and then dried to form a catalyst metal unsupported electrode. Next, the catalyst metal unsupported electrode is immersed in a solution containing a catalyst metal cation, and the cation is adsorbed on the proton conduction path of the cation exchange resin contained in the catalyst metal unsupported electrode. Finally, the catalytic metal is selectively supported on the contact surface between the proton conduction path of the cation exchange resin and the surface of the carbon material by chemically reducing the adsorbed cation.

また、特許文献２には、電極触媒層を親水性にし、その層を薄膜にすることにより、電極触媒層内の濡れ性を改善し、プロトン移動性を容易にすることで、電極細孔での電極反応を促進させる技術が開示され、特許文献３には、吸水性部材は分子内にスルホン基、カルボキシル基、アンモニウム基等のイオン性基、あるいはカルボニル基、ヒドロキシ基、オキシ基等の極性基を持ち、水はこれらに水素結合する形で、分子間または結晶層間に取り込まれることにより吸収されることが記載されている。   In Patent Document 2, the electrode catalyst layer is made hydrophilic and the layer is made into a thin film to improve the wettability in the electrode catalyst layer and facilitate proton mobility. A technique for accelerating the electrode reaction is disclosed. Patent Document 3 discloses that the water-absorbing member has an ionic group such as a sulfone group, a carboxyl group, and an ammonium group in the molecule, or a polar group such as a carbonyl group, a hydroxy group, and an oxy group. It is described that water is absorbed by being incorporated between molecules or between crystal layers in the form of hydrogen bonds with these groups.

さらに、プロトン伝導性高分子固体電解質の吸水性を高めるために、高分子の成分にアミド系ポリマーを含ませる技術が特許文献４に、高分子に親水性官能基としてのアミノ基を導入する技術が特許文献５に開示されている。また、特許文献６には、アミド基を含むイオン伝導性高分子化合物が開示されている。   Furthermore, in order to increase the water absorption of the proton-conductive polymer solid electrolyte, a technique in which an amide polymer is included in the polymer component is disclosed in Patent Document 4, and an amino group as a hydrophilic functional group is introduced into the polymer. Is disclosed in Patent Document 5. Patent Document 6 discloses an ion conductive polymer compound containing an amide group.

特開２０００−１２０４１号公報JP 2000-12041 A 特開平６−２７５２８２号公報JP-A-6-275282 特開平７−１３４９９２号公報Japanese Patent Laid-Open No. 7-134992 特開平９−０８７３６９号公報JP-A-9-087369 特開２００１−２１６９７３号公報JP 2001-216773 A 特開２００３−００２９７７号公報JP 2003-002977 A

従来の超少量触媒金属担持電極の製造方法では、表面の濡れ性が低い炭素材料や陽イオン交換樹脂との親和性が弱い炭素材料と、陽イオン交換樹脂の溶液とを混合するので、炭素材料の表面に陽イオン交換樹脂が不均一に付着した。そのために、触媒金属（例えば白金）の担持状態が不均一であったので、電極触媒の活性が低くなる。したがって、従来の超少量触媒金属担持電極を備えたＰＥＦＣの出力は低いものであった。   In the conventional method for producing an ultra-small catalyst metal-supported electrode, a carbon material having a low surface wettability or a carbon material having a weak affinity with a cation exchange resin is mixed with a solution of the cation exchange resin. The cation exchange resin adhered unevenly to the surface. For this reason, the catalyst metal (for example, platinum) is not uniformly supported, so that the activity of the electrode catalyst is lowered. Therefore, the output of the PEFC provided with the conventional ultra-small catalyst metal-supporting electrode was low.

また、カルボキシル基やアミノ基等を導入して親水性を高める技術は上記特許文献２〜６に記載のように周知技術であるが、超少量触媒金属担持電極の製造方法において、炭素材料の表面の濡れ性や親和性と触媒金属の担持状態の関係については開示されていない。   In addition, a technique for increasing hydrophilicity by introducing a carboxyl group, an amino group, or the like is a well-known technique as described in Patent Documents 2 to 6, but in the method for producing an ultra-small catalyst metal-supported electrode, the surface of the carbon material is used. The relationship between the wettability and affinity of the catalyst and the supported state of the catalyst metal is not disclosed.

本発明は、炭素材料の表面に親水性の官能基を備えることによって、その表面に形成した陽イオン交換樹脂の被膜の状態を制御できること、また、炭素材料の表面に陽イオン交換樹脂との親和性の高い酸素原子または窒素原子を含む官能基を形成することによって、その表面に陽イオン交換樹脂の被膜を均一に形成することができることを見出したことに基づくものである。   In the present invention, by providing hydrophilic functional groups on the surface of the carbon material, it is possible to control the state of the cation exchange resin coating formed on the surface of the carbon material, and the affinity for the cation exchange resin on the surface of the carbon material. This is based on the finding that a cation exchange resin film can be uniformly formed on the surface of a functional group containing a highly functional oxygen atom or nitrogen atom.

本発明の目的は、炭素材料の表面に均一な陽イオン交換樹脂の被膜を形成することにより、出力特性に優れた、固体高分子形燃料電池用超少量触媒金属担持電極およびその製造方法を提供することにある。   An object of the present invention is to provide an ultra-small amount catalyst metal-supporting electrode for a polymer electrolyte fuel cell having excellent output characteristics by forming a uniform cation exchange resin film on the surface of a carbon material and a method for producing the same. There is to do.

請求項１の発明は、固体高分子形燃料電池用電極において、炭素材料の表面に、０．１ｍｅｑ／ｇ以上１０．０ｍｅｑ／ｇ以下の範囲で、酸素原子または窒素原子を含む官能基を備え、前記炭素材料の表面と陽イオン交換樹脂のプロトン伝導経路との接面に触媒金属が主に担持していることを特徴とする。   According to the first aspect of the present invention, in the polymer electrolyte fuel cell electrode, a functional group containing an oxygen atom or a nitrogen atom is provided on the surface of the carbon material in a range of 0.1 meq / g to 10.0 meq / g. The catalytic metal is mainly supported on the contact surface between the surface of the carbon material and the proton conduction path of the cation exchange resin.

請求項２の発明は、固体高分子形燃料電池用電極の製造方法において、炭素材料の表面に酸素原子または窒素原子を含む官能基を０．１ｍｅｑ／ｇ以上１０．０ｍｅｑ／ｇ以下の範囲で形成する第１の工程と、前記炭素材料を陽イオン交換樹脂の溶液に分散して分散物を得る第２の工程と、前記分散物から溶媒を除去して炭素材料と陽イオン交換樹脂の混合物を得る第３の工程と、前記陽イオン交換樹脂の固定イオンに触媒金属の陽イオンを吸着させる第４の工程と、前記陽イオンを化学的に還元する第５の工程を経ることを特徴とする。   According to a second aspect of the present invention, in the method for producing an electrode for a polymer electrolyte fuel cell, a functional group containing an oxygen atom or a nitrogen atom on the surface of the carbon material is within a range of 0.1 meq / g to 10.0 meq / g. A first step of forming, a second step of dispersing the carbon material in a cation exchange resin solution to obtain a dispersion, and a mixture of the carbon material and the cation exchange resin by removing the solvent from the dispersion. And a fourth step of adsorbing a cation of a catalytic metal to a fixed ion of the cation exchange resin, and a fifth step of chemically reducing the cation. To do.

本発明の固体高分子形燃料電池用電極に用いる炭素材料の表面には、カルボニル基、スルホン酸基あるいはヒドロキシル基などに代表される酸素原子を含む官能基またはアミド基あるいはアミノ基などに代表される窒素原子を含む官能基が０．１ｍｅｑ／ｇ以上１０．０ｍｅｑ／ｇ以下の範囲で備わる。   The surface of the carbon material used for the electrode for the polymer electrolyte fuel cell of the present invention is represented by a functional group containing an oxygen atom represented by a carbonyl group, a sulfonic acid group or a hydroxyl group, an amide group or an amino group. The functional group containing a nitrogen atom is provided in the range of 0.1 meq / g to 10.0 meq / g.

炭素材料の表面に酸素原子を含む官能基がこの範囲で備わることによって、その表面が親水性に変化する。その結果、炭素材料の表面と陽イオン交換樹脂との親和性が増すので、炭素材料の表面に均一な陽イオン交換樹脂の被膜が形成される。   By providing functional groups containing oxygen atoms in this range on the surface of the carbon material, the surface changes to hydrophilic. As a result, the affinity between the surface of the carbon material and the cation exchange resin is increased, so that a uniform cation exchange resin film is formed on the surface of the carbon material.

また、窒素原子を含む官能基に含まれる窒素原子の非共有電子対の存在によって、炭素材料表面は正に帯電する。一方、陽イオン交換樹脂のプロトン伝導経路はスルホン酸基などが存在することによって負に帯電している。その結果、窒素原子を含む官能基を備える炭素材料の表面に陽イオン交換樹脂のプロトン伝導経路が電気的に引き寄せられるので、炭素材料の表面と陽イオン交換樹脂との親和性が増大するので、炭素材料の表面に均一な陽イオン交換樹脂の被膜が形成される。   In addition, the surface of the carbon material is positively charged due to the presence of the lone pair of nitrogen atoms contained in the functional group containing nitrogen atoms. On the other hand, the proton conduction path of the cation exchange resin is negatively charged due to the presence of sulfonic acid groups and the like. As a result, since the proton conduction path of the cation exchange resin is electrically attracted to the surface of the carbon material having a functional group containing a nitrogen atom, the affinity between the surface of the carbon material and the cation exchange resin is increased. A uniform cation exchange resin film is formed on the surface of the carbon material.

炭素材料の表面に均一な陽イオン交換樹脂の被膜が形成されることによって、触媒金属が均一に担持され、超少量触媒金属担持電極の触媒金属の活性が高くなる。さらに、炭素材料の表面を被覆する陽イオン交換樹脂の厚みが減少することによって、陽イオン交換樹脂に含まれるプロトン伝導経路内での水素あるいは酸素の拡散距離が短縮され、そのことで電極反応の進行が促進され、この電極を用いたＰＥＦＣの出力は著しく向上する。   By forming a uniform cation exchange resin film on the surface of the carbon material, the catalyst metal is uniformly supported, and the activity of the catalyst metal of the ultra-small amount of catalyst metal-supporting electrode is increased. Furthermore, by reducing the thickness of the cation exchange resin that coats the surface of the carbon material, the diffusion distance of hydrogen or oxygen in the proton conduction path contained in the cation exchange resin is shortened. Progress is promoted, and the output of PEFC using this electrode is remarkably improved.

本発明による固体高分子形燃料電池用超少量触媒金属担持電極の、陽イオン交換樹脂と接触した炭素材料の表層の状態を示す模式図を図１に示す。比較のために、従来の超少量触媒金属担持電極の場合を図２に示す。   FIG. 1 is a schematic diagram showing the state of the surface layer of the carbon material in contact with the cation exchange resin of the ultra-small catalyst metal-supported electrode for polymer electrolyte fuel cells according to the present invention. For comparison, FIG. 2 shows a conventional ultra-small catalyst metal-supported electrode.

図１および図２において、１１および２１は炭素材料、１２および２２は陽イオン交換樹脂、１３および２３は陽イオン交換樹脂のプロトン伝導経路、１４および２４は陽イオン交換樹脂の骨格部分、１５および２５は電極反応に関与する触媒金属である。   1 and 2, 11 and 21 are carbon materials, 12 and 22 are cation exchange resins, 13 and 23 are proton conduction paths of the cation exchange resins, 14 and 24 are skeleton portions of the cation exchange resins, 15 and 25 is a catalyst metal involved in the electrode reaction.

図１に示す本発明の固体高分子形燃料電池用電極の場合では炭素材料１１の表面には、たとえばカルボニル基、スルホン酸基あるいはヒドロキシル基などの酸素原子を含む官能基またはアミド基あるいはアミノ基などの窒素原子を含む官能基が０．１ｍｅｑ／ｇ以上１０．０ｍｅｑ／ｇ以下の範囲で備わる。   In the case of the polymer electrolyte fuel cell electrode of the present invention shown in FIG. 1, the surface of the carbon material 11 has a functional group containing oxygen atoms such as a carbonyl group, a sulfonic acid group or a hydroxyl group, an amide group or an amino group. And a functional group containing a nitrogen atom such as 0.1 meq / g to 10.0 meq / g.

炭素材料の表面にこれらの官能基が備わることによって、炭素材料の表面と陽イオン交換樹脂のプロトン伝導経路との親和性が増大し、陽イオン交換樹脂１２が炭素材料の表面に均一に付着するので、プロトン伝導経路１３は従来のものよりも均一に分散した状態となる。その結果、プロトン伝導経路１３に吸着された陽イオンが還元されて生成した触媒金属１５も炭素質材料１１の表面の広い範囲に分散された状態となる。   By providing these functional groups on the surface of the carbon material, the affinity between the surface of the carbon material and the proton conduction path of the cation exchange resin is increased, and the cation exchange resin 12 is uniformly attached to the surface of the carbon material. Therefore, the proton conduction path 13 is more uniformly dispersed than the conventional one. As a result, the catalytic metal 15 generated by reduction of the cation adsorbed on the proton conduction path 13 is also dispersed in a wide range on the surface of the carbonaceous material 11.

図２に示す従来に電極の場合では、炭素材料２１の表面に備わる酸素原子を含む官能基や窒素原子を含む官能基が０．１ｍｅｑ／ｇより少ないので、陽イオン交換樹脂との親和性が低い。その結果、陽イオン交換樹脂２２はその表面に不均一に付着する。したがって、プロトン伝導経路２３は不均一に分散するので、触媒金属２５も炭素質材料２１の表面に不均一に分散した状態で担持される。   In the case of the conventional electrode shown in FIG. 2, the functional group containing oxygen atoms and the functional group containing nitrogen atoms provided on the surface of the carbon material 21 are less than 0.1 meq / g, so that the affinity with the cation exchange resin is low. Low. As a result, the cation exchange resin 22 adheres unevenly to the surface. Therefore, since the proton conduction path 23 is dispersed non-uniformly, the catalyst metal 25 is also supported on the surface of the carbonaceous material 21 in a non-uniformly dispersed state.

本発明に用いられる固体高分子形燃料電池用電極では、触媒金属の利用率は著しく高い。なぜならば、この電極の触媒金属は、反応に関与するプロトン、水、水素および酸素が主に移動できるプロトン伝導経路経路と炭素材料の表面との接面に主に担持しているからである。   In the polymer electrolyte fuel cell electrode used in the present invention, the utilization rate of the catalyst metal is remarkably high. This is because the catalytic metal of this electrode is mainly supported on the surface of the carbon material and the proton conduction path through which protons, water, hydrogen and oxygen involved in the reaction can mainly move.

本発明の固体高分子形燃料電池用電極の触媒層において、「触媒金属が炭素材料の表面と陽イオン交換樹脂のプロトン伝導経路との接面に主に担持されている」とは、陽イオン交換樹脂のプロトン伝導経路に接するカーボン粒子表面に担持された触媒金属量が全触媒金属担持量の５０ｗｔ％以上であることを意味する。すなわち、全触媒金属担持量の５０ｗｔ％以上が、電極反応に対して活性な触媒金属であるため、触媒金属の利用率が著しく高くなる。   In the catalyst layer of the polymer electrolyte fuel cell electrode of the present invention, “the catalytic metal is mainly supported on the contact surface between the surface of the carbon material and the proton conduction path of the cation exchange resin” It means that the amount of catalyst metal supported on the surface of carbon particles in contact with the proton conduction path of the exchange resin is 50 wt% or more of the total amount of catalyst metal supported. That is, 50% by weight or more of the total amount of the catalyst metal supported is a catalyst metal active for the electrode reaction, so that the utilization rate of the catalyst metal is remarkably increased.

なお、本発明においては、陽イオン交換樹脂のプロトン伝導経路に接するカーボン粒子表面に担持された触媒金属量の全触媒金属担持量に対する割合は高いほど好ましく、特に８０ｗｔ％を超えていることが好ましい。このようにして、プロトン伝導経路とカーボン粒子との接触面に触媒金属を高率で担持させることによって、電極の高活性化がはかられる。   In the present invention, the ratio of the amount of catalyst metal supported on the surface of the carbon particles in contact with the proton conduction path of the cation exchange resin to the total amount of supported catalyst metal is preferably as high as possible, and more preferably exceeds 80 wt%. . In this way, the electrode is highly activated by supporting the catalytic metal at a high rate on the contact surface between the proton conduction path and the carbon particles.

陽イオン交換樹脂を備えた触媒金属担持カーボン粒子の全触媒金属の量に対するカーボン粒子表面と陽イオン交換樹脂のイオンクラスターとの接面に担持された触媒金属量の割合はつぎの式で定義される。   The ratio of the amount of catalyst metal supported on the surface of the carbon particle surface and the ion cluster of the cation exchange resin to the total amount of catalyst metal supported carbon particles with the cation exchange resin is defined by the following equation: .

Ｒ＝Ｗ１／Ｗ２・・・・・・・・・・・（１）
式（１）では、Ｒが全触媒金属の量に対するカーボン粒子表面と陽イオン交換樹脂のイオンクラスター（プロトン伝導経路）との接面に担持された触媒金属量の割合、Ｗ１がカーボン粒子表面と陽イオン交換樹脂のイオンクラスターとの接面に担持された触媒金属量（単位はg）、Ｗ２が全触媒金属の量（単位はｇ）を示す。Ｗ１とＷ２との値はたとえば以下の方法でそれぞれ得ることができる。 R = W 1 / W 2 (1)
In the formula (1), R is the ratio of the amount of catalyst metal supported on the contact surface between the surface of the carbon particle and the ion cluster (proton conduction path) of the cation exchange resin with respect to the amount of the total catalyst metal, and W 1 is the surface of the carbon particle. The amount of catalytic metal supported on the contact surface between the cation exchange resin and the ion cluster of the cation exchange resin (unit: g), and W 2 indicates the amount of total catalytic metal (unit: g) The values of W 1 and W 2 can be obtained by the following methods, for example.

Ｗ１の値は、陽イオン交換樹脂を備えた触媒金属担持カーボン粒子のすべての触媒金属のうちの、カーボン粒子表面と陽イオン交換樹脂のイオンクラスターとの接面に担持された触媒金属の表面積を測定したのちに、その値をつぎの式に代入することによって得ることができる。 The value of W 1 is the surface area of the catalyst metal supported on the contact surface between the carbon particle surface and the ion cluster of the cation exchange resin among all the catalyst metals of the catalyst metal supported carbon particles provided with the cation exchange resin. Can be obtained by substituting the value into the following equation.

Ｗ１＝Ｓ１（ＷＮ／ＳＮ）・・・・・・・・（２）
式（２）では、Ｓ１がカーボン粒子表面と陽イオン交換樹脂のイオンクラスターとの接面に担持された触媒金属の表面積（単位はｃｍ２）、ＷＮがすべての触媒金属から無作為に選んだＮ個の触媒金属の量の合計（単位はｇ）、ＳＮがすべての触媒金属から無作為に選んだＮ個の触媒金属の表面積の合計（単位はｃｍ２）を示す。Ｓ１は、触媒金属の表面で生じる水素の脱離反応に起因する電荷量を求めて、この電荷量をつぎの式に代入することによって計算することができる。 W 1 = S 1 (W N / S N ) (2)
In the formula (2), S 1 is the surface area (unit: cm 2 ) of the catalytic metal supported on the contact surface between the carbon particle surface and the ion cluster of the cation exchange resin, and W N is randomly derived from all the catalytic metals. The total amount of N selected catalyst metals (unit: g), and S N is the total surface area (unit: cm 2 ) of N catalyst metals randomly selected from all the catalyst metals. S 1 can be calculated by obtaining the amount of charge resulting from the elimination reaction of hydrogen occurring on the surface of the catalyst metal and substituting this amount of charge into the following equation.

Ｓ１＝Ｑ／ａ・・・・・・・・・・・・・（３）
式（３）では、Ｑが水素の脱離反応に起因する電荷量（単位はＣ）、ａが触媒金属の表面１ｃｍ２での水素の脱離反応に起因する電荷量（単位はＣ／ｃｍ２）である。ａの値は、たとえば触媒金属が白金の場合、２１０×１０−６である。 S 1 = Q / a (3)
In the formula (3), Q is the amount of charge resulting from the elimination reaction of hydrogen (unit is C), and a is the amount of charge resulting from the elimination reaction of hydrogen on the surface of the catalyst metal at 1 cm 2 (unit is C / cm). 2 ). The value of a is, for example, 210 × 10 −6 when the catalyst metal is platinum.

電荷量Ｑは、まず、陽イオン交換樹脂を備えた触媒金属担持カーボン粒子を含むシートを製作したのちに、このシートを触媒層として備えた燃料電池を製作し、つぎに、その触媒層を含む電極にアルゴンガスを流しながらその電極電位を０．０５Ｖｖｓ．ＳＨＥから１Ｖｖｓ．ＳＨＥまで２０ｍＶ／ｓｅｃで走査したときに検出されるアノード電流のうち触媒金属表面で水素の脱離反応に起因する電流を時間で積分することによって得ることができる。   For the charge amount Q, first, a sheet including catalytic metal-supported carbon particles including a cation exchange resin is manufactured, then a fuel cell including the sheet as a catalyst layer is manufactured, and then the catalyst layer is included. While flowing argon gas through the electrode, the electrode potential was set to 0.05 Vvs. 1V vs. from SHE. Of the anode current detected when scanning at 20 mV / sec until SHE, the current resulting from the desorption reaction of hydrogen on the catalytic metal surface can be obtained by integrating with time.

つぎに、ＷＮとＳＮとは、無作為に選んだＮ個の触媒金属の粒子半径（ｒ１、ｒ２、・・・ｒＮ）を透過形電子顕微鏡で観察することによってそれぞれ測定したのちに、その粒子半径をつぎの式（４）と式（５）とに代入することによってそれぞれ得ることができる。 Next, W N and S N were measured by observing the particle radii (r 1 , r 2 ,... R N ) of N randomly selected catalytic metals with a transmission electron microscope, respectively. Later, the particle radius can be obtained by substituting the particle radius into the following equations (4) and (5).

Figure 2006209999
Figure 2006209999

Figure 2006209999
Figure 2006209999

これらの式では、ρが触媒金属の密度、Ｎが触媒金属の個数、ｒｋは触媒金属の粒子半径である。なお、Ｎの値は、統計的な有意性を高めるために少なくとも３０以上であることが好ましい。ただし、触媒金属の粒子の大きさのバラツキが少ないときは、Ｎの値が３０より小さくても統計的な優位性は充分に高い。Ｗ２の値は、陽イオン交換樹脂を備えた触媒金属担持カーボン粒子中のすべての触媒金属を王水で抽出したのちに、その王水中の触媒金属量を定量することによって得ることができる。定量にはたとえばＩＣＰ発光分析法を用いることができる。 In these formulas, [rho is the density of the catalytic metal, N is the number of the catalytic metal, r k is the particle radius of the catalytic metal. The value of N is preferably at least 30 in order to increase statistical significance. However, when there is little variation in the size of the catalyst metal particles, the statistical advantage is sufficiently high even if the value of N is smaller than 30. The value of W 2 can be obtained by quantifying the amount of catalyst metal in the aqua regia after extracting all the catalyst metals in the catalyst metal-supported carbon particles provided with the cation exchange resin with aqua regia. For example, ICP emission analysis can be used for quantification.

さらに、本発明の固体高分子形燃料電池用電極を備える固体高分子形燃料電池の出力は、既存の電極を備える場合よりも優れることが研究の結果から明らかになった。その既存の電極は、たとえば、触媒としての白金が担持された炭素材料と陽イオン交換樹脂との混合物を調製したのちに、その混合物を高分子シートに塗布・乾燥したものを高分子電解質膜に接合することによって製作される。しかしながら、既存の電極では、白金の利用率が低いので、多量の白金が必要になる。   Furthermore, it has become clear from research results that the output of the polymer electrolyte fuel cell including the electrode for the polymer electrolyte fuel cell of the present invention is superior to the case where the electrode is provided with an existing electrode. The existing electrode is prepared, for example, by preparing a mixture of a carbon material supporting platinum as a catalyst and a cation exchange resin, and then applying the mixture to a polymer sheet and drying it to form a polymer electrolyte membrane. Manufactured by joining. However, since the utilization rate of platinum is low in the existing electrodes, a large amount of platinum is required.

触媒としての白金の利用率低下の理由をつぎに説明する。既存の電極における、陽イオン交換樹脂と触媒を担持した炭素材料の表面との界面を模式的に図３に示す。図３において、３１は炭素材料、３２は陽イオン交換樹脂、３３は陽イオン交換樹脂のプロトン伝導経路、３４は陽イオン交換樹脂の骨格部分、３５は電極反応に関与する触媒金属、３６は電極反応に対する活性が低い触媒金属、３７は触媒金属が存在しない領域である。   The reason for the decrease in the utilization rate of platinum as a catalyst will be described below. FIG. 3 schematically shows the interface between the cation exchange resin and the surface of the carbon material carrying the catalyst in the existing electrode. In FIG. 3, 31 is a carbon material, 32 is a cation exchange resin, 33 is a proton conduction path of the cation exchange resin, 34 is a skeleton portion of the cation exchange resin, 35 is a catalyst metal involved in the electrode reaction, and 36 is an electrode. A catalytic metal having a low activity for the reaction, 37 is a region where no catalytic metal exists.

炭素材料３１の表面は、陽イオン交換樹脂３２によって被覆している。炭素材料３１の表面と陽イオン交換樹脂３２との界面には、触媒金属３５と触媒金属３６とがランダムに担持している。その触媒金属粒子３５は、炭素材料３１の表面とプロトン伝導経路３３との接面に存在するので、電気化学反応に対する活性が高い。   The surface of the carbon material 31 is covered with a cation exchange resin 32. On the interface between the surface of the carbon material 31 and the cation exchange resin 32, the catalyst metal 35 and the catalyst metal 36 are randomly supported. Since the catalytic metal particles 35 are present on the contact surface between the surface of the carbon material 31 and the proton conduction path 33, the catalytic metal particles 35 are highly active against electrochemical reactions.

一方、触媒金属３６は、炭素材料３１の表面と骨格部分３４との接面に存在するので、電気化学反応に対する活性が低い。したがって、触媒金属３６が存在する既存の電極は、触媒金属の利用率が低いものである。   On the other hand, since the catalyst metal 36 exists on the contact surface between the surface of the carbon material 31 and the skeleton part 34, the activity against the electrochemical reaction is low. Therefore, the existing electrode in which the catalyst metal 36 exists has a low utilization rate of the catalyst metal.

さらに、既存の電極では、炭素材料３１の表面とプロトン伝導経路３３との界面に触媒金属が存在しない領域３７が部分的に形成される。この領域３７は反応に関与しないので、この領域３７が存在することによって、既存の電極の電気化学的な活性が低下する。   Further, in the existing electrode, a region 37 where no catalytic metal exists is partially formed at the interface between the surface of the carbon material 31 and the proton conduction path 33. Since this region 37 is not involved in the reaction, the presence of this region 37 reduces the electrochemical activity of the existing electrode.

触媒金属が担持された炭素材料に酸素原子または窒素原子を含む官能基を形成させた場合は、陽イオン交換樹脂のプロトン伝導経路が触媒金属が存在しない炭素材料表面に接触する可能性が高くなること、および親水処理によって触媒金属が脱落することから、触媒金属が存在しない領域３７が増加する。このことから触媒金属が担持された炭素材料に親水処理を施した場合では、その材料を用いた電極を備えたＰＥＦＣの出力は、本発明のものと比べて著しく低いものであった。   When a functional group containing an oxygen atom or a nitrogen atom is formed on a carbon material on which a catalytic metal is supported, there is a high possibility that the proton conduction path of the cation exchange resin will come into contact with the surface of the carbon material where the catalytic metal does not exist. In addition, since the catalytic metal is dropped due to the hydrophilic treatment, the region 37 where the catalytic metal does not exist increases. Therefore, when the carbon material carrying the catalyst metal was subjected to a hydrophilic treatment, the output of the PEFC provided with an electrode using the material was significantly lower than that of the present invention.

本発明の電極に用いる炭素材料１１としては、とくに限定されず、ファーネスブラック、アセチレンブラック、ランプブラック、サーマルブラック、チャンネルブラックなどのカーボンブラックを用いることができる。炭素材料は、触媒金属の陽イオンを含んだ化合物の還元に対して高い活性を示すものが好ましく、たとえば、デンカブラック、バルカンＸＣ−７２、ケッチェンブラックＥＣ、ブラックパール２０００等のカーボンブラックが好ましい。   The carbon material 11 used for the electrode of the present invention is not particularly limited, and carbon black such as furnace black, acetylene black, lamp black, thermal black, and channel black can be used. The carbon material is preferably one exhibiting high activity for reduction of a compound containing a cation of a catalytic metal. For example, carbon black such as Denka Black, Vulcan XC-72, Ketjen Black EC, Black Pearl 2000, etc. is preferable. .

炭素材料１１の表面には、陽イオン交換樹脂１２を均一に付着させるために０．１ｍｅｑ／ｇ以上１０．０ｍｅｑ／ｇ以下の範囲で酸素原子または窒素原子を含む官能基を形成している。これらの官能基の種類は、カルボニル基、スルホン酸基あるいはヒドロキシル基などの酸素原子を含む官能基またはアミド基あるいはアミノ基などの窒素原子を含む官能基などである。   On the surface of the carbon material 11, functional groups containing oxygen atoms or nitrogen atoms are formed in the range of 0.1 meq / g or more and 10.0 meq / g or less in order to uniformly attach the cation exchange resin 12. The types of these functional groups include functional groups containing oxygen atoms such as carbonyl groups, sulfonic acid groups or hydroxyl groups, or functional groups containing nitrogen atoms such as amide groups or amino groups.

それらの官能基を形成させた炭素材料の表面と陽イオン交換樹脂との親和性は非常に高くなるので、炭素材料の表面に広くかつ均一に陽イオン交換樹脂を被覆させることができる。したがって、炭素材料の表面と陽イオン交換樹脂のプロトン伝導経路との接面に触媒金属を均一かつ高分散に担持することができる。   Since the affinity between the surface of the carbon material on which these functional groups are formed and the cation exchange resin is extremely high, the surface of the carbon material can be coated with the cation exchange resin widely and uniformly. Therefore, the catalyst metal can be supported uniformly and highly dispersed on the contact surface between the surface of the carbon material and the proton conduction path of the cation exchange resin.

従来のように、酸素原子または窒素原子を含む官能基の量が０．１ｍｅｑ／ｇ未満の場合では、炭素材料の表面と陽イオン交換樹脂との親和性が低いので、炭素材料表面に陽イオン交換樹脂が均一に付着することができない。その結果、触媒金属を均一かつ高分散に担持することができない。   Conventionally, when the amount of functional groups containing oxygen atoms or nitrogen atoms is less than 0.1 meq / g, the affinity between the surface of the carbon material and the cation exchange resin is low. Exchange resin cannot adhere uniformly. As a result, the catalyst metal cannot be supported uniformly and highly dispersed.

一方、それらの官能基の量が１０．０ｍｅｑ／ｇより大きい場合では、後述の官能基を形成する工程で炭素材料を強い酸化剤や反応性の大きい薬品で処理するので、炭素材料が損壊する。その結果、電極内の電子伝導経路が断絶するので、固体高分子形燃料電池の出力が著しく低下する。   On the other hand, when the amount of these functional groups is larger than 10.0 meq / g, the carbon material is damaged because the carbon material is treated with a strong oxidizing agent or a highly reactive chemical in the step of forming the functional group described later. . As a result, since the electron conduction path in the electrode is interrupted, the output of the polymer electrolyte fuel cell is significantly reduced.

酸素原子または窒素原子を含む官能基の量を測定する方法は、特に限定されないが、昇温脱離ガス分析装置を用いて定量する方法が好ましい。その方法は、例えばつぎのとおりである。最初に１×１０−７Ｐａ以下の真空内で炭素材料を赤外線ランプで加熱する。つぎに、脱離するガス成分の質量スペクトルから官能基を定量する。この親水性の官能基を定性する方法は、前述の昇温脱離ガス分析装置あるいは赤外吸収スペクトルから求めるのが好ましい。 A method for measuring the amount of the functional group containing an oxygen atom or a nitrogen atom is not particularly limited, but a method of quantifying using a temperature programmed desorption gas analyzer is preferable. The method is as follows, for example. First, the carbon material is heated with an infrared lamp in a vacuum of 1 × 10 −7 Pa or less. Next, the functional group is quantified from the mass spectrum of the desorbed gas component. The method for qualifying the hydrophilic functional group is preferably obtained from the above-described temperature-programmed desorption gas analyzer or infrared absorption spectrum.

本発明の固体高分子形燃料電池用電極において、１２の陽イオン交換樹脂にはパーフルオロスルホン酸樹脂あるいはスチレンージビニルベンゼンスルホン酸樹脂などが好ましい。陽イオン交換樹脂の側鎖の末端では、スルホン酸基などの陽イオン交換基が備わる。プロトン伝導経路１３は、複数の陽イオン交換基が水とともに集合して形成されており、プロトン、酸素あるいは水素はプロトン伝導経路を移動することができる。したがって、プロトン伝導経路と炭素材料との接する面に存在する触媒金属は電極反応に対して活性が高い。   In the polymer electrolyte fuel cell electrode of the present invention, the 12 cation exchange resins are preferably perfluorosulfonic acid resin or styrene-divinylbenzenesulfonic acid resin. A cation exchange group such as a sulfonic acid group is provided at the end of the side chain of the cation exchange resin. The proton conduction path 13 is formed by aggregating a plurality of cation exchange groups together with water, and protons, oxygen, or hydrogen can move through the proton conduction path. Therefore, the catalytic metal present on the surface where the proton conduction path and the carbon material are in contact has high activity for the electrode reaction.

主鎖部分は分子間力により集合することによって骨格部分１４を形成する。骨格部分では、対イオン、酸素あるいは水素は移動することが困難なので、電極反応に対する活性は低い。   The main chain portion forms a skeleton portion 14 by being assembled by intermolecular force. In the skeletal portion, the counter ion, oxygen or hydrogen is difficult to move, so the activity for the electrode reaction is low.

１５の触媒金属には、電気化学的な酸素の還元反応、水素の酸化反応に対する触媒活性が高いので、白金、ロジウム、ルテニウム、イリジウム、パラジウム、オスニウムなどの白金族金属が好ましい。特に白金とルテニウムとを含む合金は、高い耐ＣＯ被毒性が期待できるのでアノードの触媒として好ましい。さらに、マグネシウム、アルミニウム、バナジウム、クロム、マンガン、鉄、コバルト、ニッケル、銅、亜鉛、銀またはタングステンとからなる群より選ばれた少なくとも一つの元素と白金族金属とを含む合金を触媒金属に用いることによって、白金族金属使用量の低減、耐ＣＯ被毒性の向上および酸素の還元反応に対する高い活性が期待できる。   The 15 catalyst metals are preferably platinum group metals such as platinum, rhodium, ruthenium, iridium, palladium, and osnium because they have high catalytic activity for electrochemical oxygen reduction reaction and hydrogen oxidation reaction. In particular, an alloy containing platinum and ruthenium is preferable as an anode catalyst because high CO poisoning resistance can be expected. Furthermore, an alloy containing at least one element selected from the group consisting of magnesium, aluminum, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, silver, or tungsten and a platinum group metal is used as the catalyst metal. Thus, a reduction in the amount of platinum group metal used, an improvement in CO poisoning resistance, and a high activity for oxygen reduction reaction can be expected.

本発明の電極に含まれる触媒金属は、粒子径が３．０ｎｍ以下の粒子状、とくに０．５ｎｍ以上２．０ｎｍ以下の粒子状であることおよびその量が０．１ｍｇ／ｃｍ２以下、とくに白金族金属量が０．０５ｍｇ／ｃｍ２以下であることは単位重量あたりの触媒活性が高いことから好ましい。 The catalyst metal contained in the electrode of the present invention is in the form of particles having a particle size of 3.0 nm or less, particularly 0.5 nm to 2.0 nm, and the amount thereof is 0.1 mg / cm 2 or less. A platinum group metal amount of 0.05 mg / cm 2 or less is preferable because of high catalytic activity per unit weight.

炭素材料表面と陽イオン交換樹脂との界面の面積を評価する方法は、触媒金属未担持電極の０．４Ｖｖｓ．ＲＨＥでの電気二重層容量で評価する方法が好ましい。０．４Ｖｖｓ．ＲＨＥでは、炭素材料表面の官能基の反応が電流密度におよぼす影響が少ないため、０．４Ｖｖｓ．ＲＨＥでの電流密度はほぼ電気二重層容量に比例する。電気二重層容量は炭素材料と陽イオン交換樹脂との界面の面積と比例関係にあると報告されているので、電気二重層容量は界面の面積を比較する指標となる（城間純，五百蔵勉，藤原直子，西村靖雄，安田和明，笹倉丈博，東正志，Ｊ．Ｈｉｇｈｆｉｅｌｄ，第7回燃料電池シンポジウム予稿集，ｐ．９３（２０００）、Ｚ．Ｓｉｒｏｍａ，Ｔ．Ｓａｓａｋｕｒａ，Ｋ．Ｙａｓｕｄａ，Ｍ．Ａｚｕｍａ ａｎｄ Ｙ．Ｍｉｙａｚａｋｉ，Ｊ．Ｅｌｅｃｔｒｏａｎａｌ．Ｃｈｅｍ．，５４６，７３（２００３））。 A method for evaluating the area of the interface between the carbon material surface and the cation exchange resin is as follows: 0.4 Vvs. A method of evaluating by electric double layer capacity in RHE is preferable. 0.4Vvs. In RHE, since the reaction of the functional group on the surface of the carbon material has little influence on the current density, 0.4 Vvs. The current density at RHE is approximately proportional to the electric double layer capacity. Since the electric double layer capacity is reported to be proportional to the area of the interface between the carbon material and the cation exchange resin, the electric double layer capacity is an index for comparing the area of the interface (Jun Jouma, Tsutomu Hyakuzo, Naoko Fujiwara, Ikuo Nishimura, Kazuaki Yasuda, Takehiro Sasakura, Masashi Higashi, J. Highfield, Proceedings of the 7th Fuel Cell Symposium, p. 93 (2000), Z. Siroma, T. Sasakura, K. Yasuda, M. et al. Azuma and Y. Miyazaki, J. Electroanal. Chem., 546 , 73 (2003)).

電気二重層容量の測定方法は、例えばつぎのとおりである。最初に、作用極として触媒金属未担持電極と、対極として白金担持電極を陽イオン交換膜に加熱圧接することによって膜／電極接合体を作製する。この膜／電極接合体を用いて単セルを作製した後、作用極の電位を０．０５Ｖｖｓ．ＲＨＥから１．００Ｖｖｓ．ＲＨＥまでの範囲を１００ｍＶ／ｓで走査する。この時、作用極側にはＮ２ガス、対極側にはＨ２ガスをそれぞれ加湿温度２５℃で供給する。この測定で得られたサイクリックボルタモグラムの０．４Ｖｖｓ．ＲＨＥの電流密度を式（６）に代入することによって、電気二重層容量を算出する。この値は、触媒層（作用極）の重量で除することにより規格化する。式（６）の記号はそれぞれＣ：電気二重層容量（単位、Ｆ／ｃｍ２、ｊ０．４Ｖ）：０．４Ｖｖｓ．ＲＨＥにおける電流密度（単位、Ａ／ｃｍ２）、ｖ：掃引速度（単位、Ｖ／ｓ）である。 The measurement method of the electric double layer capacity is, for example, as follows. First, a membrane / electrode assembly is fabricated by heat-pressing a catalytic metal unsupported electrode as a working electrode and a platinum supported electrode as a counter electrode to a cation exchange membrane. After producing a single cell using this membrane / electrode assembly, the potential of the working electrode was set to 0.05 Vvs. 1.00 V vs. RHE. The range up to RHE is scanned at 100 mV / s. At this time, N 2 gas is supplied to the working electrode side and H 2 gas is supplied to the counter electrode side at a humidification temperature of 25 ° C., respectively. The cyclic voltammogram obtained by this measurement has 0.4 Vvs. The electric double layer capacity is calculated by substituting the RHE current density into equation (6). This value is normalized by dividing by the weight of the catalyst layer (working electrode). Symbols in the formula (6) are respectively C: electric double layer capacity (unit, F / cm 2 , j 0.4 V ): 0.4 V vs. Current density in RHE (unit, A / cm 2 ), v: sweep rate (unit, V / s).

Ｃ＝（ｊ０．４Ｖ／ｖ）・・・・・・・・・（６）
本発明に用いられる固体高分子形燃料電池用超少量触媒金属担持電極は、炭素材料に酸素原子または窒素原子を含む官能基を備えた後、炭素材料と陽イオン交換樹脂との混合物をシート状に形成した触媒金属未担持電極に触媒金属を担持する方法、あるいは、炭素材料に酸素原子または窒素原子を含む官能基を備えた後、炭素材料と陽イオン交換樹脂との混合物を粉末状にした触媒金属未担持粉末に触媒金属を担持し、この粉末をシート状に形成する方法で製造することができる。 C = (j 0.4V / v) (6)
The ultra-small catalyst metal-supported electrode for a polymer electrolyte fuel cell used in the present invention has a functional group containing an oxygen atom or a nitrogen atom in a carbon material, and then a mixture of the carbon material and a cation exchange resin in a sheet form. A method of supporting a catalyst metal on the catalyst metal non-supported electrode formed in the above, or after providing the carbon material with a functional group containing an oxygen atom or a nitrogen atom, the mixture of the carbon material and the cation exchange resin is powdered It can be produced by a method in which a catalyst metal is supported on a catalyst metal non-supported powder and this powder is formed into a sheet.

つぎに、触媒金属未担持電極および触媒金属未担持粉末のそれぞれの製造方法について説明する。触媒金属未担持電極の具体的な製造方法はつぎのとおりである。   Next, respective methods for producing the catalyst metal unsupported electrode and the catalyst metal unsupported powder will be described. A specific method for producing the catalyst metal unsupported electrode is as follows.

第１の工程では、炭素材料を化学処理することによってその表面に酸素原子を含む官能基を備える。炭素材料を化学処理させる方法は特に限定されないが、例えばオゾン水、硫酸水溶液、過酸化水素水、硝酸水溶液、シュウ酸水溶液、塩酸水溶液、酢酸水溶液あるいは過マンガン酸カリウム水溶液などの酸性溶液に浸漬して酸化させる方法、酸素ガス、オゾンガスなどの酸化性ガスに接触させて酸化させる方法、あるいはプラズマを照射して酸化させる方法などを用いることができる。   In the first step, a functional group containing oxygen atoms is provided on the surface of the carbon material by chemical treatment. The method for chemically treating the carbon material is not particularly limited. For example, the carbon material is immersed in an acidic solution such as ozone water, sulfuric acid aqueous solution, hydrogen peroxide water, nitric acid aqueous solution, oxalic acid aqueous solution, hydrochloric acid aqueous solution, acetic acid aqueous solution or potassium permanganate aqueous solution. The method of oxidizing by oxidizing, the method of oxidizing by contacting with oxidizing gas, such as oxygen gas and ozone gas, or the method of oxidizing by irradiating with plasma can be used.

オゾン水、硫酸水溶液、過酸化水素水、硝酸水溶液、シュウ酸水溶液、塩酸水溶液、酢酸水溶液あるいは過マンガン酸カリウム水溶液などの酸性溶液は単独あるいは２種類以上混合して用いてもよい。酸化剤の水溶液の濃度は０．０１ｍｏｌ／ｌ以上、１０ｍｏｌ／ｌ以下であることが好ましい。濃度が０．０１ｍｏｌ／ｌ未満の場合は、炭素材料表面の酸化反応が遅いことによって酸素原子を含む官能基が備わりにくく、逆に１０ｍｏｌ／ｌより大きい場合は酸化反応が著しく速いため炭素材料の構造が破壊される。   Acidic solutions such as ozone water, sulfuric acid aqueous solution, hydrogen peroxide aqueous solution, nitric acid aqueous solution, oxalic acid aqueous solution, hydrochloric acid aqueous solution, acetic acid aqueous solution or potassium permanganate aqueous solution may be used alone or in combination of two or more. The concentration of the oxidizing agent aqueous solution is preferably 0.01 mol / l or more and 10 mol / l or less. When the concentration is less than 0.01 mol / l, the oxidation reaction on the surface of the carbon material is slow, so that it is difficult to provide a functional group containing an oxygen atom. Conversely, when the concentration is greater than 10 mol / l, the oxidation reaction is remarkably fast. The structure is destroyed.

溶液と炭素材料とを分離する方法は、特に限定されず、一般の遠心分離機、吸引式の濾過器あるいは加圧式の濾過器を用いることができる。酸化剤の水溶液を用いて炭素材料を酸化した後、脱イオン水で洗浄することが好ましい。洗浄しない場合は、炭素材料内に酸化剤が付着しているので、陽イオン交換樹脂あるいは固体高分子形燃料電池の部材を腐食させるので好ましくない。   A method for separating the solution and the carbon material is not particularly limited, and a general centrifugal separator, a suction filter, or a pressure filter can be used. It is preferable that the carbon material is oxidized using an aqueous solution of an oxidizing agent and then washed with deionized water. If not washed, the oxidant is adhered in the carbon material, which is not preferable because the member of the cation exchange resin or the polymer electrolyte fuel cell is corroded.

酸素ガス、オゾンガスなどの酸化性ガスは窒素、アルゴンあるいはヘリウム等の不活性ガスで希釈したものでも良い。混合比は、酸化性ガスと不活性ガスとの容積比で１：１の割合より酸化性ガスの割合が多い方が好ましい。酸化性ガスと不活性ガスとの容積比が１：１の割合より酸化性ガスの割合が少ない場合は炭素材料表面の酸化が進行しにくい。   The oxidizing gas such as oxygen gas or ozone gas may be diluted with an inert gas such as nitrogen, argon or helium. The mixing ratio is preferably such that the ratio of the oxidizing gas is larger than the ratio of 1: 1 by the volume ratio of the oxidizing gas and the inert gas. When the volume ratio of the oxidizing gas to the inert gas is less than the ratio of 1: 1, the oxidation of the carbon material surface is difficult to proceed.

プラズマを照射する方法は、特に限定されないが、常温常圧の空気中で放電するコロナ放電処理装置を用いることが簡便であることから好ましい。   The method of irradiating plasma is not particularly limited, but it is preferable to use a corona discharge treatment apparatus that discharges in air at normal temperature and pressure.

炭素材料の表面に窒素原子を含む官能基を形成する方法は特に限定されない。アミド基を形成させる方法は、例えば炭素材料にカルボニル基を形成した後、カルボニル基とアンモニアとを反応させる方法を用いることができる。炭素材料にカルボニル基を形成する方法は、上記の方法と同じである。   The method for forming a functional group containing a nitrogen atom on the surface of the carbon material is not particularly limited. As a method of forming an amide group, for example, a method of reacting a carbonyl group and ammonia after forming a carbonyl group on a carbon material can be used. The method for forming a carbonyl group in the carbon material is the same as that described above.

カルボニル基をアミド基へ変換させる方法はつぎのとおりである。カルボニル基からアミド基へは、カルボニル基とアンモニアとの付加−脱離反応によって進行する。この反応は、カルボニル基を備えた炭素材料とアンモニア水溶液とを混合する方法、あるいはその材料にアンモニアガスを接触させる方法を用いることができる。   The method for converting a carbonyl group to an amide group is as follows. From the carbonyl group to the amide group proceeds by an addition-elimination reaction between the carbonyl group and ammonia. In this reaction, a method of mixing a carbon material having a carbonyl group and an aqueous ammonia solution, or a method of bringing ammonia gas into contact with the material can be used.

アンモニア水溶液の濃度は、１．０×１０−４ｍｏｌ／ｌ以上であること、さらにこの水溶液には炭素材料に形成されているカルボニル基の量以上のアンモニアが含まれていることが好ましい。この濃度よりも低い場合は、付加−脱離反応が遅いことによってアミド基が形成しにくい。 It is preferable that the concentration of the aqueous ammonia solution is 1.0 × 10 −4 mol / l or more, and that the aqueous solution contains more ammonia than the amount of carbonyl groups formed in the carbon material. When the concentration is lower than this concentration, an amide group is hardly formed due to a slow addition-elimination reaction.

アンモニアガスは、窒素、アルゴンあるいはヘリウム等の不活性ガスで希釈したものでもよい。この時の混合比は、アンモニアガスと不活性ガスとの容積比で１：１の割合よりアンモニアガスの割合が多い方が好ましい。アンモニアガスと不活性ガスとの容積比が１：１の割合よりアンモニアガスの割合が少ない場合では、付加−脱離反応が遅いことによってアミド基が形成しにくい。   The ammonia gas may be diluted with an inert gas such as nitrogen, argon or helium. The mixing ratio at this time is preferably such that the ratio of ammonia gas is larger than the ratio of 1: 1 by volume ratio of ammonia gas to inert gas. When the volume ratio of ammonia gas to inert gas is less than the ratio of 1: 1, the addition-elimination reaction is slow and amide groups are difficult to form.

アミノ基は、炭素材料にニトロ基を付与した後、ニトロ基を還元することによって形成する方法、あるいはハロゲン元素を炭素材料に導入した後、アンモニアと反応させることによって形成する方法を用いることができる。   The amino group can be formed by adding a nitro group to the carbon material and then reducing the nitro group, or by introducing a halogen element into the carbon material and then reacting with ammonia. .

ニトロ基からアミノ基を形成する方法はつぎのとおりである。ニトロ基の形成は、例えば濃硝酸と濃硫酸との混合液あるいは濃硝酸によってニトロ化する方法を用いることができる。濃硝酸と濃硫酸との混合液あるいは濃硝酸のそれぞれの濃度は５．０ｍｏｌ／ｌ以上であることが好ましい。濃度が５．０ｍｏｌ／ｌ未満の場合は、炭素材料表面のニトロ化反応が遅いことによってニトロ基が備わりにくい。   A method for forming an amino group from a nitro group is as follows. The nitro group can be formed by, for example, using a mixed solution of concentrated nitric acid and concentrated sulfuric acid or a method of nitration with concentrated nitric acid. The concentration of concentrated nitric acid and concentrated sulfuric acid or each concentration of concentrated nitric acid is preferably 5.0 mol / l or more. When the concentration is less than 5.0 mol / l, a nitro group is hardly provided due to a slow nitration reaction on the surface of the carbon material.

ニトロ基からアミノ基へ還元するには、たとえば鉄と塩酸との混合物を用いることができる。鉄の代わりに亜鉛あるいは錫等、ニトロ基からアミノ基への還元反応に対して活性が高いものを用いることができる。これらの金属は単独あるいは混合しても用いることができる。   For reduction from a nitro group to an amino group, for example, a mixture of iron and hydrochloric acid can be used. Instead of iron, one having high activity for the reduction reaction from a nitro group to an amino group, such as zinc or tin, can be used. These metals can be used alone or in combination.

混合溶液に含まれる金属および塩酸の濃度は、それぞれ１．０×１０−４ｍｏｌ／ｌおよび１．０ｍｏｌ／ｌ以上であること、さらにそれらの量は炭素材料に形成されているニトロ基の量より多い方が好ましい。これらの濃度よりも小さい場合は、還元反応が遅いことによってアミノ基が備わりにくい。この反応で用いた金属は、後述の触媒金属の吸着工程の前に触媒金属未担持電極を硫酸あるいは硝酸等の酸化剤水溶液で洗浄することによって取り除くことができる。 The concentration of the metal and hydrochloric acid contained in the mixed solution is 1.0 × 10 −4 mol / l and 1.0 mol / l or more, respectively, and the amount thereof is the amount of nitro groups formed in the carbon material. More is preferable. When the concentration is lower than these concentrations, the amino group is hardly provided due to the slow reduction reaction. The metal used in this reaction can be removed by washing the catalyst metal unsupported electrode with an aqueous oxidizing agent such as sulfuric acid or nitric acid before the catalytic metal adsorption step described later.

ハロゲン元素を導入したのちにアンモニアと反応させることによってアミノ基を形成させる方法はつぎのとおりである。ハロゲン元素を炭素材料に導入する方法は、たとえば臭素水、塩酸あるいはヨウ素水と炭素材料を混合する方法あるいは炭素材料に臭素ガス、塩素ガスあるいはヨウ素ガスを接触させる方法を用いることができる。   A method for forming an amino group by reacting with ammonia after introducing a halogen element is as follows. As a method for introducing the halogen element into the carbon material, for example, a method of mixing bromine water, hydrochloric acid or iodine water and the carbon material, or a method of bringing the carbon material into contact with bromine gas, chlorine gas or iodine gas can be used.

臭素水，塩酸あるいはヨウ素水を用いる場合は、それらの濃度が０．０１ｍｏｌ／ｌ以上であることが好ましい。その濃度が０．０１ｍｏｌ／ｌ未満の場合は、炭素材料表面のハロゲン化反応が遅いことによってハロゲン元素が導入しにくい。   When bromine water, hydrochloric acid or iodine water is used, the concentration is preferably 0.01 mol / l or more. When the concentration is less than 0.01 mol / l, the halogen element is difficult to be introduced due to the slow halogenation reaction on the surface of the carbon material.

臭素ガス、塩素ガスあるいはヨウ素ガスなどのハロゲンガスを用いる場合は、アルゴンあるいはヘリウム等の不活性ガスで希釈したものでもよい。その時の混合比は、ハロゲンガス と不活性ガスとの容積比で１：１の割合よりハロゲンガスの割合が多い方が好ましい。ハロゲンガスと不活性ガスとの容積比が１：１の割合より酸化性ガスの割合が少ない場合では、炭素材料表面のハロゲン化が進行しにくい。   When a halogen gas such as bromine gas, chlorine gas or iodine gas is used, it may be diluted with an inert gas such as argon or helium. The mixing ratio at that time is preferably such that the proportion of halogen gas is larger than the proportion of 1: 1 by the volume ratio of halogen gas to inert gas. When the volume ratio of the halogen gas to the inert gas is less than the ratio of 1: 1, the halogenation of the carbon material surface is difficult to proceed.

ハロゲンガスと炭素材料を接触させる際には、反応を促進させるために加熱あるいは紫外線を照射しても良い。ハロゲン元素からアミノ基に置換する方法は、たとえばハロゲン元素が導入された炭素材料とアンモニア水溶液とを混合する方法あるいはその材料にアンモニアガスを接触させる方法を用いることができる。   When the halogen gas is brought into contact with the carbon material, heating or ultraviolet irradiation may be performed to promote the reaction. As a method of substituting an amino group with a halogen element, for example, a method of mixing a carbon material into which a halogen element is introduced and an aqueous ammonia solution, or a method of bringing ammonia gas into contact with the material can be used.

アンモニア水溶液の濃度は、１．０×１０−４ｍｏｌ／ｌ以上であること、さらに炭素材料に導入されているハロゲン元素の量より多い方が好ましい。この濃度よりも小さい場合は、アミノ基への置換反応が遅いことによってアミノ基が備わりにくい。 The concentration of the aqueous ammonia solution is preferably 1.0 × 10 −4 mol / l or more, and more preferably than the amount of the halogen element introduced into the carbon material. If the concentration is lower than this concentration, the amino group is hardly provided due to the slow substitution reaction with the amino group.

アンモニアガスは、窒素、アルゴンあるいはヘリウム等の不活性ガスで希釈したものでも良い。その時の混合比は、アンモニアガスと不活性ガスとの容積比で１：１の割合よりアンモニアガスの割合が多い方が好ましい。アンモニアガスと不活性ガスとの容積比が１：１の割合よりアンモニアガスの割合が少ない場合では、炭素材料表面へのアミノ基の導入が進行しにくい。
第２の工程では、第１の工程で得られた酸素原子または窒素原子を含む官能基を０．１ｍｅｑ／ｇ以上１０．０ｍｅｑ／ｇの範囲で備えた炭素材料を、陽イオン交換樹脂の溶液に分散して、分散物とする。 The ammonia gas may be diluted with an inert gas such as nitrogen, argon or helium. The mixing ratio at that time is preferably such that the ratio of ammonia gas is larger than the ratio of 1: 1 by volume ratio of ammonia gas to inert gas. When the volume ratio of ammonia gas to inert gas is less than the ratio of 1: 1, introduction of amino groups on the carbon material surface is difficult to proceed.
In the second step, a carbon material provided with the functional group containing the oxygen atom or nitrogen atom obtained in the first step in a range of 0.1 meq / g to 10.0 meq / g is used as a cation exchange resin solution. To give a dispersion.

第３の工程では、第２の工程で得られた分散物を電極基材に塗布することによってシート状に形成し、このシート状分散物を乾燥し、分散物に含まれる溶媒を除去することによって、炭素材料と陽イオン交換樹脂の混合物からなる触媒金属未担持電極を形成する。電極基材はとくに限定されず、ポリテトラフルオロエチレン（ＰＴＦＥ）あるいはポリエチレンテレフタレート（ＰＥＴ）等の高分子シート、あるいはチタンなどの金属のシートを用いることができる。   In the third step, the dispersion obtained in the second step is applied to the electrode base material to form a sheet, the sheet-like dispersion is dried, and the solvent contained in the dispersion is removed. Thus, a catalyst metal unsupported electrode made of a mixture of a carbon material and a cation exchange resin is formed. The electrode substrate is not particularly limited, and a polymer sheet such as polytetrafluoroethylene (PTFE) or polyethylene terephthalate (PET), or a metal sheet such as titanium can be used.

第３の工程では、第２の工程で得られた分散物を粉末状に乾燥することも可能である。この場合は、粉末状態で、後述の第４の工程（触媒金属の陽イオンの吸着）および第５の工程（還元）をおこなう。粉末状に乾燥する方法は、炭素材料と陽イオン交換樹脂の溶液との分散物をシート状に形成し乾燥した後に粉砕する方法、あるいは混合物を噴霧乾燥する方法により、触媒金属未担持粉末が得られる。   In the third step, the dispersion obtained in the second step can be dried in a powder form. In this case, a fourth step (adsorption of cation of catalytic metal) and a fifth step (reduction) described later are performed in a powder state. As a method of drying into powder, a catalyst metal unsupported powder is obtained by forming a dispersion of a carbon material and a solution of a cation exchange resin into a sheet and drying it, or by pulverizing the mixture or spray drying the mixture. It is done.

乾燥温度は特に限定されないが、５０℃以上であることは、溶媒を完全に気化させる時間が短いことから好ましい。一方、温度が２００℃以上になると陽イオン交換樹脂が劣化する。   The drying temperature is not particularly limited, but it is preferably 50 ° C. or higher because the time for completely evaporating the solvent is short. On the other hand, when the temperature is 200 ° C. or higher, the cation exchange resin deteriorates.

第４の工程では、上記の第１の工程から第３の工程で得られた触媒金属未担持電極または触媒金属未担持粉末に、触媒金属の陽イオンを吸着させる。   In the fourth step, the catalyst metal cation is adsorbed on the catalyst metal unsupported electrode or the catalyst metal unsupported powder obtained in the first to third steps.

触媒金属未担持電極または触媒金属未担持粉末を、触媒金属の陽イオンを含んだ溶液に浸漬し、触媒金属未担持電極または触媒金属未担持粉末に含まれる陽イオン交換樹脂のプロトン伝導経路に陽イオンを吸着させる。触媒金属の陽イオンを含んだ溶液の触媒金属の陽イオンの濃度は、陽イオン交換樹脂が被覆していない箇所への物理吸着を防ぐために１００ｍｍｏｌ／ｌ以下であることが好ましく、その溶液が陽イオン交換樹脂のプロトン伝導経路に吸着できる最大モル量以上の触媒金属イオンを含んでいることが好ましい。触媒金属の陽イオンを含んだ溶液に用いる溶媒としては、特に限定されないが、水あるいは水とアルコールとの混合溶液を用いることができる。   The catalyst metal unsupported electrode or the catalyst metal unsupported powder is immersed in a solution containing a catalyst metal cation, and the positive electrode is added to the proton conduction path of the cation exchange resin contained in the catalyst metal unsupported electrode or the catalyst metal unsupported powder. Adsorb ions. The concentration of the cation of the catalyst metal in the solution containing the cation of the catalyst metal is preferably 100 mmol / l or less in order to prevent physical adsorption to the portion not covered with the cation exchange resin. It is preferable that the catalyst metal ion is contained in a molar amount or more that can be adsorbed on the proton conduction path of the ion exchange resin. Although it does not specifically limit as a solvent used for the solution containing the cation of a catalyst metal, Water or the mixed solution of water and alcohol can be used.

第５の工程では、第４の工程で得られた触媒金属未担持電極あるいは触媒金属未担持粉末に吸着した触媒金属の陽イオンを化学的に還元する。   In the fifth step, the catalyst metal cation adsorbed on the catalyst metal unsupported electrode or the catalyst metal unsupported powder obtained in the fourth step is chemically reduced.

陽イオン交換樹脂のプロトン伝導経路に吸着した陽イオンを還元するには、量産に適した還元剤を用いる化学的な還元方法を用いることが好ましい。特に水素ガスあるいは水素混合ガスによって気相還元する方法、あるいはヒドラジンを含む不活性ガスによって気相還元する方法が好ましい。   In order to reduce the cation adsorbed on the proton conduction path of the cation exchange resin, it is preferable to use a chemical reduction method using a reducing agent suitable for mass production. In particular, a method of gas phase reduction with hydrogen gas or a hydrogen mixed gas, or a method of gas phase reduction with an inert gas containing hydrazine is preferable.

還元の温度は、１００℃以上、２５０℃以下であることが好ましい。１００℃未満の場合では、触媒金属イオンの還元反応の進行が著しく遅い。一方、２５０℃より高い場合では、陽イオン交換樹脂が著しく劣化する。   The reduction temperature is preferably 100 ° C. or higher and 250 ° C. or lower. When the temperature is lower than 100 ° C., the progress of the catalytic metal ion reduction reaction is extremely slow. On the other hand, when the temperature is higher than 250 ° C., the cation exchange resin significantly deteriorates.

超少量触媒金属担持粉末を用いて超少量触媒金属担持電極を作製する方法は、例えばつぎのとおりである。まず、超少量触媒金属担持粉末と溶媒とを混合することによって、スラリー状の混合物を製造する。つぎに、この混合物を電極基材に塗布したのちに乾燥することによって溶媒を除去することでシート状に形成する。これらの工程を経て超少量触媒金属担持電極は、その粉末から作製される。   For example, a method for producing an ultra-small catalyst metal-supported electrode using an ultra-small catalyst metal-supported powder is as follows. First, a slurry-like mixture is produced by mixing an ultra-small amount of catalyst metal-supported powder and a solvent. Next, after applying this mixture to an electrode substrate, it is dried to form a sheet by removing the solvent. Through these steps, the ultra-small catalyst metal-supported electrode is produced from the powder.

この工程で用いる溶媒は、水などの無機化合物、ヘキサン、ペンタン、シクロヘキサン、オクタン、ベンゼンなどの炭化水素系の液体、ジクロロメタン、１，１，２−トリクロロ−１，１，２−トリフルオロエタンなどのハロゲン化合物、メタノール、エタノール、エチレングリコール、グリセリンなどのアルコール、アニソールなどのエーテル、アセトンなどのケトン、Ｎ−メチル−２−ピロリドン、ピリジン、ジメチルスルホキシドなどの有機化合物を使用することができる。電極基材はとくに限定されず、ＰＴＦＥあるいはＰＥＴ等の高分子シート、あるいはチタン、アルミニウム、銅などの金属のシートを用いることができる。   Solvents used in this step include inorganic compounds such as water, hydrocarbon liquids such as hexane, pentane, cyclohexane, octane, and benzene, dichloromethane, 1,1,2-trichloro-1,1,2-trifluoroethane, and the like. Organic compounds such as alcohols such as methanol, ethanol, ethylene glycol and glycerine, ethers such as anisole, ketones such as acetone, N-methyl-2-pyrrolidone, pyridine and dimethyl sulfoxide. The electrode substrate is not particularly limited, and a polymer sheet such as PTFE or PET, or a metal sheet such as titanium, aluminum, or copper can be used.

超少量触媒金属担持電極を陽イオン交換膜に接合することによって、本発明の固体高分子形燃料電池用電極が得えられる。陽イオン交換膜には、たとえば、パーフルオロカーボンスルホン酸樹脂、スチレン-ビニルベンゼンスルホン酸樹脂、パーフルオロカーボンカルボン酸樹脂、スチレン-ビニルベンゼンカルボン酸樹脂などのプロトン伝導性の陽イオン交換樹脂を用いることができるが、化学的な安定性とプロトン伝導性とが高いパーフルオロカーボンスルホン酸樹脂からなるものを用いることが好ましい。たとえば、その高分子電解質膜として、デュポン社製のナフィオン膜を用いることができる。   The electrode for a polymer electrolyte fuel cell of the present invention can be obtained by joining an ultra-small amount of catalytic metal-supporting electrode to a cation exchange membrane. For the cation exchange membrane, for example, a proton conductive cation exchange resin such as a perfluorocarbon sulfonic acid resin, a styrene-vinylbenzene sulfonic acid resin, a perfluorocarbon carboxylic acid resin, or a styrene-vinylbenzene carboxylic acid resin may be used. However, it is preferable to use a perfluorocarbon sulfonic acid resin having high chemical stability and high proton conductivity. For example, a DuPont Nafion membrane can be used as the polymer electrolyte membrane.

超少量触媒金属担持電極の陽イオン交換膜への接合は、加熱圧着によりおこなうことができる。加熱温度は、陽イオン交換樹脂のガラス転移温度に近い９０℃から１６０℃であることがこの好ましい。加熱圧着には、平プレス機あるいはロールプレス機を用いることができる。   The joining of the ultra-small catalyst metal-supporting electrode to the cation exchange membrane can be performed by thermocompression bonding. The heating temperature is preferably 90 ° C. to 160 ° C. close to the glass transition temperature of the cation exchange resin. A flat press or a roll press can be used for thermocompression bonding.

以下実施例を挙げて詳細に説明する。   Examples will be described in detail below.

［実施例１〜７および比較例１〜４］
［実施例1］
炭素材料の表面に酸素原子を含む官能基を備えた後、触媒金属未担持電極を製作した。その製作方法は、つぎのとおりである。 [Examples 1 to 7 and Comparative Examples 1 to 4]
[Example 1]
After a functional group containing oxygen atoms was provided on the surface of the carbon material, a catalyst metal unsupported electrode was manufactured. The manufacturing method is as follows.

第１の工程では、最初に、炭素材料（バルカンＸＣ−７２、キャボット社製）２０ｇを５Ｌビーカーに採取し、エタノール１０ｍｌおよび酸化剤水溶液（硫酸、０．０１ｍｏｌ／ｌ）２ｌを加えた。この炭素材料、酸化剤水溶液およびエタノールの混合物を撹拌しながら真空に引いた後、プロペラ式撹拌機で1時間撹拌した。   In the first step, 20 g of a carbon material (Vulcan XC-72, manufactured by Cabot) was first collected in a 5 L beaker, and 10 ml of ethanol and 2 l of an oxidizing agent aqueous solution (sulfuric acid, 0.01 mol / l) were added. The mixture of the carbon material, the oxidizing agent aqueous solution and ethanol was evacuated while stirring, and then stirred with a propeller type stirrer for 1 hour.

つぎに、この混合物を吸引ろ過して炭素材料と酸化剤水溶液とを分離した。炭素材料に脱イオン水（２ｌ）を加えて１０分間撹拌した後、吸引ろ過で炭素材料と脱イオン水とを分離した。この炭素材料の洗浄を５回繰り返した。最後に、この炭素材料を真空乾燥（１００℃、２４時間）した後、ブレンダーミルで粉砕した。   Next, this mixture was suction filtered to separate the carbon material and the aqueous oxidizer solution. After adding deionized water (2 l) to the carbon material and stirring for 10 minutes, the carbon material and deionized water were separated by suction filtration. This cleaning of the carbon material was repeated 5 times. Finally, the carbon material was vacuum-dried (100 ° C., 24 hours) and then pulverized with a blender mill.

炭素材料の表面に存在する酸素原子を含む官能基を昇温脱離ガス分析装置で定量したところ、カルボニル基、スルホン酸基およびヒドロキシル基などが合わせて０．１０ｍｅｑ／ｇ存在していた。   When the functional group containing oxygen atoms present on the surface of the carbon material was quantified with a temperature programmed desorption gas analyzer, carbonyl group, sulfonic acid group, hydroxyl group and the like were present in total of 0.10 meq / g.

第２の工程では、最初に、０．１０ｍｅｑ／ｇの酸素原子を含む官能基を備えた炭素材料８．０ｇにナフィオン溶液（５質量％溶液、アルドリッチ社製）を８６．４ｇ加えた後、撹拌して分散物を調製した。つぎに、この分散物をプロペラ式撹拌機で撹拌しながら加熱濃縮（６０℃）してスラリー状の混合物を調製した。分散物に対するナフィオンの固形分の質量比は６．５質量％であった。   In the second step, first, 86.4 g of a Nafion solution (5 mass% solution, manufactured by Aldrich) was added to 8.0 g of a carbon material having a functional group containing an oxygen atom of 0.10 meq / g, A dispersion was prepared by stirring. Next, this dispersion was heated and concentrated (60 ° C.) while stirring with a propeller type stirrer to prepare a slurry mixture. The mass ratio of Nafion solids to the dispersion was 6.5% by mass.

第３の工程では、スラリー状の分散物を高分子シート（ＰＴＦＥ、厚み５０μｍ）に塗布した後、自然乾燥して、高分子シート上に実施例1の触媒金属未担持電極Ａを作製した。の触媒金属未担持電極の重量は、２．２ｍｇ／ｃｍ２であった。塗布にはスリット幅が００μｍのアプリケーターを用いた。最後に、この電極を５０ｍｍ×５０ｍｍの大きさに裁断した。 In the third step, the slurry-like dispersion was applied to a polymer sheet (PTFE, thickness 50 μm), and then naturally dried to produce the catalyst metal unsupported electrode A of Example 1 on the polymer sheet. The weight of the catalyst metal unsupported electrode was 2.2 mg / cm 2 . An applicator with a slit width of 00 μm was used for coating. Finally, this electrode was cut into a size of 50 mm × 50 mm.

触媒金属未担持電極Ａから、本発明の超少量触媒金属担持電極Ａを、以下の方法で製作した。第４の工程では、まず、触媒金属未担持電極Ａを５０ｍｍｏｌ／ｌの［Ｐｔ（ＮＨ３）４］Ｃｌ２の水溶液（６０℃）に２４時間浸漬して、電極に含まれるナフィオンのプロトン伝導経路に［Ｐｔ（ＮＨ３）４］２＋を吸着させた。つぎに、この電極を脱イオン水（２５℃）で３回洗浄した後、脱イオン水（６０℃）に１時間浸漬した。さらに、この電極を乾燥機（６０℃）で１時間乾燥した。 From the catalyst metal non-supported electrode A, an ultra-small amount of catalyst metal-supported electrode A of the present invention was produced by the following method. In the fourth step, first, catalyst metal unsupported electrode A is immersed in an aqueous solution (60 ° C.) of 50 mmol / l [Pt (NH 3 ) 4 ] Cl 2 for 24 hours, and proton conduction of Nafion contained in the electrode is performed. [Pt (NH 3 ) 4 ] 2+ was adsorbed on the route. Next, this electrode was washed three times with deionized water (25 ° C.) and then immersed in deionized water (60 ° C.) for 1 hour. Furthermore, this electrode was dried with a dryer (60 ° C.) for 1 hour.

第５の工程では、プロトン伝導経路に吸着した［Ｐｔ（ＮＨ３）４］２＋を０．１５気圧、１８０℃の水素雰囲気下で６時間還元して、炭素材料とプロトン伝導経路との接面に触媒金属である白金を選択的に析出させて、超少量触媒金属担持電極Ａを作製した。別途化学分析によって定量した白金担持量は０．０５ｍｇ／ｃｍ２であった。 In the fifth step, [Pt (NH 3 ) 4 ] 2+ adsorbed on the proton conduction path is reduced for 6 hours in a hydrogen atmosphere of 0.15 atm and 180 ° C., and the contact surface between the carbon material and the proton conduction path Then, platinum, which is a catalytic metal, was selectively deposited to prepare an ultra-small amount of catalytic metal-supported electrode A. The platinum loading determined by chemical analysis separately was 0.05 mg / cm 2 .

［実施例２］
第１の工程において、０．０１ｍｏｌ／ｌの硫酸の代わりに０．０５ｍｏｌ／ｌの硫酸を用いたこと以外は実施例１と同様にして、０．５８ｍｅｑ／ｇの酸素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例１と同様にして、実施例２の触媒金属未担持電極Ｂ（重量２．２ｍｇ／ｃｍ２）を作製した。この触媒金属未担持電極Ｂを用いて、実施例１と同様にして、超少量触媒金属担持電極Ｂ（白金担持量０．０５ｍｇ／ｃｍ２）を製作した。 [Example 2]
In the first step, a functional group containing 0.58 meq / g oxygen atom was prepared in the same manner as in Example 1 except that 0.05 mol / l sulfuric acid was used instead of 0.01 mol / l sulfuric acid. The prepared carbon material was produced, and using this, the catalyst metal unsupported electrode B (weight 2.2 mg / cm 2 ) of Example 2 was produced in the same manner as in Example 1 in the second step and thereafter. Using this catalyst metal unsupported electrode B, an ultra-small amount of catalyst metal-supported electrode B (platinum supported amount 0.05 mg / cm 2 ) was produced in the same manner as in Example 1.

［実施例３］
第１の工程において、０．０１ｍｏｌ／ｌの硫酸の代わりに２．５ｍｏｌ／ｌの硫酸を用いたこと以外は実施例１と同様にして、２．５８ｍｅｑ／ｇの酸素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例１と同様にして、実施例３の触媒金属未担持電極Ｃ（重量２．２ｍｇ／ｃｍ２）を作製した。この触媒金属未担持電極Ｂを用いて、実施例１と同様にして、超少量触媒金属担持電極Ｃ（白金担持量０．０５ｍｇ／ｃｍ２）を製作した。 [Example 3]
In the first step, a functional group containing 2.58 meq / g oxygen atom was prepared in the same manner as in Example 1 except that 2.5 mol / l sulfuric acid was used instead of 0.01 mol / l sulfuric acid. The provided carbon material was produced, and using this, the catalyst metal unsupported electrode C (weight 2.2 mg / cm 2 ) of Example 3 was produced in the same manner as in Example 1 in the second step and thereafter. Using this catalyst metal unsupported electrode B, an ultra-small catalyst metal supported electrode C (platinum supported amount 0.05 mg / cm 2 ) was produced in the same manner as in Example 1.

［実施例４］
第１の工程において、０．０１ｍｏｌ／ｌの硫酸の代わりに５．０ｍｏｌ／ｌの硫酸を用いたこと以外は実施例１と同様にして、５．２１ｍｅｑ／ｇの酸素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例１と同様にして、実施例４の触媒金属未担持電極Ｄ（重量２．２ｍｇ／ｃｍ２）を作製した。この触媒金属未担持電極Ｄを用いて、実施例１と同様にして、超少量触媒金属担持電極Ｄ（白金担持量０．０５ｍｇ／ｃｍ２）を製作した。 [Example 4]
In the first step, a functional group containing 5.21 meq / g oxygen atom was prepared in the same manner as in Example 1 except that 5.0 mol / l sulfuric acid was used instead of 0.01 mol / l sulfuric acid. The provided carbon material was produced, and using this, the catalyst metal unsupported electrode D (weight: 2.2 mg / cm 2 ) of Example 4 was produced in the same manner as in Example 1 in the second step and thereafter. Using this catalyst metal unsupported electrode D, an ultra-small amount of catalyst metal-supported electrode D (platinum supported amount of 0.05 mg / cm 2 ) was produced in the same manner as in Example 1.

［実施例５］
第１の工程において、０．０１ｍｏｌ／ｌの硫酸の代わりに７．５ｍｏｌ／ｌの硫酸を用いたこと以外は実施例１と同様にして、７．８１ｍｅｑ／ｇの酸素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例１と同様にして、実施例５の触媒金属未担持電極Ｅ（重量２．２ｍｇ／ｃｍ２）を作製した。この触媒金属未担持電極Ｅを用いて、実施例１と同様にして、超少量触媒金属担持電極Ｅ（白金担持量０．０５ｍｇ／ｃｍ２）を製作した。 [Example 5]
In the first step, a functional group containing 7.81 meq / g oxygen atom was prepared in the same manner as in Example 1 except that 7.5 mol / l sulfuric acid was used instead of 0.01 mol / l sulfuric acid. The prepared carbon material was produced, and using this, the catalyst metal unsupported electrode E (weight: 2.2 mg / cm 2 ) of Example 5 was produced in the same manner as in Example 1 in the second step and thereafter. Using this catalyst metal unsupported electrode E, an ultra-small catalyst metal supported electrode E (platinum supported amount 0.05 mg / cm 2 ) was produced in the same manner as in Example 1.

［実施例６］
第１の工程において、０．０１ｍｏｌ／ｌの硫酸の代わりに１０．０ｍｏｌ／ｌの硫酸を用いたこと以外は実施例１と同様にして、１０．０ｍｅｑ／ｇの酸素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例１と同様にして、実施例６の触媒金属未担持電極Ｆ（重量２．２ｍｇ／ｃｍ２）を作製した。触媒金属未担持電極Ｆの重量は、２．２ｍｇ／ｃｍ２であった。この触媒金属未担持電極Ｆを用いて、実施例１と同様にして、超少量触媒金属担持電極Ｆ（白金担持量０．０５ｍｇ／ｃｍ２）を製作した。 [Example 6]
In the first step, a functional group containing 10.0 meq / g oxygen atom was prepared in the same manner as in Example 1 except that 10.0 mol / l sulfuric acid was used instead of 0.01 mol / l sulfuric acid. The prepared carbon material was produced, and using this, the catalyst metal unsupported electrode F (weight: 2.2 mg / cm 2 ) of Example 6 was produced in the same manner as in Example 1 in the second step and thereafter. The weight of the catalyst metal unsupported electrode F was 2.2 mg / cm 2 . Using this catalyst metal unsupported electrode F, an ultra-small amount of catalyst metal-supported electrode F (platinum supported amount 0.05 mg / cm 2 ) was produced in the same manner as in Example 1.

［実施例７］
実施例1と同様の製法で、第１の工程では、０．１０ｍｅｑ／ｇの酸素原子を含む官能基を備えた炭素材料（バルカンＸＣ−７２、キャボット社製）を製作した。 [Example 7]
In the first step, a carbon material (Vulcan XC-72, manufactured by Cabot Corporation) having a functional group containing an oxygen atom of 0.10 meq / g was manufactured in the same process as in Example 1.

第２の工程では、最初に、炭素材料４５．０ｇに陽イオン交換樹脂溶液（Ｎａｆｉｏｎ溶液、５質量％、アルドリッチ社製）を４８６．０ｇ加えたのち、撹拌して分散物を得た。つぎに、この分散物をプロペラ式撹拌機で撹拌しながら加熱濃縮（６０℃）してスラリー状の混合物を得た。濃縮後の分散物に対するナフィオンの固形分の質量比は６．５質量％であった。   In the second step, first, 486.0 g of a cation exchange resin solution (Nafion solution, 5% by mass, manufactured by Aldrich) was added to 45.0 g of a carbon material, followed by stirring to obtain a dispersion. Next, this dispersion was heated and concentrated (60 ° C.) while stirring with a propeller type stirrer to obtain a slurry-like mixture. The mass ratio of Nafion solids to the dispersion after concentration was 6.5% by mass.

第３の工程では、スラリー状の分散物をガラス板上に塗布した後、自然乾燥し、乾燥した混合物をガラス板からはがした後、遊星形ボールミルで粉砕して触媒金属未担持粉末Ｇを製作した。   In the third step, the slurry-like dispersion is applied on a glass plate, and then air-dried. After the dried mixture is peeled off from the glass plate, the catalyst metal unsupported powder G is crushed by a planetary ball mill. Produced.

触媒金属未担持粉末Ｇから、本発明の超少量触媒金属担持粉末Ｇをつぎの手順で製作した。第４の工程では、最初に、触媒金属未担持粉末Ｇ２５．０ｇと５０ｍｍｏｌ／ｌの［Ｐｔ（ＮＨ３）４］Ｃｌ２の水溶液約３８０ｍｌとを１Ｌビーカーに移した後、減圧しながらプロペラ式撹拌機を用いて室温で撹拌した。つぎに、圧力を大気圧に戻した後、度を８０℃に保持しながら２４時間撹拌した。 From the catalyst metal unsupported powder G, the ultra-small amount of catalyst metal-supported powder G of the present invention was produced by the following procedure. In the fourth step, first, 25.0 g of catalyst metal unsupported powder G and about 380 ml of an aqueous solution of 50 mmol / l [Pt (NH 3 ) 4 ] Cl 2 were transferred to a 1 L beaker, and then propeller type while reducing pressure. Stir at room temperature using a stirrer. Next, after returning the pressure to atmospheric pressure, the mixture was stirred for 24 hours while maintaining the temperature at 80 ° C.

つづいて、［Ｐｔ（ＮＨ３）４］Ｃｌ２の水溶液を吸引ろ過で取り除いた後、粉末を脱イオン水で洗浄した。この洗浄を５回繰り返した。さらに、この粉末を乾燥機（６０℃）で１時間乾燥した。 Subsequently, the aqueous solution of [Pt (NH 3 ) 4 ] Cl 2 was removed by suction filtration, and the powder was washed with deionized water. This washing was repeated 5 times. Furthermore, this powder was dried with a dryer (60 ° C.) for 1 hour.

第５の工程では、プロトン伝導経路に吸着した［Ｐｔ（ＮＨ３）４］２＋を０．１５気圧、１８０℃の水素雰囲気下で６時間還元して、炭素材料とプロトン伝導経路との接面に触媒金属である白金を選択的に析出させ、超少量触媒金属担持粉末Ｇを作製した。 In the fifth step, [Pt (NH 3 ) 4 ] 2+ adsorbed on the proton conduction path is reduced for 6 hours in a hydrogen atmosphere of 0.15 atm and 180 ° C., and the contact surface between the carbon material and the proton conduction path Then, platinum as a catalytic metal was selectively deposited to prepare an ultra-small amount of catalytic metal-supported powder G.

この粉末を用いた超少量白金担持電極Ｇは、次の手順で製作した。最初に、超少量触媒金属担持粉末Ｇ４．０ｇとＮ−メチル−２−ピロリドン（ＮＭＰ）１９．０ｇとを混合した後、遊星形ボールミルを用いて超少量触媒金属担持粉末Ｇをスラリー状にした。つぎに、このスラリーを高分子シート（ＰＴＦＥ、厚み５０μｍ）の上に塗布した後、１３０℃で乾燥して、超少量触媒金属担持電極Ｇを製作した。塗布にはスリット幅３００μｍのアプリケーターを用いた。   An ultra-small amount of platinum-supported electrode G using this powder was manufactured by the following procedure. First, 4.0 g of ultra-small catalyst metal-supported powder G and 19.0 g of N-methyl-2-pyrrolidone (NMP) were mixed, and then ultra-small catalyst metal-supported powder G was made into a slurry using a planetary ball mill. . Next, this slurry was applied onto a polymer sheet (PTFE, thickness 50 μm), and then dried at 130 ° C. to produce an ultra-small amount of catalytic metal-carrying electrode G. An applicator with a slit width of 300 μm was used for coating.

最後に、この電極を５０ｍｍ×５０ｍｍの大きさに裁断した。化学分析で求めたこの電極Ｇの白金担持量は０．０５ｍｇ／ｃｍ２であった。 Finally, this electrode was cut into a size of 50 mm × 50 mm. The amount of platinum supported on this electrode G determined by chemical analysis was 0.05 mg / cm 2 .

［比較例1］
炭素材料を酸化剤水溶液で化学処理しなかったこと以外は実施例１と同様にして、比較例１の触媒金属未担持電極Ｈおよび超少量触媒金属担持電極Ｈを製作した。炭素材料の表面に存在する親水性官能基の量は、昇温脱離ガス分析装置で定量し、カルボニル基、スルホン酸基およびヒドロキシル基など合計０．０２ｍｅｑ／ｇであった。化学分析で求めたこの電極Ｈの白金担持量は０．０５ｍｇ／ｃｍ２であった。 [Comparative Example 1]
Except that the carbon material was not chemically treated with the oxidizing agent aqueous solution, the catalyst metal unsupported electrode H and the ultra-small catalyst metal supported electrode H of Comparative Example 1 were manufactured in the same manner as in Example 1. The amount of the hydrophilic functional group present on the surface of the carbon material was quantified with a temperature-programmed desorption gas analyzer, and the total amount of carbonyl group, sulfonic acid group, hydroxyl group, etc. was 0.02 meq / g. The amount of platinum supported on this electrode H determined by chemical analysis was 0.05 mg / cm 2 .

［比較例２］
第１の工程において、０．０１ｍｏｌ／ｌの硫酸の代わりに１５．０ｍｏｌ／ｌの硫酸を用いたこと以外は実施例１と同様にして、２０．０ｍｅｑ／ｇの酸素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例１と同様にして、比較例２の触媒金属未担持電極Ｉ（重量２．２ｍｇ／ｃｍ２）を作製した。この触媒金属未担持電極Ｉを用いて、実施例１と同様にして、超少量触媒金属担持電極Ｉを製作した。化学分析で求めたこの電極Ｉの白金担持量は０．０５ｍｇ／ｃｍ２であった。 [Comparative Example 2]
In the first step, a functional group containing 20.0 meq / g oxygen atom was prepared in the same manner as in Example 1 except that 15.0 mol / l sulfuric acid was used instead of 0.01 mol / l sulfuric acid. The provided carbon material was produced, and using this, the catalyst metal unsupported electrode I (weight 2.2 mg / cm 2 ) of Comparative Example 2 was produced in the same manner as in Example 1 in the second step and thereafter. Using this catalyst metal unsupported electrode I, an ultra-small amount of catalyst metal supported electrode I was produced in the same manner as in Example 1. The amount of platinum supported on this electrode I determined by chemical analysis was 0.05 mg / cm 2 .

［比較例３］
炭素材料を酸化剤水溶液で化学処理しなかったこと以外は実施例７と同様にして、比較例３の触媒金属未担持電極Ｊおよび超少量触媒金属担持電極Ｊを製作した。炭素材料の表面に存在する酸素原子を含む官能基の量は、昇温脱離ガス分析装置で定量し、カルボニル基、スルホン酸基およびヒドロキシル基など合計０．０２ｍｅｑ／ｇであった。化学分析で求めたこの電極Ｊの白金担持量は０．０５ｍｇ／ｃｍ２であった。 [Comparative Example 3]
Except that the carbon material was not chemically treated with the oxidizing agent aqueous solution, the catalyst metal unsupported electrode J and the ultra-small amount of catalyst metal supported electrode J of Comparative Example 3 were produced in the same manner as in Example 7. The amount of functional groups containing oxygen atoms present on the surface of the carbon material was quantified by a temperature programmed desorption gas analyzer, and the total amount of carbonyl groups, sulfonic acid groups, hydroxyl groups, etc. was 0.02 meq / g. The amount of platinum supported on this electrode J determined by chemical analysis was 0.05 mg / cm 2 .

［比較例４］
白金をあらかじめ炭素材料に担持した触媒（白金担持カーボン粉末）を０．０１ｍｏｌ／ｌ硫酸を用いて親水処理を施した。白金担持カーボン粉末の炭素材料の表面に存在する酸素原子を含む官能基の量を昇温脱離ガス分析装置で定量し、カルボニル基、スルホン酸基およびヒドロキシル基など合計０．１０ｍｅｑ／ｇであった。この触媒を用いた既存の電極Ｋは、つぎの手順で製作した。 [Comparative Example 4]
A catalyst in which platinum was previously supported on a carbon material (platinum-supported carbon powder) was subjected to a hydrophilic treatment using 0.01 mol / l sulfuric acid. The amount of functional groups containing oxygen atoms present on the surface of the carbon material of the platinum-supported carbon powder was quantified with a temperature programmed desorption gas analyzer, and the total of carbonyl groups, sulfonic acid groups, hydroxyl groups, etc. was 0.10 meq / g. It was. The existing electrode K using this catalyst was manufactured by the following procedure.

最初に、脱イオン水１５ｍｌおよび２-プロパノール１ｍｌの溶液に、化学処理を施した白金担持カーボン粉末（ＴＥＣ１０Ｅ７０ＴＰＭ、田中貴金属社製）１０．０ｇを徐々に加えた。   First, 10.0 g of platinum-supported carbon powder (TEC10E70TPM, manufactured by Tanaka Kikinzoku Co., Ltd.) subjected to chemical treatment was gradually added to a solution of 15 ml of deionized water and 1 ml of 2-propanol.

つぎに、白金担持カーボン粉末と脱イオン水との混合物にナフィオン溶液（５質量％溶液、アルドリッチ社製）４４．２ｇおよびＮ，Ｎ−ジメチルスルホキシド１５．０ｇを加えた後、プロペラ式撹拌機を用いて撹拌し、白金担持カーボン粉末とナフィオン溶液との混合物を作製した。この混合物の固形分に対するナフィオンの固形分の質量の割合は１８質量％であった。   Next, after adding 44.2 g of Nafion solution (5% by mass solution, manufactured by Aldrich) and 15.0 g of N, N-dimethyl sulfoxide to a mixture of platinum-supported carbon powder and deionized water, a propeller type stirrer was added. And a mixture of platinum-supported carbon powder and Nafion solution was prepared. The ratio of the solid content of Nafion to the solid content of this mixture was 18% by mass.

その混合物を高分子シート（ＰＴＦＥ、厚み５０μｍ）に塗布した後、１３０℃で乾燥し、白金担持カーボン粉末を用いた電極（白金担持量０．２ｍｇ／ｃｍ２）を製作した。塗布にはスリット幅が３０μｍのアプリケーターを用いた。最後に、この電極を５０ｍｍ×５０ｍｍの大きさに裁断した。 The mixture was applied to a polymer sheet (PTFE, thickness 50 μm) and dried at 130 ° C. to produce an electrode (platinum supported amount 0.2 mg / cm 2 ) using platinum supported carbon powder. An applicator with a slit width of 30 μm was used for coating. Finally, this electrode was cut into a size of 50 mm × 50 mm.

［実施例８〜１５および比較例５、６］
［実施例８］
炭素材料の表面に窒素原子を含む官能基を形成した後、触媒金属未担持電極を製作した。その製作方法は、つぎのとおりである。 [Examples 8 to 15 and Comparative Examples 5 and 6]
[Example 8]
After forming functional groups containing nitrogen atoms on the surface of the carbon material, a catalyst metal unsupported electrode was manufactured. The manufacturing method is as follows.

第１の工程では、炭素材料の表面に酸素原子を含む官能基を形成した。まず、炭素材料（バルカンＸＣ−７２、キャボット社製）５０ｇを５Ｌビーカーに採取し、エタノール１０ｍｌおよび酸化剤水溶液（過酸化水素水、０．０１ｍｏｌ／ｌ）２ｌを加えた。この炭素材料、酸化剤水溶液およびエタノールの混合物を撹拌しながら真空に引いた後、プロペラ式撹拌機で1時間撹拌した。   In the first step, a functional group containing an oxygen atom was formed on the surface of the carbon material. First, 50 g of a carbon material (Vulcan XC-72, manufactured by Cabot) was collected in a 5 L beaker, and 10 ml of ethanol and 2 l of an oxidizing agent aqueous solution (hydrogen peroxide solution, 0.01 mol / l) were added. The mixture of the carbon material, the oxidizing agent aqueous solution and ethanol was evacuated while stirring, and then stirred with a propeller type stirrer for 1 hour.

つぎに、この混合物を吸引ろ過して炭素材料と酸化剤水溶液とを分離した。この炭素材料に脱イオン水（２ｌ）を加えて１０分間撹拌した後、吸引ろ過で炭素材料と脱イオン水とを分離した。最後に、この洗浄を５回繰り返して、炭素材料を洗浄し、真空乾燥（１００℃、２４時間）した。得られた炭素材料の表面に存在するカルボニル基は、昇温脱離ガス分析装置で定量したところ０．１４ｍｅｑ／ｇ存在していた。
カルボニル基からアミド基への付加−脱離反応は、つぎの方法でおこなった。まず、カルボニル基が形成された炭素材料２０ｇを５Ｌビーカーに採取し、エタノール１０ｍｌおよびアンモニア水溶液溶液（１．０ｍｏｌ／ｌ）２ｌを加えた。この炭素材料、アンモニア水溶液溶液およびエタノールの混合物を撹拌しながら真空に引いた後、プロペラ式撹拌機で1時間撹拌した。 Next, this mixture was suction filtered to separate the carbon material and the aqueous oxidizer solution. After adding deionized water (2 l) to this carbon material and stirring for 10 minutes, the carbon material and deionized water were separated by suction filtration. Finally, this washing was repeated 5 times to wash the carbon material and vacuum-dried (100 ° C., 24 hours). The carbonyl group present on the surface of the obtained carbon material was 0.14 meq / g as determined by a temperature programmed desorption gas analyzer.
The addition-elimination reaction from the carbonyl group to the amide group was carried out by the following method. First, 20 g of a carbon material in which a carbonyl group was formed was collected in a 5 L beaker, and 10 ml of ethanol and 2 l of an aqueous ammonia solution (1.0 mol / l) were added. The mixture of the carbon material, aqueous ammonia solution and ethanol was evacuated while stirring and then stirred with a propeller stirrer for 1 hour.

つぎに、この混合物を吸引ろ過して炭素材料とアンモニア水溶液溶液とを分離した。この炭素材料に脱イオン水（２ｌ）を加えて１０分間撹拌した後、吸引ろ過で炭素材料と脱イオン水とを分離した。最後に、この洗浄を5回繰り返すことによって、炭素材料を洗浄し、真空乾燥（１００℃、２４時間）した。
得られた炭素材料の表面に存在する窒素原子を含む官能基を昇温脱離ガス分析装置で定量したところ、アミド基が０．０９ｍｅｑ／ｇおよびアミノ基０．０１ｍｅｑ／ｇ存在していた。したがって、炭素材料の表面に存在する窒素原子を含む官能基は合計０．１０ｍｅｑ／ｇであった。 Next, this mixture was subjected to suction filtration to separate the carbon material and the aqueous ammonia solution. After adding deionized water (2 l) to this carbon material and stirring for 10 minutes, the carbon material and deionized water were separated by suction filtration. Finally, the carbon material was washed by repeating this washing 5 times and vacuum-dried (100 ° C., 24 hours).
When functional groups containing nitrogen atoms present on the surface of the obtained carbon material were quantified with a temperature programmed desorption gas analyzer, amide groups were present at 0.09 meq / g and amino groups at 0.01 meq / g. Therefore, the total number of functional groups containing nitrogen atoms present on the surface of the carbon material was 0.10 meq / g.

第１の工程で得られた表面に窒素原子を含む官能基を０．１０ｍｅｑ／ｇ備えた炭素材料を用いて、第２の工程〜第５の工程は実施例１と同様にして、触媒金属未担持電極Ｌおよび超少量触媒金属担持電極Ｌ（白金担持量０．０５ｍｇ／ｃｍ２）を作製した。 Using a carbon material having a functional group containing a nitrogen atom on the surface obtained in the first step and having a functional group containing 0.10 meq / g, the second step to the fifth step are performed in the same manner as in Example 1 to obtain a catalyst metal. An unsupported electrode L and an ultra-small catalyst metal-supported electrode L (platinum supported amount 0.05 mg / cm 2 ) were prepared.

［実施例９］
第１の工程のカルボニル基を形成する際、０．０１ｍｏｌ／ｌの過酸化水素水の代わりに０．２ｍｏｌ／ｌの過酸化水素水を用いたこと以外は実施例８と同様にして、０．５２ｍｅｑ／ｇの窒素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例８と同様にして、実施例９の触媒金属未担持電極Ｍ（重量２．２ｍｇ／ｃｍ２）を作製した。この触媒金属未担持電極Ｍを用いて、実施例８と同様にして、白金担持量０．０５ｍｇ／ｃｍ２の超少量触媒金属担持電極Ｍを製作した。 [Example 9]
In the same manner as in Example 8 except that 0.2 mol / l hydrogen peroxide solution was used instead of 0.01 mol / l hydrogen peroxide solution in forming the carbonyl group in the first step, 0 A carbon material having a functional group containing a nitrogen atom of .52 meq / g was produced, and using this, the second step and subsequent steps were carried out in the same manner as in Example 8, and the catalyst metal unsupported electrode M in Example 9 ( A weight of 2.2 mg / cm 2 ) was produced. Using this catalyst metal unsupported electrode M, an ultra-small amount of catalyst metal supported electrode M having a platinum load of 0.05 mg / cm 2 was manufactured in the same manner as in Example 8.

［実施例１０］
第１の工程のカルボニル基を形成する際、０．０１ｍｏｌ／ｌの過酸化水素水の代わりに０．５ｍｏｌ／ｌの過酸化水素水を用いたこと以外は実施例８と同様にして、１．２０ｍｅｑ／ｇの窒素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例８と同様にして、実施例１０の触媒金属未担持電極Ｎ（重量２．２ｍｇ／ｃｍ２）を作製した。この触媒金属未担持電極Ｎを用いて、実施例８と同様にして、白金担持量０．０５ｍｇ／ｃｍ２の超少量触媒金属担持電極Ｎを製作した。 [Example 10]
In the same manner as in Example 8 except that 0.5 mol / l hydrogen peroxide solution was used instead of 0.01 mol / l hydrogen peroxide solution when forming the carbonyl group in the first step, 1 A carbon material having a functional group containing a nitrogen atom of 20 meq / g was prepared, and using this, the second step and subsequent steps were performed in the same manner as in Example 8, and the catalyst metal unsupported electrode N in Example 10 ( A weight of 2.2 mg / cm 2 ) was produced. Using this catalyst metal unsupported electrode N, an ultra-small amount of catalyst metal supported electrode N having a platinum load of 0.05 mg / cm 2 was manufactured in the same manner as in Example 8.

［実施例１１］
第１の工程のカルボニル基を形成する際、０．０１ｍｏｌ／ｌの過酸化水素水の代わりに１．５ｍｏｌ／ｌの過酸化水素水を用いたこと以外は実施例８と同様にして、５．３０ｍｅｑ／ｇの窒素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例８と同様にして、実施例１１の触媒金属未担持電極Ｏ（重量２．２ｍｇ／ｃｍ２）を作製した。この触媒金属未担持電極Ｏを用いて、実施例８と同様にして、白金担持量０．０５ｍｇ／ｃｍ２の超少量触媒金属担持電極Ｎを製作した。 [Example 11]
When forming the carbonyl group in the first step, the same procedure as in Example 8 was conducted except that 1.5 mol / l hydrogen peroxide solution was used instead of 0.01 mol / l hydrogen peroxide solution. A carbon material having a functional group containing a nitrogen atom of 30 meq / g was produced, and using this, the second step and subsequent steps were performed in the same manner as in Example 8, and the catalyst metal unsupported electrode O in Example 11 ( A weight of 2.2 mg / cm 2 ) was produced. Using this catalyst metal unsupported electrode O, an ultra-small amount of catalyst metal-supported electrode N having a platinum load of 0.05 mg / cm 2 was produced in the same manner as in Example 8.

［実施例１２］
第１の工程のカルボニル基を形成する際、０．０１ｍｏｌ／ｌの過酸化水素水の代わりに２．５ｍｏｌ／ｌの過酸化水素水を用いたこと以外は実施例８と同様にして、７．６０ｍｅｑ／ｇの窒素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例８と同様にして、実施例９の触媒金属未担持電極Ｐ（重量２．２ｍｇ／ｃｍ２）を作製した。この触媒金属未担持電極Ｐを用いて、実施例８と同様にして、白金担持量０．０５ｍｇ／ｃｍ２の超少量触媒金属担持電極Ｐを製作した。 [Example 12]
In the same manner as in Example 8 except that 2.5 mol / l hydrogen peroxide solution was used instead of 0.01 mol / l hydrogen peroxide solution in forming the carbonyl group in the first step, 7 A carbon material having a functional group containing a nitrogen atom of .60 meq / g was produced, and using this, the second step and subsequent steps were carried out in the same manner as in Example 8, and the catalyst metal unsupported electrode P in Example 9 ( A weight of 2.2 mg / cm 2 ) was produced. Using this catalyst metal unsupported electrode P, an ultra-small amount of catalyst metal supported electrode P having a platinum load of 0.05 mg / cm 2 was manufactured in the same manner as in Example 8.

［実施例１３］
第１の工程のカルボニル基を形成する際、０．０１ｍｏｌ／ｌの過酸化水素水の代わりに５．０ｍｏｌ／ｌの過酸化水素水を用いたこと以外は実施例８と同様にして、１０．０ｍｅｑ／ｇの窒素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例８と同様にして、実施例９の触媒金属未担持電極Ｑ（重量２．２ｍｇ／ｃｍ２）を作製した。この触媒金属未担持電極Ｑを用いて、実施例８と同様にして、白金担持量０．０５ｍｇ／ｃｍ２の超少量触媒金属担持電極Ｑを製作した。 [Example 13]
In the same manner as in Example 8 except that 5.0 mol / l of hydrogen peroxide was used instead of 0.01 mol / l of hydrogen peroxide when forming the carbonyl group in the first step, 10 A carbon material having a functional group containing a nitrogen atom of 0.0 meq / g was produced, and using this, the second step and subsequent steps were carried out in the same manner as in Example 8, and the catalyst metal unsupported electrode Q ( A weight of 2.2 mg / cm 2 ) was produced. Using this catalyst metal unsupported electrode Q, an ultra-small amount of catalyst metal-supported electrode Q having a platinum load of 0.05 mg / cm 2 was produced in the same manner as in Example 8.

［実施例１４］
実施例８と同様の製法で、第１の工程では、０．１０ｍｅｑ／ｇの窒素原子を含む官能基を表面に備えた炭素材料（バルカンＸＣ−７２、キャボット社製）を製作し、この炭素材料を用いて、実施例７と同様にして、超少量触媒金属未担持粉末Ｒおよび超少量触媒金属担持電極Ｒを作製した。この電極の白金担持量は０．０５ｍｇ／ｃｍ２であった。 [Example 14]
In the first step, a carbon material (Vulcan XC-72, manufactured by Cabot Corp.) having a functional group containing a nitrogen atom of 0.10 meq / g on the surface was manufactured in the same manner as in Example 8. Using the materials, an ultra-small catalyst metal unsupported powder R and an ultra-small catalyst metal-supported electrode R were produced in the same manner as in Example 7. The amount of platinum supported on this electrode was 0.05 mg / cm 2 .

［実施例１５］
第１の工程において、酸素原子を含む官能基の代わりにニトロ基を形成したこと以外は実施例８と同様にして、０．１０ｍｅｑ／ｇの窒素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例８と同様にして、実施例１５の触媒金属未担持電極Ｓ（重量２．２ｍｇ／ｃｍ２）を作製した。この触媒金属未担持電極Ｓを用いて、実施例８と同様にして、白金担持量０．０５ｍｇ／ｃｍ２の超少量触媒金属担持電極Ｓを製作した。 [Example 15]
A carbon material having a functional group containing a nitrogen atom of 0.10 meq / g was prepared in the same manner as in Example 8 except that a nitro group was formed instead of a functional group containing an oxygen atom in the first step. Using this, the catalyst metal unsupported electrode S (weight: 2.2 mg / cm 2 ) of Example 15 was produced in the same manner as in Example 8 in the second step and thereafter. Using this catalyst metal unsupported electrode S, an ultra-small amount of catalyst metal-supported electrode S having a platinum load of 0.05 mg / cm 2 was manufactured in the same manner as in Example 8.

炭素材料にニトロ基を形成させる方法は、つぎのとおりである。最初に、炭素材料５０ｇを５Ｌビーカーに採取し、濃硝酸水溶液（１０ｍｏｌ／ｌ）１ｌと濃硫酸（１０ｍｏｌ／ｌ）１ｌとを混合した混合水溶液を加えた。この炭素材料と混合水溶液との混合物を撹拌しながら真空に引いた後、プロペラ式撹拌機で６０℃、１時間撹拌し、吸引ろ過して炭素材料と混合水溶液とを分離した。   The method for forming a nitro group on the carbon material is as follows. First, 50 g of the carbon material was collected in a 5 L beaker, and a mixed aqueous solution obtained by mixing 1 liter of concentrated nitric acid aqueous solution (10 mol / l) and 1 liter of concentrated sulfuric acid (10 mol / l) was added. The mixture of the carbon material and the mixed aqueous solution was evacuated while stirring, and then stirred with a propeller stirrer at 60 ° C. for 1 hour, and suction filtered to separate the carbon material and the mixed aqueous solution.

この炭素材料に脱イオン水（２ｌ）を加え、１０分間撹拌した後、吸引ろ過で炭素材料と脱イオン水とを分離した。最後に、この洗浄を５回繰り返して炭素材料を洗浄し、真空乾燥（１００℃、２４時間）した。この炭素材料の表面のニトロ基を昇温脱離ガス分析装置で定量したところ、０．１９ｍｅｑ／ｇ存在していた。
ニトロ基からアミノ基への変換は以下の工程でおこなった。まず、ニトロ基が形成された炭素材料２０ｇを５Ｌビーカーに採取し、塩酸水溶液（１．０ｍｏｌ／ｌ）２ｌに鉄を２．０ｇ溶解させた混合液を加えた。この炭素材料および塩酸と鉄との混合溶液の混合物を撹拌しながら真空に引いた後、プロペラ式撹拌機で1時間撹拌した。つぎに、この混合物を吸引ろ過して炭素材料から鉄と塩酸の混合液を分離した。 Deionized water (2 l) was added to the carbon material and stirred for 10 minutes, and then the carbon material and deionized water were separated by suction filtration. Finally, this cleaning was repeated 5 times to clean the carbon material and vacuum dried (100 ° C., 24 hours). When the nitro group on the surface of the carbon material was quantified with a temperature programmed desorption gas analyzer, it was found to be 0.19 meq / g.
Conversion from a nitro group to an amino group was performed in the following steps. First, 20 g of a carbon material in which a nitro group was formed was collected in a 5 L beaker, and a mixed solution in which 2.0 g of iron was dissolved in 2 l of a hydrochloric acid aqueous solution (1.0 mol / l) was added. The mixture of the carbon material and a mixed solution of hydrochloric acid and iron was evacuated while stirring, and then stirred with a propeller stirrer for 1 hour. Next, this mixture was subjected to suction filtration to separate a mixed solution of iron and hydrochloric acid from the carbon material.

この炭素材料に脱イオン水（２ｌ）を加え１０分間撹拌した後、吸引ろ過で炭素材料と脱イオン水とを分離した。最後に、この洗浄を５回繰り返して炭素材料を洗浄した後、真空乾燥（１００℃、２４時間）した。
［比較例５］
第１の工程において、０．０１ｍｏｌ／ｌの過酸化水素水の代わりに１５．０ｍｏｌ／ｌの硫酸を用いたこと以外は実施例８と同様にして、２０ｍｅｑ／ｇの窒素原子を含む官能基を備えた炭素材料を作製し、これを用いて、第２の工程以下は実施例８と同様にして、比較例５の触媒金属未担持電極Ｔを作製した。この触媒金属未担持電極Ｔを用いて、実施例８と同様にして、超少量触媒金属担持電極Ｔ（白金担持量０．０５ｍｇ／ｃｍ２）を製作した。 After adding deionized water (2 l) to this carbon material and stirring for 10 minutes, the carbon material and deionized water were separated by suction filtration. Finally, this washing was repeated 5 times to wash the carbon material, and then vacuum drying (100 ° C., 24 hours).
[Comparative Example 5]
A functional group containing 20 meq / g nitrogen atom in the same manner as in Example 8 except that 15.0 mol / l sulfuric acid was used instead of 0.01 mol / l hydrogen peroxide solution in the first step. A carbon material having a catalyst metal unsupported electrode T of Comparative Example 5 was produced in the same manner as in Example 8 in the second step and thereafter. Using this catalyst metal unsupported electrode T, an ultra-small amount of catalyst metal-supported electrode T (platinum supported amount of 0.05 mg / cm 2 ) was produced in the same manner as in Example 8.

［比較例６］
炭素材料を親水処理しなかったこと以外は実施例１４と同様にして、比較例６の触媒金属未担持電極Ｕおよび超少量触媒金属担持電極Ｕを製作した。炭素材料の表面に存在する窒素原子を含む官能基の量は、昇温脱離ガス分析装置で定量したところ０．０２ｍｅｑ／ｇであった。化学分析で求めたこの電極Ｕの白金担持量は０．０５ｍｇ／ｃｍ２であった。 [Comparative Example 6]
A catalyst metal unsupported electrode U and an ultra-small amount of catalyst metal supported electrode U of Comparative Example 6 were manufactured in the same manner as in Example 14 except that the carbon material was not subjected to hydrophilic treatment. The amount of the functional group containing nitrogen atoms present on the surface of the carbon material was 0.02 meq / g as determined by a temperature programmed desorption gas analyzer. The amount of platinum supported on this electrode U determined by chemical analysis was 0.05 mg / cm 2 .

［特性測定］
［電気二重層容量の測定］
実施例１〜６で作製した触媒金属未担持電極Ａ〜Ｆ、実施例８〜１３で作製した触媒金属未担持電極Ｌ〜Ｑ、比較例１の触媒金属未担持電極Ｈ、比較例２の触媒金属未担持電極Ｉ、比較例５の触媒金属未担持電極Ｔの電気二重層容量は、作用極にこれらの電極を備えた電気化学セルを作製することによって測定した。 [Characteristic measurement]
[Measurement of electric double layer capacity]
Catalyst metal unsupported electrodes A to F prepared in Examples 1 to 6, catalyst metal unsupported electrodes L to Q prepared in Examples 8 to 13, catalyst metal unsupported electrodes H of Comparative Example 1 and catalyst of Comparative Example 2 The electric double layer capacity of the metal unsupported electrode I and the catalyst metal unsupported electrode T of Comparative Example 5 was measured by preparing an electrochemical cell having these electrodes on the working electrode.

電気化学セルに用いる膜／電極接合体は、作用極として触媒金属未担持電極Ａ〜Ｆ、Ｌ〜Ｑ、Ｈ、ＩおよびＴ、対極として白金担持カーボンを用いた電極を陽イオン交換膜（ナフィオン１１５、厚み１２５μｍ、デュポン社製）の両側に加熱圧着することによって製作した。加熱圧着条件は、プレス面の温度を１３０℃で５分間保持することである。対極用電極は比較例４で製作したものと同様の電極を用いた。   The membrane / electrode assembly used in the electrochemical cell is a cation exchange membrane (Nafion), which is a catalyst metal unsupported electrode A to F, L to Q, H, I and T as a working electrode, and an electrode using platinum supported carbon as a counter electrode. 115, thickness 125 μm, manufactured by DuPont). The thermocompression bonding condition is to keep the temperature of the press surface at 130 ° C. for 5 minutes. The counter electrode was the same as that manufactured in Comparative Example 4.

つぎに、測定で用いる電気化学セルは、その接合体のそれぞれの面に、撥水性を付与した導電性多孔質体のカーボンペーパーを配したのちに、一対のガスフロープレートで挟持することによって製作した。そのセルを用いて、作用極のサイクリックボルタモグラムはアノードを対極として測定したのちに、電気二重層容量を算出した。   Next, the electrochemical cell used in the measurement is manufactured by placing conductive porous carbon paper with water repellency on each surface of the joined body and sandwiching it between a pair of gas flow plates. did. Using the cell, the cyclic voltammogram of the working electrode was measured with the anode as the counter electrode, and then the electric double layer capacity was calculated.

測定条件は次のとおりである。掃引速度は１００ｍＶ／ｓとし、作用極側にはＮ２ガス、対極側にはＨ２ガスをそれぞれ加湿温度２５℃で供給した。この測定で得られた０．４Ｖｖｓ．ＲＨＥでの電流密度を掃引速度および白金未担持電極１ｃｍ２当たりの重量で除することによって電気二重層容量を算出した。 The measurement conditions are as follows. The sweep rate was 100 mV / s, and N 2 gas was supplied to the working electrode side and H 2 gas was supplied to the counter electrode side at a humidification temperature of 25 ° C. The 0.4 V vs. obtained by this measurement. The electric double layer capacity was calculated by dividing the current density at RHE by the sweep rate and the weight per 1 cm 2 of platinum unsupported electrode.

実施例１〜６、比較例１および比較例２で製作した白金未担持電極の、炭素材料の表面に形成された親水性官能基の量と炭素電気二重層容量との関係を図４に示す。図４において、記号Ａ〜Ｆ、ＨおよびＩは、それぞれ触媒金属未担持電極Ａ〜Ｆ、ＨおよびＩの関係を示す。図４から、実施例1〜６の触媒金属未担持電極Ａ〜Ｆの電気二重層容量は、比較例１の触媒金属未担持電極Ｈの場合（２．４Ｆ／ｇ）と比べて、１１５％（実施例1、５．２Ｆ／ｇ）〜１５０％（実施例５、６．０Ｆ／ｇ）向上したことがわかる。   FIG. 4 shows the relationship between the amount of hydrophilic functional groups formed on the surface of the carbon material and the carbon electric double layer capacity of the platinum unsupported electrodes manufactured in Examples 1 to 6, Comparative Example 1 and Comparative Example 2. . In FIG. 4, symbols A to F, H, and I indicate the relationship between the catalyst metal unsupported electrodes A to F, H, and I, respectively. From FIG. 4, the electric double layer capacity of the catalyst metal unsupported electrodes A to F of Examples 1 to 6 is 115% as compared with the case of the catalyst metal unsupported electrode H of Comparative Example 1 (2.4 F / g). It can be seen that (Example 1, 5.2 F / g) to 150% (Example 5, 6.0 F / g) was improved.

電気二重層容量は、炭素材料と陽イオン交換樹脂と界面の面積と比例関係にある。したがって、実施例１〜６の触媒金属未担持電極Ａ〜Ｆの炭素材料と陽イオン交換樹脂と界面の面積は、比較例１の触媒金属未担持電極Ｈと比べて１１５％〜１５０％向上したことを示す。この界面の面積の増加は、炭素材料の表面が親水性に変化したことに起因するものと考えられる。   The electric double layer capacity is proportional to the area of the carbon material, the cation exchange resin, and the interface. Therefore, the area of the interface between the carbon material and the cation exchange resin of the catalyst metal unsupported electrodes A to F of Examples 1 to 6 was improved by 115% to 150% as compared with the catalyst metal unsupported electrode H of Comparative Example 1. It shows that. This increase in the area of the interface is considered to be caused by the change in the surface of the carbon material to hydrophilicity.

親水性官能基は、その官能基同士配向しやすい性質がある。すなわち、硫酸処理によって炭素材料の表面には親水性の官能基が備えられているので、陽イオン交換樹脂の親水性部分すなわちプロトン伝導経路部分は官能基が備えられている炭素材料の表面に配向しやすくなる。したがって、炭素材料の表面に陽イオン交換樹脂が均一かつ広域に被覆したと考えられる。   The hydrophilic functional group has a property of easily aligning the functional groups. That is, since the surface of the carbon material is provided with a hydrophilic functional group by the sulfuric acid treatment, the hydrophilic portion of the cation exchange resin, that is, the proton conduction path portion is oriented on the surface of the carbon material provided with the functional group. It becomes easy to do. Therefore, it is considered that the surface of the carbon material was uniformly and widely coated with the cation exchange resin.

さらに、図４から、比較例２の触媒金属未担持電極Ｉの電気二重層容量は、実施例１〜６の触媒金属未担持電極Ａ〜Ｆと比べて減少したことがわかる。電気二重層容量の減少は、親水性の官能基を形成する工程で炭素材料を強い酸化剤で処理したことによって、炭素材料が損壊したことに起因する。その結果、電極内の電子伝導経路が断絶し、電気二重層容量が低下したと考えられる。   Furthermore, it can be seen from FIG. 4 that the electric double layer capacity of the catalyst metal unsupported electrode I of Comparative Example 2 decreased as compared with the catalyst metal unsupported electrodes A to F of Examples 1 to 6. The decrease in the electric double layer capacity is caused by damage of the carbon material due to the treatment of the carbon material with a strong oxidizing agent in the step of forming the hydrophilic functional group. As a result, it is considered that the electron conduction path in the electrode was interrupted and the electric double layer capacity was reduced.

つぎに、実施例８〜１３、比較例１および比較例５で製作した白金未担持電極の、炭素材料の表面に形成された窒素原子を含む官能基の量と炭素電気二重層容量との関係を図５に示す。図５において、記号Ｌ〜Ｑ、ＨおよびＴは、それぞれ触媒金属未担持電極Ｌ〜Ｑ、ＨおよびＴの関係を示す。   Next, the relationship between the amount of functional groups containing nitrogen atoms formed on the surface of the carbon material and the carbon electric double layer capacity of the platinum-unsupported electrodes manufactured in Examples 8 to 13, Comparative Example 1 and Comparative Example 5 Is shown in FIG. In FIG. 5, symbols L to Q, H, and T indicate the relationship between the catalyst metal unsupported electrodes L to Q, H, and T, respectively.

図５から、実施例８〜１３の触媒金属未担持電極Ｌ〜Ｑの電気二重層容量は、比較例１の触媒金属未担持電極Ｈ（２．４Ｆ／ｇ）の場合と比べて１０４％（実施例８、４．９Ｆ／ｇ）〜１５０％（実施例１２、６．０Ｆ／ｇ）向上したことがわかる。   From FIG. 5, the electric double layer capacity of the catalyst metal unsupported electrodes L to Q of Examples 8 to 13 is 104% (compared to the case of the catalyst metal unsupported electrode H (2.4 F / g) of Comparative Example 1). It turns out that it improved by Example 8 and 4.9 F / g) -150% (Example 12, 6.0 F / g).

したがって、実施例８〜１３の触媒金属未担持電極Ｌ〜Ｑの炭素材料と陽イオン交換樹脂と界面の面積は、比較例１の触媒金属未担持電極Ｈと比べて１０４％〜１５０％向上したことを示す。この界面の面積の増加は、炭素材料の表面が親和性に変化したことに起因するものと考えられる。   Therefore, the area of the interface between the carbon material and the cation exchange resin of the catalyst metal unsupported electrodes L to Q of Examples 8 to 13 was improved by 104% to 150% as compared with the catalyst metal unsupported electrode H of Comparative Example 1. It shows that. This increase in the area of the interface is considered to be caused by the change in the surface of the carbon material to affinity.

炭素材料の表面に窒素原子を含む官能基を形成することにより、炭素材料表面と陽イオン交換樹脂との親和性が向上するので、炭素材料の表面に陽イオン交換樹脂が均一かつ広域に被覆したと考えられる。   By forming functional groups containing nitrogen atoms on the surface of the carbon material, the affinity between the surface of the carbon material and the cation exchange resin is improved, so that the surface of the carbon material is uniformly and widely coated with the cation exchange resin. it is conceivable that.

さらに、図５から、比較例５の触媒金属未担持電極Ｔの電気二重層容量は、実施例８の触媒金属未担持電極Ｌと比べて減少したことがわかる。この原因は、窒素原子を含む官能基を形成する工程で、炭素材料を反応性の大きい薬品で処理したことで、炭素材料が損壊したことに起因する。その結果、電極内の電子伝導経路が断絶し、電気二重層容量が低下したと考えられる。   Furthermore, it can be seen from FIG. 5 that the electric double layer capacity of the catalyst metal unsupported electrode T of Comparative Example 5 decreased as compared with the catalyst metal unsupported electrode L of Example 8. This is because the carbon material is damaged by treating the carbon material with a highly reactive chemical in the step of forming a functional group containing a nitrogen atom. As a result, it is considered that the electron conduction path in the electrode was interrupted and the electric double layer capacity was reduced.

［固体高分子形燃料電池特性の測定］
実施例１〜１５および比較例１〜６で製作した超少量触媒金属担持電極Ａ〜Ｕを備えた固体高分子形燃料電池の性能は、これらの電極を用いた膜／電極接合体を製作して測定した。膜／電極接合体は、カソード側、アノード側ともに超少量触媒金属担持電極を、陽イオン交換膜（ナフィオン１１５、厚み１２５μｍ、デュポン社製）の両側に加熱圧着することによって製作した。加熱条件は、プレス面の温度１３０℃で５分間保持である。 [Measurement of polymer electrolyte fuel cell characteristics]
The performance of the polymer electrolyte fuel cells having the ultra-small catalyst metal-supported electrodes A to U manufactured in Examples 1 to 15 and Comparative Examples 1 to 6 is based on the production of membrane / electrode assemblies using these electrodes. Measured. The membrane / electrode assembly was manufactured by thermocompression bonding an ultra-small amount of catalytic metal-supporting electrode on both the cathode side and the anode side to both sides of a cation exchange membrane (Nafion 115, thickness 125 μm, manufactured by DuPont). The heating condition is a press surface temperature of 130 ° C. for 5 minutes.

測定で用いる固体高分子形燃料電池は、膜／電極接合体のそれぞれの面に、撥水性を付与した導電性多孔質体のカーボンペーパーを配し、一対のガスフロープレートで挟持して製作した。超少量触媒金属担持電極Ａ〜Ｕを用いて、それぞれ固体高分子形燃料電池Ａ〜Ｕを製作した。   The polymer electrolyte fuel cell used in the measurement was manufactured by placing conductive porous carbon paper with water repellency on each surface of the membrane / electrode assembly and sandwiching it between a pair of gas flow plates. . Solid polymer fuel cells A to U were produced using ultra-small amount of catalytic metal-supported electrodes A to U, respectively.

これらの電池の性能は、電流−電圧特性の３００ｍＡ／ｃｍ２におけるセル電圧とした。測定条件は、セル温度を７０℃、アノードガスを純水素、アノード利用率を７０％、アノード加湿温度を７０℃、カソードガスを空気、カソード利用率４０％、カソード加湿温度を７０℃とした。 The performance of these batteries was a cell voltage at a current-voltage characteristic of 300 mA / cm 2 . The measurement conditions were a cell temperature of 70 ° C., an anode gas of pure hydrogen, an anode utilization factor of 70%, an anode humidification temperature of 70 ° C., a cathode gas of air, a cathode utilization factor of 40%, and a cathode humidification temperature of 70 ° C.

測定の結果、実施例１〜６（固体高分子形燃料電池Ａ〜Ｆ）、比較例１（固体高分子形燃料電池Ｈ）および比較例２（固体高分子形燃料電池Ｉ）で製作した燃料電池の、炭素材料に形成された親水性官能基の量と３００ｍＡ／ｃｍ２におけるセル電圧の関係を図６に示す。図６において、記号Ａ〜Ｆ、ＨおよびＩは、それぞれ固体高分子形燃料電池Ａ〜Ｆ、ＨおよびＩの関係を示す。 As a result of the measurement, the fuels produced in Examples 1 to 6 (solid polymer fuel cells A to F), Comparative example 1 (solid polymer fuel cell H) and Comparative example 2 (solid polymer fuel cell I). FIG. 6 shows the relationship between the amount of hydrophilic functional groups formed on the carbon material and the cell voltage at 300 mA / cm 2 in the battery. In FIG. 6, symbols A to F, H, and I indicate relationships among the polymer electrolyte fuel cells A to F, H, and I, respectively.

図６から、比較例１の燃料電池Ｈのセル電圧は０．５９５Ｖであり、この燃料電池Ｈに比べて、実施例１の燃料電池Ａのセル電圧は４１ｍＶ向上し、実施例２の燃料電池Ｂのセル電圧は４７ｍＶ向上し、実施例３の燃料電池Ｃのセル電圧は５４ｍＶ向上し、実施例４の燃料電池Ｄのセル電圧は５６ｍＶ向上し、実施例５の燃料電池Ｅのセル電圧は５８ｍＶ向上し、実施例６の燃料電池Ｆのセル電圧は５２ｍＶ向上した。   From FIG. 6, the cell voltage of the fuel cell H of Comparative Example 1 is 0.595 V. Compared to this fuel cell H, the cell voltage of the fuel cell A of Example 1 is improved by 41 mV, and the fuel cell of Example 2 The cell voltage of B is improved by 47 mV, the cell voltage of the fuel cell C of Example 3 is improved by 54 mV, the cell voltage of the fuel cell D of Example 4 is improved by 56 mV, and the cell voltage of the fuel cell E of Example 5 is The cell voltage of the fuel cell F of Example 6 was improved by 52 mV.

一方、比較例２で製作した超少量触媒金属担持電極Ｉを備えた固体高分子形燃料電池Ｉのセル電圧は０．５９６Ｖであり、実施例１の場合と比べて低い値を示した。   On the other hand, the cell voltage of the polymer electrolyte fuel cell I provided with the ultra-small catalyst metal-supporting electrode I manufactured in Comparative Example 2 was 0.596 V, which was lower than that in Example 1.

さらに、実施例７で製作した超少量触媒金属担持電極Ｇを備えた固体高分子形燃料電池Ｇのセル性能は０．６３７Ｖであり、比較例３の超少量触媒金属担持電極Ｊを備えた固体高分子形燃料電池Ｊの場合と比べて４５ｍＶ向上した。   Furthermore, the cell performance of the polymer electrolyte fuel cell G provided with the ultra-small catalyst metal-supported electrode G manufactured in Example 7 is 0.637 V, and the solid performance provided with the ultra-small catalyst metal-supported electrode J of Comparative Example 3 Compared with the polymer fuel cell J, it was improved by 45 mV.

また、比較例４で製作した既存の電極Ｋを備えた固体高分子形燃料電池Ｋのセル電圧は０．５９０Ｖであり、実施例１の場合と比べて低い値を示した。固体高分子形燃料電池Ｋのセル電圧の低下は、白金担持カーボン粉末を親水処理したことによって、陽イオン交換樹脂のプロトン伝導経路が白金の存在しな部分に接触したこと、および親水処理によって白金が脱落したことに起因するものと推察される。   Moreover, the cell voltage of the polymer electrolyte fuel cell K provided with the existing electrode K manufactured in Comparative Example 4 was 0.590 V, which was lower than that in Example 1. The decrease in the cell voltage of the polymer electrolyte fuel cell K is due to the fact that the platinum-carrying carbon powder has been subjected to a hydrophilic treatment, the proton conduction path of the cation exchange resin has come into contact with a portion where platinum is not present, and It is inferred that this is due to the dropout of

実施例１〜６（固体高分子形燃料電池Ａ〜Ｆ）、比較例１（固体高分子形燃料電池Ｈ）および比較例２（固体高分子形燃料電池Ｉ）で製作した燃料電池の、触媒金属未担持電極の二重層容量と３００ｍＡ／ｃｍ２におけるセル電圧の関係を図７に示す。図７において、記号Ａ〜Ｆ、ＨおよびＩは、それぞれ固体高分子形燃料電池Ａ〜Ｆ、ＨおよびＴの関係をＩ示す。 Catalysts of fuel cells produced in Examples 1 to 6 (solid polymer fuel cells A to F), Comparative example 1 (solid polymer fuel cell H) and Comparative example 2 (solid polymer fuel cell I) The relationship between the double layer capacity of the metal unsupported electrode and the cell voltage at 300 mA / cm 2 is shown in FIG. In FIG. 7, symbols A to F, H, and I indicate the relationship I between the polymer electrolyte fuel cells A to F, H, and T, respectively.

図７から、二重層容量の大きい触媒金属未担持電極から作製した超少量触媒金属担持電極を備えた実施例１〜６の固体高分子形燃料電池Ａ〜Ｆの性能は、二重層容量の小さい触媒金属未担持電極から製作した超少量触媒金属担持電極を備えた比較例１の固体高分子形燃料電池Ｈおよび比較例２の固体高分子形燃料電池Ｉに比べて向上することがわかった。   From FIG. 7, the performance of the polymer electrolyte fuel cells A to F of Examples 1 to 6 having the ultra small amount of catalyst metal supported electrode produced from the catalyst metal unsupported electrode having a large double layer capacity is small in the double layer capacity. It was found that the polymer electrolyte fuel cell H of Comparative Example 1 and the polymer electrolyte fuel cell I of Comparative Example 2 were improved compared to the polymer electrolyte fuel cell H of Comparative Example 1 and the ultra-small amount of catalyst metal supported electrode manufactured from the catalyst metal unsupported electrode.

実施例８〜１３（固体高分子形燃料電池Ｌ〜Ｑ）、比較例１（固体高分子形燃料電池Ｈ）および比較例５（固体高分子形燃料電池Ｔ）で製作した燃料電池の、炭素材料に形成された窒素原子を含む官能基の量と３００ｍＡ／ｃｍ２におけるセル電圧の関係を図８に示す。図８において、記号Ｌ〜Ｑ、ＨおよびＴは、それぞれ固体高分子形燃料電池Ｌ〜Ｑ、ＨおよびＴの関係を示す。 Carbon of the fuel cells produced in Examples 8 to 13 (solid polymer fuel cells L to Q), Comparative Example 1 (solid polymer fuel cell H) and Comparative Example 5 (solid polymer fuel cell T) FIG. 8 shows the relationship between the amount of functional groups containing nitrogen atoms formed in the material and the cell voltage at 300 mA / cm 2 . In FIG. 8, symbols L to Q, H, and T indicate the relationship between the polymer electrolyte fuel cells L to Q, H, and T, respectively.

図８から、比較例１の燃料電池Ｈのセル電圧は０．５９５Ｖであり、この燃料電池Ｈに比べて、実施例８の燃料電池Ｌのセル電圧は４０ｍＶ向上し、実施例９の燃料電池Ｍのセル電圧は４５ｍＶ向上し、実施例１０の燃料電池Ｎのセル電圧は５２ｍＶ向上し、実施例１１の燃料電池Ｏのセル電圧は５４ｍＶ向上し、実施例１２の燃料電池Ｐのセル電圧は５９ｍＶ向上し、実施例１３の燃料電池Ｑのセル電圧は５７ｍＶ向上した。   From FIG. 8, the cell voltage of the fuel cell H of Comparative Example 1 is 0.595 V. Compared with this fuel cell H, the cell voltage of the fuel cell L of Example 8 is improved by 40 mV, and the fuel cell of Example 9 The cell voltage of M is improved by 45 mV, the cell voltage of the fuel cell N of Example 10 is improved by 52 mV, the cell voltage of the fuel cell O of Example 11 is improved by 54 mV, and the cell voltage of the fuel cell P of Example 12 is The cell voltage of the fuel cell Q of Example 13 was improved by 57 mV.

一方、比較例５で製作した超少量触媒金属担持電極Ｔを備えた固体高分子形燃料電池Ｔのセル電圧は０．５８９Ｖであり、実施例８の場合と比べて低い値を示した。   On the other hand, the cell voltage of the polymer electrolyte fuel cell T provided with the ultra-small catalyst metal-carrying electrode T manufactured in Comparative Example 5 was 0.589 V, which was lower than that in Example 8.

さらに、実施例１４で製作した超少量触媒金属担持電極Ｒを備えた固体高分子形燃料電池Ｒのセル性能は０．６４０Ｖであり、比較例６の超少量触媒金属担持電極Ｕを備えた固体高分子形燃料電池Ｕの場合と比べて５０ｍＶ向上した。   Further, the cell performance of the polymer electrolyte fuel cell R having the ultra-small catalyst metal-supporting electrode R manufactured in Example 14 is 0.640 V, and the solid performance having the ultra-small catalyst metal-supporting electrode U of Comparative Example 6 is obtained. Compared with the polymer fuel cell U, it was improved by 50 mV.

また、実施例１５で製作した超少量触媒金属担持電極Ｕを備えた燃料電池Ｕのセル性能は０．６３９Ｖであり、比較例１の超少量触媒金属担持電極Ｈを備えた燃料電池Ｈの場合と比べて４９ｍＶ向上した。
実施例８〜１３（固体高分子形燃料電池Ｌ〜Ｑ）、比較例１（固体高分子形燃料電池Ｈ）および比較例５（固体高分子形燃料電池Ｔ）で製作した燃料電池の、触媒金属未担持電極の二重層容量と３００ｍＡ／ｃｍ２におけるセル電圧の関係を図９に示す。図９において、記号Ｌ〜Ｑ、ＨおよびＴは、それぞれ固体高分子形燃料電池Ｌ〜Ｑ、ＨおよびＴの関係を示す。 Further, the cell performance of the fuel cell U provided with the ultra-small catalyst metal-supported electrode U manufactured in Example 15 is 0.639 V, and in the case of the fuel cell H including the ultra-small catalyst metal-supported electrode H of Comparative Example 1 49 mV compared to the above.
Catalysts of fuel cells produced in Examples 8 to 13 (solid polymer fuel cells L to Q), Comparative example 1 (solid polymer fuel cell H) and Comparative example 5 (solid polymer fuel cell T) FIG. 9 shows the relationship between the double layer capacity of the metal unsupported electrode and the cell voltage at 300 mA / cm 2 . In FIG. 9, symbols L to Q, H, and T indicate the relationship between the polymer electrolyte fuel cells L to Q, H, and T, respectively.

図９から、二重層容量の大きい触媒金属未担持電極から作製した超少量触媒金属担持電極を備えた実施例８〜１３の固体高分子形燃料電池Ｌ〜Ｑの性能は、二重層容量の小さい触媒金属未担持電極から製作した超少量触媒金属担持電極を備えた比較例１の固体高分子形燃料電池Ｈおよび比較例５の固体高分子形燃料電池Ｔに比べて向上することがわかった。   From FIG. 9, the performance of the polymer electrolyte fuel cells L to Q of Examples 8 to 13 having ultra-small amount of catalyst metal-supported electrode produced from a catalyst metal unsupported electrode having a large double-layer capacity is small in double-layer capacity. It was found that the polymer electrolyte fuel cell H of Comparative Example 1 and the polymer electrolyte fuel cell T of Comparative Example 5 were improved as compared with the polymer electrolyte fuel cell H of Comparative Example 1 and the ultra-small amount of catalyst metal supported electrode manufactured from the catalyst metal unsupported electrode.

実施例１〜１５で作製した超少量触媒金属担持電極を備える固体高分子形燃料電池のセル電圧が向上したことは、炭素材料の表面に陽イオン交換樹脂が広くかつ均一に被覆されていることに起因すると考えられる。つまり、陽イオン交換樹脂のプロトン伝導経路に担持される触媒金属が小さくかつ高分散に存在によって触媒金属の活性が向上したこと、および炭素材料に被覆している陽イオン交換樹脂の厚みが減少することによってプロトン伝導経路内での水素原子あるいは酸素原子の拡散距離が短縮したことで電極反応の進行が促進されたためと考えられる。   The improvement in the cell voltage of the polymer electrolyte fuel cell provided with the ultra-small amount of catalytic metal-supported electrode produced in Examples 1 to 15 is that the surface of the carbon material is widely and uniformly coated with the cation exchange resin. It is thought to be caused by. That is, the catalytic metal supported on the proton conduction path of the cation exchange resin is small and highly dispersed, thereby improving the activity of the catalytic metal, and reducing the thickness of the cation exchange resin coated on the carbon material. This is thought to be because the progress of the electrode reaction was promoted by shortening the diffusion distance of hydrogen atoms or oxygen atoms in the proton conduction path.

以上の結果から、本発明の製造方法で製造された燃料電池用電極を用いることによって、固体高分子形燃料電池の性能が向上することがわかった。   From the above results, it was found that the performance of the polymer electrolyte fuel cell was improved by using the fuel cell electrode produced by the production method of the present invention.

本発明による超少量触媒金属担持電極に用いられる触媒の陽イオン交換樹脂と接触した炭素材料の表層の状態を示す模式図。The schematic diagram which shows the state of the surface layer of the carbon material which contacted the cation exchange resin of the catalyst used for the ultra-small amount catalyst metal carrying | support electrode by this invention. 従来の超少量触媒金属担持電極に用いられる触媒の陽イオン交換樹脂と接触した炭素材料の表層の状態を示す模式図。The schematic diagram which shows the state of the surface layer of the carbon material which contacted the cation exchange resin of the catalyst used for the conventional ultra-small catalyst metal carrying | support electrode. 白金担持炭素材料を用いた既存の電極の触媒の陽イオン交換樹脂と接触した炭素材料の表層の状態を示す模式図。The schematic diagram which shows the state of the surface layer of the carbon material which contacted the cation exchange resin of the catalyst of the existing electrode using a platinum carrying | support carbon material. 実施例１〜６および比較例１、２で製作した触媒金属未担持電極の、炭素材料の表面に形成された酸素原子を含む官能基の量と電気二重層容量との関係を示す図。The figure which shows the relationship between the quantity of the functional group containing the oxygen atom formed in the surface of the carbon material, and the electrical double layer capacity | capacitance of the catalyst metal unsupported electrode manufactured in Examples 1-6 and Comparative Examples 1 and 2. FIG. 実施例８〜１３および比較例１、５で製作した触媒金属未担持電極の、炭素材料の表面に形成された窒素原子を含む官能基の量と電気二重層容量との関係を示す図。The figure which shows the relationship between the quantity of the functional group containing the nitrogen atom formed in the surface of the carbon material, and the electric double layer capacity | capacitance of the catalyst metal unsupported electrode manufactured in Examples 8-13 and Comparative Examples 1 and 5. FIG. 実施例１〜６、比較例１および比較例２の固体高分子形燃料電池の、炭素材料に形成された酸素原子を含む官能基の量と３００ｍＡ／ｃｍ２におけるセル電圧の関係を示す図。The figure which shows the relationship between the amount of the functional group containing the oxygen atom formed in the carbon material, and the cell voltage in 300 mA / cm < 2 > of the polymer electrolyte fuel cell of Examples 1-6, the comparative example 1, and the comparative example 2. FIG. 実施例１〜６、比較例１および比較例２の固体高分子形燃料電池の、触媒金属未担持電極の二重層容量と３００ｍＡ／ｃｍ２におけるセル電圧の関係を示す図。The figure which shows the relationship of the cell voltage in 300 mA / cm < 2 > of the double layer capacity | capacitance of the catalyst metal unsupported electrode of the polymer electrolyte fuel cell of Examples 1-6, the comparative example 1, and the comparative example 2. FIG. 実施例８〜１３、比較例１および比較例５の固体高分子形燃料電池の、炭素材料に形成された窒素原子を含む官能基の量と３００ｍＡ／ｃｍ２におけるセル電圧の関係を示す図。The figure which shows the relationship between the amount of the functional group containing the nitrogen atom formed in the carbon material, and the cell voltage in 300 mA / cm < 2 > of the polymer electrolyte fuel cell of Examples 8-13, the comparative example 1, and the comparative example 5. FIG. 実施例８〜１３、比較例１および比較例５の固体高分子形燃料電池の、触媒金属未担持電極の二重層容量と３００ｍＡ／ｃｍ２におけるセル電圧の関係を示す図。The figure which shows the relationship of the cell voltage in 300 mA / cm < 2 > of the double layer capacity | capacitance of a catalyst metal unsupported electrode of the polymer electrolyte fuel cell of Examples 8-13, the comparative example 1, and the comparative example 5. FIG.

符号の説明Explanation of symbols

１１、２１、３１ 炭素材料
１２、２２、３２ 陽イオン交換樹脂
１３、２３、３３ 陽イオン交換樹脂のプロトン伝導経路
１４、２４、３４ 陽イオン交換樹脂の骨格部分
１５、２５、３５ 電気化学反応に関与する触媒金属
３６ 電気化学反応に対する活性が低い触媒金属
３７ 炭素材料の表面とプロトン伝導経路との界面に触媒金属が存在しない領域 11, 21, 31 Carbon material 12, 22, 32 Cation exchange resin 13, 23, 33 Proton conduction path of cation exchange resin 14, 24, 34 Skeletal portion of cation exchange resin 15, 25, 35 For electrochemical reaction Participating catalytic metals 36 Catalytic metals with low activity against electrochemical reactions 37 Regions where no catalytic metal exists at the interface between the surface of the carbon material and the proton conduction path

Claims (2)

炭素材料の表面に、０．１ｍｅｑ／ｇ以上１０．０ｍｅｑ／ｇ以下の範囲で酸素原子または窒素原子を含む官能基を備え、前記炭素材料の表面と陽イオン交換樹脂のプロトン伝導経路との接面に触媒金属が主に担持していることを特徴とする固体高分子形燃料電池用電極。 The surface of the carbon material is provided with a functional group containing an oxygen atom or a nitrogen atom in a range of 0.1 meq / g to 10.0 meq / g, and the surface of the carbon material is in contact with the proton conduction path of the cation exchange resin. An electrode for a polymer electrolyte fuel cell, characterized in that a catalytic metal is mainly supported on the surface. 炭素材料の表面に、酸素原子または窒素原子を含む官能基を０．１ｍｅｑ／ｇ以上１０．０ｍｅｑ／ｇ以下の範囲で形成する第１の工程と、前記炭素材料を陽イオン交換樹脂の溶液に分散して分散物を得る第２の工程と、前記分散物から溶媒を除去して炭素材料と陽イオン交換樹脂の混合物を得る第３の工程と、前記陽イオン交換樹脂の固定イオンに触媒金属の陽イオンを吸着させる第４の工程と、前記陽イオンを化学的に還元する第５の工程を経ることを特徴とする固体高分子形燃料電池用電極の製造方法。





























A first step of forming a functional group containing an oxygen atom or a nitrogen atom on the surface of the carbon material in a range of 0.1 meq / g to 10.0 meq / g; and the carbon material in a cation exchange resin solution. A second step of dispersing to obtain a dispersion; a third step of removing a solvent from the dispersion to obtain a mixture of a carbon material and a cation exchange resin; and a catalyst metal as a fixed ion of the cation exchange resin. A method for producing an electrode for a polymer electrolyte fuel cell, comprising a fourth step of adsorbing the cation and a fifth step of chemically reducing the cation.





























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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008077956A (en) * 2006-09-21 2008-04-03 Toppan Printing Co Ltd Varnish for forming catalyst electrode for fuel cell, catalytic electrode using it, membrane electrode assembly using it, fuel cell using it
JP2008269850A (en) * 2007-04-17 2008-11-06 Nippon Steel Corp Catalyst for electrode of polymer electrolyte fuel cell
JP2009277360A (en) * 2008-05-12 2009-11-26 Japan Carlit Co Ltd:The Catalyst carrier, catalyst body, and manufacturing method for them
JP2013058436A (en) * 2011-09-09 2013-03-28 Tokyo Institute Of Technology Electrode catalyst for polymer electrolyte fuel cell and method for manufacturing the same
JP2017208224A (en) * 2016-05-18 2017-11-24 新日鐵住金株式会社 Carbon material for catalyst carrier, method for evaluation and test of resin adsorption of polyethylene glycol resin of carbon material for catalyst carrier, catalyst for solid polymer type fuel battery, catalyst layer for solid polymer type fuel battery, and solid polymer type fuel battery

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008077956A (en) * 2006-09-21 2008-04-03 Toppan Printing Co Ltd Varnish for forming catalyst electrode for fuel cell, catalytic electrode using it, membrane electrode assembly using it, fuel cell using it
JP2008269850A (en) * 2007-04-17 2008-11-06 Nippon Steel Corp Catalyst for electrode of polymer electrolyte fuel cell
JP2009277360A (en) * 2008-05-12 2009-11-26 Japan Carlit Co Ltd:The Catalyst carrier, catalyst body, and manufacturing method for them
JP2013058436A (en) * 2011-09-09 2013-03-28 Tokyo Institute Of Technology Electrode catalyst for polymer electrolyte fuel cell and method for manufacturing the same
JP2017208224A (en) * 2016-05-18 2017-11-24 新日鐵住金株式会社 Carbon material for catalyst carrier, method for evaluation and test of resin adsorption of polyethylene glycol resin of carbon material for catalyst carrier, catalyst for solid polymer type fuel battery, catalyst layer for solid polymer type fuel battery, and solid polymer type fuel battery
JP7094075B2 (en) 2016-05-18 2022-07-01 日本製鉄株式会社 Carbon material for catalyst carrier, catalyst for polymer electrolyte fuel cell, catalyst layer for polymer electrolyte fuel cell, and polymer electrolyte fuel cell

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