JP4451154B2 - Electrolyte membrane electrode assembly for polymer electrolyte fuel cell and polymer electrolyte fuel cell - Google Patents
Electrolyte membrane electrode assembly for polymer electrolyte fuel cell and polymer electrolyte fuel cell Download PDFInfo
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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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
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Description
本発明は、固体高分子型燃料電池に関し、特に固体高分子型燃料電池に用いられる電解質膜電極接合体に関する。 The present invention relates to a polymer electrolyte fuel cell, and more particularly to an electrolyte membrane electrode assembly used in a polymer electrolyte fuel cell.
ガスの電気化学反応により電気を発生させる燃料電池は、発電効率が高く、排出されるガスがクリーンで環境に対する影響が極めて少ない。そのため、近年、発電用、低公害の自動車用電源等、種々の用途が期待されている。 A fuel cell that generates electricity by an electrochemical reaction of gas has high power generation efficiency, clean gas discharged, and extremely little influence on the environment. Therefore, in recent years, various uses such as power generation and low-pollution automobile power supplies are expected.
なかでも、固体高分子型燃料電池は、80℃程度の低温で作動させることができ、大きな出力密度を有する。固体高分子型燃料電池は、通常、プロトン導電性のある高分子膜を電解質とする。電解質となる高分子膜(電解質膜)の両側にそれぞれ燃料極、酸素極となる一対の電極が設けられ電解質膜電極接合体(MEA)が構成される。この電解質膜電極接合体をセパレータで挟持した単セルが発電単位となる。そして、水素や炭化水素等の燃料ガスを燃料極に、酸素や空気等の酸化剤ガスを酸素極にそれぞれ供給し、ガスと電解質と電極との三相界面における電気化学反応により発電を行う。 Among them, the polymer electrolyte fuel cell can be operated at a low temperature of about 80 ° C. and has a large output density. In general, a polymer electrolyte fuel cell uses a polymer film having proton conductivity as an electrolyte. A pair of electrodes each serving as a fuel electrode and an oxygen electrode are provided on both sides of a polymer film (electrolyte film) serving as an electrolyte to constitute an electrolyte membrane electrode assembly (MEA). A single cell in which the electrolyte membrane electrode assembly is sandwiched between separators serves as a power generation unit. Then, a fuel gas such as hydrogen or hydrocarbon is supplied to the fuel electrode, and an oxidant gas such as oxygen or air is supplied to the oxygen electrode, and power is generated by an electrochemical reaction at the three-phase interface between the gas, the electrolyte, and the electrode.
しかし、固体高分子型燃料電池は、長期間の運転により、電池性能が低下してしまうという問題を有する。電池性能の低下の原因としては、例えば、電解質膜や電極の劣化が挙げられる。固体高分子型燃料電池の運転時には、酸素極において、水素と酸素とから水が生成される。しかし、運転条件等によっては、酸素極における酸素の還元が2電子反応で止まってしまい、過酸化水素(H2O2)が生成されることがある。生成された過酸化水素は、例えば、金属イオン等の存在下でラジカル分解する。その過酸化水素ラジカルにより、電解質膜や電極が損傷を受け劣化すると考えられる。 However, the polymer electrolyte fuel cell has a problem that the battery performance is deteriorated by long-term operation. As a cause of the decrease in battery performance, for example, deterioration of an electrolyte membrane or an electrode can be mentioned. During operation of the polymer electrolyte fuel cell, water is generated from hydrogen and oxygen at the oxygen electrode. However, depending on the operating conditions, the reduction of oxygen at the oxygen electrode may be stopped by a two-electron reaction, and hydrogen peroxide (H 2 O 2 ) may be generated. The generated hydrogen peroxide undergoes radical decomposition in the presence of, for example, metal ions. The hydrogen peroxide radical is thought to damage and deteriorate the electrolyte membrane and the electrode.
また、電解質膜の多くは、炭化水素系材料あるいはフッ素系材料からなる高分子膜である。従来、フッ素系電解質膜は、過酸化水素等の過酸化物によりほとんど損傷を受けないと考えられてきた。しかし、種々検討を重ねた結果、フッ素系電解質膜であっても、過酸化物により損傷を受ける場合があるということがわかった。この場合、過酸化物によりC−F結合が分解されるため、フッ酸等が生じる問題がある。 Many of the electrolyte membranes are polymer membranes made of a hydrocarbon material or a fluorine material. Conventionally, it has been considered that a fluorine-based electrolyte membrane is hardly damaged by peroxides such as hydrogen peroxide. However, as a result of various studies, it has been found that even a fluorine-based electrolyte membrane may be damaged by peroxide. In this case, since the C—F bond is decomposed by the peroxide, there is a problem that hydrofluoric acid or the like is generated.
過酸化物による電解質膜等の劣化を抑制し、燃料電池の耐久性を向上させる試みとして、例えば、ルテニウム、マンガン、コバルト等の金属、若しくはそれらの酸化物等を、電解質膜や電極に含有させることが提案されている(例えば、特許文献1、2参照。)。
しかしながら、上記特許文献1、2に示された手法では、含有させる金属及びその酸化物として、資源量が少なく高価な金属を用いる。そのため、資源の確保、コストの面において、実用化には問題がある。また、過酸化物の分解効果を向上させるべく、上記金属や酸化物の含有量を増加させると、電池反応が阻害されてしまうという問題もある。さらにまた、固体高分子型燃料電池の運転時には、電池内部は80℃程度の高温下、酸性雰囲気等の過酷な環境となる。このような高温かつ酸性の条件下では、含有させた金属や酸化物は溶出し易い。それ故、過酸化物の分解効果を持続させることは難しい。 However, in the methods disclosed in Patent Documents 1 and 2, an expensive metal having a small amount of resources is used as the metal to be contained and its oxide. Therefore, there is a problem in practical use in terms of securing resources and costs. Moreover, when the content of the metal or oxide is increased in order to improve the decomposition effect of the peroxide, there is a problem that the battery reaction is inhibited. Furthermore, when the polymer electrolyte fuel cell is operated, the inside of the cell becomes a severe environment such as an acidic atmosphere at a high temperature of about 80 ° C. Under such high temperature and acidic conditions, the contained metals and oxides are easily eluted. Therefore, it is difficult to maintain the peroxide decomposition effect.
本発明は、このような実状に鑑みてなされたものであり、過酸化物を分解する過酸化物分解触媒を多量に用いることなく、電池内で生成された過酸化水素等の過酸化物を効率良く分解することができる固体高分子型燃料電池用電解質膜電極接合体を提供することを課題とする。また、その電解質膜電極接合体を用いることにより、長期間運転した場合でも、電池性能が低下し難い固体高分子型燃料電池を提供することを課題とする。 The present invention has been made in view of such a situation, and without using a large amount of a peroxide decomposition catalyst for decomposing a peroxide, a peroxide such as hydrogen peroxide generated in the battery is used. It is an object of the present invention to provide an electrolyte membrane electrode assembly for a polymer electrolyte fuel cell that can be efficiently decomposed. Another object of the present invention is to provide a polymer electrolyte fuel cell in which the cell performance is hardly deteriorated even when operated for a long time by using the electrolyte membrane electrode assembly.
本発明の固体高分子型燃料電池用電解質膜電極接合体は、イオン導電性を有する電解質膜と、該電解質膜の両側に設けられた一対の電極と、を備え、前記一対の電極の少なくとも一方の触媒層は、前記電解質膜側に配置されて過酸化物を分解する過酸化物分解触媒を含有する過酸化物分解触媒含有層と、前記過酸化物分解触媒を含有しない過酸化物分解触媒非含有層とから構成され、前記過酸化物分解触媒含有層は、厚さ方向に前記過酸化物分解触媒の濃度が異なり、前記過酸化物分解触媒は、前記電解質膜側に向かって濃度値が増加するよう配置されることを特徴とする。 An electrolyte membrane electrode assembly for a polymer electrolyte fuel cell of the present invention comprises an electrolyte membrane having ionic conductivity, and a pair of electrodes provided on both sides of the electrolyte membrane, and at least one of the pair of electrodes The catalyst layer includes a peroxide decomposition catalyst-containing layer that is disposed on the electrolyte membrane side and contains a peroxide decomposition catalyst that decomposes the peroxide, and a peroxide decomposition catalyst that does not contain the peroxide decomposition catalyst. It is composed of a non-containing layer, wherein the peroxide decomposition catalyst-containing layer, the concentration of the peroxide decomposition catalyst in the thickness direction Ri Do different, the peroxide decomposition catalyst, toward the electrolyte membrane side concentration It is arranged to increase the value .
本発明の電解質膜電極接合体では、電解質膜の両側にそれぞれ燃料極、酸素極となる一対の電極が配置される。この燃料極および酸素極の少なくとも一方の触媒層は、前記電解質膜側に配置されて過酸化物分解触媒を含有する過酸化物分解触媒含有層と、過酸化物分解触媒を含有しない過酸化物分解触媒非含有層とから構成される。 In the electrolyte membrane electrode assembly of the present invention, a pair of electrodes that are respectively a fuel electrode and an oxygen electrode are disposed on both sides of the electrolyte membrane. At least one catalyst layer of the fuel electrode and the oxygen electrode includes a peroxide decomposition catalyst-containing layer that is disposed on the electrolyte membrane side and contains a peroxide decomposition catalyst, and a peroxide that does not contain a peroxide decomposition catalyst It is comprised from a cracking catalyst non-containing layer.
過酸化物分解触媒含有層は、厚さ方向に過酸化物分解触媒の濃度を異ならせる。The peroxide decomposition catalyst-containing layer varies the concentration of the peroxide decomposition catalyst in the thickness direction.
例えば、過酸化物分解触媒を、過酸化物が多く生成すると予想される領域には、その濃度が高くなるよう配置し、そうでない領域には、その濃度が低くなるよう配置する。このように配置することで、過酸化物分解触媒を増量することなく、効果的に過酸化物を分解することができる。また、過酸化物分解触媒を、電解質膜と電極との界面付近に、その濃度が高くなるよう配置すると、生成した過酸化物の電解質膜への拡散を、効果的に抑制することができる。 For example, the peroxide decomposition catalyst is disposed so that the concentration thereof is increased in a region where a large amount of peroxide is expected to be generated, and the concentration is decreased in a region where the peroxide decomposition catalyst is not. By arranging in this way, the peroxide can be effectively decomposed without increasing the amount of the peroxide decomposition catalyst. In addition, if the peroxide decomposition catalyst is arranged in the vicinity of the interface between the electrolyte membrane and the electrode so as to have a high concentration, diffusion of the generated peroxide into the electrolyte membrane can be effectively suppressed.
このように、本発明の電解質膜電極接合体では、厚さ方向に過酸化物分解触媒の濃度を異ならせることにより、過酸化物の生成、拡散状態に応じて、過酸化物を効率的に分解、無害化することができる。それ故、使用する過酸化物分解触が少量であっても、電極および電解質膜の劣化抑制効果は高い。また、本発明の電解質膜電極接合体は、少量の過酸化物分解触媒で、効率良く過酸化物を分解することができるため、コスト面でも実用的である。 As described above, in the electrolyte membrane electrode assembly of the present invention, by changing the concentration of the peroxide decomposition catalyst in the thickness direction, the peroxide is efficiently generated according to the generation and diffusion state of the peroxide. It can be decomposed and detoxified. Therefore, even if a small amount of peroxide decomposition contact is used, the effect of suppressing deterioration of the electrode and the electrolyte membrane is high. The electrolyte membrane electrode assembly of the present invention is practical in terms of cost because it can efficiently decompose peroxide with a small amount of peroxide decomposition catalyst.
本発明の固体高分子型燃料電池は、上記本発明の電解質膜電極接合体を備えることを特徴とする。すなわち、本発明の固体高分子型燃料電池では、運転時に過酸化物が生成しても、過酸化物は過酸化物分解触媒により速やかに分解される。そのため、運転時における電解質膜や電極の劣化が少なく、長期間運転した場合でも電池性能の低下は少ない。 A polymer electrolyte fuel cell according to the present invention includes the above-described electrolyte membrane electrode assembly according to the present invention. That is, in the polymer electrolyte fuel cell of the present invention, even if peroxide is generated during operation, the peroxide is rapidly decomposed by the peroxide decomposition catalyst. For this reason, there is little deterioration of the electrolyte membrane and the electrode during operation, and there is little decrease in battery performance even when operated for a long period of time.
本発明の固体高分子型燃料電池用電解質膜電極接合体では、一対の電極の少なくとも一方の触媒層は電解質膜側に配置される過酸化物分解触媒含有層と、過酸化物分解触媒非含有層とから構成され、過酸化物分解触媒含有層は厚さ方向に前記過酸化物分解触媒の濃度を異ならせ、過酸化物分解触媒は電解質膜側に向かって濃度値が増加するよう配置される。そのため、過酸化物の生成、拡散状態に応じて、過酸化物を効率的に分解、無害化することができる。したがって、本発明の電解質膜電極接合体を備えた固体高分子型燃料電池では、電極や電解質膜の劣化が少なく、長期間運転した場合でも電池性能の低下は少ない。 In the electrolyte membrane electrode assembly for a polymer electrolyte fuel cell of the present invention, at least one catalyst layer of the pair of electrodes includes a peroxide decomposition catalyst-containing layer disposed on the electrolyte membrane side, and a peroxide decomposition catalyst not contained The peroxide decomposition catalyst-containing layer is arranged so that the concentration of the peroxide decomposition catalyst varies in the thickness direction, and the concentration value of the peroxide decomposition catalyst increases toward the electrolyte membrane side. The Therefore, the peroxide can be efficiently decomposed and detoxified according to the generation and diffusion state of the peroxide. Therefore, in the polymer electrolyte fuel cell provided with the electrolyte membrane electrode assembly of the present invention, there is little deterioration of the electrode and the electrolyte membrane, and even when the battery is operated for a long time, the battery performance is hardly lowered.
以下に、本発明の固体高分子型燃料電池用電解質膜電極接合体および固体高分子型燃料電池の実施形態を説明する。なお、本発明の固体高分子型燃料電池用電解質膜電極接合体および固体高分子型燃料電池は、下記の実施形態に限定されるものではない。本発明の固体高分子型燃料電池用電解質膜電極接合体および固体高分子型燃料電池は、本発明の要旨を逸脱しない範囲において、当業者が行い得る変更、改良等を施した種々の形態にて実施することができる。 Hereinafter, embodiments of the electrolyte membrane electrode assembly for a polymer electrolyte fuel cell and the polymer electrolyte fuel cell of the present invention will be described. In addition, the electrolyte membrane electrode assembly for polymer electrolyte fuel cells and the polymer electrolyte fuel cell of the present invention are not limited to the following embodiments. The electrolyte membrane electrode assembly for a polymer electrolyte fuel cell and the polymer electrolyte fuel cell of the present invention are in various forms that have been modified or improved by those skilled in the art without departing from the gist of the present invention. Can be implemented.
〈固体高分子型燃料電池用電解質膜電極接合体〉
本発明の電解質膜電極接合体は、イオン導電性を有する電解質膜と、該電解質膜の両側に設けられた一対の電極と、を備え、前記一対の電極の少なくとも一方に、過酸化物を分解する過酸化物分解触媒が濃度差をもって配置される。
<Electrolyte membrane electrode assembly for polymer electrolyte fuel cell>
An electrolyte membrane electrode assembly of the present invention includes an electrolyte membrane having ionic conductivity and a pair of electrodes provided on both sides of the electrolyte membrane, and decomposes peroxide into at least one of the pair of electrodes. Peroxide decomposition catalysts are arranged with a concentration difference.
一般に、一対の電極、つまり、燃料極および酸素極は、それぞれ触媒層と拡散層とから構成される。触媒層は、電気化学反応の反応場であり、カーボンに担持された白金等の電極触媒と高分子電解質とを含む。拡散層は、触媒層への反応ガスの供給と、触媒層との間で電子の授受を行う役割を果たし、カーボンクロス等の多孔質材料からなる。電解質膜の両表面には、それぞれ各電極の触媒層が形成され、各々の触媒層の表面には、拡散層が積層される。 In general, a pair of electrodes, that is, a fuel electrode and an oxygen electrode are each composed of a catalyst layer and a diffusion layer. The catalyst layer is a reaction field for an electrochemical reaction, and includes an electrode catalyst such as platinum supported on carbon and a polymer electrolyte. The diffusion layer serves to supply a reaction gas to the catalyst layer and exchange electrons with the catalyst layer, and is made of a porous material such as carbon cloth. A catalyst layer for each electrode is formed on both surfaces of the electrolyte membrane, and a diffusion layer is laminated on the surface of each catalyst layer.
この場合、過酸化物分解触媒は、電極を構成する触媒層に配置されることが望ましい。過酸化物分解触媒を触媒層に配置することで、生成した過酸化物を速やかに分解することができることに加え、隣接する電解質膜への過酸化物の拡散も効果的に抑制することができる。 In this case, it is desirable that the peroxide decomposition catalyst is disposed in the catalyst layer constituting the electrode. By arranging the peroxide decomposition catalyst in the catalyst layer, in addition to being able to decompose the generated peroxide quickly, it is also possible to effectively suppress the diffusion of the peroxide to the adjacent electrolyte membrane. .
また、過酸化物分解触媒は、燃料極および酸素極のいずれか一方に配置されていてもよく、あるいは両方に配置されていてもよい。特に、生成した過酸化物を速やかに分解するという観点から、過酸化物分解触媒を酸素極に配置することが望ましい。 Further, the peroxide decomposition catalyst may be disposed on either the fuel electrode or the oxygen electrode, or may be disposed on both. In particular, it is desirable to dispose the peroxide decomposition catalyst at the oxygen electrode from the viewpoint of rapidly decomposing the generated peroxide.
過酸化物分解触媒は、電極において濃度差をもって配置される。濃度差は、電極の厚さ方向にあってもよく、電極の面方向にあってもよい。濃度差の付け方は、特に限定されるものではなく、過酸化物の生成、拡散状態に応じて、適宜調整すればよい。例えば、電極の厚さ方向あるいは面方向において、濃度が段階的に変化するよう、濃度差を階段状につけてもよく、濃度が略連続的に変化するような濃度勾配をもたせてもよい。また、ある領域にのみ過酸化物分解触媒を配置して、過酸化物分解触媒を配置しない他の領域との濃度差をつけてもよい。 The peroxide decomposition catalyst is arranged with a concentration difference in the electrode. The concentration difference may be in the thickness direction of the electrode or in the surface direction of the electrode. The method of assigning the concentration difference is not particularly limited, and may be appropriately adjusted according to the generation of peroxide and the diffusion state. For example, the concentration difference may be stepped so that the concentration changes stepwise in the thickness direction or the surface direction of the electrode, or a concentration gradient may be provided so that the concentration changes substantially continuously. Further, the peroxide decomposition catalyst may be arranged only in a certain region, and the concentration difference from other regions where the peroxide decomposition catalyst is not arranged may be given.
なかでも、過酸化物分解触媒を電極の厚さ方向に濃度差をもって配置することが望ましい。この場合、電解質膜側に向かって濃度値が増加する態様がより望ましい。電極の電解質膜側に過酸化物分解触媒を多く配置することで、電解質膜への過酸化物の拡散を、より効果的に抑制することができる。 In particular, it is desirable to dispose the peroxide decomposition catalyst with a concentration difference in the thickness direction of the electrode. In this case, a mode in which the concentration value increases toward the electrolyte membrane side is more desirable. By disposing many peroxide decomposition catalysts on the electrolyte membrane side of the electrode, it is possible to more effectively suppress the diffusion of the peroxide into the electrolyte membrane.
また、上記態様において、電解質膜と電極との界面付近における過酸化物分解触媒の濃度は、過酸化物分解触媒の種類や、供給されるガスの加湿の程度にもよるが、1wt%以上であることが望ましい。1wt%未満の場合には、過酸化物の分解効果および電解質膜への拡散抑制効果が小さいからである。3wt%以上であるとより好適である。一方、電極における電気化学反応への影響を考慮すると、過酸化物分解触媒の濃度は、8wt%以下であることが望ましい。5wt%以下であるとより好適である。これら過酸化物分解触媒の濃度値は、過酸化物分解触媒を電極の触媒層に配置した場合には、触媒層の全体重量を100wt%とした場合の過酸化物分解触媒の重量割合である。 In the above embodiment, the concentration of the peroxide decomposition catalyst in the vicinity of the interface between the electrolyte membrane and the electrode is 1 wt% or more, although it depends on the type of peroxide decomposition catalyst and the degree of humidification of the supplied gas. It is desirable to be. This is because when the content is less than 1 wt%, the effect of peroxide decomposition and the effect of suppressing diffusion into the electrolyte membrane are small. It is more preferable that it is 3 wt% or more. On the other hand, considering the influence on the electrochemical reaction at the electrode, the concentration of the peroxide decomposition catalyst is desirably 8 wt% or less. More preferably, it is 5 wt% or less. The concentration value of the peroxide decomposition catalyst is the weight ratio of the peroxide decomposition catalyst when the total weight of the catalyst layer is 100 wt% when the peroxide decomposition catalyst is arranged in the catalyst layer of the electrode. .
電極における過酸化物分解触媒の濃度差の有無は、例えば、電極をSIMS(二次イオン質量分析装置)により測定することで、あるいは、電極断面をEPMA(電子線マイクロアナリシス法)により測定することで、確認することができる。 The presence or absence of a difference in the concentration of the peroxide decomposition catalyst in the electrode can be measured, for example, by measuring the electrode with a SIMS (secondary ion mass spectrometer) or measuring the electrode cross section with an EPMA (electron beam microanalysis method). You can confirm it.
過酸化物分解触媒は、過酸化物を分解する触媒作用を有するものであれば、特に限定されるものではない。例えば、金属、金属酸化物、金属リン酸塩、金属フッ化物、大環状金属錯体等が挙げられる。これらから選ばれる一種を単独で用いるか、あるいは二種以上を併用すればよい。なかでも、金属としてはRu、Ag等、金属酸化物としては、RuO2、WO3、CeO2、Fe3O4等、金属リン酸塩としてはCePO4、CrPO4、AlPO4、FePO4等、金属フッ化物としてはCeF3、FeF3等、大環状金属錯体としてはFe−ポルフィリン、Co−ポルフィリン、ヘム、カタラーゼ等が好適である。特に、過酸化物の分解性能が高いという理由から、RuO2、CePO4を用いるとよい。 The peroxide decomposition catalyst is not particularly limited as long as it has a catalytic action for decomposing peroxide. For example, a metal, a metal oxide, a metal phosphate, a metal fluoride, a macrocyclic metal complex, etc. are mentioned. One kind selected from these may be used alone, or two or more kinds may be used in combination. Among these, as the metal is Ru, Ag, etc., as the metal oxide, RuO 2, WO 3, CeO 2, Fe 3 O 4 , etc., as metal phosphates CePO 4, CrPO 4, AlPO 4 , FePO 4 , etc. As the metal fluoride, CeF 3 , FeF 3 and the like are suitable, and as the macrocyclic metal complex, Fe-porphyrin, Co-porphyrin, heme, catalase and the like are suitable. In particular, RuO 2 and CePO 4 are preferably used because of their high peroxide decomposition performance.
本発明の電解質膜電極接合体の作製方法は、特に限定されるものではないが、例えば、以下の方法により簡便に作製することができる。 The method for producing the electrolyte membrane electrode assembly of the present invention is not particularly limited, but for example, it can be easily produced by the following method.
第一の方法は、触媒層を形成するための触媒インクに、過酸化物分解触媒を混合する方法である。まず、電極触媒と高分子電解質とを水やアルコール等の溶媒に分散させた触媒インクに、過酸化物分解触媒を適宜混合し、過酸化物分解触媒の濃度の異なる種々の触媒インクを調製する。次いで、調製した種々の触媒インクを、ドクターブレード法、スプレー法、スピンコート法等により電解質膜の表面に重ね塗りし、厚さ方向に過酸化物分解触媒濃度の異なる触媒層を、電解質膜表面に形成する。 The first method is a method in which a peroxide decomposition catalyst is mixed with catalyst ink for forming a catalyst layer. First, a catalyst ink in which an electrode catalyst and a polymer electrolyte are dispersed in a solvent such as water or alcohol is appropriately mixed with a peroxide decomposition catalyst to prepare various catalyst inks having different concentrations of the peroxide decomposition catalyst. . Next, various prepared catalyst inks are overcoated on the surface of the electrolyte membrane by the doctor blade method, spray method, spin coating method, etc., and catalyst layers having different peroxide decomposition catalyst concentrations in the thickness direction are applied to the surface of the electrolyte membrane. To form.
また、上記調製した種々の触媒インクを、PTFE製シートの表面に重ね塗りし、厚さ方向に過酸化物分解触媒濃度の異なる触媒層を、該シート表面に形成する。次いで、シート表面に形成された触媒層を、電解質膜の表面にホットプレス等により圧着する。圧着後、シートを剥離して、厚さ方向に過酸化物分解触媒濃度の異なる触媒層を、電解質膜表面に形成する。 Further, the various prepared catalyst inks are overcoated on the surface of the PTFE sheet, and catalyst layers having different peroxide decomposition catalyst concentrations in the thickness direction are formed on the sheet surface. Next, the catalyst layer formed on the sheet surface is pressure-bonded to the surface of the electrolyte membrane by hot pressing or the like. After the pressure bonding, the sheet is peeled, and catalyst layers having different peroxide decomposition catalyst concentrations in the thickness direction are formed on the electrolyte membrane surface.
第二の方法は、触媒層形成用粉末に、過酸化物分解触媒を混合する方法である。まず、電極触媒と高分子電解質とからなる触媒層形成用粉末に、過酸化物分解触媒を適宜混合し、過酸化物分解触媒の濃度の異なる種々の触媒層形成用粉末を調製する。次いで、調製した種々の触媒層形成用粉末を、金属製支持体に順次静電塗布し、あるいは、コロナ放電等により順次付着させ、厚さ方向に過酸化物分解触媒濃度の異なる触媒層を、金属製支持体表面に形成する。次いで、金属製支持体表面に形成された触媒層を、電解質膜の表面にホットプレス等により圧着する。圧着後、金属製支持体を剥離して、厚さ方向に過酸化物分解触媒濃度の異なる触媒層を、電解質膜表面に形成する。 The second method is a method of mixing a peroxide decomposition catalyst with the catalyst layer forming powder. First, a catalyst layer forming powder composed of an electrode catalyst and a polymer electrolyte is appropriately mixed with a peroxide decomposition catalyst to prepare various catalyst layer forming powders having different concentrations of the peroxide decomposition catalyst. Next, various prepared catalyst layer forming powders are sequentially electrostatically applied to a metal support, or sequentially adhered by corona discharge or the like, and catalyst layers having different peroxide decomposition catalyst concentrations in the thickness direction are obtained. It is formed on the surface of a metal support. Next, the catalyst layer formed on the surface of the metal support is pressure-bonded to the surface of the electrolyte membrane by hot pressing or the like. After the pressure bonding, the metal support is peeled off, and catalyst layers having different peroxide decomposition catalyst concentrations in the thickness direction are formed on the surface of the electrolyte membrane.
第三の方法は、加水分解処理、湿式通電処理、スパッタ法、CVD(化学気相成長法)等により、過酸化物分解触媒を電極の触媒層に配置する方法である。例えば、過酸化物分解触媒として、金属酸化物、金属リン酸塩、金属フッ化物を用いる場合、加水分解処理では、まず、過酸化物分解触媒を構成する金属の塩を水に溶解した金属塩水溶液を、触媒層と接触させる。次いで、その触媒層に酸溶液を接触させて加水分解すればよい。なお、金属塩は、水への溶解度が高い塩として、硝酸塩、硫酸塩、塩化物等が好適である。また、過酸化物分解触媒として、金属を用いる場合、該金属の塩を水に溶解した金属塩水溶液を、触媒層と接触させる。そして、その触媒層に過酸化水素、ヒドラジン、ビタミンC、蔗糖等の還元剤を接触させて、金属に還元すればよい。 The third method is a method in which a peroxide decomposition catalyst is disposed on the catalyst layer of the electrode by hydrolysis, wet energization, sputtering, CVD (chemical vapor deposition), or the like. For example, when a metal oxide, metal phosphate, or metal fluoride is used as the peroxide decomposition catalyst, in the hydrolysis treatment, first, a metal salt in which the metal salt constituting the peroxide decomposition catalyst is dissolved in water. An aqueous solution is contacted with the catalyst layer. Next, the catalyst layer may be hydrolyzed by bringing an acid solution into contact therewith. The metal salt is preferably a nitrate, sulfate, chloride or the like as a salt having high solubility in water. When a metal is used as the peroxide decomposition catalyst, an aqueous metal salt solution obtained by dissolving a metal salt in water is brought into contact with the catalyst layer. Then, a reducing agent such as hydrogen peroxide, hydrazine, vitamin C, or sucrose may be brought into contact with the catalyst layer to reduce it to a metal.
湿式通電処理では、電解質膜の表面に触媒層が形成された電解質膜電極接合体前駆体を電解用電極の少なくとも一方として、過酸化物分解触媒を構成する金属の塩を含む所定の溶液中で通電することにより、該前駆体表面に過酸化物分解触媒を析出させればよい。 In the wet energization treatment, an electrolyte membrane electrode assembly precursor having a catalyst layer formed on the surface of the electrolyte membrane is used as an electrode for electrolysis in a predetermined solution containing a metal salt constituting the peroxide decomposition catalyst. By energization, a peroxide decomposition catalyst may be deposited on the surface of the precursor.
以上説明した方法等により、過酸化物分解触媒を含む触媒層を電解質膜の表面に形成した後、拡散層となるカーボンクロス等を、両極それぞれの触媒層の表面にホットプレス等により圧着し、電解質膜電極接合体とすればよい。 After the catalyst layer containing the peroxide decomposition catalyst is formed on the surface of the electrolyte membrane by the method described above, the carbon cloth or the like that becomes the diffusion layer is pressure-bonded to the surface of each of the electrode layers by hot pressing or the like, What is necessary is just to set it as an electrolyte membrane electrode assembly.
なお、本発明の電解質膜電極接合体では、電解質膜の種類は特に限定されるものではない。例えば、全フッ素系スルホン酸膜、全フッ素系ホスホン酸膜、全フッ素系カルボン酸膜、含フッ素炭化水素系グラフト膜、全炭化水素系グラフト膜、全芳香族膜等を用いることができる。また、PTFE、ポリイミド等の補強材を含む、機械的特性を強化した複合高分子膜を用いてもよい。特に、耐久性等を考慮した場合には、全フッ素系の高分子膜を用いることが望ましい。なかでも、電解質としての性能が高いという理由から、全フッ素系スルホン酸膜を用いることが望ましい。全フッ素系スルホン酸膜の一例として、「ナフィオン」(登録商標、デュポン社製)、「アシプレックス」(登録商標、旭化成株式会社製)、「フレミオン」(登録商標、旭硝子株式会社製)等が挙げられる。 In addition, in the electrolyte membrane electrode assembly of this invention, the kind of electrolyte membrane is not specifically limited. For example, a perfluorinated sulfonic acid film, a perfluorinated phosphonic acid film, a perfluorinated carboxylic acid film, a fluorinated hydrocarbon-based graft film, a perhydrocarbon-based graft film, a wholly aromatic film, or the like can be used. Moreover, you may use the composite polymer film which strengthened mechanical characteristics containing reinforcement materials, such as PTFE and a polyimide. In particular, in consideration of durability and the like, it is desirable to use a perfluorinated polymer film. Among these, it is desirable to use a perfluorinated sulfonic acid membrane because of its high performance as an electrolyte. Examples of perfluorinated sulfonic acid membranes include “Nafion” (registered trademark, manufactured by DuPont), “Aciplex” (registered trademark, manufactured by Asahi Kasei Corporation), “Flemion” (registered trademark, manufactured by Asahi Glass Co., Ltd.), etc. Can be mentioned.
〈固体高分子型燃料電池〉
本発明の固体高分子型燃料電池は、上記本発明の電解質膜電極接合体を備える。例えば、本発明の電解質膜電極接合体を、セパレータを介して複数個積層させて構成すればよい。電解質膜電極接合体を挟持するセパレータとしては、集電性能が高く、酸化水蒸気雰囲気下でも比較的安定な焼成カーボン、成形カーボンや、ステンレス材料の表面に貴金属や炭素材料を被覆したもの等を用いればよい。
<Solid polymer fuel cell>
The polymer electrolyte fuel cell of the present invention includes the above-described electrolyte membrane electrode assembly of the present invention. For example, what is necessary is just to comprise the electrolyte membrane electrode assembly of this invention by laminating | stacking two or more through a separator. As a separator for sandwiching an electrolyte membrane electrode assembly, a fired carbon, a molded carbon, or a stainless steel material coated with a noble metal or a carbon material, which has high current collecting performance and is relatively stable even in an oxidizing water vapor atmosphere, is used. That's fine.
上記実施形態に基づいて、電極の触媒層に、厚さ方向に濃度差をもつよう過酸化物分解触媒を配置して、電解質膜電極接合体を作製した。作製した電解質膜電極接合体を用いて電池反応を行い、電解質膜および電極の劣化の程度を調査した。以下、順に説明する。 Based on the above embodiment, an electrolyte membrane electrode assembly was prepared by disposing a peroxide decomposition catalyst on the electrode catalyst layer so as to have a concentration difference in the thickness direction. A battery reaction was performed using the produced electrolyte membrane electrode assembly, and the degree of deterioration of the electrolyte membrane and the electrode was investigated. Hereinafter, it demonstrates in order.
〈電解質膜電極接合体の作製〉
(1)実施例1の電解質膜電極接合体
過酸化物分解触媒としてCePO4を用い、電解質膜電極接合体(以下、適宜「MEA」と称す。)を作製した。まず、CePO4を含まない触媒インクを調製した。カーボンに担持された白金触媒(Pt/C触媒、白金担持率60wt%)に、蒸留水、エタノール、プロピレングリコール、ナフィオン溶液(22wt%、デュポン社製)を加え、超音波ホモジナイザーで混合して、触媒インクとした。次いで、調製した触媒インクを、テフロン(登録商標、デュポン社製、以下同じ。)製のシート表面に、ドクターブレード法により塗布した。その後、室温で乾燥させて溶媒を除去し、シート表面に、過酸化物分解触媒を含まない過酸化物分解触媒非含有層を形成した。過酸化物分解触媒非含有層の厚さは、約10μmであった。
<Preparation of electrolyte membrane electrode assembly>
(1) Electrolyte Membrane / Electrode Assembly of Example 1 An electrolyte membrane / electrode assembly (hereinafter appropriately referred to as “MEA”) was prepared using CePO 4 as a peroxide decomposition catalyst. First, a catalyst ink not containing CePO 4 was prepared. Distilled water, ethanol, propylene glycol, Nafion solution (22 wt%, manufactured by DuPont) are added to a platinum catalyst supported on carbon (Pt / C catalyst, platinum loading rate 60 wt%), and mixed with an ultrasonic homogenizer. A catalyst ink was obtained. Next, the prepared catalyst ink was applied to a sheet surface made of Teflon (registered trademark, manufactured by DuPont, the same applies hereinafter) by a doctor blade method. Thereafter, the solvent was removed by drying at room temperature, and a peroxide decomposition catalyst-free layer containing no peroxide decomposition catalyst was formed on the sheet surface. The thickness of the peroxide decomposition catalyst-free layer was about 10 μm.
次に、上記触媒インクに、所定量のCePO4粉末を混合し、CePO4濃度が1wt%、3wt%、5wt%となる3種類の触媒インクを調製した。これら3種類の触媒インクを、CePO4濃度の低い順に、上記過酸化物分解触媒非含有層の表面にスプレー塗布、乾燥させて、厚さ方向にCePO4濃度の異なる過酸化物分解触媒含有層を形成した。触媒インクの塗布は、各々の濃度につき5回ずつ行い、合計15回行った。過酸化物分解触媒含有層の厚さは、約10μmであった。 Next, a predetermined amount of CePO 4 powder was mixed with the catalyst ink to prepare three types of catalyst inks with CePO 4 concentrations of 1 wt%, 3 wt%, and 5 wt%. These three types of catalyst ink, in ascending order of CePO 4 concentration, the peroxide decomposition catalyst surface spray coating non-containing layer and dried, different peroxides of CePO 4 concentration in the thickness direction decomposition catalyst-containing layer Formed. The catalyst ink was applied five times for each concentration, for a total of 15 times. The thickness of the peroxide decomposition catalyst-containing layer was about 10 μm.
過酸化物分解触媒非含有層と過酸化物分解触媒含有層とが形成された上記シートを、電解質膜(商品名「ナフィオン」、登録商標、デュポン社製、膜厚50μm、以下同じ。)の一方の表面に、圧力約4.9MPa、温度約120℃でホットプレスした。その後、シートのみを剥離して、電解質膜の表面に、電解質膜側に向かってCePO4の濃度値が増加する触媒層を形成した。この電解質膜と触媒層との接合体を実施例1のMEAとした。なお、本実施例1のMEAにおいて、触媒層は、過酸化物分解触媒非含有層と過酸化物分解触媒含有層とから構成される。 The above sheet on which the peroxide decomposition catalyst-free layer and the peroxide decomposition catalyst-containing layer are formed is an electrolyte membrane (trade name “Nafion”, registered trademark, manufactured by DuPont, film thickness 50 μm, the same applies hereinafter). One surface was hot pressed at a pressure of about 4.9 MPa and a temperature of about 120 ° C. Thereafter, only the sheet was peeled off, and a catalyst layer in which the concentration value of CePO 4 increased toward the electrolyte membrane side was formed on the surface of the electrolyte membrane. The joined body of the electrolyte membrane and the catalyst layer was used as the MEA of Example 1. In the MEA of Example 1, the catalyst layer is composed of a peroxide decomposition catalyst-free layer and a peroxide decomposition catalyst-containing layer.
(2)実施例2の電解質膜電極接合体
過酸化物分解触媒としてRuO2を用い、MEAを作製した。まず、実施例1のMEAの作製と同様にして、RuO2を含まない触媒インクを調製した。調製した触媒インクを、テフロン製のシート表面に、塗布、乾燥して、シート表面に、過酸化物分解触媒を含まない過酸化物分解触媒非含有層を形成した。過酸化物分解触媒非含有層の厚さは、約10μmであった。
(2) Electrolyte membrane electrode assembly of Example 2 MEA was produced using RuO 2 as a peroxide decomposition catalyst. First, a catalyst ink not containing RuO 2 was prepared in the same manner as in the production of the MEA of Example 1. The prepared catalyst ink was applied to a Teflon sheet surface and dried to form a peroxide decomposition catalyst-free layer containing no peroxide decomposition catalyst on the sheet surface. The thickness of the peroxide decomposition catalyst-free layer was about 10 μm.
次に、過酸化物分解触媒非含有層の表面に、Ru錯体(Ru(NO)(NO3)3)水溶液(Ruとして0.05wt%)を滴下した。その後、0.1Mのリン酸水溶液中で加水分解し、蒸留水で洗浄した。これより、シート表面には、過酸化物分解触媒非含有層の表面近傍にRuO2が固定された触媒層が形成された。 Next, an aqueous solution of Ru complex (Ru (NO) (NO 3 ) 3 ) (0.05 wt% as Ru) was dropped onto the surface of the peroxide decomposition catalyst-free layer. Then, it hydrolyzed in 0.1M phosphoric acid aqueous solution, and washed with distilled water. As a result, a catalyst layer in which RuO 2 was fixed in the vicinity of the surface of the peroxide decomposition catalyst-free layer was formed on the sheet surface.
この触媒層が形成されたシートを、電解質膜の一方の表面に、圧力約4.9MPa、温度約120℃でホットプレスした。その後、シートのみを剥離して、電解質膜の表面に、電解質膜との界面付近にRuO2を含む触媒層を形成した。この電解質膜と触媒層との接合体を実施例2のMEAとした。なお、触媒層の断面を、EPMAにより測定したところ、RuO2は、触媒層と電解質膜との界面付近に固定されていることが確認された。 The sheet on which the catalyst layer was formed was hot-pressed on one surface of the electrolyte membrane at a pressure of about 4.9 MPa and a temperature of about 120 ° C. Thereafter, only the sheet was peeled off, and a catalyst layer containing RuO 2 was formed on the surface of the electrolyte membrane in the vicinity of the interface with the electrolyte membrane. The joined body of the electrolyte membrane and the catalyst layer was used as the MEA of Example 2. When the cross section of the catalyst layer was measured by EPMA, it was confirmed that RuO 2 was fixed near the interface between the catalyst layer and the electrolyte membrane.
(3)比較例の電解質膜電極接合体
実施例1のMEAの作製で調製した触媒インク(CePO4濃度:3wt%)を用いて触媒層を形成した。すなわち、CePO4濃度が3wt%の触媒インクを、テフロン製のシート表面にスプレー塗布、乾燥させて、厚さ方向にCePO4濃度が一定の触媒層を形成した。触媒インクの塗布は15回行い、触媒層全体で添加されたCePO4量を、実施例1のMEAと同じとした。形成された触媒層の厚さは、約10μmであった。
(3) Electrolyte Membrane / Electrode Assembly of Comparative Example A catalyst layer was formed using the catalyst ink (CePO 4 concentration: 3 wt%) prepared in the production of the MEA of Example 1. That is, a catalyst ink having a CePO 4 concentration of 3 wt% was spray-coated on the surface of a Teflon sheet and dried to form a catalyst layer having a constant CePO 4 concentration in the thickness direction. The catalyst ink was applied 15 times, and the amount of CePO 4 added in the entire catalyst layer was the same as that of the MEA of Example 1. The formed catalyst layer had a thickness of about 10 μm.
触媒層が形成された上記シートを、電解質膜の一方の表面に、圧力約4.9MPa、温度約120℃でホットプレスした。その後、シートのみを剥離して、電解質膜の表面に、一定の濃度でCePO4が含まれる触媒層を形成した。この電解質膜と触媒層との接合体を比較例のMEAとした。 The sheet on which the catalyst layer was formed was hot-pressed on one surface of the electrolyte membrane at a pressure of about 4.9 MPa and a temperature of about 120 ° C. Thereafter, only the sheet was peeled off to form a catalyst layer containing CePO 4 at a constant concentration on the surface of the electrolyte membrane. The joined body of the electrolyte membrane and the catalyst layer was used as a comparative example MEA.
〈電解質膜等の劣化調査〉
作製した各MEAを、耐久試験用のセルに組み込んだ。すなわち、MEAの両側に、ガス流路が形成されたカーボン製のセパレータを配置して、それをSUS製の支持体で保持した。そして、触媒層が形成された方の電極(酸素極)に加湿した空気を、他方の電極(燃料極)に加湿した水素をそれぞれ供給して、24時間作動させた。空気および水素の加湿温度は90℃、流量は100ml/min、セルの作動温度は90℃とした。
<Deterioration investigation of electrolyte membrane, etc.>
Each produced MEA was incorporated in a cell for durability test. That is, carbon separators with gas flow paths formed on both sides of the MEA were placed and held by a SUS support. Then, humidified air was supplied to the electrode (oxygen electrode) on which the catalyst layer was formed, and humidified hydrogen was supplied to the other electrode (fuel electrode), respectively, and operated for 24 hours. The humidification temperature of air and hydrogen was 90 ° C., the flow rate was 100 ml / min, and the operating temperature of the cell was 90 ° C.
セル作動中に、酸素極および燃料極から排出された水を回収した。回収水中のフッ化物イオン(F-)濃度を、イオンクロマト装置PIA−1000(株式会社島津製作所製)にて測定し、フッ化物イオン溶出速度(μg/(cm2・hr))を求めた。フッ化物イオン溶出速度は、単位時間、単位電極面積当たりに溶出されたフッ化物イオン量であり、各電極からの回収水の量と、回収水中のフッ化物イオン濃度とから算出される。フッ化物イオン溶出速度は、電解質膜および電極の劣化の程度を示す指標となる。つまり、フッ化物イオン溶出速度が大きいほど、電解質膜等の劣化が進行していることを示す。 During the operation of the cell, water discharged from the oxygen electrode and the fuel electrode was collected. The concentration of fluoride ions (F − ) in the recovered water was measured with an ion chromatograph PIA-1000 (manufactured by Shimadzu Corporation), and the fluoride ion elution rate (μg / (cm 2 · hr)) was determined. The fluoride ion elution rate is the amount of fluoride ions eluted per unit time and unit electrode area, and is calculated from the amount of recovered water from each electrode and the concentration of fluoride ions in the recovered water. The fluoride ion elution rate is an index indicating the degree of deterioration of the electrolyte membrane and the electrode. That is, as the fluoride ion elution rate increases, the deterioration of the electrolyte membrane or the like progresses.
図1に、各MEAにおけるフッ化物イオン溶出速度の測定結果を示す。図1に示すように、触媒層に過酸化物分解触媒の濃度差がある実施例1、2のMEAでは、フッ化物イオン溶出速度は0.1μg/(cm2・hr)以下と小さくなった。これに対して、過酸化物分解触媒の濃度差がない比較例のMEAでは、フッ化物イオン溶出速度が0.15μg/(cm2・hr)と大きくなった。特に、実施例1のMEAと比較例のMEAとを比較すると、同じ量の過酸化物分解触媒を使用しても、濃度差をつけて配置した実施例1のMEAの方が、電解質膜等の劣化抑制効果が高いことがわかる。また、実施例2のMEAのように、過酸化物分解触媒を、電極と電解質膜との界面付近に配置すると、電解質膜等の劣化抑制効果が高いことがわかる。 In FIG. 1, the measurement result of the fluoride ion elution rate in each MEA is shown. As shown in FIG. 1, in the MEAs of Examples 1 and 2 in which the concentration of the peroxide decomposition catalyst is different in the catalyst layer, the fluoride ion elution rate was as small as 0.1 μg / (cm 2 · hr) or less. . On the other hand, in the MEA of the comparative example with no concentration difference of the peroxide decomposition catalyst, the fluoride ion elution rate was as large as 0.15 μg / (cm 2 · hr). In particular, when the MEA of Example 1 is compared with the MEA of the comparative example, the MEA of Example 1 arranged with a difference in concentration is used even when the same amount of peroxide decomposition catalyst is used. It can be seen that the effect of suppressing the deterioration of is high. Moreover, when the peroxide decomposition catalyst is arranged in the vicinity of the interface between the electrode and the electrolyte membrane as in the MEA of Example 2, it can be seen that the effect of suppressing deterioration of the electrolyte membrane or the like is high.
以上より、電極に過酸化物分解触媒が濃度差をもって配置された本発明のMEAでは、電解質膜および電極の劣化が進行し難いことが確認できた。したがって、本発明のMEAを用いれば、長期間運転した場合でも電池性能の低下の少ない固体高分子型燃料電池を経済的に実現できる。 From the above, it was confirmed that in the MEA of the present invention in which the peroxide decomposition catalyst is arranged on the electrode with a concentration difference, the deterioration of the electrolyte membrane and the electrode is difficult to proceed. Therefore, by using the MEA of the present invention, it is possible to economically realize a polymer electrolyte fuel cell with little deterioration in battery performance even when operated for a long time.
Claims (5)
前記一対の電極の少なくとも一方の触媒層は、前記電解質膜側に配置されて過酸化物を分解する過酸化物分解触媒を含有する過酸化物分解触媒含有層と、前記過酸化物分解触媒を含有しない過酸化物分解触媒非含有層とから構成され、
前記過酸化物分解触媒含有層は、厚さ方向に前記過酸化物分解触媒の濃度が異なり、
前記過酸化物分解触媒は、前記電解質膜側に向かって濃度値が増加するよう配置されることを特徴とする固体高分子型燃料電池用電解質膜電極接合体。 An electrolyte membrane having ionic conductivity, and a pair of electrodes provided on both sides of the electrolyte membrane,
At least one catalyst layer of the pair of electrodes includes a peroxide decomposition catalyst-containing layer containing a peroxide decomposition catalyst that is disposed on the electrolyte membrane side and decomposes the peroxide, and the peroxide decomposition catalyst. It is composed of a peroxide decomposition catalyst-free layer that does not contain,
The peroxide decomposition catalyst-containing layer, Ri is the concentration of the peroxide decomposition catalyst in the thickness direction Do different,
The electrolyte membrane electrode assembly for a polymer electrolyte fuel cell, wherein the peroxide decomposition catalyst is disposed so that a concentration value increases toward the electrolyte membrane side .
該酸素極に前記過酸化物分解触媒が配置される請求項1に記載の固体高分子型燃料電池用電解質膜電極接合体。 The pair of electrodes includes a fuel electrode supplied with a fuel gas containing hydrogen and an oxygen electrode supplied with an oxidant gas containing oxygen,
The electrolyte membrane electrode assembly for a polymer electrolyte fuel cell according to claim 1 , wherein the peroxide decomposition catalyst is disposed on the oxygen electrode.
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