JP2006224095A - Electrode catalyst for fuel cell - Google Patents

Electrode catalyst for fuel cell Download PDF

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JP2006224095A
JP2006224095A JP2006008993A JP2006008993A JP2006224095A JP 2006224095 A JP2006224095 A JP 2006224095A JP 2006008993 A JP2006008993 A JP 2006008993A JP 2006008993 A JP2006008993 A JP 2006008993A JP 2006224095 A JP2006224095 A JP 2006224095A
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catalyst
electrode catalyst
electrode
fuel cell
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Kuninori Miyazaki
邦典 宮碕
Atsushi Okamura
淳志 岡村
Noboru Sugishima
昇 杉島
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Nippon Shokubai Co Ltd
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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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Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode catalyst having the catalytic performance superior to that of the conventional electrode catalyst and to provide an electrode catalyst composition for a fuel cell and a proton exchange membrane fuel cell in each of which the electrode catalyst is used. <P>SOLUTION: This electrode catalyst for the fuel cell is obtained by depositing a catalyst component on such a compound oxide of Ti and at least one selected from the group consisting of Si, Zr, W, Fe, Ce and Ta that the molar ratio of a titania component to each of oxide components of other metals is ≥1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、固体高分子型燃料電池用の電極触媒、当該電極触媒を含む電極触媒組成物、および当該電極触媒組成物により形成された電極を有する燃料電池に関するものである。   The present invention relates to an electrode catalyst for a polymer electrolyte fuel cell, an electrode catalyst composition containing the electrode catalyst, and a fuel cell having an electrode formed from the electrode catalyst composition.

燃料電池は、水素やメタノールなどの燃料と酸素を電気化学的に反応させ、直接電気エネルギーとして取り出す発電装置である。従って、火力発電システムの様に有害な窒素酸化物や硫黄酸化物は排出されない。その上、他の発電システムと比較して熱エネルギーや運動エネルギーのロスが少ないために発電効率が高い。よって、燃料電池は、極めてクリーンで効率的な次世代発電システムとして期待されている。   A fuel cell is a power generation device that takes out fuel directly such as hydrogen or methanol and oxygen and directly takes it out as electric energy. Therefore, harmful nitrogen oxides and sulfur oxides are not discharged as in a thermal power generation system. In addition, the power generation efficiency is high because there is less loss of thermal energy and kinetic energy compared to other power generation systems. Therefore, the fuel cell is expected as a very clean and efficient next generation power generation system.

燃料電池は、電解質の種類から、リン酸型燃料電池、溶融炭酸型燃料電池、固体高分子型燃料電池、固体酸化物型燃料電池などに分類することができる。その中でも固体高分子型燃料電池は、他の燃料電池より低い温度領域において発電させることができ、小型化が容易なことから、自動車用電源、家庭用電源、携帯用電源など種々の用途に適用できる可能性がある。   Fuel cells can be classified into phosphoric acid fuel cells, molten carbonate fuel cells, polymer electrolyte fuel cells, solid oxide fuel cells, etc., depending on the type of electrolyte. Among them, the polymer electrolyte fuel cell can generate power in a lower temperature range than other fuel cells and is easy to downsize, so it can be applied to various applications such as automobile power supplies, household power supplies, and portable power supplies. There is a possibility.

固体高分子型燃料電池は、パーフルオロスルホン酸イオン交換樹脂など、プロトン伝導性を有する一方で電子伝導性（導電性）を有しない高分子電解質膜の両面にアノードとカソードが形成されている膜電極接合体を基本単位とする。各電極は、高分子電解質膜側にプロトン伝導性を示す高分子電解質と触媒とを含む触媒層と、その外側に通気性と導電性を併せ持つガス拡散層からなる。   A polymer electrolyte fuel cell is a membrane in which an anode and a cathode are formed on both sides of a polymer electrolyte membrane such as perfluorosulfonic acid ion exchange resin that has proton conductivity but does not have electron conductivity (conductivity). The electrode assembly is the basic unit. Each electrode comprises a catalyst layer containing a polymer electrolyte exhibiting proton conductivity and a catalyst on the polymer electrolyte membrane side, and a gas diffusion layer having both air permeability and conductivity on the outside thereof.

発電時には、アノードに水素などの燃料を、カソードには酸素や空気を供給する。その結果、アノードでは触媒の作用によりプロトンと電子が発生し、このプロトンが高分子電解質膜を透過してカソード側で酸化されて水が生じるという反応が進行し、電気を取り出すことができる。   During power generation, fuel such as hydrogen is supplied to the anode, and oxygen or air is supplied to the cathode. As a result, protons and electrons are generated by the action of the catalyst at the anode, and a reaction occurs in which the protons pass through the polymer electrolyte membrane and are oxidized on the cathode side to generate water, and electricity can be taken out.

アノードにおいて使用される触媒としては、カーボンブラックなどの導電性炭素材料にＰｔ−Ｒｕなどの合金を担持した触媒が、また、カソードに使用する触媒としては、カーボンブラックなどの導電性炭素材料に、ＰｔやＰｔ−Ｆｅ、Ｐｔ−Ｃｒなどの合金を担持した触媒が提案されている。   The catalyst used in the anode is a catalyst in which an alloy such as Pt-Ru is supported on a conductive carbon material such as carbon black, and the catalyst used in the cathode is a conductive carbon material such as carbon black. A catalyst supporting an alloy such as Pt, Pt—Fe, or Pt—Cr has been proposed.

ここで、アノードにおいて主にＰｔ単独ではなくＰｔ−Ｒｕなどが使われるのは、Ｐｔのみでは発電効率の低下が生じるからである。即ち、純粋な水素ガスは高価であるため、燃料としては炭化水素燃料を改質した富水素ガスが用いられる。この富水素ガスには一酸化炭素が含まれており、これがＰｔ触媒を被毒して触媒活性を低下させる。そこでＲｕ等と合金化することによって、一酸化炭素を酸化し、二酸化炭素として除去することが行なわれている。   Here, the reason why Pt-Ru or the like is mainly used in the anode instead of Pt alone is that the power generation efficiency is lowered only by Pt. That is, since pure hydrogen gas is expensive, a hydrogen-rich gas obtained by reforming a hydrocarbon fuel is used as the fuel. This rich hydrogen gas contains carbon monoxide, which poisons the Pt catalyst and lowers the catalytic activity. Thus, carbon monoxide is oxidized and removed as carbon dioxide by alloying with Ru or the like.

この様に燃料電池では、発電効率を向上させるために様々な工夫がされており、貴金属触媒の構成以外に、担体についても種々の検討が行われている。例えば、導電性炭素材料であるカーボンブラック以外の担体として、酸化チタンなどの金属酸化物を担体に用いた触媒系が提案されている（非特許文献１を参照）。   As described above, in the fuel cell, various devices have been devised in order to improve the power generation efficiency, and various studies have been made on the support in addition to the configuration of the noble metal catalyst. For example, a catalyst system using a metal oxide such as titanium oxide as a carrier other than carbon black, which is a conductive carbon material, has been proposed (see Non-Patent Document 1).

また、従来方法で製造した電極触媒を用いた燃料電池は電池特性にばらつきがあるとの問題に鑑みて、ＳｉＯ2を主成分とする担体に触媒粒子を担持した電極触媒が特許文献１に開示されている。 Further, in view of the problem that fuel cells using an electrode catalyst manufactured by a conventional method have variations in cell characteristics, an electrode catalyst in which catalyst particles are supported on a carrier mainly composed of SiO 2 is disclosed in Patent Document 1. Has been.

さらに燃料電池では、運転時間の経過と共に生成水や反応ガス中の水分により触媒層で反応ガスの供給路である細孔が閉塞されてしまい、反応ガスが十分に供給されなくなり、電池性能が低下する現象が見られる。そこで、担体として表面に親水性官能基を持たない導電性炭素粒子または導電性炭素繊維を用い、また、金属酸化物を電極に添加することによって、電池性能を高める技術もある（特許文献２）。この特許文献２の実施例では、触媒層にジルコニア（ＺｒＯ2）を混在させることで、セル電圧が３３ｍＶ向上している。
第９回燃料電池シンポジウム、第１４頁、２００２年５月１５、１６日、燃料電池開発情報センター 特開２００２−２４６０３３号公報（特許請求の範囲） 特開２００２−２８９２０１号公報（段落［００３９］、図３） Furthermore, in the fuel cell, as the operating time elapses, the pores that are the reaction gas supply path are blocked by the catalyst layer due to the water in the generated water and the reaction gas, the reaction gas is not sufficiently supplied, and the battery performance deteriorates. The phenomenon is seen. Therefore, there is a technique for improving battery performance by using conductive carbon particles or conductive carbon fibers having no hydrophilic functional group on the surface as a carrier and adding a metal oxide to an electrode (Patent Document 2). . In the example of this Patent Document 2, the cell voltage is improved by 33 mV by mixing zirconia (ZrO 2 ) in the catalyst layer.
9th Fuel Cell Symposium, Page 14, May 15, 16th, 2002, Fuel Cell Development Information Center JP 2002-246033 A (Claims) JP 2002-289201 A (paragraph [0039], FIG. 3)

上述した様に、高分子電解質型燃料電池においては一酸化炭素による触媒被毒などにより発電効率が低下するという問題があり、燃料電池の実用化のために、より一層高い触媒性能を発揮できる電極触媒が求められていた。   As described above, in the polymer electrolyte fuel cell, there is a problem that the power generation efficiency is lowered due to catalyst poisoning by carbon monoxide, etc., and an electrode that can exhibit even higher catalytic performance for practical use of the fuel cell. There was a need for a catalyst.

そこで本発明の目的は、従来の電極触媒に比べて触媒性能に優れた電極触媒を提供することにある。また、本発明は、当該電極触媒を用いた燃料電池用電極組成物と固体高分子型燃料電池を提供することも目的とする。   Accordingly, an object of the present invention is to provide an electrode catalyst having superior catalytic performance as compared with a conventional electrode catalyst. Another object of the present invention is to provide a fuel cell electrode composition and a polymer electrolyte fuel cell using the electrode catalyst.

本発明者らは、上記課題を解決すべく、電極触媒の構成について鋭意研究を重ねた。その結果、特定の構成を有する担体に触媒成分を担持した電極触媒は、触媒性能が極めて優れていることを見出して、本発明を完成した。   In order to solve the above-mentioned problems, the present inventors have made extensive studies on the configuration of the electrode catalyst. As a result, the inventors have found that an electrode catalyst in which a catalyst component is supported on a carrier having a specific configuration is extremely excellent in catalytic performance, thereby completing the present invention.

即ち、本発明の燃料電池用電極触媒は、Ｓｉ、Ｚｒ、Ｗ、Ｆｅ、ＣｅおよびＴａからなる群より選択される少なくとも１種とＴｉとの複合酸化物であって、他の酸化物成分に対するチタニア成分（ＴｉＯ2）のモル比が１以上である複合酸化物に、触媒成分が担持されていることを特徴とする。 That is, the fuel cell electrode catalyst of the present invention is a composite oxide of Ti and at least one selected from the group consisting of Si, Zr, W, Fe, Ce, and Ta, and with respect to other oxide components. A catalyst component is supported on a composite oxide having a titania component (TiO 2 ) molar ratio of 1 or more.

触媒成分としては、（１）Ｐｔ、Ｐｄ、Ｒｕ、Ｒｈ、Ｉｒ、Ａｕ、Ａｇ、Ｆｅ、Ｍｏ、Ｗ、Ｖ、Ｉｎ、Ｔａ、Ｓｎ、Ｃｕ、Ｓｂ、Ｍｇ、Ｎｉ、ＣｏおよびＭｎからなる群より選ばれる少なくとも１種、（２）Ｐｔ、Ｐｄ、Ｒｕ、Ｒｈ、Ｉｒ、ＡｕおよびＡｇからなる群より選ばれる少なくとも１種、または（３）Ｐｔ、Ｐｄ、Ｒｕ、Ｒｈ、Ｉｒ、ＡｕおよびＡｇからなる群より選ばれる少なくとも１種と、Ｆｅ、Ｍｏ、Ｗ、Ｖ、Ｉｎ、Ｔａ、Ｓｎ、Ｃｕ、Ｓｂ、Ｍｇ、Ｎｉ、ＣｏおよびＭｎからなる群より選ばれる少なくとも１種との組合せが好適である。これら触媒成分を担持した電極触媒の優れた性能は、後述する実施例で実証されている。   The catalyst component includes (1) a group consisting of Pt, Pd, Ru, Rh, Ir, Au, Ag, Fe, Mo, W, V, In, Ta, Sn, Cu, Sb, Mg, Ni, Co, and Mn. (2) at least one selected from the group consisting of Pt, Pd, Ru, Rh, Ir, Au and Ag, or (3) Pt, Pd, Ru, Rh, Ir, Au and Ag. A combination of at least one selected from the group consisting of and at least one selected from the group consisting of Fe, Mo, W, V, In, Ta, Sn, Cu, Sb, Mg, Ni, Co, and Mn is preferable. It is. The excellent performance of the electrode catalyst carrying these catalyst components has been demonstrated in the examples described later.

また、本発明の燃料電池用電極触媒組成物は、上記燃料電池用電極触媒、導電性炭素材料および高分子電解質を含有するものである。   The fuel cell electrode catalyst composition of the present invention comprises the fuel cell electrode catalyst, a conductive carbon material, and a polymer electrolyte.

本発明の燃料電池は、上記燃料電池用電極触媒組成物により形成された電極を有するものである。   The fuel cell of the present invention has an electrode formed of the above-described fuel cell electrode catalyst composition.

本発明の燃料電池用電極触媒（以下、単に「電極触媒」ということもある）は、従来の電極触媒よりも優れた触媒性能を有する。このため、本発明の電極触媒を用いた固体高分子型燃料電池によれば、長期にわたり安定した電圧を得ることができる。   The fuel cell electrode catalyst of the present invention (hereinafter sometimes simply referred to as “electrode catalyst”) has catalytic performance superior to that of conventional electrode catalysts. For this reason, according to the polymer electrolyte fuel cell using the electrode catalyst of the present invention, a stable voltage can be obtained over a long period of time.

本発明の燃料電池用電極触媒は、Ｓｉ、Ｚｒ、Ｗ、Ｆｅ、ＣｅおよびＴａからなる群より選ばれる少なくとも１種とＴｉとの複合酸化物であって、他の酸化物成分に対するチタニア成分（ＴｉＯ2）のモル比が１以上である複合酸化物に、触媒成分が担持されていることを特徴とする。 The fuel cell electrode catalyst of the present invention is a composite oxide of Ti and at least one selected from the group consisting of Si, Zr, W, Fe, Ce and Ta, and a titania component (other than the oxide component) A catalyst component is supported on a composite oxide having a molar ratio of TiO 2 ) of 1 or more.

本発明の燃料電池用電極触媒で用いられる触媒成分は、アノードにおいて水素からプロトンと電子を生じさせ、カソードで酸素とプロトンと電子から水を生じさせる反応を触媒できるものであれば、特にその種類は問わない。例えば、Ｐｔ、Ｐｄ、Ｒｕ、Ｒｈ、Ｉｒ、Ａｕ、Ａｇ、Ｆｅ、Ｍｏ、Ｗ、Ｖ、Ｉｎ、Ｔａ、Ｓｎ、Ｃｕ、Ｓｂ、Ｍｇ、Ｎｉ、ＣｏおよびＭｎからなる群より１または２以上を選択して用いることができる。また、２以上を組合わせて用いる場合には、それら金属をそれぞれ独立して使用してもよいし、それらを合金化して用いてもよい。   The catalyst component used in the fuel cell electrode catalyst of the present invention is of a type that can catalyze a reaction that generates protons and electrons from hydrogen at the anode and water from oxygen, protons, and electrons at the cathode. Does not matter. For example, 1 or 2 or more from the group consisting of Pt, Pd, Ru, Rh, Ir, Au, Ag, Fe, Mo, W, V, In, Ta, Sn, Cu, Sb, Mg, Ni, Co and Mn It can be selected and used. Moreover, when using 2 or more in combination, these metals may be used independently, respectively, and they may be alloyed and used.

好適な触媒成分としては、Ｐｔ、Ｐｄ、Ｒｕ、Ｒｈ、Ｉｒ、ＡｕおよびＡｇからなる群より選ばれる少なくとも１種を挙げることができる。これら触媒成分は、固体高分子型燃料電池の電極触媒として性能が高いからである。特に、Ｐｔ、Ｒｕ、Ｐｔ・Ｒｕ、Ｐｔ・Ｒｈ、Ｐｔ・Ｒｕ・Ｒｈ、Ｐｔ・Ｒｕ・Ｉｒ、Ｐｔ・Ｒｕ・Ｐｄなどが好適である。   Suitable catalyst components include at least one selected from the group consisting of Pt, Pd, Ru, Rh, Ir, Au, and Ag. This is because these catalyst components have high performance as electrode catalysts for polymer electrolyte fuel cells. Pt, Ru, Pt · Ru, Pt · Rh, Pt · Ru · Rh, Pt · Ru · Ir, Pt · Ru · Pd, etc. are particularly suitable.

また、Ｐｔ、Ｐｄ、Ｒｕ、Ｒｈ、Ｉｒ、ＡｕおよびＡｇからなる群より選ばれる少なくとも１種（以下、「触媒成分１」という場合がある）と、Ｆｅ、Ｍｏ、Ｗ、Ｖ、Ｉｎ、Ｔａ、Ｓｎ、Ｃｕ、Ｓｂ、Ｍｇ、Ｎｉ、ＣｏおよびＭｎからなる群より選ばれる少なくとも１種（以下、「触媒成分２」という場合がある）との組み合わせも好適である。より具体的には、Ｐｔ・Ｍｏ、Ｐｔ・Ｒｕ・Ｍｏ、Ｐｔ・Ｗ、Ｐｔ・Ｒｕ・Ｗ、Ｐｔ・Ｓｎ、Ｐｔ・Ｒｕ・Ｓｎ、Ｐｔ・Ｉｎ、Ｐｔ・Ｒｕ・Ｉｎ、Ｐｔ・Ｒｕ・Ｆｅ、Ｐｔ・Ｒｕ・Ｃｏなどを挙げることができる。   Further, at least one selected from the group consisting of Pt, Pd, Ru, Rh, Ir, Au and Ag (hereinafter sometimes referred to as “catalyst component 1”), Fe, Mo, W, V, In, Ta A combination with at least one selected from the group consisting of Sn, Cu, Sb, Mg, Ni, Co and Mn (hereinafter sometimes referred to as “catalyst component 2”) is also suitable. More specifically, Pt.Mo, Pt.Ru.Mo, Pt.W, Pt.Ru.W, Pt.Sn, Pt.Ru.Sn, Pt.In, Pt.Ru.In, Pt.Ru .. Fe, Pt.Ru.Co and the like can be mentioned.

触媒成分１と２を組合わせて使用する場合、両者の割合は、質量比で触媒成分１：触媒成分２＝１０〜５５：５〜３０程度にすることができ、より好ましくは１５〜５５：５〜２５％である。   When the catalyst components 1 and 2 are used in combination, the ratio of the two can be about catalyst component 1: catalyst component 2 = 10 to 55: 5 to 30 by mass ratio, more preferably 15 to 55: 5-25%.

担体と触媒成分との組合せは、適宜選択すればよい。例えば、Ｐｔと（Ｔｉ−Ｓｉ複合酸化物）、Ｐｔ・Ｒｕと（Ｔｉ−Ｓｉ複合酸化物）、Ｐｔ・Ｒｕ・Ｗと（Ｔｉ−Ｓｉ複合酸化物）、Ｐｔと（Ｔｉ−Ｚｒ複合酸化物）、Ｐｔ・Ｒｕと（Ｔｉ−Ｚｒ複合酸化物）、Ｐｔと（Ｔｉ−Ｆｅ複合酸化物）、Ｐｔ・Ｉｎと（Ｔｉ−Ｆｅ複合酸化物）、Ｐｔ・Ｉｎと（Ｔｉ−Ｆｅ−Ｚｒ複合酸化物）、Ｐｔ・Ｗと（Ｔｉ−Ｆｅ複合酸化物）、Ｐｔ・Ｉｎ・Ｒｕと（Ｔｉ−Ｆｅ複合酸化物）を例示することができる。   What is necessary is just to select the combination of a support | carrier and a catalyst component suitably. For example, Pt and (Ti-Si composite oxide), Pt.Ru and (Ti-Si composite oxide), Pt.Ru.W and (Ti-Si composite oxide), Pt and (Ti-Zr composite oxide) ), Pt.Ru and (Ti-Zr composite oxide), Pt and (Ti-Fe composite oxide), Pt.In and (Ti-Fe composite oxide), Pt.In and (Ti-Fe-Zr composite) Oxides), Pt · W and (Ti—Fe composite oxide), Pt · In · Ru and (Ti—Fe composite oxide).

本発明の電極触媒における触媒成分の割合、即ち、触媒成分と担体の合計に対する触媒成分の割合は、電極触媒が優れた触媒性能を発揮できる限り特に制限されないが、好ましくは５〜８０質量％、より好ましくは２０〜７０質量％とすることができる。   The ratio of the catalyst component in the electrode catalyst of the present invention, that is, the ratio of the catalyst component to the total of the catalyst component and the carrier is not particularly limited as long as the electrode catalyst can exhibit excellent catalyst performance, but preferably 5 to 80% by mass, More preferably, it can be 20-70 mass%.

本発明の担体は、Ｓｉ、Ｚｒ、Ｗ、Ｆｅ、ＣｅおよびＴａからなる群より選ばれる少なくとも１種とＴｉとの複合酸化物であって、他の酸化物成分に対するチタニア成分（ＴｉＯ2）のモル比が１以上の複合酸化物である。この様な複合酸化物としては、例えば、Ｔｉ−Ｓｉ、Ｔｉ−Ｚｒ、Ｔｉ−Ｆｅ、Ｔｉ−Ｓｉ−Ｚｒ、Ｔｉ−Ｓｉ−Ｗ、Ｔｉ−Ｆｅ−Ｚｒ、Ｔｉ−Ｆｅ−Ｃｅなどの組合せからなる二元または多元のチタン系複合酸化物を例示することができる。 The carrier of the present invention is a composite oxide of Ti and at least one selected from the group consisting of Si, Zr, W, Fe, Ce and Ta, and is a titania component (TiO 2 ) with respect to other oxide components. It is a complex oxide having a molar ratio of 1 or more. Examples of such complex oxides include combinations of Ti—Si, Ti—Zr, Ti—Fe, Ti—Si—Zr, Ti—Si—W, Ti—Fe—Zr, Ti—Fe—Ce, and the like. Examples of such binary or multicomponent titanium-based composite oxides can be given.

ここで「他の酸化物成分」とは、Ｔｉ以外のＳｉ、Ｚｒ、Ｗ、Ｆｅ、ＣｅまたはＴａの酸化物の合計をいう。即ち、Ｔｉ−Ｓｉ−Ｚｒ三元複合酸化物の場合、ＳｉＯ2とＺｒＯ2の合計モル数に対するＴｉＯ2のモル数の比が１以上である必要がある。 Here, the “other oxide component” refers to the sum of oxides of Si, Zr, W, Fe, Ce or Ta other than Ti. That is, in the case of a Ti—Si—Zr ternary composite oxide, the ratio of the number of moles of TiO 2 to the total number of moles of SiO 2 and ZrO 2 needs to be 1 or more.

本発明の「複合酸化物」は、チタニア成分と上記他の酸化物成分から構成されており、明確な結晶構造を有さない非晶質の複合酸化物をいう。この様な複合酸化物は、Ｘ線回折分析において、チタニアや他の酸化物による明確なピークを有さず、ピークが現れたとしてもブロードなもののみであることにより確認することができる。   The “composite oxide” of the present invention refers to an amorphous composite oxide that is composed of a titania component and the other oxide components and does not have a clear crystal structure. Such a complex oxide can be confirmed by the fact that it does not have a clear peak due to titania or other oxides in the X-ray diffraction analysis, and even if a peak appears, it is only a broad one.

本発明の担体の製法は、常法に従えばよい。例えば、水系溶媒にＴｉ以外の元素（Ｓｉ等）の酸化物の前駆体を溶解し、攪拌しながら硫酸チタニル（オキシ硫酸チタン、ＴｉＯＳＯ4）の硫酸溶液を滴下する。次いで、当該混合液を攪拌しながら、ｐＨが７程度になるまでアンモニア水を滴下してゲルを生成させる。得られたゲルを濾過して乾燥した後に焼成し、粉砕することにより担体の粉末を得ることができる。 The production method of the carrier of the present invention may be in accordance with a conventional method. For example, a precursor of an oxide of an element other than Ti (such as Si) is dissolved in an aqueous solvent, and a sulfuric acid solution of titanyl sulfate (titanium oxysulfate, TiOSO 4 ) is added dropwise with stirring. Next, while stirring the mixed solution, ammonia water is added dropwise until the pH reaches about 7, thereby generating a gel. The obtained gel is filtered, dried, fired, and pulverized to obtain a carrier powder.

本発明の電極触媒は、例えば含浸などの一般に知られている方法に従って、担体に触媒成分を担持することにより得られる。具体的には、例えば、ジニトロジアンミン白金や硝酸ルテニウム等の貴金属塩など、貴金属元素を含む水溶性化合物を水に溶解し、この水溶液を担体に含浸させて乾燥した後、還元性雰囲気で加熱して、還元処理を行えばよい。この還元処理により貴金属化合物は還元されて、触媒成分が金属の形態で担体に担持されることになる。この還元処理を行う際の還元性雰囲気、加熱温度などについては特に制限はなく、触媒成分が金属の形態で担持される限り、適宜選択して決定することができる。具体的には、例えば、水素と窒素とからなる混合ガス中で１００〜８００℃で加熱すればよい。   The electrode catalyst of the present invention can be obtained by supporting a catalyst component on a carrier according to a generally known method such as impregnation. Specifically, for example, a water-soluble compound containing a noble metal element such as a noble metal salt such as dinitrodiammine platinum or ruthenium nitrate is dissolved in water, impregnated with this aqueous solution and dried, and then heated in a reducing atmosphere. Thus, a reduction process may be performed. By this reduction treatment, the noble metal compound is reduced and the catalyst component is supported on the support in the form of metal. There are no particular limitations on the reducing atmosphere, heating temperature, and the like when performing this reduction treatment, and any suitable selection can be made as long as the catalyst component is supported in the form of a metal. Specifically, for example, heating may be performed at 100 to 800 ° C. in a mixed gas composed of hydrogen and nitrogen.

本発明の電極触媒は、アノードまたはカソードのいずれにも使用することができるが、アノードには一酸化炭素による触媒被毒の問題があるので、本発明の電極触媒を使って発電効率を高めるべく、特にアノードに使用するのが好ましい。   The electrode catalyst of the present invention can be used for either the anode or the cathode. However, since the anode has a problem of catalyst poisoning by carbon monoxide, the electrode catalyst of the present invention should be used to increase the power generation efficiency. In particular, it is preferably used for the anode.

本発明の電極触媒組成物には、本発明に係る燃料電池用電極触媒の他に、導電性炭素材料と高分子電解質を含有する。導電性炭素材料は、触媒層の導電性を確保するために添加するものであって、カーボンブラック、カーボン粒子、カーボンファイバー、カーボンナノチューブなどを用いることができる。   The electrode catalyst composition of the present invention contains a conductive carbon material and a polymer electrolyte in addition to the fuel cell electrode catalyst according to the present invention. The conductive carbon material is added to ensure the conductivity of the catalyst layer, and carbon black, carbon particles, carbon fibers, carbon nanotubes, and the like can be used.

導電性炭素材料の添加量は、本発明の電極触媒が有効に触媒性能を発揮することができ且つ導電性を示す程度とすればよい。例えば、電極触媒１００質量部に対し、導電性炭素材料を５０〜５００質量部の割合で配合することができる。   The addition amount of the conductive carbon material may be set to such an extent that the electrode catalyst of the present invention can effectively exhibit catalytic performance and exhibits conductivity. For example, a conductive carbon material can be mix | blended in the ratio of 50-500 mass parts with respect to 100 mass parts of electrode catalysts.

高分子電解質は、触媒反応により燃料から生じたプロトンを高分子電解質膜へ送達する役割を有する。例えば、ナフィオン（デュポン社製）、フレミオン（旭化成（株）製）、アシブレック（旭硝子（株）製）などのスルホン酸基を有するフッ素樹脂や、タングステン酸、リンタングステン酸などの無機物などを使用することができる。   The polymer electrolyte has a role of delivering protons generated from the fuel by the catalytic reaction to the polymer electrolyte membrane. For example, fluorine resin having a sulfonic acid group such as Nafion (manufactured by DuPont), Flemion (manufactured by Asahi Kasei Co., Ltd.), and Ashiburek (manufactured by Asahi Glass Co., Ltd.), and inorganic substances such as tungstic acid and phosphotungstic acid are used. be able to.

本発明の電極組成物における高分子電解質の割合については、電極としたときに必要なプロトン伝導性が得られるように適宜決定すればよい。例えば、電極触媒１００質量部に対して高分子電解質を１０〜２００質量部の割合で適宜配合すればよい。   What is necessary is just to determine suitably about the ratio of the polymer electrolyte in the electrode composition of this invention so that required proton conductivity may be acquired when it is set as an electrode. For example, what is necessary is just to mix | blend a polymer electrolyte suitably in the ratio of 10-200 mass parts with respect to 100 mass parts of electrode catalysts.

本発明の電極触媒組成物には、本発明の電極触媒の他に電極触媒を添加してもよい。例えば、導電性炭素材料の全部または一部に触媒成分を担持してもよい。この場合の担持方法は、本発明担体への担持方法と同様のものを用いることができる。但し、本発明の電極触媒の性能を有効に発揮せしめるために、他の電極触媒を添加する場合には、全電極触媒に対する本発明の電極触媒を１０質量％以上とすることが好ましく、より好ましくは２０質量％以上、さらに好ましくは５０質量％以上、さらに好ましくは６０質量％以上とする。好適には、本発明の電極触媒組成物に含まれる電極触媒を、全て本発明の電極触媒とする。   In addition to the electrode catalyst of the present invention, an electrode catalyst may be added to the electrode catalyst composition of the present invention. For example, the catalyst component may be supported on all or part of the conductive carbon material. In this case, the same loading method as that on the carrier of the present invention can be used. However, in order to effectively exhibit the performance of the electrode catalyst of the present invention, when adding another electrode catalyst, the electrode catalyst of the present invention is preferably 10% by mass or more based on the total electrode catalyst, more preferably. Is 20% by mass or more, more preferably 50% by mass or more, and further preferably 60% by mass or more. Suitably, all the electrode catalysts contained in the electrode catalyst composition of the present invention are used as the electrode catalyst of the present invention.

本発明の電極触媒組成物において、触媒成分（導電性炭素材料へ触媒成分を担持する場合には、その触媒成分を含む）、担体および導電性炭素材料の好適な割合は、触媒成分：担体：導電性炭素材料＝１〜６０：５〜６０：２０〜７０（合計１００）、より好ましくは１０〜６０：５〜５０：２０〜６０（合計１００）である。   In the electrode catalyst composition of the present invention, a suitable ratio of the catalyst component (including the catalyst component when the catalyst component is supported on the conductive carbon material), the support, and the conductive carbon material is the catalyst component: support: Conductive carbon material = 1 to 60: 5 to 60:20 to 70 (total 100), more preferably 10 to 60: 5 to 50:20 to 60 (total 100).

固体高分子型燃料電池の電極（アノードとカソード）は、高分子電解質側の触媒層と、その外側のガス拡散層からなる。このガス拡散層としては、優れたガス透過性と導電性を有するものとして、厚さ１００〜３００μｍ程度のカーボンペーパーやカーボンクロスが用いられる。これらカーボンペーパー等は、例えばポリテトラフルオロエチレン（ＰＴＦＥ）などで撥水処理を施してもよい。よって、本発明の電極組成物により電極を形成する場合には、本発明の電極触媒、導電性炭素材料、高分子電解質へ、必要に応じて撥水材やバインダーなどを加え、水やイソプロピルアルコールなどの有機溶媒と均一混合してペーストを調製し、これをカーボンペーパーなどのガス拡散層に塗布後、乾燥することによって、電極を形成することができる。   The electrodes (anode and cathode) of the polymer electrolyte fuel cell are composed of a catalyst layer on the polymer electrolyte side and a gas diffusion layer on the outside thereof. As this gas diffusion layer, carbon paper or carbon cloth having a thickness of about 100 to 300 μm is used as having excellent gas permeability and conductivity. These carbon papers may be subjected to water repellent treatment with, for example, polytetrafluoroethylene (PTFE). Therefore, when an electrode is formed from the electrode composition of the present invention, a water-repellent material or a binder is added to the electrode catalyst, conductive carbon material, or polymer electrolyte of the present invention as necessary, and water or isopropyl alcohol is added. An electrode can be formed by preparing a paste by uniformly mixing with an organic solvent such as the above, applying the paste to a gas diffusion layer such as carbon paper, and drying.

得られたアノードとカソードは、高分子電解質膜を間に挟んでホットプレスすることによって、膜電極接合体とすることができる。この際、各電極において、触媒層が高分子電解質膜に接する様に配置する必要がある。また、ホットプレスにおける圧力や温度は、常法の条件に従えばよい。   The obtained anode and cathode can be made into a membrane electrode assembly by hot pressing with a polymer electrolyte membrane interposed therebetween. At this time, in each electrode, it is necessary to dispose the catalyst layer in contact with the polymer electrolyte membrane. Moreover, the pressure and temperature in a hot press should just follow the conditions of a conventional method.

得られた膜電極接合体は、セパレータなどと共に、常法に従って固体高分子型燃料電池とすることができる。こうして得られた本発明の固体高分子型燃料電池は、高性能の電極触媒を有することから発電性能に極めて優れる。よって、本発明の固体高分子型燃料電池は、携帯機器や自動車用の電源、或いは家庭用の発電システムなどに適するものである。   The obtained membrane electrode assembly can be made into a polymer electrolyte fuel cell according to a conventional method together with a separator and the like. The solid polymer fuel cell of the present invention thus obtained has extremely high power generation performance because it has a high-performance electrode catalyst. Therefore, the polymer electrolyte fuel cell of the present invention is suitable for portable devices, automobile power supplies, household power generation systems, and the like.

以下、実施例を挙げて本発明をより具体的に説明するが、本発明はもとより下記実施例により制限を受けるものではなく、前・後記の趣旨に適合し得る範囲で適当に変更を加えて実施することも可能であり、それらはいずれも本発明の技術的範囲に含まれる。   EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. It is also possible to implement, and they are all included in the technical scope of the present invention.

実施例１
導電性炭素粉末であるカーボンブラック（Ｃａｂｏｔ社製、ＶｕｌｃａｎＸＣ７２）に、ジニトロジアンミン白金と塩化ルテニウムとの混合水溶液を含浸させた。次に、窒素雰囲気下９０℃で乾燥した後、水素を用いて４５０℃で１時間還元処理して、ＰｔとＲｕをカーボンブラックに担持した電極触媒ａ１（Ｐｔ・Ｒｕ／Ｃ）を得た。この電極触媒ａ１における白金とルテニウムの担持量は、それぞれ２０質量％および１０質量％であった。 Example 1
Carbon black (made by Cabot, Vulcan XC72), which is a conductive carbon powder, was impregnated with a mixed aqueous solution of dinitrodiammineplatinum and ruthenium chloride. Next, after drying at 90 ° C. in a nitrogen atmosphere, reduction treatment was performed using hydrogen at 450 ° C. for 1 hour to obtain an electrode catalyst a1 (Pt · Ru / C) having Pt and Ru supported on carbon black. The supported amounts of platinum and ruthenium in this electrode catalyst a1 were 20% by mass and 10% by mass, respectively.

別途、２０質量％アンモニア水２１０Ｌにスノーテックス３０（日産化学社製、シリカゾル、約３０質量％のＳｉＯ2含有）１０．８ｋｇを加え、攪拌混合した後、硫酸チタニルの硫酸溶液（ＴｉＯ2として７０ｇ／Ｌ、硫酸濃度３１０ｇ／Ｌ）３５０Ｌを攪拌しながら徐々に滴下した。得られたゲルを室温にて３時間静置した後、ろ過、水洗した。次いで１５０℃で１０時間乾燥した後、５００℃で５時間焼成し、さらにハンマーミルを用いて粉砕し、粉体を得た。得られた粉体の組成は、モル比でＴｉＯ2：ＳｉＯ2＝８．５：１．５、ＳｉＯ2に対するＴｉＯ2のモル比は約５．７であった。粉体のＸ線回折チャートではＴｉＯ2やＳｉＯ2の明らかな固有ピークは認められず、ブロードな回折ピークによって非晶質な微細構造を有するチタンとケイ素との複合酸化物（Ｔｉ−Ｓｉ複合酸化物）であることが確認された。 Separately, 10.8 kg of Snowtex 30 (manufactured by Nissan Chemical Co., silica sol, containing about 30% by mass of SiO 2 ) was added to 210 L of 20% by mass ammonia water, and after stirring and mixing, sulfuric acid solution of titanyl sulfate (70 g as TiO 2) / L, sulfuric acid concentration 310 g / L) 350 L was gradually added dropwise with stirring. The obtained gel was allowed to stand at room temperature for 3 hours, and then filtered and washed with water. Subsequently, after drying at 150 degreeC for 10 hours, it baked at 500 degreeC for 5 hours, and also grind | pulverized using the hammer mill, and obtained powder. The composition of the obtained powder, TiO 2 molar ratio: SiO 2 = 8.5: 1.5, the molar ratio of TiO 2 with respect to SiO 2 was about 5.7. In the X-ray diffraction chart of the powder, no obvious intrinsic peak of TiO 2 or SiO 2 was observed, but a complex oxide of titanium and silicon (Ti-Si composite oxidation) having an amorphous microstructure due to a broad diffraction peak. ).

この複合酸化物粉体に塩化白金酸と塩化ルテニウムの混合水溶液を含浸させた。次に、１２０℃で乾燥した後、水素を用いて３５０℃で２時間還元処理をして、ＰｔとＲｕをＴｉ−Ｓｉ複合酸化物に担持した電極触媒ｂ１（Ｐｔ・Ｒｕ／Ｔｉ−Ｓｉ複合酸化物）を得た。この電極触媒ｂ１における白金とルテニウムの担持量は、それぞれ１０質量％および５質量％であった。   The composite oxide powder was impregnated with a mixed aqueous solution of chloroplatinic acid and ruthenium chloride. Next, after drying at 120 ° C., reduction treatment was performed at 350 ° C. for 2 hours using hydrogen, and the electrode catalyst b1 (Pt · Ru / Ti—Si composite) in which Pt and Ru were supported on a Ti—Si composite oxide. Oxide). The supported amounts of platinum and ruthenium in the electrode catalyst b1 were 10% by mass and 5% by mass, respectively.

上記の電極触媒ａ１と電極触媒ｂ１とを、総質量に対して、電極触媒ａ１が８０質量％、電極触媒ｂ１が２０質量％となるように混合した。ここで、触媒成分の合計：担体：導電性炭素材料の質量比は、２７：１７：５６である。そこにプロトン伝導性ポリマー（米国Ａｌｄｒｉｃｈ社製、５質量％ナフィオン分散液）と水を添加し、触媒ペーストを作成した。この触媒ペーストを、ＰＴＦＥで撥水処理化したカーボンペーパー（東レ製、ＴＧＰ−Ｈ０６０−Ｈ）へ白金担持量が０．８ｍｇ／ｃｍ2となるように塗布し、触媒層を形成した。この電極をアノードとした。 Said electrode catalyst a1 and electrode catalyst b1 were mixed so that electrode catalyst a1 might be 80 mass% and electrode catalyst b1 might be 20 mass% with respect to the total mass. Here, the mass ratio of the total catalyst components: support: conductive carbon material is 27:17:56. A proton conductive polymer (manufactured by Aldrich, USA, 5% by mass Nafion dispersion) and water were added thereto to prepare a catalyst paste. This catalyst paste was applied to carbon paper (TGP-H060-H, manufactured by Toray Industries, Inc.) made water-repellent with PTFE so that the amount of platinum supported was 0.8 mg / cm 2 to form a catalyst layer. This electrode was used as an anode.

また、導電性炭素粉末であるカーボンブラック（Ｃａｂｏｔ社製、ＶｕｌｃａｎＸＣ７２）にジニトロジアンミン白金の水溶液を含浸させ、窒素雰囲気下９０℃で乾燥した後、水素を用いて２００℃で２時間還元処理して、白金の担持量が２０質量％の電極触媒を得た。この電極触媒を用い、上記アノードと同様にして、カソードを作製した（白金担持量：０．８ｍｇ／ｃｍ2）。 Carbon black (Cabot Co., Vulcan XC72) is impregnated with an aqueous solution of dinitrodiammine platinum, dried at 90 ° C. in a nitrogen atmosphere, and then reduced with hydrogen at 200 ° C. for 2 hours. An electrode catalyst having a platinum loading of 20% by mass was obtained. Using this electrode catalyst, a cathode was produced in the same manner as the anode (platinum supported amount: 0.8 mg / cm 2 ).

上記で得られたアノードとカソードを、ホットプレス機にて固体高分子電解質膜（米国デュポン社製、ナフィオン１１２）の両面に接合し、電極膜接合体（ＭＥＡ）を作製した。このＭＥＡを用い、燃料電池特性測定用セル（単セル）を組立て、試験を実施した。アノード側には水素ガスを、カソード側には酸素を供給し、セル温度を８０℃、圧力は大気圧、水素利用率（Ｕｆ）を７０％、酸素利用率（Ｕｏ）を４０％とし、ガス加湿は水素および酸素を８５℃のバブラーを通して行うことで、電流−電圧特性試験を実施した。０．２Ａ／ｃｍ2および０．６Ａ／ｃｍ2における電圧（ｍＶ）を表１に示す。 The anode and the cathode obtained above were joined to both surfaces of a solid polymer electrolyte membrane (Nafion 112, manufactured by DuPont, USA) with a hot press machine to produce an electrode membrane assembly (MEA). Using this MEA, a fuel cell characteristic measurement cell (single cell) was assembled and tested. Hydrogen gas is supplied to the anode side, oxygen is supplied to the cathode side, the cell temperature is 80 ° C., the pressure is atmospheric pressure, the hydrogen utilization rate (Uf) is 70%, and the oxygen utilization rate (Uo) is 40%. Humidification was conducted with hydrogen and oxygen through a bubbler at 85 ° C., and a current-voltage characteristic test was conducted. Table 1 shows the voltage (mV) at 0.2 A / cm 2 and 0.6 A / cm 2 .

また、アノードのＣＯ触媒被毒性については、アノード側ハーフセルを作製し、確認を行なった。この試験においては、白金ブラック（Ｐｔ Ｂｌａｃｋ、Ｕｍｉｃｏｒｅ製、Ｐｌａｔｉｎｕｍ Ｂｌａｃｋ−Ｆｕｅｌ Ｃｅｌｌ ｇｒａｄｅ ＴｙｐｅＢＺ）を用い、上記の作製方法に準じて作製した電極をカソードとした（白金担持量：５．０ｍｇ／ｃｍ2）。このカソードとアノードとを用いて、上記と同様にしてＭＥＡを作製した。このように作製したＭＥＡを単セルに組み込み、試験を実施した。このＭＥＡでは、カソードに水素ガスを供給することによりカソードは参照極（Ｒｅｖｅｒｓｉｂｌｅ Ｈｙｄｒｏｇｅｎ Ｅｌｅｃｔｒｏｄｅ（ＲＨＥ））となる。セル温度は８０℃で、カソードには水素ガスを、アノードには１００ｐｐｍの一酸化炭素を含んだ水素ガスを供給して測定を行なった。この試験では、電流密度：０．６Ａ／ｃｍ2における分極値（電圧）の測定を行なった。この分極値はカソード電圧（参照極）に対する値である。結果を表１に示す。 Moreover, the anode side half cell was manufactured and confirmed about the CO catalyst poisoning of an anode. In this test, platinum black (Pt Black, manufactured by Umicore, Platinum Black-Fuel Cell grade Type BZ) was used, and an electrode produced according to the above production method was used as a cathode (platinum supported amount: 5.0 mg / cm 2). ). Using this cathode and anode, an MEA was produced in the same manner as described above. The MEA produced in this way was incorporated into a single cell and tested. In this MEA, by supplying hydrogen gas to the cathode, the cathode becomes a reference electrode (Reversible Hydrogen Electrode (RHE)). The cell temperature was 80 ° C., hydrogen gas was supplied to the cathode, and hydrogen gas containing 100 ppm of carbon monoxide was supplied to the anode. In this test, the polarization value (voltage) was measured at a current density of 0.6 A / cm 2 . This polarization value is a value with respect to the cathode voltage (reference electrode). The results are shown in Table 1.

実施例２
ジニトロジアンミン白金とモリブデン酸アンモニウム（（ＮＨ4）6Ｍｏ7Ｏ24・４Ｈ2Ｏ）を用いた以外は、実施例１の電極触媒ａ１の調製法に準じて、電極触媒ａ２（Ｐｔ・Ｍｏ／Ｃ）を調製した。電極触媒ａ２における白金とモリブデンの担持量は、それぞれ４０質量％および２０質量％であった。 Example 2
According to the preparation method of the electrode catalyst a1 of Example 1, except that dinitrodiammine platinum and ammonium molybdate ((NH 4 ) 6 Mo 7 O 24 · 4H 2 O) were used, the electrode catalyst a2 (Pt · Mo / C) was prepared. The supported amounts of platinum and molybdenum in the electrode catalyst a2 were 40% by mass and 20% by mass, respectively.

別途、水１００Ｌに硝酸鉄（Ｆｅ（ＮＯ3）3・９Ｈ2Ｏ）４．０ｋｇと硝酸第一セリウム（Ｃｅ（ＮＯ3）3・６Ｈ2Ｏ）２．６ｋｇを溶解させ、硫酸チタニルの硫酸溶液（ＴｉＯ2として２５０ｇ／Ｌ、硫酸濃度１１００ｇ／Ｌ）９．６Ｌを用いた以外は、実施例１における電極触媒ｂ１のＴｉ−Ｓｉ複合酸化物の調製法に準じて複合酸化物粉体を調製した。この複合酸化物粉体の組成は、モル比でＴｉＯ2：Ｆｅ2Ｏ3：ＣｅＯ2＝５：４：１、Ｆｅ2Ｏ3とＣｅＯ2の合計に対するＴｉＯ2のモル比は１であった。次に、上記の複合酸化物粉体にジニトロジアンミン白金、塩化ルテニウムおよび硝酸コバルト（Ｃｏ（ＮＯ3）3・６Ｈ2Ｏ）の混合水溶液を含浸させた。次に、１５０℃で乾燥させた後、水素を用いて３５０℃で２時間還元処理し、電極触媒ｂ２（Ｐｔ・Ｒｕ・Ｃｏ／Ｔｉ−Ｆｅ−Ｃｅ複合酸化物）を得た。この電極触媒ｂ２における、白金、ルテニウムおよびコバルトの担持量は、それぞれ３０質量％、２０質量％および１０質量％であった。 Separately, 4.0 kg of iron nitrate (Fe (NO 3 ) 3 · 9H 2 O) and 2.6 kg of ceric nitrate (Ce (NO 3 ) 3 · 6H 2 O) are dissolved in 100 L of water, and sulfuric acid of titanyl sulfate is used. Except for using 9.6 L of a solution (250 g / L as TiO 2 , sulfuric acid concentration 1100 g / L), a composite oxide powder was prepared in accordance with the preparation method of the Ti—Si composite oxide of the electrode catalyst b1 in Example 1. Prepared. The composite oxide powder had a molar ratio of TiO 2 : Fe 2 O 3 : CeO 2 = 5: 4: 1, and the molar ratio of TiO 2 to the total of Fe 2 O 3 and CeO 2 was 1. . Next, the mixed oxide powder was impregnated with a mixed aqueous solution of dinitrodiammine platinum, ruthenium chloride and cobalt nitrate (Co (NO 3 ) 3 .6H 2 O). Next, after drying at 150 ° C., reduction treatment was performed using hydrogen at 350 ° C. for 2 hours to obtain an electrode catalyst b2 (Pt.Ru.Co/Ti—Fe—Ce composite oxide). The supported amounts of platinum, ruthenium and cobalt in the electrode catalyst b2 were 30% by mass, 20% by mass and 10% by mass, respectively.

上記で得た電極触媒ａ２と電極触媒ｂ２を各々５０質量％の割合で混合した。ここで、触媒成分の合計：担体：導電性炭素材料の質量比は、６０：２０：２０である。   The electrode catalyst a2 and the electrode catalyst b2 obtained above were mixed at a ratio of 50% by mass. Here, the mass ratio of the total catalyst components: support: conductive carbon material is 60:20:20.

この電極触媒をアノードとした以外は実施例１と同様にＭＥＡを作製し、テストを行なった。０．２Ａ／ｃｍ2および０．６Ａ／ｃｍ2における電圧（ｍＶ）を表１に示す。さらに、実施例１と同様にしてアノード側ハーフセルを作製し、０．６Ａ／ｃｍ2における分極値よりアノードのＣＯ触媒被毒特性を評価した。結果を表１に示す。 An MEA was produced and tested in the same manner as in Example 1 except that this electrode catalyst was used as an anode. Table 1 shows the voltage (mV) at 0.2 A / cm 2 and 0.6 A / cm 2 . Further, an anode-side half cell was prepared in the same manner as in Example 1, and the anode's CO catalyst poisoning characteristics were evaluated from the polarization value at 0.6 A / cm 2 . The results are shown in Table 1.

実施例３
２０質量％アンモニア水２１０Ｌ（リットル）にスノーテックス３０（日産化学（株）シリカゾル、約３０質量％のＳｉＯ2含有）１０．８ｋｇを加え、攪拌、混合した後、硫酸チタニルの硫酸溶液（ＴｉＯ2として７０ｇ／Ｌ、硫酸濃度３１０ｇ／Ｌ）３５０Ｌを攪拌しながら徐々に滴下した。得られたゲルを室温にて３時間静置した後、ろ過、水洗し、次いで１５０℃で１０時間乾燥した後、５００℃で５時間焼成し、さらにハンマーミルを用いて粉砕し、粉体を得た。得られた粉体の組成はモル比でＴｉＯ2：ＳｉＯ2＝８．５：１．５、ＳｉＯ2に対するＴｉＯ2のモル比は約５．７であり、粉体のＸ線回折チャートではＴｉＯ2やＳｉＯ2の明らかな固有ピークは認められず、ブロードな回折ピークによって非晶質な微細構造を有するチタンとケイ素との複合酸化物（Ｔｉ−Ｓｉ複合酸化物）であることが確認された。 Example 3
After adding 10.8 kg of Snowtex 30 (Nissan Chemical Co., Ltd. silica sol, containing about 30% by mass of SiO 2 ) to 210 L (liter) of 20% by mass of aqueous ammonia, stirring and mixing, a sulfuric acid solution of titanyl sulfate (TiO 2) (70 g / L, sulfuric acid concentration 310 g / L) was gradually added dropwise with stirring. The obtained gel was allowed to stand at room temperature for 3 hours, then filtered, washed with water, then dried at 150 ° C. for 10 hours, then calcined at 500 ° C. for 5 hours, and further pulverized using a hammer mill. Obtained. The composition of the obtained powder molar ratio TiO 2: SiO 2 = 8.5: 1.5, the molar ratio of TiO 2 with respect to SiO 2 is about 5.7, TiO by X-ray diffraction chart of the powder No obvious intrinsic peak of SiO 2 or SiO 2 was observed, and it was confirmed by a broad diffraction peak that it was a complex oxide of titanium and silicon (Ti-Si complex oxide) having an amorphous microstructure. .

この複合酸化物粉体に、ジニトロジアンミン白金と塩化ルテニウムの混合水溶液を含浸させた。次に、１２０℃で乾燥した後、水素を用いて３５０℃で２時間還元処理して、ＰｔとＲｕをＴｉ−Ｓｉ複合酸化物に担持した電極触媒ａ３［Ｐｔ・Ｒｕ／（Ｔｉ−Ｓｉ複合酸化物）］を得た。この電極触媒ａ３における白金とルテニウムの担持量は、それぞれ３５質量％および２０質量％であった。   This composite oxide powder was impregnated with a mixed aqueous solution of dinitrodiammineplatinum and ruthenium chloride. Next, after drying at 120 ° C., the electrode catalyst a3 [Pt · Ru / (Ti—Si composite) in which Pt and Ru are supported on a Ti—Si composite oxide by reducing with hydrogen at 350 ° C. for 2 hours. Oxide)]. The supported amounts of platinum and ruthenium in the electrode catalyst a3 were 35% by mass and 20% by mass, respectively.

上記電極触媒ａ３と、導電性炭素粉末であるカーボンブラック（Ｃａｂｏｔ社製、ＶｕｌｃａｎＸＣ７２）とを、総質量に対して電極触媒が６０質量％、カーボンブラックが４０質量％となるように混合した。ここで、触媒成分の合計：担体：導電性炭素材料の質量比は、３３：２７：４０である。当該混合物へ、プロトン伝導性ポリマー（米国Ａｌｄｒｉｃｈ社製、５質量％ナフィオン分散液）と水を添加し、触媒ペーストを作成した。この触媒ペーストをＰＴＦＥで撥水処理化したカーボンペーパー（東レ製、ＴＧＰ−Ｈ０６０−Ｈ）に白金担持量が０．８ｍｇ／ｃｍ2となる様に塗布し、触媒層を形成した。この電極をアノードとした。 The above-mentioned electrode catalyst a3 and carbon black as a conductive carbon powder (Vulcan XC72, manufactured by Cabot) were mixed so that the electrode catalyst was 60% by mass and the carbon black was 40% by mass with respect to the total mass. Here, the mass ratio of the total catalyst components: support: conductive carbon material is 33:27:40. A proton conductive polymer (manufactured by Aldrich, USA, 5% by mass Nafion dispersion) and water were added to the mixture to prepare a catalyst paste. This catalyst paste was applied to carbon paper (TGP-H060-H, manufactured by Toray Industries, Inc.) made water repellent with PTFE so that the amount of platinum supported was 0.8 mg / cm 2 to form a catalyst layer. This electrode was used as an anode.

また、導電性炭素粉末であるカーボンブラック（Ｃａｂｏｔ社製、ＶｕｌｃａｎＸＣ７２）にジニトロジアンミン白金の水溶液を含浸させ、次に、窒素雰囲気下９０℃で乾燥した後、水素を用いて２００℃で２時間還元処理して、白金の担持量が２０質量％の電極触媒を得た。この電極触媒を用い、上記アノードと同様にして、カソード電極を作製した。   Also, carbon black (Cabot Co., Vulcan XC72), which is a conductive carbon powder, is impregnated with an aqueous solution of dinitrodiammine platinum, then dried at 90 ° C. in a nitrogen atmosphere, and then reduced at 200 ° C. with hydrogen for 2 hours. By processing, an electrode catalyst having a platinum loading of 20% by mass was obtained. Using this electrode catalyst, a cathode electrode was produced in the same manner as the anode.

上述で得られたアノードおよびカソードをホットプレス機にて固体高分子電解質膜（米国デュポン社製、ナフィオン１１２）の両面に接合し、電極膜接合体（ＭＥＡ）を作製した。このようにして作製したＭＥＡを用い、燃料電池特性測定用セル（単セル）を組立て、試験を実施した。アノード側には水素ガスを、カソード側には酸素を供給し、セル温度を８０℃、圧力は大気圧、水素利用率（Ｕｆ）を７０％、酸素利用率（Ｕｏ）を４０％とし、ガス加湿は水素および酸素を８５℃のバブラーを通して行うことで、電流−電圧特性試験を実施した。０．２Ａ／ｃｍ2および０．６Ａ／ｃｍ2における電圧（ｍｖ）を表１に示す。また、実施例１と同様にしてアノード側ハーフセルを作製し、０．６Ａ／ｃｍ2における分極値よりアノードのＣＯ触媒被毒特性を評価した。結果を表１に示す。 The anode and cathode obtained as described above were bonded to both surfaces of a solid polymer electrolyte membrane (Nafion 112, manufactured by DuPont, USA) using a hot press machine to produce an electrode membrane assembly (MEA). Using the MEA thus produced, a fuel cell characteristic measurement cell (single cell) was assembled and tested. Hydrogen gas is supplied to the anode side, oxygen is supplied to the cathode side, the cell temperature is 80 ° C., the pressure is atmospheric pressure, the hydrogen utilization rate (Uf) is 70%, and the oxygen utilization rate (Uo) is 40%. Humidification was conducted with hydrogen and oxygen through a bubbler at 85 ° C., and a current-voltage characteristic test was conducted. Table 1 shows the voltage (mv) at 0.2 A / cm 2 and 0.6 A / cm 2 . Further, an anode-side half cell was prepared in the same manner as in Example 1, and the anode's CO catalyst poisoning characteristics were evaluated from the polarization value at 0.6 A / cm 2 . The results are shown in Table 1.

比較例１
導電性炭素粉末であるカーボンブラック（Ｃａｂｏｔ社製、ＶｕｌｃａｎＸＣ７２）に、ジニトロジアンミン白金と塩化ルテニウムとの混合水溶液を含浸させた。次に、窒素雰囲気下９０℃で乾燥した後、水素を用いて４５０℃で１時間還元処理して触媒（Ｐｔ・Ｒｕ／Ｃ）を得た。この触媒における、白金とルテニウムの担持量は、それぞれ２０質量％および１０質量％であった。上記触媒１００質量％からなるアノード触媒を用いた以外は実施例１と同様にＭＥＡを作製し、電流−電圧特性試験を行なった。０．２Ａ／ｃｍ2および０．６Ａ／ｃｍ2における電圧（ｍＶ）を表１に示す。さらに、実施例１と同様にしてアノード側ハーフセルを作製し、０．６Ａ／ｃｍ2における分極値よりアノードのＣＯ触媒被毒特性を評価した。結果を表１に示す。 Comparative Example 1
Carbon black (made by Cabot, Vulcan XC72), which is a conductive carbon powder, was impregnated with a mixed aqueous solution of dinitrodiammineplatinum and ruthenium chloride. Next, after drying at 90 ° C. in a nitrogen atmosphere, reduction treatment was performed using hydrogen at 450 ° C. for 1 hour to obtain a catalyst (Pt · Ru / C). The supported amounts of platinum and ruthenium in this catalyst were 20% by mass and 10% by mass, respectively. An MEA was produced in the same manner as in Example 1 except that the anode catalyst composed of 100% by mass of the catalyst was used, and a current-voltage characteristic test was performed. Table 1 shows the voltage (mV) at 0.2 A / cm 2 and 0.6 A / cm 2 . Further, an anode-side half cell was prepared in the same manner as in Example 1, and the anode's CO catalyst poisoning characteristics were evaluated from the polarization value at 0.6 A / cm 2 . The results are shown in Table 1.

比較例２
上記実施例１において、電極触媒ａ１を使用せず電極触媒ｂ１のみを用いた以外は同様にして、電流−電圧特性試験を行なった。その結果、触媒層に導電性炭素材料が含まれず、金属酸化物のみでは導電性が低いため発電は認められなかった。 Comparative Example 2
A current-voltage characteristic test was performed in the same manner as in Example 1 except that only the electrode catalyst b1 was used without using the electrode catalyst a1. As a result, no electroconductive carbon material was contained in the catalyst layer, and power generation was not recognized because only the metal oxide had low conductivity.

Figure 2006224095
Figure 2006224095

表１に示す結果の通り、担体としてカーボンブラックのみを用いる従来の触媒では、発電性能が十分でない。その上、燃料に一酸化炭素が混入していると、触媒被毒のために発電性能が低下する。   As shown in Table 1, the conventional catalyst using only carbon black as the carrier does not have sufficient power generation performance. In addition, when carbon monoxide is mixed in the fuel, the power generation performance is reduced due to catalyst poisoning.

一方、担体として本発明のＴｉ系複合酸化物を含む本発明の電極触媒をアノードの触媒層に用いた場合には、一酸化炭素の混入の有無にかかわらず高い発電性能が発揮される。よって、本発明の電極触媒は、固体高分子型燃料電池の発電性能を高め得ることが実証された。   On the other hand, when the electrode catalyst of the present invention containing the Ti-based composite oxide of the present invention as a support is used for the catalyst layer of the anode, high power generation performance is exhibited regardless of whether carbon monoxide is mixed. Therefore, it was demonstrated that the electrode catalyst of the present invention can improve the power generation performance of the polymer electrolyte fuel cell.

Claims (6)

Ｓｉ、Ｚｒ、Ｗ、Ｆｅ、ＣｅおよびＴａからなる群より選ばれる少なくとも１種とＴｉとの複合酸化物であって、他の酸化物成分に対するチタニア成分のモル比が１以上である複合酸化物に、触媒成分が担持されていることを特徴とする燃料電池用電極触媒。   A composite oxide of Ti and at least one selected from the group consisting of Si, Zr, W, Fe, Ce and Ta, wherein the molar ratio of the titania component to other oxide components is 1 or more And an electrode catalyst for a fuel cell, on which a catalyst component is supported. 触媒成分が、Ｐｔ、Ｐｄ、Ｒｕ、Ｒｈ、Ｉｒ、Ａｕ、Ａｇ、Ｆｅ、Ｍｏ、Ｗ、Ｖ、Ｉｎ、Ｔａ、Ｓｎ、Ｃｕ、Ｓｂ、Ｍｇ、Ｎｉ、ＣｏおよびＭｎからなる群より選ばれる少なくとも１種である請求項１に記載の燃料電池用電極触媒。   The catalyst component is at least selected from the group consisting of Pt, Pd, Ru, Rh, Ir, Au, Ag, Fe, Mo, W, V, In, Ta, Sn, Cu, Sb, Mg, Ni, Co and Mn The electrode catalyst for fuel cells according to claim 1, which is one type. 触媒成分が、Ｐｔ、Ｐｄ、Ｒｕ、Ｒｈ、Ｉｒ、ＡｕおよびＡｇからなる群より選ばれる少なくとも１種である請求項１に記載の燃料電池用電極触媒。   2. The fuel cell electrode catalyst according to claim 1, wherein the catalyst component is at least one selected from the group consisting of Pt, Pd, Ru, Rh, Ir, Au, and Ag. 触媒成分が、Ｐｔ、Ｐｄ、Ｒｕ、Ｒｈ、Ｉｒ、ＡｕおよびＡｇからなる群より選ばれる少なくとも１種と、Ｆｅ、Ｍｏ、Ｗ、Ｖ、Ｉｎ、Ｔａ、Ｓｎ、Ｃｕ、Ｓｂ、Ｍｇ、Ｎｉ、ＣｏおよびＭｎからなる群より選ばれる少なくとも１種との組合せである請求項１に記載の固体高分子型燃料電池用電極触媒。   The catalyst component is at least one selected from the group consisting of Pt, Pd, Ru, Rh, Ir, Au and Ag, and Fe, Mo, W, V, In, Ta, Sn, Cu, Sb, Mg, Ni, The electrode catalyst for a polymer electrolyte fuel cell according to claim 1, which is a combination with at least one selected from the group consisting of Co and Mn. 請求項１〜４のいずれかに記載の燃料電池用電極触媒、導電性炭素材料および高分子電解質を含有する燃料電池用電極触媒組成物。   The electrode catalyst composition for fuel cells containing the electrode catalyst for fuel cells in any one of Claims 1-4, a conductive carbon material, and a polymer electrolyte. 請求項５に記載の燃料電池用電極触媒組成物により形成された電極を有する燃料電池。   A fuel cell having an electrode formed from the electrode catalyst composition for a fuel cell according to claim 5.
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008040222A1 (en) * 2006-09-22 2008-04-10 Ocean University Of China Nanometer powder catalyst and its prepartion method
JP2008243436A (en) * 2007-03-26 2008-10-09 Toshiba Corp Support catalyst for fuel cell electrode
JP2010010101A (en) * 2008-06-30 2010-01-14 Toshiba Corp Cathode for fuel cell
WO2011065471A1 (en) * 2009-11-27 2011-06-03 国立大学法人山梨大学 Oxide-based stable high-potential carrier for solid polymer fuel cell
JP2013046913A (en) * 2012-11-22 2013-03-07 Showa Denko Kk Electrode catalyst and use thereof, and method for manufacturing the electrode catalyst
WO2024057960A1 (en) * 2022-09-14 2024-03-21 三菱自動車工業株式会社 Fuel cell electrode

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008040222A1 (en) * 2006-09-22 2008-04-10 Ocean University Of China Nanometer powder catalyst and its prepartion method
US8946116B2 (en) 2006-09-22 2015-02-03 Ocean University Of China Nanometer powder catalyst and its preparation method
JP2008243436A (en) * 2007-03-26 2008-10-09 Toshiba Corp Support catalyst for fuel cell electrode
JP2010010101A (en) * 2008-06-30 2010-01-14 Toshiba Corp Cathode for fuel cell
WO2011065471A1 (en) * 2009-11-27 2011-06-03 国立大学法人山梨大学 Oxide-based stable high-potential carrier for solid polymer fuel cell
JP2013046913A (en) * 2012-11-22 2013-03-07 Showa Denko Kk Electrode catalyst and use thereof, and method for manufacturing the electrode catalyst
WO2024057960A1 (en) * 2022-09-14 2024-03-21 三菱自動車工業株式会社 Fuel cell electrode

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