JP2006205088A - Electrode catalyst, its manufacturing method and fuel cell - Google Patents

Electrode catalyst, its manufacturing method and fuel cell Download PDF

Info

Publication number
JP2006205088A
JP2006205088A JP2005021559A JP2005021559A JP2006205088A JP 2006205088 A JP2006205088 A JP 2006205088A JP 2005021559 A JP2005021559 A JP 2005021559A JP 2005021559 A JP2005021559 A JP 2005021559A JP 2006205088 A JP2006205088 A JP 2006205088A
Authority
JP
Japan
Prior art keywords
noble metal
electrode catalyst
alloy
electrode
platinum
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2005021559A
Other languages
Japanese (ja)
Other versions
JP4776240B2 (en
Inventor
Takahiro Nagata
貴寛 永田
Tomoaki Terada
智明 寺田
Tetsuo Ito
哲男 伊藤
Toshiharu Tabata
寿晴 田端
Hiroaki Takahashi
宏明 高橋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cataler Corp
Toyota Motor Corp
Original Assignee
Cataler Corp
Toyota Motor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cataler Corp, Toyota Motor Corp filed Critical Cataler Corp
Priority to JP2005021559A priority Critical patent/JP4776240B2/en
Publication of JP2006205088A publication Critical patent/JP2006205088A/en
Application granted granted Critical
Publication of JP4776240B2 publication Critical patent/JP4776240B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • 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
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Landscapes

  • Fuel Cell (AREA)
  • Catalysts (AREA)
  • Inert Electrodes (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode catalyst that can suppress degradation of electrolyte membrane by preventing a transition metal from eluting from a noble metal alloy containing the transition metal, its manufacturing method and a fuel cell that can hold a stable cell voltage for a long time using the electrode catalyst. <P>SOLUTION: The electrode catalyst having the noble metal alloy containing a noble metal and the transition metal supported on a carrier is characterized by having the surface of the noble metal alloy coated with the noble metal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、電極触媒、特に、貴金属及び遷移金属から成る貴金属アロイを担体上に担持している電極触媒であって、当該貴金属アロイの表面が貴金属で皮膜されていることを特徴とする電極触媒、その製造方法、及び当該電極触媒を利用した燃料電池、に関する。   The present invention relates to an electrode catalyst, in particular, an electrode catalyst in which a noble metal alloy composed of a noble metal and a transition metal is supported on a carrier, and the surface of the noble metal alloy is coated with the noble metal. , A manufacturing method thereof, and a fuel cell using the electrode catalyst.

近年、燃料電池は自動車用動力源や発電機への適用が期待されており、特に固体高分子形燃料電池（PEFC）は、高効率で且つ低環境負荷という特性から特に注目されている。PEFCは、イオン交換膜、触媒層、及び電極が一体となっており、それらをセパレーターが支持している構造になっている。またPEFCは、水素を燃料とし、アノード（燃料極）及びカソード（空気極）における電極反応によって起電力を得ている。PEFCのカソードでは酸素の還元反応が起こるが、アノードの酸化反応と比較してこの還元反応が遅いため、電極反応全体では律速段階が生じる。   In recent years, fuel cells are expected to be applied to power sources and generators for automobiles. In particular, polymer electrolyte fuel cells (PEFC) are attracting particular attention because of their high efficiency and low environmental impact. PEFC has a structure in which an ion exchange membrane, a catalyst layer, and an electrode are integrated, and these are supported by a separator. PEFC uses hydrogen as a fuel and obtains an electromotive force by an electrode reaction at an anode (fuel electrode) and a cathode (air electrode). Although the reduction reaction of oxygen occurs at the cathode of PEFC, this reduction reaction is slower than the oxidation reaction of the anode, so that the rate-determining step occurs in the overall electrode reaction.

従来、燃料電池用カソード電極触媒として白金が採用されており、主としてカーボンブラックの表面上に白金粒子を分散担持したものが利用されてきた。しかし、上記律速段階を解決するためには白金触媒の触媒能の更なる向上が必要とされており、これまでにも、他の金属、例えば、チタン、クロム、マンガン、鉄、コバルト、ニッケル、銅、ガリウム、ジルコニウム、ハフニウム等を一種以上を含む白金アロイ及びそれらを電極触媒として用いる燃料電池などが提案されている（特許文献１〜５参照）。
特開平４−３５８５４０号公報 特開平５−１５７８０号公報 特開平５−２０８１３５号公報 特開平１０−３０２８１０号公報 特開２００４−２５３３８５号公報 Conventionally, platinum has been employed as a cathode electrode catalyst for a fuel cell, and a catalyst in which platinum particles are dispersedly supported on the surface of carbon black has been used. However, in order to solve the rate-determining step, further improvement in the catalytic ability of the platinum catalyst is required, and so far other metals such as titanium, chromium, manganese, iron, cobalt, nickel, Platinum alloys containing one or more of copper, gallium, zirconium, hafnium, etc., and fuel cells using these as electrode catalysts have been proposed (see Patent Documents 1 to 5).
JP-A-4-358540 Japanese Patent Laid-Open No. 5-15780 JP-A-5-208135 Japanese Patent Laid-Open No. 10-302810 JP 2004-253385 A

上記白金アロイは、白金単独のものと比較して、初期には高い電池電圧を得られることが明らかとなっている。しかしながら、上記白金アロイは長時間運転時に電池電圧の低下を招くという欠点を有していた。   It has been clarified that the platinum alloy can obtain a high battery voltage in the initial stage as compared with platinum alone. However, the platinum alloy has a drawback in that the battery voltage is lowered during long-time operation.

このような事情に鑑み、本発明は、長時間安定した電池電圧を保持できる燃料電池用の電極触媒、その製造方法、及び当該電極触媒を利用した燃料電池、を提供することを目的とする。   In view of such circumstances, an object of the present invention is to provide an electrode catalyst for a fuel cell that can maintain a stable battery voltage for a long time, a manufacturing method thereof, and a fuel cell using the electrode catalyst.

上記課題を解決するために本発明者らが検討を重ねた結果、上記電池電圧の低下は、白金アロイを形成できなかった金属、又は白金アロイ表面上に存在する白金以外の金属が、発電の際の高熱化、電解液中の酸性環境等により溶出し、電解質膜のスルホン酸基と結合し、電解質膜を分解するなどの劣化の要因となるためであろうとの考えの下に、担体上に担持された貴金属アロイ表面を貴金属で被覆したところ、合金による触媒効果を維持しつつ、貴金属アロイからの遷移金属の溶出を防ぐことができることが明らかとなった。   As a result of repeated studies by the present inventors in order to solve the above problems, the decrease in the battery voltage is caused by the fact that a metal that could not form a platinum alloy, or a metal other than platinum present on the platinum alloy surface, On the carrier under the assumption that it may be a cause of deterioration such as elution due to high heat during the process, acidic environment in the electrolyte, etc., binding to the sulfonic acid group of the electrolyte membrane, and decomposing the electrolyte membrane. When the surface of the noble metal alloy supported on the noble metal was coated with the noble metal, it became clear that the elution of the transition metal from the noble metal alloy could be prevented while maintaining the catalytic effect of the alloy.

上記結果を基に、本発明は、貴金属及び遷移金属から成る貴金属アロイを担体上に担持している電極触媒であって、当該貴金属アロイの表面が貴金属で皮膜されていることを特徴とする電極触媒、を提供する（図１）。   Based on the above results, the present invention provides an electrode catalyst in which a noble metal alloy composed of a noble metal and a transition metal is supported on a carrier, the surface of the noble metal alloy being coated with the noble metal. A catalyst is provided (FIG. 1).

更に、本発明は、上記電極触媒の製造方法及び上記電極触媒を利用した燃料電池、を提供する。   Furthermore, this invention provides the manufacturing method of the said electrode catalyst, and the fuel cell using the said electrode catalyst.

本発明の電極触媒は、貴金属で被覆することで貴金属アロイに含まれる遷移金属の溶出が抑制され、その合金効果が持続する。その結果、本発明の電極触媒を利用した燃料電池は、電解質膜の劣化が抑制され、長時間安定して高い電圧を保持することが可能となる。   When the electrode catalyst of the present invention is coated with a noble metal, elution of transition metal contained in the noble metal alloy is suppressed, and the alloy effect is maintained. As a result, in the fuel cell using the electrode catalyst of the present invention, the deterioration of the electrolyte membrane is suppressed, and it becomes possible to stably maintain a high voltage for a long time.

貴金属アロイを形成する貴金属としては、例えば、白金、ロジウム、パラジウム、ルテニウム等が挙げられるが、白金が好ましく、貴金属アロイを形成する遷移金属としては、鉄、コバルト、クロム、ニッケル、マンガン、バナジウム等が挙げられる。尚、これらの貴金属アロイを形成する貴金属及び遷移金属は、それぞれ１又は複数の種類のものであってもよい。   Examples of the noble metal forming the noble metal alloy include platinum, rhodium, palladium, ruthenium, etc., but platinum is preferable, and the transition metal forming the noble metal alloy includes iron, cobalt, chromium, nickel, manganese, vanadium, etc. Is mentioned. In addition, the noble metal and transition metal which form these noble metal alloys may each be one or more types.

貴金属アロイの組成比は、貴金属の割合が多いと合金効果による電池電圧向上効果が小さくなり、一方、遷移金属の割合が多いと遷移金属添加による電池電圧効果が一定となってしまうため、貴金属：遷移金属の原子比が２：１〜９：１であることが好ましい。   As for the composition ratio of the noble metal alloy, when the ratio of the noble metal is large, the effect of improving the battery voltage due to the alloy effect becomes small. On the other hand, when the ratio of the transition metal is large, the battery voltage effect due to the addition of the transition metal becomes constant. It is preferable that the atomic ratio of the transition metal is 2: 1 to 9: 1.

貴金属アロイを担持させる担体は、一般的には、導電性を有する高比表面積の材料から成る担体であるが、本発明はこれらに限定されるものではない。好ましくは、カーボンブラック、黒鉛、炭素繊維等の炭素材料が、導電性が良好で安価であるという理由から利用される。   The carrier for supporting the noble metal alloy is generally a carrier made of a material having a high specific surface area having conductivity, but the present invention is not limited thereto. Preferably, carbon materials such as carbon black, graphite, and carbon fiber are used because they have good conductivity and are inexpensive.

続いて、上記担体に担持された貴金属アロイは貴金属により皮膜される。皮膜された状態のイメージは図１の通りである。図１において、カーボンブラック等の担体３に担持されている貴金属アロイ２は、表面が貴金属１によって皮膜されている。   Subsequently, the noble metal alloy supported on the carrier is coated with the noble metal. The image of the coated state is as shown in FIG. In FIG. 1, the surface of a noble metal alloy 2 supported on a carrier 3 such as carbon black is coated with a noble metal 1.

皮膜に用いる貴金属としては、例えば、白金、ロジウム、パラジウム、ルテニウム等が挙げられるが、白金が好ましい。尚、被覆に用いられる貴金属は、貴金属のみに限定されず、貴金属合金であってもよい。   Examples of the noble metal used for the film include platinum, rhodium, palladium, ruthenium and the like, and platinum is preferable. The noble metal used for the coating is not limited to the noble metal but may be a noble metal alloy.

貴金属による皮膜形成量としては、皮膜形成量が多く皮膜が厚すぎると、初期電池電圧の低下を招き、逆に上記形成量が少なく皮膜が薄すぎると、遷移金属の溶出防止効果が乏しく、長時間運転時の電池電圧低下を招くため、貴金属アロイの金属量の0.5〜10wt%であることが望ましい。更に好ましくは、貴金属による皮膜形成量は、貴金属アロイの金属量の1.0〜5.0wt%である。同様の理由から、触媒粒子表面上における全金属に対する遷移金属の割合(atm%)は、好ましくは触媒粒子全体における全金属に対する遷移金属の(atm%)の50%以下であり、特に好ましくは35%以下である。   As the amount of film formed by noble metal, if the amount of film formation is large and the film is too thick, the initial battery voltage is reduced. Conversely, if the amount of film formation is too small and the film is too thin, the transition metal elution prevention effect is poor and long. In order to reduce the battery voltage during the time operation, it is desirable that the amount is 0.5 to 10 wt% of the metal amount of the noble metal alloy. More preferably, the film formation amount by the noble metal is 1.0 to 5.0 wt% of the metal amount of the noble metal alloy. For the same reason, the ratio (atm%) of the transition metal to the total metal on the surface of the catalyst particles is preferably 50% or less of the transition metal (atm%) to the total metal in the entire catalyst particle, and particularly preferably 35%. % Or less.

皮膜後の粒子径は、触媒粒子が高活性であるためには、0.2〜7.0nmであることが望ましい。触媒粒子径が2.0nmより小さいと容易に凝集を起こし電池電圧の低下を招き、また、7.0nm以上であると、貴金属使用量に対して触媒の表面積が小さくなるために十分な活性を得ることができない。   The particle diameter after coating is preferably 0.2 to 7.0 nm in order for the catalyst particles to be highly active. If the catalyst particle size is smaller than 2.0 nm, aggregation easily occurs and the battery voltage is lowered, and if it is 7.0 nm or more, sufficient activity is obtained because the surface area of the catalyst is smaller than the amount of noble metal used. I can't.

本発明の電極触媒は、例えば、以下の方法によって貴金属アロイの表面上を貴金属で皮膜することによって製造される。１）担体上に担持されている貴金属アロイを水中で懸濁した溶液に対して貴金属溶液を滴下する。２）続いて還元剤を添加し、貴金属溶液中の貴金属を上記アロイに還元担持する。３）上記溶液を濾過洗浄することで得られたケーキを真空中で乾燥する。当該方法により、貴金属アロイを貴金属で被覆した触媒が得られる。   The electrode catalyst of the present invention is produced, for example, by coating the surface of a noble metal alloy with a noble metal by the following method. 1) A noble metal solution is dropped into a solution in which a noble metal alloy supported on a carrier is suspended in water. 2) Subsequently, a reducing agent is added, and the noble metal in the noble metal solution is reduced and supported on the alloy. 3) The cake obtained by filtering and washing the above solution is dried in vacuum. By this method, a catalyst obtained by coating a noble metal alloy with a noble metal can be obtained.

上記方法の１）において使用される貴金属アロイは、当業界で一般的に利用されている方法を用いて製造される。例えば、白金と鉄から成るアロイの場合、純水とカーボン粉末の分散液にヘキサヒドロキソ白金硝酸溶液を滴下し、更に純水を滴下した後に濾過洗浄する。得られたケーキを再び純水に均一に分散させた後、純水と硝酸鉄の分散液を滴下する。アンモニア水溶液で中和後、濾過洗浄して得られたケーキを真空中高温下で乾燥させ、電気炉中で還元処理して合金化処理することによって白金鉄触媒が得られる。   The noble metal alloy used in the above method 1) is produced by a method generally used in the art. For example, in the case of an alloy made of platinum and iron, a hexahydroxo platinum nitric acid solution is dropped into a dispersion of pure water and carbon powder, and then pure water is dropped, followed by filtration and washing. After the obtained cake is uniformly dispersed again in pure water, a dispersion of pure water and iron nitrate is added dropwise. A platinum iron catalyst is obtained by neutralizing with an aqueous ammonia solution, drying the cake obtained by filtration and washing, drying in a vacuum at high temperature, reduction treatment in an electric furnace, and alloying treatment.

上記方法の１）において使用される上記貴金属溶液は、限定しないが、貴金属の塩化物、硝酸塩、水酸化物、アンモニウム塩等を酸・アルカリ溶液中で溶解したものである。   The noble metal solution used in the above method 1) is not limited, but is a solution obtained by dissolving a noble metal chloride, nitrate, hydroxide, ammonium salt or the like in an acid / alkali solution.

２）の還元担持で利用する還元剤としては、限定しないが、アルコール、ヒドラジン等の弱い還元剤が挙げられる。   Although it does not limit as a reducing agent utilized by the reduction | restoration carrying | support of 2), Weak reducing agents, such as alcohol and hydrazine, are mentioned.

本発明の１つの態様として、１）における貴金属溶液としてヘキサヒドロキソ白金硝酸溶液、そして２）の還元剤としてヒドラジンが使用される。   In one embodiment of the invention, hexahydroxoplatinum nitrate solution is used as the noble metal solution in 1) and hydrazine is used as the reducing agent in 2).

上記方法において製造される本発明の触媒は、燃料電池、例えば固体高分子形燃料電池の電極において使用される（図２を参照のこと）。図２において、拡散層４及び本発明の電極触媒を含む触媒層５から成る電極７及び８が、高分子電解質膜６上に貼り合わされることによって単セル電極を形成している。尚、上述したカソード電極の反応速度の問題から、本発明の触媒は特にカソード電極に利用されることを目的とするが、アノード電極においても利用されうる。更に、本発明の触媒はこれらの利用に限定されるものではなく、燃料電池以外の分野でも合金触媒を利用する分野であれば適用可能であると考えられる。   The catalyst of the present invention produced in the above method is used in an electrode of a fuel cell, for example, a polymer electrolyte fuel cell (see FIG. 2). In FIG. 2, electrodes 7 and 8 comprising a diffusion layer 4 and a catalyst layer 5 containing the electrode catalyst of the present invention are bonded to a polymer electrolyte membrane 6 to form a single cell electrode. The catalyst of the present invention is intended to be used particularly for the cathode electrode because of the above-mentioned problem of the reaction rate of the cathode electrode, but can also be used for the anode electrode. Furthermore, the catalyst of the present invention is not limited to these uses, and it can be applied to fields other than fuel cells as long as they use alloy catalysts.

以下に実施例、比較例を挙げて本発明を更に具体的に説明するが、本発明はこれらに限定されるものではない。   Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited thereto.

（白金で被覆された白金鉄触媒の製造）
比表面積が約1000m2/gの市販のカーボン粉末4.7gを純水0.2Lに加え分散させた。この分散液に白金4.7gを含むヘキサヒドロキソ白金硝酸溶液を滴下し、十分にカーボンとなじませた。純水1Lを滴下した後、濾過洗浄した。得られたケーキを再び純水1Lに均一に分散させた後、Feを0.5g含む硝酸鉄4.8gを純水130g中に溶解させた分散液を滴下した。アンモニア水溶液を添加してpH7まで中和した後、濾過洗浄して得られたケーキを真空中で100℃で10時間乾燥させた。その後電気炉において、水素雰囲気のもと700℃で2時間還元処理し、アルゴン雰囲気のもと800℃で5時間合金化処理した。こうして得られた白金鉄触媒を再び純水中に懸濁させ、白金0.10gを含むヘキサヒドロキソ白金硝酸溶液を滴下した。その後、ヒドラジン0.2gを添加し、90℃以上で2時間熱処理後放冷し、続いて濾過洗浄を行った。濾過洗浄して得られたケーキを真空中で100℃で10時間乾燥させ、白金鉄粒子表面を白金で被覆した触媒（実施例１）を得た。比較例として、白金で被覆していない白金鉄触媒を調製した（比較例１）。尚、触媒の保管は窒素雰囲気で行った。 (Production of platinum iron catalyst coated with platinum)
4.7 g of commercially available carbon powder having a specific surface area of about 1000 m 2 / g was added and dispersed in 0.2 L of pure water. To this dispersion, a hexahydroxo platinum nitric acid solution containing 4.7 g of platinum was dropped, and the mixture was sufficiently blended with carbon. After adding 1 L of pure water dropwise, it was washed by filtration. The obtained cake was uniformly dispersed again in 1 L of pure water, and then a dispersion obtained by dissolving 4.8 g of iron nitrate containing 0.5 g of Fe in 130 g of pure water was added dropwise. After adding an aqueous ammonia solution to neutralize to pH 7, the cake obtained by filtration and washing was dried in vacuum at 100 ° C. for 10 hours. Thereafter, reduction treatment was performed in an electric furnace at 700 ° C. for 2 hours under a hydrogen atmosphere, and alloying treatment was performed at 800 ° C. for 5 hours under an argon atmosphere. The platinum iron catalyst thus obtained was again suspended in pure water, and a hexahydroxo platinum nitric acid solution containing 0.10 g of platinum was added dropwise. Thereafter, 0.2 g of hydrazine was added, the mixture was heat treated at 90 ° C. or higher for 2 hours, allowed to cool, and then filtered and washed. The cake obtained by filtration and washing was dried in vacuum at 100 ° C. for 10 hours to obtain a catalyst (Example 1) in which the surface of platinum iron particles was coated with platinum. As a comparative example, a platinum iron catalyst not coated with platinum was prepared (Comparative Example 1). The catalyst was stored in a nitrogen atmosphere.

（触媒の分析）
続いて、上記触媒をエネルギー分散型X線解析装置EDX（日本電子社製２０１０型）にかけ、触媒粒子全体の鉄／白金の組成比を分析した。この際、視野は２０万倍に拡大して触媒粒子に焦点を絞った。また、触媒粒子の表面組成比の分析をX線光電子分光法XPSにて測定した。測定装置にはアルバックファイ社のＰＨ５７００を利用した。尚、白金は４ｆ軌道、鉄は３ｄ軌道を用いた。EDXによる触媒粒子全体の組成比と、XPSによる粒子表面の組成比を以下の表１に示す。 (Catalyst analysis)
Subsequently, the catalyst was subjected to an energy dispersive X-ray analyzer EDX (2010 model manufactured by JEOL Ltd.) to analyze the iron / platinum composition ratio of the entire catalyst particles. At this time, the field of view was enlarged 200,000 times to focus on the catalyst particles. The analysis of the surface composition ratio of the catalyst particles was measured by X-ray photoelectron spectroscopy XPS. As a measuring apparatus, PH5700 manufactured by ULVAC-PHI was used. Platinum used 4f orbit and iron used 3d orbit. The composition ratio of the entire catalyst particle by EDX and the composition ratio of the particle surface by XPS are shown in Table 1 below.

Figure 2006205088
Figure 2006205088

上記表１より、比較例１の触媒が、触媒粒子全体と触媒粒子表面の鉄の組成比がほとんど変わらないのに対し（触媒粒子全体：26.1%、触媒粒子表面：27.8%）、白金鉄触媒を白金で被覆した実施例１のものは、触媒粒子全体の鉄の組成比(25.3 atm%)と比較して、３割程度の組成比(8.2 atm%)に低下している。   From Table 1 above, the catalyst of Comparative Example 1 shows almost no change in the composition ratio of the entire catalyst particle and iron on the catalyst particle surface (total catalyst particle: 26.1%, catalyst particle surface: 27.8%). In Example 1, which was coated with platinum, the composition ratio was reduced to about 30% (8.2 atm%) as compared with the composition ratio of iron in the entire catalyst particles (25.3 atm%).

（固体高分子形燃料電池用単セル電極の作製）
続いて、上記触媒を用いて、以下のようにして固体高分子形燃料電池用の単セル電極を作製した。まず、触媒粉末を有機溶媒に分散させ、この分散液をテフロンシートへ塗布して触媒層を形成した。電極面積1cm2あたりの白金量は0.4mgであった。これらの触媒粉末から調製した電極を、それぞれ高分子電解質膜を介してホットプレスにより貼り合わせ、その両側に拡散層を設置して単セル電極を作製した。 (Production of single cell electrode for polymer electrolyte fuel cell)
Subsequently, using the catalyst, a single cell electrode for a polymer electrolyte fuel cell was produced as follows. First, the catalyst powder was dispersed in an organic solvent, and this dispersion was applied to a Teflon sheet to form a catalyst layer. The amount of platinum per 1 cm 2 of electrode area was 0.4 mg. Electrodes prepared from these catalyst powders were bonded together by hot pressing through polymer electrolyte membranes, and diffusion layers were placed on both sides to produce single cell electrodes.

（電池電圧特性の解析）
上記単セルのカソード側の電極に、70℃に加熱した、バブラを通過させた加湿空気を1L/分、80℃に加熱した、バブラを通過させた加湿水素を0.5L/分でアノード側の電極に供給し、長時間運転による電流電圧特性を電流密度0.5A/cm2の電圧値で比較した。その電池電圧の経時変化を図３に示す。 (Analysis of battery voltage characteristics)
The electrode on the cathode side of the single cell was heated to 70 ° C., 1 L / min of humidified air that passed through a bubbler, and humidified hydrogen that was heated to 80 ° C. and passed through a bubbler at 0.5 L / min on the anode side. The current-voltage characteristics of the electrodes supplied to the electrodes for a long time were compared with a voltage value of a current density of 0.5 A / cm 2 . The change with time of the battery voltage is shown in FIG.

図３より、比較例１の触媒を用いた燃料電池の電圧が3000時間経過後に50mV以上低下したのに対し、実施例１のものはほとんど変化しておらず、電池電圧低下抑制効果が確認できた。   From FIG. 3, the voltage of the fuel cell using the catalyst of Comparative Example 1 decreased by 50 mV or more after lapse of 3000 hours, while that of Example 1 hardly changed, confirming the effect of suppressing the battery voltage decrease. It was.

図１は、貴金属アロイ上に貴金属の皮膜が形成されている触媒構造のイメージである。FIG. 1 is an image of a catalyst structure in which a noble metal film is formed on a noble metal alloy. 図２は、本発明の触媒を含む単セル電極の１つの態様を表した図である。FIG. 2 is a diagram showing one embodiment of a single cell electrode including the catalyst of the present invention. 図３は、燃料電池セルの稼働時間と電圧の関係を示した表である。FIG. 3 is a table showing the relationship between the operating time of the fuel cell and the voltage.

符号の説明Explanation of symbols

１ 貴金属
２ 貴金属アロイ
３ 担体
４ 拡散層
５ 触媒層
６ 高分子電解質膜
７ アノード電極
８ カソード電極 DESCRIPTION OF SYMBOLS 1 Noble metal 2 Noble metal alloy 3 Carrier 4 Diffusion layer 5 Catalyst layer 6 Polymer electrolyte membrane 7 Anode electrode 8 Cathode electrode

Claims (15)

貴金属及び遷移金属から成る貴金属アロイを担体上に担持している電極触媒であって、当該貴金属アロイの表面が貴金属で皮膜されていることを特徴とする電極触媒。   An electrode catalyst having a noble metal alloy comprising a noble metal and a transition metal supported on a carrier, wherein the surface of the noble metal alloy is coated with the noble metal. 貴金属アロイを形成する貴金属が、白金、ロジウム、パラジウム及びルテニウムから成る群から選択される少なくとも１種の貴金属から成ることを特徴とする、請求項１に記載の電極触媒。   2. The electrocatalyst according to claim 1, wherein the noble metal forming the noble metal alloy is composed of at least one noble metal selected from the group consisting of platinum, rhodium, palladium and ruthenium. 貴金属アロイを形成する貴金属が白金から成ることを特徴とする、請求項１に記載の電極触媒。   2. The electrode catalyst according to claim 1, wherein the noble metal forming the noble metal alloy is made of platinum. 貴金属アロイを形成する遷移金属が、鉄、コバルト、クロム、ニッケル、マンガン及びバナジウムから成る群から選択される少なくとも１種の遷移金属から成ることを特徴とする、請求項１〜３のいずれか１項に記載の電極触媒。   The transition metal forming the noble metal alloy is composed of at least one transition metal selected from the group consisting of iron, cobalt, chromium, nickel, manganese and vanadium. The electrode catalyst according to item. 貴金属アロイを形成する遷移金属が鉄から成ることを特徴とする、請求項１〜３のいずれか１項に記載の電極触媒。   The electrode catalyst according to any one of claims 1 to 3, wherein the transition metal forming the noble metal alloy is made of iron. 担体が導電性担体であることを特徴とする、請求項１〜５のいずれか１項に記載の電極触媒。   The electrode catalyst according to claim 1, wherein the carrier is a conductive carrier. 導電性担体がカーボンブラックであることを特徴とする、請求項６に記載の電極触媒。   The electrocatalyst according to claim 6, wherein the conductive support is carbon black. 皮膜に用いる貴金属が、白金、ロジウム、パラジウム、ルテニウムから成る群から選択される少なくとも１つの貴金属から成ることを特徴とする、請求項１〜７のいずれか１項に記載の電極触媒。   The electrocatalyst according to any one of claims 1 to 7, wherein the noble metal used for the coating comprises at least one noble metal selected from the group consisting of platinum, rhodium, palladium, and ruthenium. 皮膜に用いる貴金属が白金から成ることを特徴とする、請求項１〜７のいずれか１項に記載の電極触媒。   The electrode catalyst according to any one of claims 1 to 7, wherein the noble metal used for the film is made of platinum. 貴金属による皮膜形成量が貴金属アロイの全金属量の0.5〜10wt%であることを特徴とする、請求項１〜９のいずれか１項に記載の電極触媒。   The electrode catalyst according to any one of claims 1 to 9, wherein the amount of film formed by the noble metal is 0.5 to 10 wt% of the total metal amount of the noble metal alloy. 触媒粒子表面上における全金属に対する遷移金属の割合(atm%)が、触媒粒子全体における全金属に対する遷移金属の割合(atm%)の50%以下となることを特徴とする、請求項１〜１０のいずれか１項に記載の電極触媒。   The ratio (atm%) of the transition metal to the total metal on the surface of the catalyst particle is 50% or less of the ratio (atm%) of the transition metal to the total metal in the entire catalyst particle. The electrode catalyst according to any one of the above. 貴金属アロイが、
１）担体上に担持されている貴金属アロイを水中で懸濁した溶液に対して貴金属溶液を滴下し、
２）還元剤を添加して貴金属溶液中の貴金属を上記アロイに還元担持し、そして
３）貴金属が還元担持された上記アロイを濾過洗浄することで得られたケーキを真空中で乾燥する、
ことによって貴金属で皮膜されることを特徴とする、電極触媒の製造方法。 Precious metal alloy
1) A noble metal solution is dropped into a solution obtained by suspending a noble metal alloy supported on a carrier in water,
2) A reducing agent is added to reduce and carry the noble metal in the noble metal solution to the alloy, and 3) the cake obtained by filtering and washing the alloy on which the noble metal is reduced and supported is dried in vacuum.
A method for producing an electrode catalyst, wherein the electrode catalyst is coated with a noble metal. 請求項１〜１１のいずれか１項に記載の電極触媒を含む電極を利用することを特徴とする燃料電池。   The fuel cell using the electrode containing the electrode catalyst of any one of Claims 1-11 is utilized. 電極がカソード電極であることを特徴とする、請求項１３に記載の燃料電池。   The fuel cell according to claim 13, wherein the electrode is a cathode electrode. 固体高分子形であることを特徴とする、請求項１３又は１４に記載の燃料電池。   The fuel cell according to claim 13 or 14, wherein the fuel cell is in a solid polymer form.
JP2005021559A 2005-01-28 2005-01-28 Electrode catalyst, method for producing the same, and fuel cell Active JP4776240B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2005021559A JP4776240B2 (en) 2005-01-28 2005-01-28 Electrode catalyst, method for producing the same, and fuel cell

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2005021559A JP4776240B2 (en) 2005-01-28 2005-01-28 Electrode catalyst, method for producing the same, and fuel cell

Publications (2)

Publication Number Publication Date
JP2006205088A true JP2006205088A (en) 2006-08-10
JP4776240B2 JP4776240B2 (en) 2011-09-21

Family

ID=36962471

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2005021559A Active JP4776240B2 (en) 2005-01-28 2005-01-28 Electrode catalyst, method for producing the same, and fuel cell

Country Status (1)

Country Link
JP (1) JP4776240B2 (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008120515A1 (en) * 2007-03-29 2008-10-09 Shin-Etsu Chemical Co., Ltd. Process for producing electrode catalyst for fuel cell
JP2009510705A (en) * 2005-08-01 2009-03-12 ブルックヘヴン サイエンス アソシエイツ Electrocatalyst comprising a gold monoatomic layer on a platinum nanoparticle core and use thereof
WO2009044587A1 (en) * 2007-10-05 2009-04-09 Shin-Etsu Chemical Co., Ltd. Method for production of electrode catalyst for fuel cell
JP2009140864A (en) * 2007-12-10 2009-06-25 Canon Inc Catalyst layer for fuel cell, membrane electrode assembly, fuel cell, and method for manufacturing catalyst layer for fuel cell
WO2011125195A1 (en) 2010-04-07 2011-10-13 トヨタ自動車株式会社 Core-shell metal nanoparticles, and method for producing core-shell metal nanoparticles
WO2011148466A1 (en) * 2010-05-25 2011-12-01 トヨタ自動車株式会社 Fuel cell system
JP2012521069A (en) * 2009-03-18 2012-09-10 ユーティーシー パワー コーポレイション Method for forming fuel cell ternary alloy catalyst
CN102822389A (en) * 2010-04-07 2012-12-12 丰田自动车株式会社 Core-shell type metal nanoparticles and method for manufacturing the same
JP2014100659A (en) * 2012-11-20 2014-06-05 Toyota Motor Corp Method for synthesizing a platinum-iron alloy
JP2015044159A (en) * 2013-08-28 2015-03-12 石福金属興業株式会社 Method for producing palladium catalyst supported in highly dispersed manner suitable for core material for core-shell catalyst
JP2017042759A (en) * 2015-08-27 2017-03-02 国立大学法人山梨大学 Catalyst for anode of fuel cell, anode and fuel cell

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS607941A (en) * 1983-06-14 1985-01-16 エンゲルハ−ド・コ−ポレ−シヨン Platinum alloy electrode catalyst
JPH09161811A (en) * 1995-12-04 1997-06-20 Tanaka Kikinzoku Kogyo Kk Anode catalyst for polyelectrolyte type fuel cell and its preparation
JP2002289208A (en) * 2001-03-26 2002-10-04 Matsushita Electric Ind Co Ltd Electrode catalyst for fuel cell and its manufacturing method
JP2003092114A (en) * 2001-09-17 2003-03-28 Toyota Central Res & Dev Lab Inc Electrode catalyst body for fuel cell and its manufacturing method
JP2003129102A (en) * 2001-08-04 2003-05-08 Omg Ag & Co Kg Powder of platinum and platinum alloy with high surface area and low chlorine content, and process for preparing the same
JP2003346814A (en) * 2002-05-29 2003-12-05 Nec Corp Catalyst carrier particle for fuel cell, compound electrolyte using the particles, catalyst electrode, fuel cell and method for manufacturing these articles
JP2005129358A (en) * 2003-10-23 2005-05-19 Cataler Corp Cathode catalyst for fuel cell
JP2005135900A (en) * 2003-10-06 2005-05-26 Nissan Motor Co Ltd Electrode catalyst for fuel cell and its manufacturing method

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS607941A (en) * 1983-06-14 1985-01-16 エンゲルハ−ド・コ−ポレ−シヨン Platinum alloy electrode catalyst
JPH09161811A (en) * 1995-12-04 1997-06-20 Tanaka Kikinzoku Kogyo Kk Anode catalyst for polyelectrolyte type fuel cell and its preparation
JP2002289208A (en) * 2001-03-26 2002-10-04 Matsushita Electric Ind Co Ltd Electrode catalyst for fuel cell and its manufacturing method
JP2003129102A (en) * 2001-08-04 2003-05-08 Omg Ag & Co Kg Powder of platinum and platinum alloy with high surface area and low chlorine content, and process for preparing the same
JP2003092114A (en) * 2001-09-17 2003-03-28 Toyota Central Res & Dev Lab Inc Electrode catalyst body for fuel cell and its manufacturing method
JP2003346814A (en) * 2002-05-29 2003-12-05 Nec Corp Catalyst carrier particle for fuel cell, compound electrolyte using the particles, catalyst electrode, fuel cell and method for manufacturing these articles
JP2005135900A (en) * 2003-10-06 2005-05-26 Nissan Motor Co Ltd Electrode catalyst for fuel cell and its manufacturing method
JP2005129358A (en) * 2003-10-23 2005-05-19 Cataler Corp Cathode catalyst for fuel cell

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009510705A (en) * 2005-08-01 2009-03-12 ブルックヘヴン サイエンス アソシエイツ Electrocatalyst comprising a gold monoatomic layer on a platinum nanoparticle core and use thereof
WO2008120515A1 (en) * 2007-03-29 2008-10-09 Shin-Etsu Chemical Co., Ltd. Process for producing electrode catalyst for fuel cell
US8748334B2 (en) 2007-03-29 2014-06-10 Shin-Etsu Chemical Co., Ltd. Process for producing electrode catalyst for fuel cell
US8178462B2 (en) 2007-10-05 2012-05-15 Shin-Etsu Chemical Co., Ltd. Method for production of electrode catalyst for fuel cell
WO2009044587A1 (en) * 2007-10-05 2009-04-09 Shin-Etsu Chemical Co., Ltd. Method for production of electrode catalyst for fuel cell
JP2009140864A (en) * 2007-12-10 2009-06-25 Canon Inc Catalyst layer for fuel cell, membrane electrode assembly, fuel cell, and method for manufacturing catalyst layer for fuel cell
JP2012521069A (en) * 2009-03-18 2012-09-10 ユーティーシー パワー コーポレイション Method for forming fuel cell ternary alloy catalyst
CN102822389A (en) * 2010-04-07 2012-12-12 丰田自动车株式会社 Core-shell type metal nanoparticles and method for manufacturing the same
DE112010005462T5 (en) 2010-04-07 2013-03-14 Toyota Jidosha Kabushiki Kaisha Core-shell metal nanoparticles and process for their preparation
WO2011125195A1 (en) 2010-04-07 2011-10-13 トヨタ自動車株式会社 Core-shell metal nanoparticles, and method for producing core-shell metal nanoparticles
WO2011148466A1 (en) * 2010-05-25 2011-12-01 トヨタ自動車株式会社 Fuel cell system
JP5257513B2 (en) * 2010-05-25 2013-08-07 トヨタ自動車株式会社 Fuel cell system
JP2014100659A (en) * 2012-11-20 2014-06-05 Toyota Motor Corp Method for synthesizing a platinum-iron alloy
JP2015044159A (en) * 2013-08-28 2015-03-12 石福金属興業株式会社 Method for producing palladium catalyst supported in highly dispersed manner suitable for core material for core-shell catalyst
JP2017042759A (en) * 2015-08-27 2017-03-02 国立大学法人山梨大学 Catalyst for anode of fuel cell, anode and fuel cell

Also Published As

Publication number Publication date
JP4776240B2 (en) 2011-09-21

Similar Documents

Publication Publication Date Title
JP4776240B2 (en) Electrode catalyst, method for producing the same, and fuel cell
JP5138584B2 (en) Method for producing electrode catalyst for fuel cell
JP5082187B2 (en) Method for producing electrode catalyst particles for polymer electrolyte fuel cell
JP4083721B2 (en) High concentration carbon supported catalyst, method for producing the same, catalyst electrode using the catalyst, and fuel cell using the same
JP5456797B2 (en) Fuel cell electrode catalyst
JP3643552B2 (en) Catalyst for air electrode of solid polymer electrolyte fuel cell and method for producing the catalyst
JP4290524B2 (en) Cathode catalyst for fuel cell
JPWO2007119640A1 (en) Fuel cell electrode catalyst and method for producing the same
JP2014239033A (en) Electrode catalyst for fuel battery, and method for activation of catalyst
JP5893305B2 (en) Electrocatalyst for polymer electrolyte fuel cell and method for producing the same
WO2005081340A1 (en) Supported catalyst for fuel cell, method for producing same and fuel cell
JPWO2009096356A1 (en) ELECTRODE CATALYST FOR FUEL CELL, PROCESS FOR PRODUCING THE SAME, AND SOLID POLYMER FUEL CELL USING THE SAME
JP2006297355A (en) Catalyst and its manufacturing method
WO2020059504A1 (en) Anode catalyst layer for fuel cell and fuel cell using same
JP5158334B2 (en) Method for producing electrode catalyst for fuel cell
JP6635976B2 (en) Electrode catalyst for fuel cell and method for producing the same
WO2020059503A1 (en) Anode catalyst layer for fuel cell and fuel cell using same
JP2006127979A (en) Fuel cell and electrode catalyst therefor
JP6956851B2 (en) Electrode catalyst for fuel cells and fuel cells using them
JP2004087454A (en) Alloy catalyst for electrode of methanol fuel cell, preparation process of the catalyst and methanol fuel cell
JP2002248350A (en) Method for preparing alloy catalyst and method for manufacturing solid high polymer type fuel cell
KR20200053431A (en) Au doped Pt alloy catalysts for fuel cell and method thereof
JP2020047430A (en) Anode catalyst layer for fuel cell and fuel cell arranged by use thereof
KR20140074099A (en) Electrode catalyst for fuel cell, method for preparing the same, membrane electrode assembly and fuel cell including the same
JP2007324092A (en) Manufacturing method of platinum or platinum alloy supported catalyst

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20071203

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20100409

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20100511

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20100709

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20110531

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20110628

R150 Certificate of patent or registration of utility model

Ref document number: 4776240

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140708

Year of fee payment: 3

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250