JP2011134477A - Method of manufacturing electrode catalyst for fuel cell - Google Patents
Method of manufacturing electrode catalyst for fuel cell Download PDFInfo
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- JP2011134477A JP2011134477A JP2009290921A JP2009290921A JP2011134477A JP 2011134477 A JP2011134477 A JP 2011134477A JP 2009290921 A JP2009290921 A JP 2009290921A JP 2009290921 A JP2009290921 A JP 2009290921A JP 2011134477 A JP2011134477 A JP 2011134477A
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- catalyst
- electrode catalyst
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- particle
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- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
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- 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
Abstract
Description
本発明は、燃料電池用電極触媒の製造方法に関する。 The present invention relates to a method for producing an electrode catalyst for a fuel cell.
近年、固体高分子形燃料電池の高性能化が進み、電気自動車用電源、家庭用コージェネレーション、携帯機器用電源等への応用が期待されている。該燃料電池には、発電効率の向上、出力の向上、信頼性の向上等が求められており、それに伴って、燃料電池の電極の触媒層に含ませる電極触媒にも、高い活性および安定性が求められている。 In recent years, solid polymer fuel cells have been improved in performance, and are expected to be applied to power sources for electric vehicles, household cogeneration, portable devices, and the like. The fuel cell is required to have improved power generation efficiency, improved output, improved reliability, and the like. Accordingly, the electrode catalyst contained in the catalyst layer of the fuel cell electrode also has high activity and stability. Is required.
該電極触媒としては、貴金属元素(白金元素等。)を含む触媒粒子を、比表面積の大きなカーボン担体に担持した電極触媒が用いられている。
しかし、該電極触媒には、下記の問題がある。
(i)触媒粒子がカーボン担体の表面で凝集しやすい。カーボンと触媒粒子との結合が必ずしも強くないためと考えられている。触媒粒子が凝集すると、触媒粒子の反応面積が減少してしまい、電極触媒の活性が低下する。
(ii)カーボン担体が酸化劣化しやすい。下記の理由からカーボン担体が酸化劣化すると、触媒粒子がカーボン担体から遊離または凝集して電極触媒の活性が低下する。
As the electrode catalyst, an electrode catalyst in which catalyst particles containing a noble metal element (platinum element or the like) are supported on a carbon support having a large specific surface area is used.
However, the electrode catalyst has the following problems.
(I) The catalyst particles tend to aggregate on the surface of the carbon support. It is considered that the bond between carbon and catalyst particles is not necessarily strong. When the catalyst particles are aggregated, the reaction area of the catalyst particles is reduced, and the activity of the electrode catalyst is reduced.
(Ii) The carbon support is prone to oxidative degradation. When the carbon support is oxidatively deteriorated for the following reasons, the catalyst particles are released or aggregated from the carbon support and the activity of the electrode catalyst is reduced.
カーボンは約0.6V(水素電極基準)に酸化・還元の平衡電位を有するため、カーボン担体は高電位に曝されると酸化劣化しやすい上、触媒粒子そのものがカーボン酸化の触媒として作用することが報告されている。たとえば、非特許文献1〜3には、カーボン担体の腐食が固体高分子形燃料電池の高電位における性能劣化の大きな原因となっていることが示され、白金とカーボン担体劣化の関係についても言及されている。非特許文献4には、固体高分子形燃料電池において自動車用燃料電池で想定される頻繁な起動停止により発生するカソード側の酸素発生やカーボン劣化に関するモデルが議論されている。非特許文献5には、担体としてのカーボンブラックとカーボンナノファイバーとの比較が示されており、前者は後者に比較して白金触媒の劣化が大きいことが報告されている。カーボン担体が酸化劣化すると、触媒粒子がカーボン担体から遊離し、電極触媒の活性が低下する。 Since carbon has an oxidation / reduction equilibrium potential of about 0.6 V (based on hydrogen electrode), the carbon support tends to oxidize and deteriorate when exposed to a high potential, and the catalyst particles themselves act as a catalyst for carbon oxidation. Has been reported. For example, Non-Patent Documents 1 to 3 show that corrosion of a carbon support is a major cause of performance deterioration at a high potential of a polymer electrolyte fuel cell, and mentions the relationship between platinum and carbon support deterioration. Has been. Non-Patent Document 4 discusses a model relating to oxygen generation and carbon deterioration on the cathode side that occurs due to frequent start and stop assumed in an automobile fuel cell in a polymer electrolyte fuel cell. Non-Patent Document 5 shows a comparison between carbon black as a carrier and carbon nanofibers, and the former reports that the platinum catalyst is greatly deteriorated compared to the latter. When the carbon support is oxidized and deteriorated, the catalyst particles are released from the carbon support and the activity of the electrode catalyst is reduced.
カーボン担体の酸化劣化が抑えられた電極触媒としては、下記の電極触媒が提案されている。
(1)触媒粒子が担持された金属酸化物粒子(シリカ粒子等。)を、カーボン担体に担持した燃料電池用電極触媒(特許文献1)。
しかし、(1)の電極触媒には、下記の問題がある。
(i)触媒粒子が金属酸化物粒子の表面で凝集しやすい。触媒粒子が凝集すると、触媒粒子の反応面積が減少してしまい、電極触媒の活性が低下する。
(ii)触媒粒子と導電体であるカーボン担体との間に、粒子径の大きい金属酸化物粒子が介在するため、触媒粒子とカーボン担体との間の導電性が低下し、燃料電池としての出力が低下する。
The following electrode catalysts have been proposed as electrode catalysts in which the oxidative deterioration of the carbon support is suppressed.
(1) An electrode catalyst for a fuel cell in which metal oxide particles (silica particles or the like) on which catalyst particles are supported are supported on a carbon support (Patent Document 1).
However, the electrode catalyst (1) has the following problems.
(I) The catalyst particles tend to aggregate on the surface of the metal oxide particles. When the catalyst particles are aggregated, the reaction area of the catalyst particles is reduced, and the activity of the electrode catalyst is reduced.
(Ii) Since metal oxide particles having a large particle diameter are interposed between the catalyst particles and the carbon carrier as a conductor, the conductivity between the catalyst particles and the carbon carrier is reduced, and the output as a fuel cell Decreases.
カーボン担体自体の耐久性を高めた電極としては、たとえば、下記の電極が提案されている。
(2)カーボンブラックまたは活性炭を加熱処理することで黒鉛化度を高め酸化耐性の向上を試みた燃料電池用電極(特許文献2)。
(2)の電極においては、1000℃以上の高温下でカーボン粉末を熱処理することにより黒鉛化度を上げることで耐食性を高めているが、カーボン粉末の比表面積が低下するため白金を高分散担持することができない。また,高電位環境で腐蝕消失を受けるカーボン担体に直接触媒粒子を担持している構造であることには変わりがなく,大幅に耐食性を向上するには至らないという問題がある.
For example, the following electrodes have been proposed as electrodes with improved durability of the carbon support itself.
(2) An electrode for a fuel cell in which carbon black or activated carbon is heated to increase the degree of graphitization and attempt to improve oxidation resistance (Patent Document 2).
In the electrode of (2), the corrosion resistance is improved by increasing the graphitization degree by heat-treating the carbon powder at a high temperature of 1000 ° C. or higher. However, since the specific surface area of the carbon powder decreases, platinum is highly dispersed and supported. Can not do it. In addition, there is no change in the structure in which the catalyst particles are directly supported on the carbon support that is subject to corrosion disappearance in a high potential environment, and there is a problem that the corrosion resistance cannot be significantly improved.
白金黒のようにカーボン担体を用いない電極触媒は、高電位保持耐性は向上するものの、燃料電池自動車のように起動停止が頻繁な用途に要求される低電位と高電位との間を繰り返し掃引する場合の耐性が充分ではない上、今後、大幅な活性向上は期待できない。 Electrocatalysts that do not use a carbon support, such as platinum black, have improved high-potential retention resistance, but repeatedly sweep between the low and high potentials required for applications that frequently start and stop like fuel cell vehicles. In this case, the resistance is not sufficient, and no significant improvement in activity can be expected in the future.
カーボン担体上に担持された、パラジウム、金等のコアの周囲に、白金シェル層を形成したコアシェル電極触媒は、カーボン担体に白金を担持した電極触媒に比較して、同じ白金質量当たりの活性を5倍以上に向上できるとの報告がある(特許文献3)。しかし、カーボン担体の酸化の問題は解決されていない。また、燃料電池自動車で必要とされる低電位と高電位の間を掃引させる場合の耐性は報告されていない。 A core-shell electrocatalyst with a platinum shell layer formed around a core of palladium, gold, etc. supported on a carbon support has the same activity per platinum mass as compared to an electrode catalyst with platinum supported on a carbon support. There is a report that it can be improved 5 times or more (Patent Document 3). However, the problem of oxidation of the carbon support has not been solved. In addition, no resistance has been reported when sweeping between a low potential and a high potential required for a fuel cell vehicle.
一方、カーボン担体上に白金粒子を担持した電極触媒上に、層状ルテニウム酸化合物から剥離した薄片粒子を被覆することにより、電位を低電位から高電位まで繰り返し掃引したときの変化率が低減することや初期活性が向上することが報告されている(非特許文献6、7)。しかし、活性向上効果は50%程度ときわめて限定的である上、白金粒子はカーボン担体上に直接接合しているため、燃料電池自動車用として求められている高電位環境でのカーボン担体の耐食性は向上しない。さらに、既存の電極触媒上に薄片粒子を担持して電極触媒を調製する場合、白金粒子と薄片粒子との結合形成は必ずしも充分でない可能性がある上、現状では作用機構の理解も不十分であり、そのため、電極触媒の工業化においては再現性よく特性を引き出すためには薄片粒子を、過剰量を相当大きくして担持することが想定され、資源量において白金以上に制約のあるルテニウムを含む薄片粒子の量を低減することは必ずしも容易ではないおそれがある。 On the other hand, the rate of change when the potential is repeatedly swept from a low potential to a high potential is reduced by coating thin electrode particles peeled from the layered ruthenic acid compound on an electrode catalyst supporting platinum particles on a carbon support. It has been reported that initial activity is improved (Non-Patent Documents 6 and 7). However, the activity improvement effect is very limited to about 50%, and the platinum particles are directly bonded to the carbon support. Therefore, the corrosion resistance of the carbon support in the high potential environment required for the fuel cell vehicle is as follows. Does not improve. Furthermore, when preparing an electrode catalyst by supporting thin particle particles on an existing electrode catalyst, the bond formation between platinum particles and thin particle particles may not always be sufficient, and at present the understanding of the mechanism of action is insufficient. Therefore, in the industrialization of electrocatalysts, it is assumed that the flake particles are supported with an excessively large amount in order to extract the characteristics with good reproducibility, and the flakes containing ruthenium, which is more limited than platinum in terms of resource It may not always be easy to reduce the amount of particles.
本発明は、発電効率、出力、および信頼性の高い燃料電池を得ることができる燃料電池用電極触媒の製造方法を提供する。 The present invention provides a method for producing an electrode catalyst for a fuel cell, which can obtain a fuel cell with high power generation efficiency, output, and reliability.
本発明の燃料電池用電極触媒の製造方法は、カーボン担体上に、層状ルテニウム酸化合物から剥離した薄片粒子と、貴金属を含む触媒粒子とが担持された燃料電池用電極触媒の製造方法であって、前記カーボン担体に前記薄片粒子が担持した薄片粒子担持カーボン担体を得る工程と、前記薄片粒子担持カーボン担体に前記触媒粒子を担持させる工程とを有することを特徴とする。
本発明の燃料電池用電極触媒の製造方法は、カーボン担体上に、層状ルテニウム酸化合物から剥離した薄片粒子と、貴金属を含む触媒粒子とが担持された燃料電池用電極触媒の製造方法であって、前記カーボン担体に前記薄片粒子が担持した薄片粒子担持カーボン担体を得る工程と、前記薄片粒子担持カーボン担体に前記触媒粒子の前駆体を担持させる工程と、前記前駆体を前記触媒粒子に変換する工程とを有することを特徴とする。
The method for producing an electrode catalyst for a fuel cell of the present invention is a method for producing an electrode catalyst for a fuel cell in which thin particles separated from a layered ruthenate compound and catalyst particles containing a noble metal are supported on a carbon support. And a step of obtaining a flake particle-supporting carbon carrier in which the flake particles are carried on the carbon carrier, and a step of carrying the catalyst particles on the flake particle-supporting carbon carrier.
The method for producing an electrode catalyst for a fuel cell of the present invention is a method for producing an electrode catalyst for a fuel cell in which thin particles separated from a layered ruthenate compound and catalyst particles containing a noble metal are supported on a carbon support. A step of obtaining a flake particle-supporting carbon carrier in which the flake particles are carried on the carbon carrier, a step of carrying a precursor of the catalyst particles on the flake particle-supporting carbon carrier, and converting the precursor into the catalyst particles. And a process.
これらの工程において形成される触媒粒子の多くはやや扁平で薄片粒子基体に強く束縛を受けていると推定される。これは薄片粒子と触媒粒子または触媒前駆体との結合が極めて強いためと推定される。そのため、詳細な理由は必ずしも明らかではないが、カーボン担体上に直接触媒粒子を形成させる従来の電極触媒に比較して安定であるにもかかわらず、高い活性が得られると考えられる。 It is presumed that many of the catalyst particles formed in these processes are somewhat flat and strongly bound to the thin particle base. This is presumably because the bonding between the flake particles and the catalyst particles or the catalyst precursor is extremely strong. Therefore, although the detailed reason is not necessarily clear, it is considered that high activity can be obtained although it is more stable than a conventional electrode catalyst in which catalyst particles are directly formed on a carbon support.
本発明の燃料電池用電極触媒の製造方法は、前記カーボン担体に前記薄片粒子が担持した薄片粒子担持カーボン担体を得る工程の前または後に、前記カーボン担体または薄片粒子担持カーボン担体に、金または金合金のナノ粒子またはナノシートを担持する工程をさらに有していてもよい。
前記金または金合金のナノ粒子の粒子径は、1〜50nmであることが好ましい。
前記金または金合金のナノシートの厚さは、1〜10nmであることが好ましい。
The method for producing an electrode catalyst for a fuel cell according to the present invention comprises: before or after the step of obtaining a thin particle-supported carbon carrier in which the thin particle is supported on the carbon carrier; You may further have the process of carry | supporting the nanoparticle or nanosheet of an alloy.
The gold or gold alloy nanoparticles preferably have a particle diameter of 1 to 50 nm.
The thickness of the gold or gold alloy nanosheet is preferably 1 to 10 nm.
前記触媒粒子は、白金を含むことが好ましい。
前記薄片粒子の厚さは、5nm以下であることが好ましい。
前記層状ルテニウム酸化合物は、層状ルテニウム酸カリウムであることが好ましい。
前記薄片粒子は、層状ルテニウム酸カリウムを酸処理して得られるプロトン型層状ルテニウム酸水和物に、(R)mNH4−mもしくは(R)m−p(R’)pNH4−m(式中、RおよびR’はCH3(CH2)q、m=0〜4、p=0〜3、q=0〜18、ただし、m=4、p=3、q=15、R=C16H33およびR’=CH3の場合を除く。)で表されるアルキルアンモニウム、または、(R)mNH3−mもしくは(R)m−p(R’)pNH3−m(式中、RおよびR’はCH3(CH2)q、m=0〜3、p=0〜2、q=0〜18)で表されるアルキルアミンを反応させて得られることが好ましい。
前記カーボン担体に担持された前記薄片粒子と前記触媒粒子との比は、前記薄片粒子に含まれるルテニウムと前記触媒粒子に含まれる貴金属との原子比(ルテニウム/貴金属)が0.01〜4となる比であることが好ましい。
The catalyst particles preferably contain platinum.
The thickness of the flake particles is preferably 5 nm or less.
The layered ruthenate compound is preferably layered potassium ruthenate.
The flake particles are obtained by adding (R) m NH 4-m or (R) m-p (R ′) p NH 4-m to proton-type layered ruthenate hydrate obtained by acid treatment of layered potassium ruthenate. Wherein R and R ′ are CH 3 (CH 2 ) q , m = 0-4, p = 0-3, q = 0-18, where m = 4, p = 3, q = 15, R ═C 16 H 33 and R′═CH 3 are excluded.) Or (R) m NH 3-m or (R) mp (R ′) p NH 3-m (Wherein R and R ′ are preferably obtained by reacting an alkylamine represented by CH 3 (CH 2 ) q , m = 0-3, p = 0-2, q = 0-18). .
The ratio between the flake particles carried on the carbon support and the catalyst particles is such that the atomic ratio (ruthenium / noble metal) of ruthenium contained in the flake particles and noble metal contained in the catalyst particles is 0.01 to 4. The ratio is preferably
本発明の燃料電池用電極触媒の製造方法によれば、発電効率、出力、および信頼性の高い燃料電池を得ることができる燃料電池用電極触媒を製造できる。 According to the method for producing a fuel cell electrode catalyst of the present invention, a fuel cell electrode catalyst capable of obtaining a fuel cell with high power generation efficiency, output, and reliability can be produced.
本明細書においては、式(1)で表される化合物を化合物(1)と記す。他の式で表される化合物も同様に記す。 In the present specification, a compound represented by the formula (1) is referred to as a compound (1). The same applies to compounds represented by other formulas.
<電極触媒>
本発明の製造方法によって得られる燃料電池用電極触媒は、カーボン担体上に、層状ルテニウム酸化合物から剥離した薄片粒子と、貴金属元素を含む触媒粒子とが担持された電極触媒である。なお、本発明においては、カーボン担体上に薄片粒子を介して触媒粒子が間接的に担持されている場合、およびカーボン担体上に触媒粒子を介して薄片粒子が間接的に担持されている場合についても、カーボン担体上に薄片粒子と触媒粒子とが担持されているものとする。
<Electrocatalyst>
The electrode catalyst for fuel cells obtained by the production method of the present invention is an electrode catalyst in which thin particles separated from a layered ruthenate compound and catalyst particles containing a noble metal element are supported on a carbon support. In the present invention, when the catalyst particles are indirectly supported via the flake particles on the carbon support and when the flake particles are indirectly supported via the catalyst particles on the carbon support. Also, it is assumed that the flake particles and the catalyst particles are supported on the carbon support.
(カーボン担体)
カーボン担体としては、ファーネスブラックのようにグラファイト化度の低いカーボンであってもよく、VulcanXC−72、アセチレンブラックやカーボンナノチューブのようにグラファイト化度の高いカーボンであってもよい。
(Carbon support)
The carbon carrier may be carbon having a low degree of graphitization such as furnace black, or carbon having a high degree of graphitization such as Vulcan XC-72, acetylene black, and carbon nanotube.
カーボン担体の比表面積は、10〜2000m2/gが好ましく、50〜1500m2/gがより好ましい。カーボン担体の比表面積が50m2/g以上であれば、触媒粒子が、分散性よく担持され、電極触媒の活性が向上する。カーボン担体の比表面積が1500m2/g以下であれば、ミクロ細孔の発達が抑えられ、触媒粒子がミクロ細孔内に入り込むことなく、触媒粒子を有効に活用できる。ミクロ細孔内に入り込んだ触媒粒子は、イオン交換樹脂と接触できず、反応に寄与できない。
カーボン担体の比表面積は、BET比表面積装置を用い、カーボン担体の表面への窒素吸着によって測定される。
The specific surface area of the carbon support preferably is 10~2000m 2 / g, 50~1500m 2 / g is more preferable. When the specific surface area of the carbon support is 50 m 2 / g or more, the catalyst particles are supported with good dispersibility, and the activity of the electrode catalyst is improved. When the specific surface area of the carbon support is 1500 m 2 / g or less, the development of micropores is suppressed, and the catalyst particles can be effectively utilized without the catalyst particles entering the micropores. The catalyst particles that have entered the micropores cannot contact the ion exchange resin and cannot contribute to the reaction.
The specific surface area of the carbon support is measured by nitrogen adsorption on the surface of the carbon support using a BET specific surface area apparatus.
(触媒粒子)
触媒粒子は、貴金属を含む粒子である。
触媒粒子としては、貴金属の粒子、または貴金属合金の粒子が好ましい。
貴金属としては、白金が好ましい。貴金属合金としては、白金合金が好ましい。
白金合金としては、白金と;鉄、コバルト、ニッケル、クロム、ルテニウム、ロジウム、パラジウム、レニウム、マンガン、イリジウム、銅、銀および金からなる群から選ばれる元素の1種以上との合金が挙げられる。
(Catalyst particles)
The catalyst particles are particles containing a noble metal.
The catalyst particles are preferably noble metal particles or noble metal alloy particles.
As the noble metal, platinum is preferable. As the noble metal alloy, a platinum alloy is preferable.
Examples of platinum alloys include alloys of platinum and one or more elements selected from the group consisting of iron, cobalt, nickel, chromium, ruthenium, rhodium, palladium, rhenium, manganese, iridium, copper, silver, and gold. .
触媒粒子の粒子径は、1〜20nmが好ましく、2〜10nmがより好ましい。触媒粒子の粒子径が該範囲内であれば、充分に高い活性を有する電極触媒が得られる。
触媒粒子の粒子径は、X線回折(XRD)法によって測定される。
The particle diameter of the catalyst particles is preferably 1 to 20 nm, and more preferably 2 to 10 nm. If the particle diameter of the catalyst particles is within this range, an electrode catalyst having sufficiently high activity can be obtained.
The particle diameter of the catalyst particles is measured by an X-ray diffraction (XRD) method.
触媒粒子の金属表面積(金属分散度ともいう。)は、20〜300m2/gが好ましく、50〜250m2/gがより好ましい。触媒粒子の金属表面積が300m2/gを超えると、触媒粒子の安定性が低下するほか、粒子径の小さすぎる触媒粒子は却って電極触媒の活性を低下させるとの報告もある。触媒粒子の金属表面積が20m2/g未満では、電極触媒の活性が低くなる。
触媒粒子の金属表面積は、一酸化炭素(CO)吸着法によって測定できる。また、窒素を吹き込んだ酸水溶液中で電極電位を0V(vs.RHE)近傍から0.6Vを超える電位の間で掃引したときに得られる水素吸脱着電流と電気二重層電流との差から推定することもできる。
(Also referred to as metal dispersity.) Metal surface area of the catalyst particles is preferably 20~300m 2 / g, 50~250m 2 / g is more preferable. There are reports that when the metal surface area of the catalyst particles exceeds 300 m 2 / g, the stability of the catalyst particles decreases, and catalyst particles with too small particle diameters decrease the activity of the electrode catalyst. When the metal surface area of the catalyst particles is less than 20 m 2 / g, the activity of the electrode catalyst is lowered.
The metal surface area of the catalyst particles can be measured by a carbon monoxide (CO) adsorption method. Estimated from the difference between the hydrogen adsorption / desorption current and the electric double layer current obtained when the electrode potential is swept between 0 V (vs. RHE) and a potential exceeding 0.6 V in an acid aqueous solution in which nitrogen is blown. You can also
触媒粒子の担持率は、電極触媒(100質量%)中、5〜80質量%が好ましく、10〜70質量%がより好ましい。触媒粒子の担持率が5質量%以上であれば、電極触媒の活性が向上する。触媒粒子の担持率が80質量%以下であれば、触媒粒子が凝集しにくく、電極触媒の活性が向上する。
触媒粒子の担持率は、触媒粒子を酸で溶解し、溶出イオンの濃度を測定することにより求めることができる。
5-80 mass% is preferable in an electrode catalyst (100 mass%), and, as for the loading rate of a catalyst particle, 10-70 mass% is more preferable. When the catalyst particle loading is 5% by mass or more, the activity of the electrode catalyst is improved. If the loading ratio of the catalyst particles is 80% by mass or less, the catalyst particles hardly aggregate and the activity of the electrode catalyst is improved.
The catalyst particle loading rate can be determined by dissolving the catalyst particles with an acid and measuring the concentration of eluted ions.
(薄片粒子)
薄片粒子は、層状ルテニウム酸化合物から剥離した、形状異方性(たとえば、厚さ1nm以下、一辺の長さ数百nm。)のルテニウム酸ナノシートである。
層状ルテニウム酸化合物としては、層状ルテニウム酸カリウムが特に好適であり、KxRuO2+0.5x・nH2Oで表される。
xは、焼成温度、焼成時間、原料の混合比等の合成条件によって異なり、0<x<1を満たす。
含水量nは、乾燥条件によって異なり、0〜10の範囲で変動する。室温乾燥では、n=0.7、120℃乾燥では0〜0.4である。
(Thin particles)
The flake particle is a ruthenic acid nanosheet having a shape anisotropy (for example, a thickness of 1 nm or less and a length of one side of several hundred nm) peeled from the layered ruthenate compound.
As the layered ruthenate compound, layered potassium ruthenate is particularly suitable, and is represented by K x RuO 2 + 0.5x · nH 2 O.
x varies depending on the synthesis conditions such as the firing temperature, firing time, and mixing ratio of raw materials, and satisfies 0 <x <1.
The water content n varies depending on the drying conditions and varies in the range of 0-10. N = 0.7 for room temperature drying and 0 to 0.4 for 120 ° C. drying.
薄片粒子としては、層状ルテニウム酸カリウムを酸処理して得られるプロトン型層状ルテニウム酸水和物に、(R)mNH4−mもしくは(R)m−p(R’)pNH4−m(式中、RおよびR’はCH3(CH2)q、m=0〜4、p=0〜3、q=0〜18、ただし、m=4、p=3、q=15、R=C16H33およびR’=CH3の場合を除く。)で表されるアルキルアンモニウム、または、(R)mNH3−mもしくは(R)m−p(R’)pNH3−m(式中、RおよびR’はCH3(CH2)q、m=0〜3、p=0〜2、q=0〜18)で表されるアルキルアミンを反応させて得られるルテニウム酸水和物ナノシートが好ましい。該薄片粒子は、電子伝導性を有することが確認されており、触媒粒子とカーボン担体の間に複数層の薄片粒子が介在しても触媒粒子とカーボン担体の間に充分な電子伝導性が得られる。 As the flake particles, proton type layered ruthenium acid hydrate obtained by acid treatment of layered potassium ruthenate is added to (R) m NH 4-m or (R) mp (R ′) p NH 4-m. Wherein R and R ′ are CH 3 (CH 2 ) q , m = 0-4, p = 0-3, q = 0-18, where m = 4, p = 3, q = 15, R ═C 16 H 33 and R′═CH 3 are excluded.) Or (R) m NH 3-m or (R) mp (R ′) p NH 3-m (Wherein R and R ′ are CH 3 (CH 2 ) q , m = 0 to 3, p = 0 to 2, q = 0 to 18) and an aqueous ruthenate obtained by reacting with an alkylamine. Japanese nanosheets are preferred. The flake particles have been confirmed to have electronic conductivity, and even when a plurality of flake particles are interposed between the catalyst particles and the carbon support, sufficient electron conductivity is obtained between the catalyst particles and the carbon support. It is done.
原料の層状ルテニウム酸化合物により薄片粒子の厚さは異なるが、代表的な薄片粒子の厚さは、約0.4〜5nmであり、0.4〜2nmが好ましい。
薄片粒子の厚さは、原料の層状ルテニウム酸化合物の断面を透過型電子顕微鏡で測定することで確認できる。また、薄片粒子の分散液に、水溶液中で安定な固体物質(たとえば、石英ガラス板、シリコンウェハー、マイカ板、グラファイト板、アルミナ板等。)を充分に洗浄したものを浸漬し、純水で洗浄した後、乾燥して、固体物質の表面に薄片粒子の単層を形成し、該薄片粒子の厚さを、AFM(分子間力顕微鏡)を用いて測定できる。
Although the thickness of the flake particles varies depending on the raw material layered ruthenate compound, the typical flake particle thickness is about 0.4 to 5 nm, preferably 0.4 to 2 nm.
The thickness of the flake particles can be confirmed by measuring the cross section of the raw material layered ruthenate compound with a transmission electron microscope. Also, immerse a thin particle dispersion in which a solid substance (for example, a quartz glass plate, a silicon wafer, a mica plate, a graphite plate, an alumina plate, etc.) that is stable in an aqueous solution is thoroughly washed with pure water. After washing and drying, a single layer of flake particles is formed on the surface of the solid substance, and the thickness of the flake particles can be measured using an AFM (Intermolecular Force Microscope).
薄片粒子の担持率は、カーボン担体100質量部に対して、0.01〜50質量部が好ましく、0.01〜40質量部がより好ましい。薄片粒子の担持率が0.02質量部以上であれば、カーボン担体の酸化劣化が充分に抑えられる。薄片粒子の担持率が50質量部以下であれば、カーボン担体への担持が容易であり、比較的短時間に担持を終えることができる。
薄片粒子の担持率は、蛍光X線法による元素分析から求めることができる。また、担持率が特に高い場合には、たとえば炭酸ナトリウムを用いるアルカリ溶融法により溶解してルテニウムの存在量を定量して担持率を求めることができる。
The supporting rate of the flake particles is preferably 0.01 to 50 parts by mass, more preferably 0.01 to 40 parts by mass with respect to 100 parts by mass of the carbon support. When the loading rate of the flake particles is 0.02 parts by mass or more, the oxidative deterioration of the carbon support can be sufficiently suppressed. If the loading rate of the flake particles is 50 parts by mass or less, the loading on the carbon carrier is easy and the loading can be completed in a relatively short time.
The loading rate of the flake particles can be determined from elemental analysis by the fluorescent X-ray method. Further, when the loading rate is particularly high, the loading rate can be obtained by quantifying the amount of ruthenium dissolved by, for example, an alkali melting method using sodium carbonate.
前記カーボン担体に担持された前記薄片粒子と前記触媒粒子との比は、前記薄片粒子に含まれるルテニウムと前記触媒粒子に含まれる貴金属との原子比(ルテニウム/貴金属)が0.01〜4となるような比が好ましい。ルテニウム/貴金属(原子比)が0.01以上であれば、カーボン担体の酸化劣化が充分に抑えられる。ルテニウム/貴金属(原子比)が4以下であれば、触媒粒子とカーボン担体との間の導電性の低下が抑えられる。
ルテニウム/貴金属(原子比)は、蛍光X線法により求めることができる。
The ratio between the flake particles carried on the carbon support and the catalyst particles is such that the atomic ratio (ruthenium / noble metal) of ruthenium contained in the flake particles and noble metal contained in the catalyst particles is 0.01 to 4. Such a ratio is preferred. When the ruthenium / noble metal (atomic ratio) is 0.01 or more, the oxidative deterioration of the carbon support is sufficiently suppressed. When the ruthenium / noble metal (atomic ratio) is 4 or less, a decrease in conductivity between the catalyst particles and the carbon support can be suppressed.
Ruthenium / noble metal (atomic ratio) can be determined by the fluorescent X-ray method.
薄片粒子は、たとえば、特開2004−315347号公報に記載された、下記の工程(a)〜(d)を有する方法により製造できる。
(a)アルカリ金属型層状ルテニウム酸化合物を得る工程。
(b)アルカリ金属型層状ルテニウム酸化合物を酸性溶液中で処理し、アルカリ金属の少なくとも一部をプロトンで交換してプロトン型層状ルテニウム酸水和物を得る工程。
(c)プロトン型層状ルテニウム酸水和物にアルキルアンモニウムまたはアルキルアミンを反応させてアルキルアンモニウム−層状ルテニウム酸層間化合物を得る工程。
(d)アルキルアンモニウム−層状ルテニウム酸層間化合物を溶媒と混合し、1nm以下の厚さを有するルテニウム酸ナノシートの分散液を得る工程。
The flake particles can be produced by a method having the following steps (a) to (d) described in JP-A No. 2004-315347, for example.
(A) A step of obtaining an alkali metal layered ruthenic acid compound.
(B) A step of treating the alkali metal type layered ruthenium acid compound in an acidic solution and exchanging at least part of the alkali metal with protons to obtain a proton type layered ruthenium acid hydrate.
(C) a step of reacting proton-type layered ruthenium acid hydrate with alkylammonium or alkylamine to obtain an alkylammonium-layered ruthenate acid intercalation compound.
(D) A step of mixing the alkylammonium-layered ruthenate intercalation compound with a solvent to obtain a dispersion of ruthenate nanosheets having a thickness of 1 nm or less.
工程(a):
工程(a)で得られるアルカリ金属型層状ルテニウム酸化合物は、たとえば、化合物(1)である。
MxRuO2+0.5x・nH2O ・・・(1)。
ただし、Mは、アルカリ金属(Li、Na、K、Rb、Cs等。)であり、0<x<1、0≦n≦10である。
Step (a):
The alkali metal layered ruthenic acid compound obtained in step (a) is, for example, compound (1).
M x RuO 2 + 0.5x · nH 2 O (1).
However, M is an alkali metal (Li, Na, K, Rb, Cs, etc.), and 0 <x <1, 0 ≦ n ≦ 10.
化合物(1)を得る方法としては、下記の方法(a−1)〜(a−4)が挙げられる。
(a−1)アルカリ金属炭酸塩またはアルカリ金属硝酸塩と、酸化ルテニウムとを混合し、得られた混合物を好ましくは不活性雰囲気中において、700〜900℃の温度で加熱処理する方法(固相反応法)。
(a−2)アルカリ金属水酸化物と酸化ルテニウムとを混合し、得られた混合物を500〜700℃で溶融処理する方法(溶融法)。
(a−3)層状ルテニウム酸化合物とアルカリ金属硝酸塩とを混合し、得られた混合物を好ましくは不活性雰囲気中において、アルカリ金属硝酸塩の融点以上の温度で溶融処理する方法(溶融イオン交換法)。
(a−4)プロトン型層状ルテニウム酸水和物をアルカリ金属の水酸化物(水酸化カリウム等。)または塩化物(塩化カリウム等。)の水溶液に分散し、撹拌する方法。
Examples of the method for obtaining the compound (1) include the following methods (a-1) to (a-4).
(A-1) A method in which an alkali metal carbonate or alkali metal nitrate is mixed with ruthenium oxide, and the resulting mixture is preferably heated in an inert atmosphere at a temperature of 700 to 900 ° C. (solid phase reaction) Law).
(A-2) A method (melting method) in which an alkali metal hydroxide and ruthenium oxide are mixed and the obtained mixture is melted at 500 to 700 ° C.
(A-3) A method in which a layered ruthenate compound and an alkali metal nitrate are mixed, and the obtained mixture is melt-treated at a temperature equal to or higher than the melting point of the alkali metal nitrate, preferably in an inert atmosphere (molten ion exchange method) .
(A-4) A method in which proton-type layered ruthenium hydrate is dispersed in an aqueous solution of an alkali metal hydroxide (such as potassium hydroxide) or chloride (such as potassium chloride) and stirred.
工程(b):
工程(b)で得られるプロトン型層状ルテニウム酸水和物は、たとえば、化合物(2)または化合物(3)である。
Mx−yHyRuO2+0.5x・nH2O ・・・(2)。
ただし、Mは、アルカリ金属であり、0<x<1、0≦y<x、0≦n≦10である。
Step (b):
The proton-type layered ruthenium acid hydrate obtained in the step (b) is, for example, the compound (2) or the compound (3).
M x-y H y RuO 2 + 0.5x · nH 2 O ··· (2).
However, M is an alkali metal, and 0 <x <1, 0 ≦ y <x, and 0 ≦ n ≦ 10.
Hx−yMyRuO2+0.5x・nH2O ・・・(3)。
ただし、Mは、2価の金属(Mg、Ca、Sr、Ba等。)または3価の金属(Y、Ln等。)であり、0<x<1、0≦y<x、0≦n≦10である。
H x-y M y RuO 2 + 0.5x · nH 2 O ··· (3).
M is a divalent metal (Mg, Ca, Sr, Ba, etc.) or a trivalent metal (Y, Ln, etc.), and 0 <x <1, 0 ≦ y <x, 0 ≦ n. ≦ 10.
化合物(2)を得る方法としては、下記の方法(b−1)が挙げられる。
(b−1)アルカリ金属型層状ルテニウム酸化合物を、酸性水溶液中でプロトン交換反応させる方法(プロトン交換法)。
As a method for obtaining the compound (2), the following method (b-1) may be mentioned.
(B-1) A method in which an alkali metal layered ruthenic acid compound is subjected to a proton exchange reaction in an acidic aqueous solution (proton exchange method).
化合物(3)を得る方法としては、下記の方法(b−2)が挙げられる。
(b−2)化合物(2)を、2価の金属イオンまたは3価の金属イオンを含む水溶液と反応させる方法(溶液イオン交換法)。
As a method for obtaining the compound (3), the following method (b-2) may be mentioned.
(B-2) A method of reacting the compound (2) with an aqueous solution containing a divalent metal ion or a trivalent metal ion (solution ion exchange method).
工程(c):
工程(c)で得られるアルキルアンモニウム−層状ルテニウム酸層間化合物は、層状ルテニウム酸化合物にアルキルアンモニウムがインターカレートした構造を有する化合物である。該化合物は、たとえば、化合物(4)である。
Mx−yHy−zBzRuO2+0.5x・nH2O ・・・(4)。
ただし、Mは、アルカリ金属であり、Bは、化合物(5)または化合物(6)であり、0<x<1、0≦y<x、0≦z<y、0≦n≦10である。
Step (c):
The alkylammonium-layered ruthenate intercalation compound obtained in the step (c) is a compound having a structure in which alkylammonium is intercalated into the layered ruthenate compound. This compound is, for example, compound (4).
M x-y H y-z B z RuO 2 + 0.5x · nH 2 O ··· (4).
However, M is an alkali metal, B is a compound (5) or a compound (6), and 0 <x <1, 0 ≦ y <x, 0 ≦ z <y, 0 ≦ n ≦ 10. .
(R)mNH4−m ・・・(5)、
(R)m−p(R’)pNH4−m ・・・(6)。
ただし、RおよびR’は、それぞれ炭素数1〜19のアルキル基であり、mは、0〜4の整数であり、pは、0〜3の整数である。
(R) m NH 4-m (5),
(R) mp (R ′) p NH 4-m (6).
However, R and R ′ are each an alkyl group having 1 to 19 carbon atoms, m is an integer of 0 to 4, and p is an integer of 0 to 3.
化合物(4)を得る方法としては、下記の方法(c−1)〜(c−3)が挙げられる。
(c−1)プロトン型層状ルテニウム酸水和物を、アルキルアンモニウム塩を含む溶液と混合し、両者を反応させる方法(イオン交換法)。
(c−2)プロトン型層状ルテニウム酸水和物を、アルキルアミンを含む溶液と混合し、両者を反応させる方法(酸塩基反応法)。
(c−3)化合物(4)を得た後、さらに第2のアルキルアンモニウム塩を含む溶液と混合し、両者を反応させる方法(ゲスト交換反応法)。
Examples of the method for obtaining the compound (4) include the following methods (c-1) to (c-3).
(C-1) A method in which proton-type layered ruthenium acid hydrate is mixed with a solution containing an alkylammonium salt and both are reacted (ion exchange method).
(C-2) A method in which proton-type layered ruthenium acid hydrate is mixed with a solution containing an alkylamine and both are reacted (acid-base reaction method).
(C-3) A method (guest exchange reaction method) in which, after obtaining the compound (4), it is further mixed with a solution containing a second alkylammonium salt and reacted.
工程(d):
層間化合物を溶媒に分散させると、層間化合物から薄片粒子(ナノシート)が一層単位で剥離し、ルテニウム酸の薄片粒子が分散した分散液(コロイド)が得られる。なお、該分散液には、薄片粒子がいくつか重なった積層体が部分的に含まれていてもよい。
溶媒としては、高誘電率溶媒が好ましい。高誘電率溶媒としては、水、アルコール、アセトニトリル、ジメチルスルホキシド、ジメチルホルムアミド、プロピレンカーボネート等が挙げられ、誘電率が高く、粘性率が低く、沸点が低い点から、水、アルコールまたはアセトニトリルが好ましく、メタノールが特に好ましい。
Step (d):
When the intercalation compound is dispersed in the solvent, the flake particles (nanosheet) are peeled from the intercalation compound in a single unit, and a dispersion (colloid) in which the ruthenic acid flake particles are dispersed is obtained. Note that the dispersion may partially include a laminate in which several thin particles are overlapped.
As the solvent, a high dielectric constant solvent is preferable. Examples of the high dielectric constant solvent include water, alcohol, acetonitrile, dimethyl sulfoxide, dimethylformamide, propylene carbonate, and the like. From the viewpoint of high dielectric constant, low viscosity, and low boiling point, water, alcohol or acetonitrile is preferable. Methanol is particularly preferred.
(金または金合金のナノ粒子またはナノシート)
カーボン担体上に薄片粒子および触媒粒子を担持することで、高活性で高安定な電極触媒が得られるが、さらに、金または金合金(ただし、白金は含まない。)のナノ粒子またはナノシートを担持することによって、一層高い触媒特性が得られる。
(Gold or gold alloy nanoparticles or nanosheets)
By supporting thin particles and catalyst particles on a carbon support, a highly active and highly stable electrode catalyst can be obtained, but in addition, gold or gold alloy (but not platinum) nanoparticles or nanosheets are supported. By doing so, higher catalytic properties can be obtained.
金または金合金のナノ粒子の粒子径は、1〜50nmが好ましく、1〜20nmがより好ましい。粒子径が小さすぎると、安定性が不充分となる。粒子径が50nmを超えると、薄片粒子や触媒粒子との充分な相互作用を得ることが難しくなる。
金または金合金のナノシートの厚さは、1〜10nmが好ましい。薄すぎると安定性が不充分となるほか、調製も難しくなる。厚すぎると、金属量当たりの表面積が減少するため、効果が不充分となる。
金合金は、安定性を確保する点から、金を20質量%以上含むことが好ましい。合金成分としては、パラジウム、ロジウム、銀、銅、イリジウム、オスミウム、ルテニウム、レニウムが好適である。
The particle diameter of the gold or gold alloy nanoparticles is preferably 1 to 50 nm, and more preferably 1 to 20 nm. If the particle size is too small, the stability will be insufficient. When the particle diameter exceeds 50 nm, it becomes difficult to obtain sufficient interaction with the flake particles and the catalyst particles.
The thickness of the gold or gold alloy nanosheet is preferably 1 to 10 nm. If it is too thin, the stability becomes insufficient and preparation becomes difficult. If it is too thick, the surface area per metal amount is reduced, and the effect becomes insufficient.
The gold alloy preferably contains 20% by mass or more of gold from the viewpoint of ensuring stability. As the alloy component, palladium, rhodium, silver, copper, iridium, osmium, ruthenium and rhenium are suitable.
<電極触媒の製造方法>
本発明の燃料電池用電極触媒の製造方法としては、下記の方法(I)、(II)が挙げられる。
<Method for producing electrode catalyst>
Examples of the method for producing an electrode catalyst for a fuel cell of the present invention include the following methods (I) and (II).
(方法(I))
方法(I)は、下記の工程(I−1)、(I−2)を有する方法である。
(I−1)カーボン担体に薄片粒子が担持した薄片粒子担持カーボン担体を得る工程。
(I−2)薄片粒子担持カーボン担体に触媒粒子を担持させて燃料電池用電極触媒を得る工程。
(Method (I))
Method (I) is a method having the following steps (I-1) and (I-2).
(I-1) A step of obtaining a thin particle-supported carbon carrier in which thin particles are supported on a carbon carrier.
(I-2) A step of obtaining a fuel cell electrode catalyst by supporting catalyst particles on a thin particle-supported carbon carrier.
工程(I−1):
薄片粒子の分散液と、カーボン担体またはその分散液とを混合し、撹拌して混合液を得る。
混合液から沈澱物を回収した後、沈澱物を乾燥して薄片粒子担持カーボン担体を得る。
Step (I-1):
The dispersion of flake particles and the carbon carrier or dispersion thereof are mixed and stirred to obtain a mixture.
After collecting the precipitate from the mixed solution, the precipitate is dried to obtain a flake particle-supporting carbon support.
撹拌方法としては、機械的に撹拌する方法、超音波照射により撹拌する方法等が挙げられる。
沈澱物の回収方法としては、混合液を静置し、上澄み液と沈澱物とに分離した後、上澄み液を除去する方法;混合物をろ過する方法等が挙げられる。
乾燥温度は、80〜300℃が好ましい。
Examples of the stirring method include a mechanical stirring method, a stirring method by ultrasonic irradiation, and the like.
Examples of the method for recovering the precipitate include a method in which the mixed solution is allowed to stand and separated into a supernatant and a precipitate, and then the supernatant is removed; a method in which the mixture is filtered, and the like.
The drying temperature is preferably 80 to 300 ° C.
工程(I−2):
触媒粒子のコロイド液と、薄片粒子担持カーボン担体またはその分散液とを混合し、撹拌して混合液を得る。
混合液から沈澱物を回収した後、沈澱物を乾燥して燃料電池用電極触媒を得る。
Step (I-2):
A colloidal liquid of catalyst particles and a flake particle-supporting carbon carrier or a dispersion thereof are mixed and stirred to obtain a mixed liquid.
After collecting the precipitate from the mixed solution, the precipitate is dried to obtain a fuel cell electrode catalyst.
触媒粒子のコロイド液の分散媒としては、水、アルコール等が挙げられる。
撹拌方法、沈澱物の回収方法としては、工程(I−1)における方法と同様の方法が挙げられる。
乾燥温度は、80〜300℃が好ましい。
Examples of the dispersion medium of the catalyst particle colloid liquid include water and alcohol.
Examples of the stirring method and the precipitate collecting method include the same methods as in the step (I-1).
The drying temperature is preferably 80 to 300 ° C.
(方法(II))
方法(II)は、下記の工程(II−1)〜(II−3)を有する方法である。
(II−1)カーボン担体に薄片粒子が担持した薄片粒子担持カーボン担体を得る工程。
(II−2)薄片粒子担持カーボン担体に触媒粒子の前駆体を担持させて燃料電池用電極触媒の前駆体を得る工程。
(II−3)触媒粒子の前駆体を触媒粒子に変換して燃料電池用電極触媒を得る工程。
(Method (II))
Method (II) is a method having the following steps (II-1) to (II-3).
(II-1) A step of obtaining a thin particle-supported carbon carrier in which thin particles are supported on a carbon carrier.
(II-2) A step of obtaining a precursor of a fuel cell electrode catalyst by carrying a catalyst particle precursor on a thin particle-supported carbon carrier.
(II-3) A step of obtaining a fuel cell electrode catalyst by converting a catalyst particle precursor into catalyst particles.
工程(II−1):
工程(II−1)は、工程(I−1)と同様に行う。
Step (II-1):
Step (II-1) is carried out in the same manner as in step (I-1).
工程(II−2):
触媒粒子の前駆体の溶液と、薄片粒子担持カーボン担体またはその分散液とを混合し、撹拌して混合液を得る。
混合液から沈澱物を回収した後、沈澱物を乾燥して燃料電池用電極触媒の前駆体を得る。
Step (II-2):
The catalyst particle precursor solution and the flake particle-supporting carbon carrier or dispersion thereof are mixed and stirred to obtain a mixed solution.
After collecting the precipitate from the mixed solution, the precipitate is dried to obtain a precursor of an electrode catalyst for a fuel cell.
触媒粒子の前駆体とは、還元することにより触媒粒子となる化合物である。触媒粒子の前駆体としては、溶媒に溶解できるものを用いる。具体的な触媒粒子の前駆体としては、ジニトロジアンミン白金硝酸溶液、ジニトロジアンミン白金、塩化白金酸、塩化白金酸塩等が挙げられる。
触媒粒子の前駆体の溶液の溶媒としては、水、アルコール等が挙げられる。
撹拌方法、沈澱物の回収方法としては、工程(I−1)における方法と同様の方法が挙げられる。
乾燥温度は、80〜300℃が好ましい。
The catalyst particle precursor is a compound that becomes catalyst particles by reduction. As the catalyst particle precursor, one that can be dissolved in a solvent is used. Specific precursors of catalyst particles include dinitrodiammine platinum nitrate solution, dinitrodiammine platinum, chloroplatinic acid, chloroplatinate, and the like.
Examples of the solvent for the catalyst particle precursor solution include water and alcohol.
Examples of the stirring method and the precipitate collecting method include the same methods as in the step (I-1).
The drying temperature is preferably 80 to 300 ° C.
工程(II−3):
触媒粒子の前駆体を触媒粒子に変換する方法としては、ギ酸、エタノール、メタノール、アミンボラン、水素化ホウ素ナトリウム、ヒドラジン、チオ硫酸ナトリウム、クエン酸、クエン酸ナトリウム、L−アスコルビン酸、ホルムアルデヒド、水素等による還元等が挙げられる。
たとえば、ヒドラジン等の水溶液で供給できるものは、濃度0.1〜40質量%の水溶液とし供給できる。水素化ホウ素ナトリウムなどの固体はそのまま供給できる。水素等の常温でガス状の物質は、バブリングで供給できる。
Step (II-3):
As a method for converting the catalyst particle precursor into catalyst particles, formic acid, ethanol, methanol, amine borane, sodium borohydride, hydrazine, sodium thiosulfate, citric acid, sodium citrate, L-ascorbic acid, formaldehyde, hydrogen, etc. The reduction by etc. are mentioned.
For example, what can be supplied as an aqueous solution such as hydrazine can be supplied as an aqueous solution having a concentration of 0.1 to 40% by mass. Solids such as sodium borohydride can be supplied as they are. A gaseous substance at room temperature such as hydrogen can be supplied by bubbling.
(金または金合金のナノ粒子またはナノシートの担持)
金または金合金のナノ粒子またはナノシートを担持させる場合、前述した方法(I)または(II)において、カーボン担体に薄片粒子が担持した薄片粒子担持カーボン担体を得る工程の前または後に、金または金合金のナノ粒子またはナノシートを担持させることが好ましい。具体的には、以下のように行うことができる。
(Supporting gold or gold alloy nanoparticles or nanosheets)
When gold or gold alloy nanoparticles or nanosheets are supported, the gold or gold in the method (I) or (II) described above is performed before or after the step of obtaining the flake particle-supported carbon support in which the flake particles are supported on the carbon support. It is preferred to carry alloy nanoparticles or nanosheets. Specifically, it can be performed as follows.
方法A:
工程(I−1)または工程(II−1)によりカーボン担体に薄片粒子が担持した薄片粒子担持カーボン担体を得た後、金または金合金のナノ粒子コロイド溶液と混合して、金または金合金のナノ粒子を担持させる。これを水洗後80〜300℃で乾燥させた後、工程(I−2)または工程(II−2)、(II−3)を行う。
Method A:
After obtaining the flake particle-supporting carbon carrier in which the flake particles are carried on the carbon carrier by the step (I-1) or the step (II-1), the gold carrier or the gold alloy is mixed with the gold or gold alloy nanoparticle colloid solution. Of nanoparticles. After washing with water and drying at 80 to 300 ° C., the step (I-2) or the steps (II-2) and (II-3) are performed.
方法B:
工程(I−1)または工程(II−1)によりカーボン担体に薄片粒子が担持した薄片粒子担持カーボン担体を得た後、金または金合金の元素を含む金属塩をカーボン担体上に担持し、還元して、金または金合金のナノ粒子を担持させる。これを水洗後80〜300℃で乾燥させた後、工程(I−2)または工程(II−2)、(II−3)を行う。
Method B:
After obtaining the flake particle-supporting carbon support in which the flake particles are supported on the carbon support in the step (I-1) or the step (II-1), a metal salt containing gold or a gold alloy element is supported on the carbon support, Reduction to support gold or gold alloy nanoparticles. After washing with water and drying at 80 to 300 ° C., the step (I-2) or the steps (II-2) and (II-3) are performed.
方法C:
工程(I−1)または工程(II−1)によりカーボン担体に薄片粒子が担持した薄片粒子担持カーボン担体を得た後、金または金合金のナノシートの分散液と混合して、金または金合金のナノシートを担持させる。これを水洗後80〜300℃で乾燥させた後、工程(I−2)または工程(II−2)、(II−3)を行う。
Method C:
After obtaining the flake particle-supporting carbon carrier in which the flake particles are carried on the carbon carrier by the step (I-1) or the step (II-1), the gold carrier or the gold alloy is mixed with the gold or gold alloy nanosheet dispersion. The nanosheet is supported. After washing with water and drying at 80 to 300 ° C., the step (I-2) or the steps (II-2) and (II-3) are performed.
方法D:
カーボン担体と金または金合金のナノ粒子コロイド溶液とを混合して、カーボン担体上に金または金合金のナノ粒子を担持させる。これを水洗後80〜300℃で乾燥させた後、工程(I−1)または工程(II−1)により薄片粒子を担持させる。さらに、工程(I−2)または工程(II−2)、(II−3)を行う。
Method D:
A carbon support and a gold or gold alloy nanoparticle colloid solution are mixed to support gold or gold alloy nanoparticles on the carbon support. After washing with water and drying at 80 to 300 ° C., the flake particles are supported by the step (I-1) or the step (II-1). Further, step (I-2) or steps (II-2) and (II-3) are performed.
方法E:
カーボン担体と金または金合金のナノシートの分散液とを混合して、カーボン担体上に金または金合金のナノシートを担持させる。これを水洗後80〜300℃で乾燥させた後、工程(I−1)または工程(II−1)により薄片粒子を担持させる。さらに、工程(I−2)または工程(II−2)、(II−3)を行う。
Method E:
The carbon support and the gold or gold alloy nanosheet dispersion are mixed to support the gold or gold alloy nanosheet on the carbon support. After washing with water and drying at 80 to 300 ° C., the flake particles are supported by the step (I-1) or the step (II-1). Further, step (I-2) or steps (II-2) and (II-3) are performed.
金の融点は1063℃と低く、析出基体との相互作用が弱い場合や金合金中の金含量が多い場合には微粒子を得ることが困難な場合が多い。そのため、特に数nmの小さい粒子径の金または金合金のナノ粒子を担持させる場合は、金または金合金のナノ粒子を溶液中に分散させたコロイド粒子を用いることが有効である。粒子径が10nmを超えるナノ粒子を担持させる場合は、金または金合金を構成する元素を含む塩をカーボン担体上に担持して還元する方法が適用できる。薄片粒子を担持した後では金または金合金を構成する金属塩を担持した後に還元することで、粒径が10nm以下のナノ粒子を形成することが可能である。
なお、金属コロイドや薄片粒子には通常保護剤が含まれるが、保護剤は酸による洗浄、硫酸等の適当な電解質溶液中での電解酸化、または空気中での酸化等、保護剤の種類により適宜処理することで特性を調整できる。
The melting point of gold is as low as 1063 ° C., and it is often difficult to obtain fine particles when the interaction with the precipitation substrate is weak or when the gold content in the gold alloy is large. Therefore, particularly when gold or gold alloy nanoparticles having a small particle diameter of several nanometers are supported, it is effective to use colloidal particles in which gold or gold alloy nanoparticles are dispersed in a solution. When nanoparticles having a particle diameter exceeding 10 nm are supported, a method of reducing by supporting a salt containing an element constituting gold or a gold alloy on a carbon support can be applied. After supporting the flake particles, it is possible to form nanoparticles having a particle size of 10 nm or less by reducing after supporting the metal salt constituting the gold or gold alloy.
Metal colloids and flake particles usually contain a protective agent, which depends on the type of protective agent, such as washing with acid, electrolytic oxidation in a suitable electrolyte solution such as sulfuric acid, or oxidation in air. The characteristics can be adjusted by appropriate processing.
以上説明した本発明の製造方法で得られた燃料電池用電極触媒にあっては、下記の理由から発電効率、出力、および信頼性の高い燃料電池を得ることができると考えられる。
(i)触媒粒子の間に薄片粒子が介在することによって、触媒粒子の凝集が抑制され、電極触媒の活性が低下しにくい。そして、電極触媒の活性および安定性が高ければ、燃料電池の発電効率、出力、および信頼性も高くなる。
(ii)触媒粒子とカーボン担体との間に薄片粒子が介在することによって、カーボン担体の酸化劣化が抑えられる。その結果、触媒粒子のカーボン担体からの遊離が抑えられ、電極触媒の活性が低下しにくい。そして、電極触媒の活性および安定性が高ければ、燃料電池の発電効率、出力、および信頼性も高くなる。
(iii)触媒粒子とカーボン担体との間に介在する薄片粒子はたいへん薄いため、従来の、比較的粒子径の大きい球状の金属酸化物粒子に比べ、触媒粒子とカーボン担体との間の導電性を低下させにくい。その結果、燃料電池の出力が低下しにくい。
(iv)触媒粒子とルテニウムを含む酸化物の薄片粒子が接触することにより触媒粒子が安定化するため、触媒粒子が溶解しにくくなる。
(v)金または金合金のナノ粒子またはナノシートをあらかじめ担持する場合は、金または金合金のナノ粒子またはナノシートを安定化させるとともに、薄片粒子を介して電子が触媒粒子に供与され、触媒粒子の活性および安定性が増加すると考えられる。
In the fuel cell electrode catalyst obtained by the production method of the present invention described above, it is considered that a fuel cell with high power generation efficiency, output, and reliability can be obtained for the following reasons.
(I) Since the flake particles are present between the catalyst particles, aggregation of the catalyst particles is suppressed, and the activity of the electrode catalyst is unlikely to decrease. And if the activity and stability of an electrode catalyst are high, the power generation efficiency, output, and reliability of a fuel cell will also become high.
(Ii) Oxidation deterioration of the carbon support can be suppressed by interposing the flake particles between the catalyst particles and the carbon support. As a result, the release of the catalyst particles from the carbon support is suppressed, and the activity of the electrode catalyst is unlikely to decrease. And if the activity and stability of an electrode catalyst are high, the power generation efficiency, output, and reliability of a fuel cell will also become high.
(Iii) Since the flake particles interposed between the catalyst particles and the carbon support are very thin, the conductivity between the catalyst particles and the carbon support is smaller than the conventional spherical metal oxide particles having a relatively large particle size. Is difficult to reduce. As a result, the output of the fuel cell is unlikely to decrease.
(Iv) Since the catalyst particles are stabilized by contact between the catalyst particles and the oxide flake particles containing ruthenium, the catalyst particles are hardly dissolved.
(V) In the case of supporting gold or gold alloy nanoparticles or nanosheets in advance, the nanoparticles or nanosheets of gold or gold alloy are stabilized and electrons are donated to the catalyst particles through the flake particles. It is believed that activity and stability are increased.
本発明の製造方法で得られた燃料電池用電極触媒は、空気が供給されるカソードの触媒層の電極触媒に用いることが好ましい。また、本発明の製造方法で得られた燃料電池用電極触媒は、水素が供給されるアノードの触媒層の電極触媒に用いてもよい。 The fuel cell electrode catalyst obtained by the production method of the present invention is preferably used as an electrode catalyst of a cathode catalyst layer to which air is supplied. Further, the fuel cell electrode catalyst obtained by the production method of the present invention may be used as an electrode catalyst of an anode catalyst layer to which hydrogen is supplied.
<膜電極接合体>
図1は、固体高分子形燃料電池用膜電極接合体(以下、膜電極接合体と記す。)の一例を示す概略断面図である。膜電極接合体10は、触媒層11およびガス拡散層12を有するアノード13と、触媒層11およびガス拡散層12を有するカソード14と、アノード13とカソード14との間に、触媒層11に接した状態で介在する電解質膜15とを具備する。
<Membrane electrode assembly>
FIG. 1 is a schematic cross-sectional view showing an example of a membrane electrode assembly for a polymer electrolyte fuel cell (hereinafter referred to as a membrane electrode assembly). The
(触媒層)
触媒層11は、電極触媒およびイオン交換樹脂を含む。
触媒層11は、少なくとも一方の触媒層11が本発明の製造方法で得られた燃料電池用電極触媒を含むことが好ましく、カソード14の触媒層11が本発明の製造方法で得られた燃料電池用電極触媒を含むことがより好ましく、両方の触媒層11が本発明の製造方法で得られた燃料電池用電極触媒を含むことが特に好ましい。
(Catalyst layer)
The
The
イオン交換樹脂のイオン交換容量は、導電性およびガス透過性の点から、0.5〜2.0ミリ当量/グラム乾燥樹脂が好ましく、0.8〜1.5ミリ当量/グラム乾燥樹脂が特に好ましい。 The ion exchange capacity of the ion exchange resin is preferably 0.5 to 2.0 meq / g dry resin, particularly 0.8 to 1.5 meq / g dry resin from the viewpoint of conductivity and gas permeability. preferable.
イオン交換樹脂としては、耐久性の点から、イオン性基を有する含フッ素重合体が好ましい。イオン性基としては、スルホン酸基、カルボン酸基等が挙げられる。
イオン性基を有する含フッ素重合体としては、スルホン酸基を有するパーフルオロカーボン重合体(エーテル性酸素原子を含んでいてもよい。)が好ましく、テトラフルオロエチレン(以下、TFEと記す。)に基づく単位と、スルホン酸基を有する繰り返し単位とを有する共重合体(以下、共重合体Hと記す。)が特に好ましい。スルホン酸基を有する繰り返し単位としては、下式(7)で表される繰り返し単位が好ましい。
As the ion exchange resin, a fluoropolymer having an ionic group is preferable from the viewpoint of durability. Examples of the ionic group include a sulfonic acid group and a carboxylic acid group.
The fluorinated polymer having an ionic group is preferably a perfluorocarbon polymer having a sulfonic acid group (which may contain an etheric oxygen atom), and is based on tetrafluoroethylene (hereinafter referred to as TFE). A copolymer having a unit and a repeating unit having a sulfonic acid group (hereinafter referred to as copolymer H) is particularly preferred. The repeating unit having a sulfonic acid group is preferably a repeating unit represented by the following formula (7).
ただし、Xはフッ素原子またはトリフルオロメチル基であり、mは0〜3の整数であり、nは1〜12の整数であり、pは0または1である。 However, X is a fluorine atom or a trifluoromethyl group, m is an integer of 0 to 3, n is an integer of 1 to 12, and p is 0 or 1.
共重合体Hは、TFEおよび−SO2F基を有するモノマーの混合物を重合して前駆体ポリマーFを得た後、前駆体ポリマーF中の−SO2F基をスルホン酸基に変換することにより得られる。−SO2F基のスルホン酸基への変換は、加水分解および酸型化処理により行われる。 Copolymer H after obtaining a precursor polymer F mixture polymerized monomers having TFE and -SO 2 F group, to convert the -SO 2 F groups in the precursor polymer F to sulfonic acid groups Is obtained. Conversion of the —SO 2 F group into a sulfonic acid group is performed by hydrolysis and acidification treatment.
−SO2F基を有するモノマーとしては、化合物(8)が好ましい。
CF2=CF(OCF2CFX)m−Op−(CF2)n−SO2F ・・・(8)。
ただし、mは0〜3の整数であり、nは1〜12の整数であり、pは0または1であり、XはFまたはCF3である。
As the monomer having a —SO 2 F group, the compound (8) is preferable.
CF 2 = CF (OCF 2 CFX ) m -O p - (CF 2) n -SO 2 F ··· (8).
However, m is an integer of 0 to 3, n is an integer from 1 to 12, p is 0 or 1, X is F or CF 3.
化合物(8)としては、化合物(8−1)〜(8−3)が好ましい。
CF2=CFO(CF2)qSO2F ・・・(8−1)、
CF2=CFOCF2CF(CF3)O(CF2)rSO2F ・・・(8−2)、
CF2=CF(OCF2CF(CF3))tO(CF2)sSO2F ・・・(8−3)。
ただし、q、r、sは1〜8の整数であり、tは1〜3の整数である。
As the compound (8), compounds (8-1) to (8-3) are preferable.
CF 2 = CFO (CF 2 ) q SO 2 F (8-1),
CF 2 = CFOCF 2 CF (CF 3 ) O (CF 2 ) r SO 2 F (8-2),
CF 2 = CF (OCF 2 CF (CF 3)) t O (CF 2) s SO 2 F ··· (8-3).
However, q, r, and s are integers of 1 to 8, and t is an integer of 1 to 3.
電極触媒とイオン交換樹脂との比(電極触媒/イオン交換樹脂)は、導電性および撥水性の点から、0.4/0.6〜0.95/0.05(質量比)が好ましく、0.6/0.4〜0.8/0.2(質量比)がより好ましい。 The ratio of the electrode catalyst to the ion exchange resin (electrode catalyst / ion exchange resin) is preferably 0.4 / 0.6 to 0.95 / 0.05 (mass ratio) from the viewpoint of conductivity and water repellency. 0.6 / 0.4-0.8 / 0.2 (mass ratio) is more preferable.
(ガス拡散層)
ガス拡散層12としては、カーボンクロス、カーボンペーパー、カーボンフェルト等が挙げられる。
ガス拡散層は、ポリテトラフルオロエチレン(以下、PTFEと記す。)等によって撥水処理されていることが好ましい。
(Gas diffusion layer)
Examples of the
The gas diffusion layer is preferably water repellent treated with polytetrafluoroethylene (hereinafter referred to as PTFE) or the like.
(カーボン層)
アノード13およびカソード14は、触媒層11とガス拡散層12との間にカーボン層(図示略)を有していてもよい。カーボン層を配置することにより、触媒層11の表面のガス拡散性が向上し、固体高分子形燃料電池の発電性能が大きく向上する。
(Carbon layer)
The
カーボン層は、カーボンと非イオン性含フッ素重合体とを含む層である。
カーボンとしては、繊維径1〜1000nm、繊維長1〜1000μm以下のカーボンナノファイバーが好ましい。
非イオン性含フッ素重合体としては、PTFE等が挙げられる。
The carbon layer is a layer containing carbon and a nonionic fluoropolymer.
As carbon, carbon nanofibers having a fiber diameter of 1-1000 nm and a fiber length of 1-1000 μm or less are preferable.
Examples of the nonionic fluorine-containing polymer include PTFE.
(電解質膜)
電解質膜15としては、イオン交換樹脂の膜が挙げられる。
イオン交換樹脂としては、触媒層11のイオン交換樹脂と同様のものが挙げられる。
(Electrolyte membrane)
Examples of the
Examples of the ion exchange resin include those similar to the ion exchange resin of the
電解質膜15は、補強材を含んでいてもよい。補強材としては、多孔体、繊維、織布、不織布等が挙げられる。補強材の材料としては、PTFE、テトラフルオロエチレン−ヘキサフルオロプロピレン共重合体、テトラフルオロエチレン−パーフルオロ(アルキルビニルエーテル)共重合体、ポリエチレン、ポリプロピレン、ポリフェニレンスルフィド等が挙げられる。
The
<固体高分子形燃料電池>
膜電極接合体と、ガスの流路となる溝が形成されたセパレータとを交互に積み重ね、いわゆるスタックを構成することにより、固体高分子形燃料電池が得られる。
セパレータとしては、金属製セパレータ、カーボン製セパレータ、黒鉛と樹脂とを混合した材料からなるセパレータ等、各種導電性材料からなるセパレータが挙げられる。
該固体高分子形燃料電池においては、カソードに酸素を含むガス、アノードに水素を含むガスを供給することにより、発電が行われる。また、アノードにメタノールを供給して発電を行うメタノール燃料電池にも、膜電極接合体を適用できる。
<Solid polymer fuel cell>
A polymer electrolyte fuel cell can be obtained by alternately stacking membrane electrode assemblies and separators in which grooves serving as gas flow paths are formed to form a so-called stack.
Examples of the separator include a separator made of various conductive materials such as a metal separator, a carbon separator, and a separator made of a material in which graphite and a resin are mixed.
In the polymer electrolyte fuel cell, power is generated by supplying a gas containing oxygen to the cathode and a gas containing hydrogen to the anode. The membrane electrode assembly can also be applied to a methanol fuel cell that generates power by supplying methanol to the anode.
以下に、実施例を挙げて本発明を具体的に説明するが、本発明はこれらの例によって限定されない。
例1〜10は実施例であり、例11〜13は比較例である。
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
Examples 1 to 10 are examples, and examples 11 to 13 are comparative examples.
(薄片粒子の厚さ)
薄片粒子の分散液に、シリコンウェハー(Agar社、スーパースムーズシリコン台板(マウント)、製品番号G3390)を充分に洗浄したものを浸漬し、純水で洗浄した後、乾燥して、薄片粒子の単層を形成し、該薄片粒子の厚さを、AFM(分子間力顕微鏡)を用いて測定した。
(Thickness of flake particles)
In a dispersion of flake particles, a silicon wafer (Agar, super smooth silicon base plate (mount), product number G3390) that has been thoroughly washed is immersed, washed with pure water, dried, and dried. A single layer was formed, and the thickness of the flake particles was measured using an AFM (Intermolecular Force Microscope).
(触媒粒子の粒子径)
触媒粒子の粒子径は、透過型電子鏡(TEM)を用いて測定した。具体的には、触媒粒子を純水中に分散させ、適当量を試料ホルダーに固定したものについて、複数の視野における50個の粒子径を平均して求めた。
(Catalyst particle diameter)
The particle diameter of the catalyst particles was measured using a transmission electron mirror (TEM). Specifically, the average particle diameter of 50 particles in a plurality of fields of view was obtained by dispersing catalyst particles in pure water and fixing an appropriate amount to a sample holder.
(触媒粒子の金属表面積)
触媒粒子の金属表面積(金属分散度)は、CO吸着法によって測定した。具体的には、パルス吸着装置(日本ベル社製、BEL−CAT)を用い、30mgの触媒粒子をヘリウム、酸素、ヘリウム、水素、ヘリウムの順に流通ガスで前処理を施した後、ヘリウムをキャリアガスとしてCOをパルス状に供給し、排出ガス中のCO量が一定になるまでのパルス数から吸着水素量を計算して、触媒粒子の金属表面積を求めた。なお、本方法で評価する程の触媒量が得られない場合には、後述する電極触媒の活性に記載の方法と同様にして、GC(グラッシーカーボン)上に触媒粒子を堆積し,酸水溶液中で0.05〜1.2V(RHE基準)で掃引したときに得られる水素の吸脱着波から推定する方法(高須芳雄、吉武優、石原達己編、「燃料電池の解析手法」、化学同人、2005年、第4章を参照)を用いて測定した。
(Metal surface area of catalyst particles)
The metal surface area (metal dispersion degree) of the catalyst particles was measured by a CO adsorption method. Specifically, using a pulse adsorption device (BEL-CAT, manufactured by Nippon Bell Co., Ltd.), 30 mg of catalyst particles were pretreated with flowing gas in the order of helium, oxygen, helium, hydrogen, and helium, and then helium was used as a carrier. CO was supplied as a gas in pulses, and the amount of adsorbed hydrogen was calculated from the number of pulses until the amount of CO in the exhaust gas became constant, thereby obtaining the metal surface area of the catalyst particles. In addition, when the amount of catalyst to be evaluated by this method cannot be obtained, catalyst particles are deposited on GC (glassy carbon) in the same manner as described in the electrode catalyst activity described later, Estimated from hydrogen adsorption / desorption waves obtained when swept at 0.05 to 1.2 V (RHE standard) (Yoshio Takasu, Yuu Yoshitake, Tatsumi Ishihara, “Fuel cell analysis method”, 2005, see Chapter 4).
(触媒粒子の担持率)
触媒粒子の担持率は、触媒粒子を酸で溶解して得た金属塩の液をICP発光分析法で定量し求めた。
(Catalyst particle loading)
The catalyst particle loading was determined by quantifying a metal salt solution obtained by dissolving the catalyst particles with an acid by ICP emission spectrometry.
(ルテニウムと貴金属との原子比)
カーボン担体に担持された、薄片粒子に含まれるルテニウムと触媒粒子に含まれる貴金属との原子比(ルテニウム/貴金属)は、蛍光X線法を用いて求めた。
(Atomic ratio of ruthenium and noble metal)
The atomic ratio (ruthenium / noble metal) between the ruthenium contained in the flake particles and the noble metal contained in the catalyst particles supported on the carbon support was determined using a fluorescent X-ray method.
(電極触媒の活性)
電極触媒をフッ素系溶剤(旭硝子社製、AE−3000)とHPLC用テトラヒドロフラン(THF)との混合溶媒(1:1質量比)中に分散させた分散液を、回転電極装置(北斗電工社社製、HR−301)に附属の回転リングディスク電極のGC(グラッシーカーボン)ディスク上に、マイクロピペットを用いて滴下、乾燥し、電極触媒をできるだけ均一に堆積した。該回転リングディスク電極を60℃、0.5M硫酸水溶液中にセットし、窒素を吹き込んだ。最初に、回転リングディスク電極の表面を清浄化するために、500mV/sの掃引速度で、0.05〜1.2V(RHE基準)の間を40回掃引した。ついで、酸素を吹き込んだ後、1.2Vから0.05Vに向けて、0.5mV/sの掃引速度で掃引して還元電流を測定した。回転数:1000rpm、電位:0.8V(vs. RHE)における単位白金量当たりの電流値を、電極触媒の酸素還元活性とした。該電流値が高ければ、燃料電池の発電効率および出力(出力電流×出力電位)も高いといえる。
(Electrocatalytic activity)
A dispersion obtained by dispersing an electrode catalyst in a mixed solvent (1: 1 mass ratio) of a fluorine-based solvent (Asahi Glass Co., Ltd., AE-3000) and HPLC tetrahydrofuran (THF) is used as a rotating electrode device (Hokuto Denko Co., Ltd.). The electrode catalyst was deposited as uniformly as possible on a GC (glassy carbon) disk of a rotating ring disk electrode attached to HR-301), using a micropipette. The rotating ring disc electrode was set in a 0.5 M sulfuric acid aqueous solution at 60 ° C., and nitrogen was blown into the rotating ring disc electrode. First, in order to clean the surface of the rotating ring disk electrode, 40 sweeps were performed between 0.05 and 1.2 V (RHE standard) at a sweep speed of 500 mV / s. Then, after blowing oxygen, the reduction current was measured by sweeping from 1.2 V to 0.05 V at a sweep rate of 0.5 mV / s. The current value per unit platinum amount at a rotational speed of 1000 rpm and a potential of 0.8 V (vs. RHE) was defined as the oxygen reduction activity of the electrode catalyst. If the current value is high, it can be said that the power generation efficiency and output (output current × output potential) of the fuel cell are also high.
(電極触媒の安定性)
窒素を吹き込んだ、60℃、0.5M硫酸水溶液中で、前記電極触媒を担持した回転リングディスク電極の電位を0.05V〜1.2V(vs. RHE)の間で300回繰り返し掃引した。その後、酸素を吹き込んだ0.5M硫酸水溶液中で、回転数:1000rpm、電位:0.8V(vs. RHE)の条件下に電流値を測定した。単位白金量当たりの電流値を、電極触媒の酸素還元活性とした。該電流値が高ければ、電極触媒の安定性が高いといえ、燃料電池の信頼性も高いといえる。
(Electrocatalytic stability)
In a 0.5 M sulfuric acid aqueous solution in which nitrogen was blown, the potential of the rotating ring disk electrode supporting the electrode catalyst was repeatedly swept 300 times between 0.05 V to 1.2 V (vs. RHE). Thereafter, the current value was measured in a 0.5 M sulfuric acid aqueous solution into which oxygen was blown, under the conditions of the rotation speed: 1000 rpm and the potential: 0.8 V (vs. RHE). The current value per unit platinum amount was defined as the oxygen reduction activity of the electrode catalyst. If the current value is high, it can be said that the stability of the electrode catalyst is high and the reliability of the fuel cell is also high.
〔例1〕
特開2004−315347号公報の実施例1に記載の方法にしたがって、0.4質量%のルテニウム酸の薄片粒子の分散液を得た。薄片粒子の厚さは0.45nmであった。
[Example 1]
According to the method described in Example 1 of JP-A No. 2004-315347, a dispersion of 0.4% by mass ruthenic acid flake particles was obtained. The thickness of the flake particles was 0.45 nm.
薄片粒子の分散液の2.6mLを20倍に希釈し、カーボンブラック(三菱化学社製、ケッチェンブラック、BET比表面積:800m2/g。)の0.5gを入れ、超音波照射下で1時間撹拌した。上澄み液を除去した後、回収された沈澱物を150℃で乾燥し、薄片粒子担持カーボン担体を得た。 2.6 mL of the dispersion of flake particles was diluted 20 times, and 0.5 g of carbon black (Mitsubishi Chemical Co., Ltd., Ketjen Black, BET specific surface area: 800 m 2 / g) was added, and under ultrasonic irradiation Stir for 1 hour. After removing the supernatant, the collected precipitate was dried at 150 ° C. to obtain a flake particle-supporting carbon support.
10質量%白金を含むジニトロジアンミン白金硝酸水溶液(石福金属興業社製)を、ロータリーエバポレータを用いて60℃で硝酸を除去した後、適当量のエタノールを添加して、ジニトロジアンミン白金エタノール溶液を調製した。薄片粒子担持カーボン担体の5gをエタノール中に入れ、超音波照射下で30分間撹拌してから、白金量として0.5gを含むジニトロジアンミン白金エタノール溶液を添加し、超音波を30分間印加したのち、ゆっくり乾燥して、電極触媒の前駆体を得た。電極触媒の前駆体を電気炉に入れ、水素を10体積%含む窒素ガスを流しながら、ゆっくりと加熱して200℃まで昇温した。2時間保持した後、加熱を停止し、温度が70℃まで降下したら窒素ガスに切り替えて、充分に時間が経過した後、電気炉より取りだして電極触媒を得た。 After removing nitric acid at 60 ° C using a rotary evaporator, dinitrodiammine platinum nitric acid aqueous solution containing 10 mass% platinum (Ishifuku Metal Industry Co., Ltd.) is added, and dinitrodiammine platinum ethanol solution is added. Prepared. After putting 5 g of the flake particle-supporting carbon carrier in ethanol and stirring for 30 minutes under ultrasonic irradiation, a dinitrodiammine platinum ethanol solution containing 0.5 g of platinum was added, and ultrasonic waves were applied for 30 minutes. Then, it was slowly dried to obtain an electrocatalyst precursor. The precursor of the electrode catalyst was put in an electric furnace and heated slowly to 200 ° C. while flowing nitrogen gas containing 10% by volume of hydrogen. After holding for 2 hours, the heating was stopped, and when the temperature dropped to 70 ° C., the gas was switched to nitrogen gas. After sufficient time had elapsed, the electrode catalyst was obtained by removing from the electric furnace.
電極触媒における白金粒子の粒子径は2.6nmであり、白金粒子の金属表面積は83m2/gであった。また、白金粒子の担持率は、44質量%であり、担持されたルテニウム/白金(原子比)は、0.03であった。
該電極触媒について、活性およびその安定性を評価した。結果を表1に示す。高い初期活性と安定性が得られた。
The particle diameter of the platinum particles in the electrode catalyst was 2.6 nm, and the metal surface area of the platinum particles was 83 m 2 / g. Moreover, the supporting rate of the platinum particles was 44% by mass, and the supported ruthenium / platinum (atomic ratio) was 0.03.
The activity and stability of the electrocatalyst were evaluated. The results are shown in Table 1. High initial activity and stability were obtained.
〔例2〕
例1と同様にして調製した0.02質量%の薄片粒子の分散液の50mLに、カーボンブラック(ケッチェンブラックEC−600JD、BET比表面積:1240m2/g。)の0.05gを入れ、超音波照射下で30分間撹拌した後、水洗、乾燥した。ジニトロジアンミン白金硝酸溶液(石福金属興業社製)の0.4mLを加えて撹拌した後、室温乾燥した。その後、90℃で乾燥して電極触媒の前駆体を得た。
電極触媒の前駆体を200℃、水素気流中で2時間還元して、電極触媒を得た。白金粒子の担持率は39.8質量%であり、ルテニウム/白金(原子比)は0.37であり、白金粒子の粒子径は2.1nmであった。例1と同様にして評価を行った。結果を表1に示す。
[Example 2]
0.05 g of carbon black (Ketjen Black EC-600JD, BET specific surface area: 1240 m 2 / g) was added to 50 mL of a dispersion of 0.02 mass% flake particles prepared in the same manner as in Example 1. The mixture was stirred for 30 minutes under ultrasonic irradiation, washed with water and dried. After adding 0.4 mL of dinitrodiammine platinum nitrate solution (Ishifuku Metal Industry Co., Ltd.) and stirring, it was dried at room temperature. Then, it dried at 90 degreeC and obtained the precursor of the electrode catalyst.
The electrode catalyst precursor was reduced in a hydrogen stream at 200 ° C. for 2 hours to obtain an electrode catalyst. The supported rate of platinum particles was 39.8% by mass, ruthenium / platinum (atomic ratio) was 0.37, and the particle size of the platinum particles was 2.1 nm. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
〔例3〕
例1と同様にして調製した0.02質量%の薄片粒子の分散液の100mLに、カーボンブラック(バルカンXC−72R、BET比表面積:約240m2/g。)の0.05gを入れ、超音波照射下で30分間撹拌した後、水洗、乾燥した。白金を10質量%含むジニトロジアンミン白金硝酸溶液(石福金属興業社製)の0.3mLを加えて撹拌した後、室温乾燥した。その後、90℃で乾燥して電極触媒の前駆体を得た。
電極触媒の前駆体を200℃、水素気流中で2時間還元して、電極触媒を得た。白金粒子の担持率は29.7質量%であり、ルテニウム/白金(原子比)は0.98であり、白金粒子の粒子径は2.2nmであった。例1と同様にして評価を行った。結果を表1に示す。
[Example 3]
0.05 g of carbon black (Vulcan XC-72R, BET specific surface area: about 240 m 2 / g) was added to 100 mL of a dispersion of 0.02 mass% flake particles prepared in the same manner as in Example 1. The mixture was stirred for 30 minutes under sonic irradiation, then washed with water and dried. After adding 0.3 mL of dinitrodiammine platinum nitric acid solution (Ishifuku Metal Industry Co., Ltd.) containing 10% by mass of platinum and stirring, it was dried at room temperature. Then, it dried at 90 degreeC and obtained the precursor of the electrode catalyst.
The electrode catalyst precursor was reduced in a hydrogen stream at 200 ° C. for 2 hours to obtain an electrode catalyst. The supporting rate of the platinum particles was 29.7% by mass, the ruthenium / platinum (atomic ratio) was 0.98, and the particle size of the platinum particles was 2.2 nm. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
〔例4〕
例1と同様にして調製した0.4質量%の薄片粒子の分散液の5mLに、エタノールの1mLを添加し、超音波撹拌を行った。これに、外径:20〜60nm、長さ:1〜20μmの仕様を満たすカーボンナノチューブの0.06gを添加して、超音波を印加した。静置後、白金を10質量%含むジニトロジアンミン白金硝酸溶液(石福金属興業社製)の3mLを添加、撹拌し静置した。室温で乾燥後、90℃で一日乾燥して電極触媒の前駆体を得た。
電極触媒の前駆体を200℃、水素気流中で還元して、電極触媒を得た。白金粒子の担持率は29.6質量%であり、ルテニウム/白金(原子比)は0.49であり、白金粒子の粒子径は2.5nmであった。例1と同様にして評価を行った。結果を表1に示す。
[Example 4]
1 mL of ethanol was added to 5 mL of a 0.4 mass% dispersion of flake particles prepared in the same manner as in Example 1, and ultrasonic stirring was performed. To this, 0.06 g of carbon nanotubes satisfying the specifications of outer diameter: 20 to 60 nm and length: 1 to 20 μm was added, and ultrasonic waves were applied. After standing, 3 mL of a dinitrodiammine platinum nitric acid solution (made by Ishifuku Metal Industry Co., Ltd.) containing 10% by mass of platinum was added, stirred and allowed to stand. After drying at room temperature, it was dried at 90 ° C. for one day to obtain an electrode catalyst precursor.
The electrode catalyst precursor was reduced in a hydrogen stream at 200 ° C. to obtain an electrode catalyst. The supporting rate of the platinum particles was 29.6% by mass, the ruthenium / platinum (atomic ratio) was 0.49, and the particle size of the platinum particles was 2.5 nm. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
〔例5〕
例1と同様にして、カーボン担体に対して10質量%の薄片粒子を担持した、薄片粒子担持カーボン担体の60mgを、ジニトロジアンミン白金硝酸溶液(石福金属興業社製)の0.26mL、硝酸パラジウムの30mgおよび超純水の1mlを混合して調製した含浸液に入れ、撹拌した後、室温乾燥した。その後、90℃で乾燥して電極触媒の前駆体を得た。
電極触媒の前駆体を200℃、水素気流中で2時間還元した後、300℃で1時間熱処理して電極触媒を得た。白金粒子の担持率は38.0質量%であり、ルテニウム/[白金+パラジウム]の原子比は0.28であり、白金粒子の粒子径は3.1nmであった。例1と同様にして評価を行った。結果を表1に示す。
[Example 5]
In the same manner as in Example 1, 60 mg of the flake particle-supporting carbon carrier carrying 10% by mass of flake particles with respect to the carbon carrier, 0.26 mL of dinitrodiammine platinum nitrate solution (Ishifuku Metal Industry Co., Ltd.), nitric acid The impregnation liquid prepared by mixing 30 mg of palladium and 1 ml of ultrapure water was mixed, stirred, and dried at room temperature. Then, it dried at 90 degreeC and obtained the precursor of the electrode catalyst.
The electrode catalyst precursor was reduced in a hydrogen stream at 200 ° C. for 2 hours and then heat treated at 300 ° C. for 1 hour to obtain an electrode catalyst. The support ratio of the platinum particles was 38.0% by mass, the atomic ratio of ruthenium / [platinum + palladium] was 0.28, and the particle diameter of the platinum particles was 3.1 nm. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
〔例6〕
例1と同様にして、カーボン担体に対して10質量%の薄片粒子を担持した、薄片粒子担持カーボン担体の60mgを、ジニトロジアンミン白金硝酸溶液(石福金属興業社製)の0.45mL、硝酸コバルトの22mgおよび超純水の0.9mLを混合して調製した含浸液に入れ、撹拌、静置した後、室温で乾燥した。その後、90℃で乾燥して電極触媒の前駆体を得た。
電極触媒の前駆体を200℃、水素気流中で2時間還元した後、350℃で1時間熱処理して、電極触媒を得た。白金粒子の担持率は32.1質量%であり、ルテニウム/白金(原子比)は0.58であり、白金粒子の粒子径は3.8nmであった。例1と同様にして評価を行った。結果を表1に示す。
[Example 6]
In the same manner as in Example 1, 60 mg of the flake particle-supporting carbon support carrying 10% by weight of flake particles with respect to the carbon support, 0.45 mL of dinitrodiammine platinum nitrate solution (Ishifuku Metal Industry Co., Ltd.), nitric acid The mixture was placed in an impregnation solution prepared by mixing 22 mg of cobalt and 0.9 mL of ultrapure water, stirred, allowed to stand, and then dried at room temperature. Then, it dried at 90 degreeC and obtained the precursor of the electrode catalyst.
The electrode catalyst precursor was reduced in a hydrogen stream at 200 ° C. for 2 hours and then heat treated at 350 ° C. for 1 hour to obtain an electrode catalyst. The supporting rate of the platinum particles was 32.1% by mass, the ruthenium / platinum (atomic ratio) was 0.58, and the particle size of the platinum particles was 3.8 nm. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
〔例7〕
金コロイド溶液(田中貴金属工業社製、粒子径:17.2nm、金濃度:66ppm)の154mLに、例1と同様にして調製した薄片粒子担持カーボン担体の60mgを含む分散液の25mLを添加し、撹拌、混合して、金ナノ粒子を担持させた。水洗後、120℃で乾燥した。金ナノ粒子−薄片粒子担持カーボン担体を、白金を1質量%含むジニトロジアンミン白金エタノール溶液の3mLに入れ、撹拌した後、35℃で減圧乾燥して、白金塩を担持させた。ついで、水素中、200℃、2時間の条件で還元し、電極触媒を得た。該電極触媒の白金粒子の担持率は29.8質量%であり、白金粒子の粒子径は2.2nmであった。窒素を吹き込んだ0.5M硫酸水溶液中で電位掃引(CV法:サイクリックボルタンメトリ)で測定した水素吸脱着波と例1で測定した脱着波の値から推定した金属表面積の比は2.7倍であった。例1と同様にして評価を行った。結果を表1に示す。
[Example 7]
To 154 mL of colloidal gold solution (Tanaka Kikinzoku Kogyo Co., Ltd., particle size: 17.2 nm, gold concentration: 66 ppm), 25 mL of a dispersion containing 60 mg of the thin particle supporting carbon support prepared in the same manner as in Example 1 was added. , Stirred and mixed to support the gold nanoparticles. After washing with water, it was dried at 120 ° C. The gold nanoparticle-flake particle-supported carbon support was placed in 3 mL of a dinitrodiammine platinum ethanol solution containing 1% by mass of platinum, stirred, and then dried under reduced pressure at 35 ° C. to support the platinum salt. Subsequently, reduction was performed in hydrogen at 200 ° C. for 2 hours to obtain an electrode catalyst. The electrode catalyst had a platinum particle loading ratio of 29.8 mass%, and the particle diameter of the platinum particles was 2.2 nm. The ratio of the metal surface area estimated from the value of the hydrogen adsorption / desorption wave measured by potential sweep (CV method: cyclic voltammetry) and the desorption wave measured in Example 1 in a 0.5 M sulfuric acid aqueous solution in which nitrogen was blown was 2. It was 7 times. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
〔例8〕
金コロイド溶液(粒子径:10.5nm、金濃度:60ppm)の170mLに、カーボンブラック(バルカンXC−72R、BET比表面積:約240m2/g。)の50mgを入れ、撹拌、混合して、金ナノ粒子を担持させた。水洗後、120℃で乾燥した。金ナノ粒子担持カーボン担体を、例7で用いたものと同様の、薄片粒子を0.04質量%含む分散液の25mLに添加し、撹拌、混合して、薄片粒子を担持させた。洗浄後、120℃で乾燥した。金ナノ粒子−薄片粒子担持カーボン担体に、例7と同様にして、白金粒子を担持させ、電極触媒を得た。該電極触媒の白金粒子の担持率は29.7質量%であり、白金粒子の粒子径は2.3nmであった。例1と同様にして評価を行った。結果を表1に示す。
[Example 8]
In 170 mL of a colloidal gold solution (particle size: 10.5 nm, gold concentration: 60 ppm), 50 mg of carbon black (Vulcan XC-72R, BET specific surface area: about 240 m 2 / g) is added, stirred and mixed, Gold nanoparticles were supported. After washing with water, it was dried at 120 ° C. The gold nanoparticle-supported carbon carrier was added to 25 mL of a dispersion containing 0.04% by mass of flake particles, similar to that used in Example 7, and stirred and mixed to support the flake particles. After washing, it was dried at 120 ° C. In the same manner as in Example 7, platinum particles were supported on a gold nanoparticle-thin particle supported carbon support to obtain an electrode catalyst. The platinum catalyst was supported on the electrode catalyst at a rate of 29.7% by mass, and the particle diameter of the platinum particles was 2.3 nm. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
〔例9〕
例1と同様にして調製した0.4質量%の薄片粒子の分散液の5mLに、エタノールの1mLを添加し、超音波撹拌を行った。これに、外径:20〜60nm、長さ:1〜20μmの仕様を満たすカーボンナノチューブの0.06gを添加して、超音波を印加した。該分散液を、金コロイド溶液(粒子径:10.5nm、金濃度:60ppm)の170mLに入れ、超音波を印加した。洗浄後、120℃で乾燥した。金ナノ粒子−薄片粒子担持カーボン担体に、例7と同様にして、白金粒子を担持させ、電極触媒を得た。該電極触媒の白金粒子の担持率は29.6質量%であり、白金粒子の粒子径は2.4nmであった。例1と同様にして評価を行った。結果を表1に示す。
[Example 9]
1 mL of ethanol was added to 5 mL of a 0.4 mass% dispersion of flake particles prepared in the same manner as in Example 1, and ultrasonic stirring was performed. To this, 0.06 g of carbon nanotubes satisfying the specifications of outer diameter: 20 to 60 nm and length: 1 to 20 μm was added, and ultrasonic waves were applied. The dispersion was placed in 170 mL of a gold colloid solution (particle size: 10.5 nm, gold concentration: 60 ppm), and ultrasonic waves were applied. After washing, it was dried at 120 ° C. In the same manner as in Example 7, platinum particles were supported on a gold nanoparticle-thin particle supported carbon support to obtain an electrode catalyst. The platinum catalyst support ratio of the electrode catalyst was 29.6% by mass, and the particle diameter of the platinum particles was 2.4 nm. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
〔例10〕
金−パラジウム合金コロイド溶液(粒子径:10.5nm、貴金属濃度:60ppm、金:パラジウム(原子比)=9:1)の170mLに、カーボンブラック(ケッチェンブランク、BET比表面積:840m2/g。)の50mgを入れ、撹拌、混合して、金ナノ粒子を担持させた。水洗後、120℃で乾燥した。金ナノ粒子担持カーボン担体を、例8で用いたものと同様の、薄片粒子を0.04質量%含む分散液の25mLに添加し、撹拌、混合して、薄片粒子を担持させた。洗浄後、120℃で乾燥した。金ナノ粒子−薄片粒子担持カーボン担体に、例5と同様にして、白金粒子を担持させ、電極触媒を得た。該電極触媒の白金粒子の担持率は29.5質量%であり、白金粒子の粒子径は2.1nmであった。例1と同様にして評価を行った。結果を表1に示す
[Example 10]
To 170 mL of gold-palladium alloy colloid solution (particle diameter: 10.5 nm, noble metal concentration: 60 ppm, gold: palladium (atomic ratio) = 9: 1), carbon black (Ketjen blank, BET specific surface area: 840 m 2 / g) .) Was added and stirred and mixed to support the gold nanoparticles. After washing with water, it was dried at 120 ° C. The gold nanoparticle-supporting carbon support was added to 25 mL of a dispersion containing 0.04% by mass of flake particles, similar to that used in Example 8, and stirred and mixed to support the flake particles. After washing, it was dried at 120 ° C. In the same manner as in Example 5, platinum particles were supported on a gold nanoparticle-thin particle supported carbon support to obtain an electrode catalyst. The supported amount of platinum particles in the electrode catalyst was 29.5% by mass, and the particle size of the platinum particles was 2.1 nm. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
〔例11〕
エタノール中にカーボンブラック(ケッチェンブラック、BET比表面積:800m2/g。)の0.4gを分散し、白金量として0.37gを含む例1と同様にして調製したジニトロジアンミン白金エタノール溶液を添加して、超音波照射下で30分間撹拌した。例1と同様に乾燥して電極触媒の前駆体を得た。
電極触媒の前駆体を電気炉に入れ、水素を10%含む窒素気流中、徐々に温度を上げ、200℃に2時間保持した。加熱を停止し、70℃に下がったら、窒素ガスを流して、冷却し電極触媒を得た。
電極触媒における白金粒子の粒子径は2.8nmであり、白金粒子の金属表面積は80m2/gであった。また、白金粒子の担持率は、40.2質量%であった。
該電極触媒について、活性およびその安定性を評価した。結果を表1に示す。
[Example 11]
A dinitrodiammine platinum ethanol solution prepared in the same manner as in Example 1 was prepared by dispersing 0.4 g of carbon black (Ketjen black, BET specific surface area: 800 m 2 / g) in ethanol and containing 0.37 g of platinum. The mixture was added and stirred for 30 minutes under ultrasonic irradiation. It dried like Example 1 and obtained the precursor of the electrode catalyst.
The precursor of the electrode catalyst was placed in an electric furnace, and the temperature was gradually raised in a nitrogen stream containing 10% hydrogen and maintained at 200 ° C. for 2 hours. When the heating was stopped and the temperature dropped to 70 ° C., nitrogen gas was passed and cooled to obtain an electrode catalyst.
The particle diameter of the platinum particles in the electrode catalyst was 2.8 nm, and the metal surface area of the platinum particles was 80 m 2 / g. Moreover, the supporting rate of the platinum particles was 40.2% by mass.
The activity and stability of the electrocatalyst were evaluated. The results are shown in Table 1.
〔例12〕
カーボン担体として薄片粒子を担持しないケッチェンブラックの60mgを用いた以外は、例10と同様にして、カーボン担体に白金−パラジウム触媒を担持した電極触媒を得た。触媒粒子の担持率は48.5%であり、触媒粒子の粒子径は3.6nmであった。例1と同様にして評価を行った。結果を表1に示す。
[Example 12]
An electrode catalyst in which a platinum-palladium catalyst was supported on a carbon support was obtained in the same manner as in Example 10 except that 60 mg of ketjen black that did not support flake particles was used as the carbon support. The catalyst particle loading was 48.5%, and the particle size of the catalyst particles was 3.6 nm. Evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
〔例13〕
カーボン担体として、2000℃で熱処理したケッチェンブラックを用いた以外は、例11と同様にして白金粒子を担持させた。白金粒子の担持率は47質量%であり、白金粒子の粒子径は3.5nmであった。例1と同様にして特性を評価した。結果を表1に示す。
[Example 13]
Platinum particles were supported in the same manner as in Example 11 except that Ketjen black heat-treated at 2000 ° C. was used as the carbon support. The support ratio of the platinum particles was 47% by mass, and the particle diameter of the platinum particles was 3.5 nm. The characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 1.
本発明の製造方法で得られた燃料電池用電極触媒は、活性が高く、安定性に優れていることから、該電極触媒を用いた燃料電池は、発電効率、出力、信頼性等が高い。該燃料電池は、電気自動車用電源、家庭用コージェネレーション、携帯機器用電源等として有用である。 Since the fuel cell electrode catalyst obtained by the production method of the present invention has high activity and excellent stability, a fuel cell using the electrode catalyst has high power generation efficiency, output, reliability, and the like. The fuel cell is useful as a power source for electric vehicles, a household cogeneration system, a power source for portable devices, and the like.
10 膜電極接合体
11 触媒層
12 ガス拡散層
13 アノード
14 カソード
15 電解質膜
DESCRIPTION OF
Claims (10)
前記カーボン担体に前記薄片粒子が担持した薄片粒子担持カーボン担体を得る工程と、
前記薄片粒子担持カーボン担体に前記触媒粒子を担持させる工程と
を有する、燃料電池用電極触媒の製造方法。 A method for producing an electrode catalyst for a fuel cell in which flake particles separated from a layered ruthenate compound and catalyst particles containing a noble metal are supported on a carbon support,
Obtaining a thin particle-supported carbon carrier in which the thin particle is supported on the carbon carrier;
And a step of supporting the catalyst particles on the thin particle-supported carbon carrier.
前記カーボン担体に前記薄片粒子が担持した薄片粒子担持カーボン担体を得る工程と、
前記薄片粒子担持カーボン担体に前記触媒粒子の前駆体を担持させる工程と、
前記前駆体を前記触媒粒子に変換する工程と
を有する、燃料電池用電極触媒の製造方法。 A method for producing an electrode catalyst for a fuel cell in which flake particles separated from a layered ruthenate compound and catalyst particles containing a noble metal are supported on a carbon support,
Obtaining a thin particle-supported carbon carrier in which the thin particle is supported on the carbon carrier;
Supporting the catalyst particle precursor on the thin particle-supported carbon carrier;
A method for producing an electrode catalyst for a fuel cell, comprising: converting the precursor into the catalyst particles.
前記カーボン担体または薄片粒子担持カーボン担体に、金または金合金のナノ粒子またはナノシートを担持する工程をさらに有する、請求項1または2に記載の燃料電池用電極触媒の製造方法。 Before or after the step of obtaining the flake particle-supporting carbon carrier in which the flake particles are supported on the carbon carrier,
The method for producing an electrode catalyst for a fuel cell according to claim 1 or 2, further comprising a step of supporting nanoparticles or nanosheets of gold or a gold alloy on the carbon support or the thin particle support carbon support.
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