JP2012248365A - Catalyst for solid polymer fuel cell - Google Patents

Catalyst for solid polymer fuel cell Download PDF

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JP2012248365A
JP2012248365A JP2011117952A JP2011117952A JP2012248365A JP 2012248365 A JP2012248365 A JP 2012248365A JP 2011117952 A JP2011117952 A JP 2011117952A JP 2011117952 A JP2011117952 A JP 2011117952A JP 2012248365 A JP2012248365 A JP 2012248365A
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catalyst
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platinum
fuel cell
particle size
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JP5601280B2 (en
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Hideaki Sawada
英明 澤田
Takashi Iijima
孝 飯島
Kenichiro Tadokoro
健一郎 田所
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Nippon Steel Corp
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract

PROBLEM TO BE SOLVED: To provide a catalyst for a solid polymer fuel cell, narrow in a macro particle size distribution of the entire catalyst particles, having a catalyst active surface area equivalent to a particle size, and excellent in catalytic activity and durability as compared with the conventional electrode catalysts.SOLUTION: A catalyst for a solid polymer fuel cell that is high in activity and excellent in durability is a catalyst comprising a platinum-containing catalyst active component supported on a carbon carrier. In the catalyst, the catalyst active component includes 10-80 mass% of platinum-containing metal, in terms of metal, relative to the total mass of the carbon carrier on which the catalyst active component is supported, a width of a macro particle size distribution obtained using a diffraction pattern that is obtained from X-ray diffraction measurement and includes information on the entire catalyst particles falls within a predetermined range, and a result obtained by measuring a catalyst active surface area by means of electrochemical measurement falls within a predetermined range, the catalyst active surface area being equivalent to a particle size estimated from the X-ray diffraction measurement.

Description

本発明は、固体高分子型燃料電池用触媒に関する。   The present invention relates to a polymer electrolyte fuel cell catalyst.

固体高分子型燃料電池は、水素を燃料とするクリーンな電源として、電気自動車の駆動電源、また、発電と熱供給を併用する定置電源として開発が進められている。また、固体高分子型燃料電池は、リチウムイオン電池などの二次電池と比較して高いエネルギー密度が特徴であり、携帯用コンピュータ、あるいは、移動用通信機器の電源としても開発が進められている。   The polymer electrolyte fuel cell is being developed as a clean power source using hydrogen as a fuel, a driving power source for an electric vehicle, and a stationary power source using both power generation and heat supply. In addition, solid polymer fuel cells are characterized by high energy density compared to secondary batteries such as lithium ion batteries, and are being developed as power sources for portable computers or mobile communication devices. .

固体高分子型燃料電池の電源部分は、アノード（燃料極）とカソード（空気極）、及び両極間に配したプロトン交換性（プロトン伝導性）の固体高分子電解質膜が基本構成となる。アノード及びカソードは、通常、白金などの貴金属を担持した触媒、フッ素樹脂紛などの造孔剤、及び固体高分子電解質等からなる薄膜電極である。   The power supply part of the polymer electrolyte fuel cell is basically composed of an anode (fuel electrode), a cathode (air electrode), and a proton exchangeable (proton conductive) solid polymer electrolyte membrane disposed between both electrodes. The anode and the cathode are usually thin film electrodes made of a catalyst supporting a noble metal such as platinum, a pore forming agent such as a fluororesin powder, and a solid polymer electrolyte.

固体高分子型燃料電池では、高エネルギー密度、すなわち、単位電極面積当たりの出力が高いことが求められる。そのためには、アノードとカソードを構成する電極触媒の電気化学反応の触媒活性を向上させることが有効な手段の一つである。   A polymer electrolyte fuel cell is required to have a high energy density, that is, a high output per unit electrode area. For this purpose, it is an effective means to improve the catalytic activity of the electrochemical reaction of the electrode catalyst constituting the anode and the cathode.

ここで、電気化学反応の触媒活性とは、水素を燃料とするアノードでは、水素分子が水素カチオン（プロトン）に酸化する電気化学的反応における触媒活性である。一方、カソードでは、電気化学反応の触媒活性とは、固体高分子電解質から来るプロトンと酸素が反応して酸素が水に還元される電気化学反応における触媒活性である。   Here, the catalytic activity of the electrochemical reaction is a catalytic activity in an electrochemical reaction in which hydrogen molecules are oxidized into hydrogen cations (protons) at an anode using hydrogen as a fuel. On the other hand, in the cathode, the catalytic activity of the electrochemical reaction is the catalytic activity in the electrochemical reaction in which protons coming from the solid polymer electrolyte react with oxygen and oxygen is reduced to water.

固体高分子型燃料電池のアノードとカソードの電極触媒には、白金などの貴金属が用いられる。しかしながら、白金をはじめとして貴金属は高価なので、固体高分子型燃料電池の実用化や普及を加速するために、電極単位面積当たりの使用量の低減が求められ、そのためには触媒活性のさらなる向上が必要である。   A noble metal such as platinum is used as an electrode catalyst for the anode and cathode of the solid polymer fuel cell. However, since noble metals such as platinum are expensive, in order to accelerate the practical use and spread of solid polymer fuel cells, it is required to reduce the amount used per unit area of the electrode. is necessary.

さらに、電極触媒を燃料電池に使用した場合には、起動停止や高負荷運転によって、触媒成分の白金が溶出したり、カーボン担体が腐食したりすることが知られており、白金の溶出やカーボン腐食を妨げる技術も非常に重要になっている。触媒粒子の触媒活性と耐久性については、これまで、合金化や粒子径のばらつきの制御によって改善が図られてきた。   Furthermore, when an electrode catalyst is used in a fuel cell, it is known that platinum as a catalyst component is eluted or the carbon support is corroded by starting and stopping or high-load operation. Technology that prevents corrosion is also very important. Up to now, the catalytic activity and durability of the catalyst particles have been improved by alloying and controlling the variation in particle diameter.

特許文献１には、白金を希土類元素と合金化し、さらにその２０質量％以上を金属間化合物にした上で、電子顕微鏡で調べた触媒粒子の８０質量％以上の粒子径が１〜２０ｎｍとなるように制御することで、白金と希土類元素との共有結合性の結合の形成により、溶解、再析出による触媒粒子の成長を著しく抑制できることが開示されている。   In Patent Document 1, platinum is alloyed with a rare earth element, and further, 20% by mass or more thereof is an intermetallic compound, and then the particle diameter of 80% by mass or more of the catalyst particles examined by an electron microscope is 1 to 20 nm. By controlling in this way, it is disclosed that the growth of catalyst particles due to dissolution and reprecipitation can be remarkably suppressed by forming a covalent bond between platinum and a rare earth element.

特許文献２には、触媒粒子の平均粒子径をＸとしたとき、ある任意の触媒粒子Ａに対して、隣接する３つ以上の触媒粒子の重心が触媒粒子Ａの重心と０．５Ｘ〜２Ｘの距離の範囲になるように触媒を担体に担持し、さらに、触媒粒子径のばらつきを０．７５Ｘ〜１．５Ｘの範囲に制御することなどによる耐久性に優れた電極触媒が開示されている。   In Patent Document 2, when the average particle diameter of the catalyst particles is X, the center of gravity of three or more adjacent catalyst particles is 0.5X to 2X with respect to the center of the catalyst particles A with respect to a certain arbitrary catalyst particle A. An electrode catalyst excellent in durability by, for example, supporting a catalyst on a support so as to be in a range of a distance of 5 mm and further controlling variation in catalyst particle diameter in a range of 0.75X to 1.5X is disclosed. .

特許文献２によれば、粒子間距離を制限する理由は、隣接する粒子間の距離が開きすぎると、導電性材料表面の暴露面積が大きくなりすぎ、導電性材料表面と水が接触する可能性が高くなるので、高電位での運転条件で導電性材料の腐食劣化が著しく生じ、逆に、隣接する粒子間の距離が短すぎると、触媒粒子同士の接触が増え、燃料又は酸化剤ガス、電極触媒、電解質との三相界面が小さくなるので、触媒活性が低下し好ましくないからである。   According to Patent Document 2, the reason for limiting the distance between particles is that if the distance between adjacent particles is too large, the exposed area of the surface of the conductive material becomes too large, and the surface of the conductive material may come into contact with water. Therefore, when the distance between adjacent particles is too short, contact between the catalyst particles increases, fuel or oxidant gas, This is because the three-phase interface between the electrode catalyst and the electrolyte is small, which is not preferable because the catalytic activity is lowered.

また、粒子径のばらつきを制限する理由は、ばらつきが大きいと、小さい粒子が溶出し、電解質膜中や大きな粒子の表面に再析出し、膜の劣化を促進したり、触媒の比表面積を低下させ、比活性の低下を引き起こす原因になるからである。   The reason for limiting the variation in particle size is that if the variation is large, small particles are eluted and re-deposited in the electrolyte membrane or on the surface of large particles to promote membrane degradation or reduce the specific surface area of the catalyst. This is because it causes a decrease in specific activity.

固体高分子型燃料電池用触媒の耐久性を向上させる試みの１つとして、粒子径分布の幅（粒子径のばらつきの幅）を狭くすることが挙げられる。粒子径の分布を測定する手段としては、透過型電子顕微鏡で得られた像から１００〜１０００個程度の粒子の粒子径を調べるのが一般的である。   One of the attempts to improve the durability of the polymer electrolyte fuel cell catalyst is to narrow the width of the particle size distribution (the width of variation in particle size). As a means for measuring the particle size distribution, it is common to examine the particle size of about 100 to 1000 particles from an image obtained with a transmission electron microscope.

しかしながら、上記の方法で判断しながら、粒子径分布の幅が狭い触媒を作製しても、得られた触媒の耐久性が優れない場合があった。また、逆に、粒子径分布の幅が広い触媒であっても、耐久性が優れる場合が散見されていた。   However, even when a catalyst having a narrow particle size distribution is prepared while judging by the above method, the durability of the obtained catalyst may not be excellent. On the other hand, even in the case of a catalyst having a wide particle size distribution, there are some cases where the durability is excellent.

本発明者らは、この現象を詳細に検討した結果、触媒粒子全体に近いマクロ的な粒子径分布の幅が、透過型電子顕微鏡で判断される局所的な粒子径分布の幅と必ずしも一致していないことが原因であることを明らかにした。つまり、透過型電子顕微鏡像から得られる粒子径分布は、どのように多くの粒子径を測定したとしても、測定領域には限界があり触媒粒子全体に近いマクロ的な粒子径分布を表すことができないのが原因である。   As a result of detailed examination of this phenomenon, the present inventors have found that the width of the macroscopic particle size distribution close to the entire catalyst particle does not necessarily match the width of the local particle size distribution determined by the transmission electron microscope. Clarified that the cause is not. In other words, the particle size distribution obtained from a transmission electron microscope image can represent a macroscopic particle size distribution close to the entire catalyst particle, regardless of how many particle sizes are measured. It is because it is not possible.

一方、触媒粒子全体に近いマクロ的な平均粒子径を測定できる方法として、粉末Ｘ線回折測定によって得られたピークの半価幅から見積もる手法がある。粉末Ｘ線回折測定による方法では、マクロ的な触媒粒子群の粒子径の平均値が得られ、さらに、特許文献３にあるように粒子径分布を表す指標を見積もることができ、触媒粒子全体に近いマクロ的な粒子径分布の幅の狭い触媒を作製することに成功していた。   On the other hand, as a method for measuring a macro average particle diameter close to the entire catalyst particle, there is a method of estimating from the half width of a peak obtained by powder X-ray diffraction measurement. In the method based on the powder X-ray diffraction measurement, the average value of the particle diameter of the macroscopic catalyst particle group can be obtained. Further, as disclosed in Patent Document 3, an index representing the particle diameter distribution can be estimated, and the entire catalyst particle can be estimated. We have succeeded in producing a catalyst with a narrow macroscopic particle size distribution.

粉末Ｘ線回折測定によって見積もられる粒子径分布に関する指標は触媒の粒子径、正確には、結晶子径を反映した指標である。しかしながら、触媒粒子が凝集している場合や、触媒粒子が高分子保護剤等で覆われている場合には、必ずしも良い指標とはなっていなかった。つまり、粉末Ｘ線回折測定の結果から、触媒粒子径とその分布が適切であると判断されても、触媒粒子の凝集や、触媒粒子を覆っている高分子保護剤によって、触媒活性を有する表面積が小さくなっている場合があった。   The index relating to the particle size distribution estimated by the powder X-ray diffraction measurement is an index reflecting the particle size of the catalyst, more precisely, the crystallite size. However, when the catalyst particles are aggregated or when the catalyst particles are covered with a polymer protective agent or the like, it is not always a good index. That is, even if it is judged from the results of powder X-ray diffraction measurement that the catalyst particle diameter and its distribution are appropriate, the surface area having catalytic activity due to the aggregation of the catalyst particles and the polymer protective agent covering the catalyst particles. May have become smaller.

特開平１０−２１４６３０号公報JP-A-10-214630 特開２００７−２２２７３２号公報JP 2007-222732 A 特開２００９−２８３２５４号公報JP 2009-283254 A

本発明は、前記の事情に鑑みなされたものであって、触媒粒子全体の粒子径分布に近いマクロ的な粒子径分布の幅が狭く、かつ、粒子径相当の触媒活性表面積を有する、従来の電極触媒に比べて触媒活性と耐久性に優れた固体高分子型燃料電池用触媒の提供を課題とする。   The present invention has been made in view of the above circumstances, and has a narrow macroscopic particle size distribution width close to the particle size distribution of the entire catalyst particles, and has a catalytic active surface area corresponding to the particle size. It is an object of the present invention to provide a catalyst for a polymer electrolyte fuel cell that is superior in catalytic activity and durability compared to an electrode catalyst.

本発明者らは、前記のように、透過型電子顕微鏡像から得られる粒子径分布は、触媒中の局所的な粒子径分布であり、必ずしも、触媒粒子全体に近いマクロ的な粒子径分布を表していないことを見出した。   As described above, the present inventors have found that the particle size distribution obtained from the transmission electron microscope image is a local particle size distribution in the catalyst, and does not necessarily have a macroscopic particle size distribution close to the entire catalyst particle. I found that it was not represented.

そして、むしろ、Ｘ線回折（以下、「ＸＲＤ」とも記す）測定から得られる触媒粒子全体の情報を含む回折パターン（以下、「ＸＲＤパターン」とも記す）を使用して、マクロ的な粒子径分布の幅を特定の範囲にし、かつ、ＸＲＤ測定から見積もられた粒子径に相当する触媒活性表面積が電気化学測定によっても得られる触媒が、高活性で、かつ、耐久性に優れることを見出した。   Rather, using a diffraction pattern (hereinafter also referred to as “XRD pattern”) including information on the entire catalyst particles obtained from X-ray diffraction (hereinafter also referred to as “XRD”) measurement, a macroscopic particle size distribution is used. It was found that a catalyst whose surface area of catalytic activity corresponding to the particle diameter estimated from XRD measurement was obtained by electrochemical measurement was highly active and excellent in durability. .

さらに、このような触媒の合成は、金属塩化物、金属硝酸塩、金属錯体を水や有機溶媒などの溶媒に溶解した上で、還元剤で還元して、白金を含む触媒活性成分を炭素担体に担持する（液相吸着する）方法で製造することができるが、この方法において、溶媒、界面活性剤、還元剤の量が触媒の粒子径分布に大きく影響を与えることを見出した。   Furthermore, such a catalyst is synthesized by dissolving a metal chloride, a metal nitrate, or a metal complex in a solvent such as water or an organic solvent, and then reducing with a reducing agent to convert a catalytically active component containing platinum into a carbon support. Although it can be produced by a method of supporting (liquid phase adsorption), it has been found that the amount of solvent, surfactant and reducing agent greatly affects the particle size distribution of the catalyst.

本発明は、上記の知見に基づきなされたものであり、その要旨は以下のとおりである。   This invention is made | formed based on said knowledge, The summary is as follows.

（１）炭素担体に、白金を含む触媒活性成分を担持した触媒であって、
上記触媒活性成分に含まれる白金を含む金属が、触媒活性成分を担持した炭素担体の全質量に対して、金属換算で１０〜８０質量％であり、
上記触媒のＸ線回折測定で得られた回折パターンからバックグラウンドを削除し、上記回折パターンにおける白金の面心立方格子の（１１１）ピークの高さに対する１／４高さでのピーク幅β1/4、及び、上記（１１１）ピークの高さに対する３／４高さでのピーク幅β3/4を求め、
上記（１１１）ピークをガウス関数とローレンツ関数の和と仮定して、上記β1/4、及び、β3/4からそれぞれ、上記（１１１）ピークの高さに対する１／２の高さでのピーク幅β'1/4、及び、β'3/4を算出し、
上記β'1/4、及び、β'3/4を用いて、Ｓｃｈｅｒｒｅｒの式でそれぞれ算出した白金の粒子径Ｄ1/2(h/4)、及び、Ｄ1/2(3h/4)の比Ｄ1/2(h/4)／Ｄ1/2(3h/4)が、０．９以上、１．１以下であり、かつ、
上記（１１１）ピークの半値幅を用いて、Ｓｃｈｅｒｒｅｒの式で算出した白金の粒子径Ｄxrdと、上記触媒の電気化学測定で得られた水素脱離波から見積もられる白金の粒子径Ｄecの比Ｄxrd／Ｄecが０．６以上、１．４以下である
ことを特徴とする固体高分子型燃料電池用触媒。 (1) A catalyst in which a catalytically active component containing platinum is supported on a carbon support,
The metal containing platinum contained in the catalytically active component is 10 to 80% by mass in terms of metal with respect to the total mass of the carbon support carrying the catalytically active component,
The background is deleted from the diffraction pattern obtained by the X-ray diffraction measurement of the catalyst, and the peak width β 1 at a height of ¼ of the height of the (111) peak of the face-centered cubic lattice of platinum in the diffraction pattern. / 4 and the peak width β 3/4 at 3/4 height relative to the height of the (111) peak,
Assuming that the (111) peak is the sum of a Gaussian function and a Lorentz function, from the above β 1/4 and β 3/4 , the height at half the height of the (111) peak is Calculate the peak widths β ' 1/4 and β' 3/4 ,
Using β ′ 1/4 and β ′ 3/4 , the platinum particle diameters D 1/2 (h / 4) and D 1/2 (3h / 4) calculated by the Scherrer equation, respectively. The ratio D1 / 2 (h / 4) / D1 / 2 (3h / 4) is 0.9 or more and 1.1 or less, and
Using the full width at half maximum of the (111) peak, the platinum particle diameter D xrd calculated by the Scherrer equation and the platinum particle diameter D ec estimated from the hydrogen desorption wave obtained by the electrochemical measurement of the catalyst A catalyst for a polymer electrolyte fuel cell, wherein the ratio D xrd / D ec is 0.6 or more and 1.4 or less.

（２）前記Ｄxrdが、３．０〜６．０ｎｍであることを特徴とする前記（１）の固体高分子型燃料電池用触媒。 (2) The polymer electrolyte fuel cell catalyst according to (1), wherein the D xrd is 3.0 to 6.0 nm.

（３）前記触媒活性成分に含まれる白金を含む金属が、触媒活性成分を担持した炭素担体の全質量に対して、金属換算で２０〜８０質量％であることを特徴とする前記（１）又は（２）の固体高分子型燃料電池用触媒。   (3) The metal according to (1), wherein the metal containing platinum contained in the catalytically active component is 20 to 80% by mass in terms of metal with respect to the total mass of the carbon support carrying the catalytically active component. Or (2) a catalyst for a polymer electrolyte fuel cell;

本発明の固体高分子型燃料電池用触媒は、従来の触媒に比べて、マクロ的に粒子径の揃った触媒粒子であり、かつ、触媒粒子の凝集や、高分子保護剤の被覆による触媒活性表面積の減少がない触媒である。その結果、高い触媒活性を持ち、さらに、特に耐久性に優れるという効果がある。   The catalyst for a solid polymer fuel cell of the present invention is a catalyst particle having a macroscopically uniform particle size as compared with a conventional catalyst, and the catalytic activity by agglomeration of catalyst particles or coating with a polymer protective agent It is a catalyst with no surface area reduction. As a result, there is an effect that it has high catalytic activity and is particularly excellent in durability.

上記の触媒を用いた電極を固体高分子型燃料電池に使用すると、エネルギー密度が高い、コンパクトな燃料電池セルスタックが達成でき、携帯用コンピュータ、あるいは、移動用通信機器の電源としても実用できるサイズになる。   When the electrode using the above catalyst is used in a polymer electrolyte fuel cell, a high energy density and compact fuel cell stack can be achieved, and the size can be used as a power source for portable computers or mobile communication devices. become.

また、本発明の固体高分子型燃料電池用触媒は、高触媒活性であり、耐久性に優れるので、貴金属の使用量を低減でき、大幅な低コスト化を実現でき、固体高分子型燃料電池の商業的な市場普及を加速することができる。   In addition, the polymer electrolyte fuel cell catalyst of the present invention has high catalytic activity and excellent durability, so that the amount of precious metal used can be reduced, and the cost can be greatly reduced. Can accelerate the commercial market spread.

本発明の実施例に係る、触媒Ｎｏ．４のＸ線回折測定で得られた白金の面心立方格子の（１１１）ピークを示す図である。According to the embodiment of the present invention, the catalyst No. 4 is a diagram showing a (111) peak of a platinum face-centered cubic lattice obtained by X-ray diffraction measurement of No. 4; FIG.

本発明の固体高分子型燃料電池用触媒は、ＸＲＤ測定で得られる回折パターンから算出される、触媒粒子全体に近いマクロ的な粒子径分布の幅と、ＸＲＤパターンから得られた粒子径と、電気化学測定で得られる水素脱離波から見積もられる粒子径の比を特定の範囲にしたものである。   The polymer electrolyte fuel cell catalyst of the present invention is calculated from the diffraction pattern obtained by XRD measurement, the width of the macroscopic particle size distribution close to the whole catalyst particle, the particle size obtained from the XRD pattern, The ratio of the particle diameter estimated from the hydrogen desorption wave obtained by electrochemical measurement is in a specific range.

ＸＲＤパターンから、マクロ的な触媒の粒子径分布の幅を表す指標を導出する手順を以下に記す。   The procedure for deriving an index representing the width of the particle size distribution of the macro catalyst from the XRD pattern is described below.

まず、ＸＲＤパターンのバックグラウンドを削除する。これは、特に、触媒担持量や触媒担体が異なる場合や、ＸＲＤ測定用サンプルホルダーに入れた触媒量が異なる場合などに、バックグラウンドを削除しないと、金属由来のピークの幅を正確に定義することができなくなるからである。   First, the background of the XRD pattern is deleted. This defines the width of the metal-derived peak accurately if the background is not deleted, especially when the amount of catalyst supported or the catalyst carrier is different, or when the amount of catalyst placed in the sample holder for XRD measurement is different. Because it becomes impossible.

次に、ＸＲＤパターンの、白金の面心立方格子（ｆｃｃ、face-centered cubic）の（１１１）ピークの頂点の高さに対する１／４高さでのピーク幅β1/4、及び、３／４高さでのピーク幅β3/4を求める。 Next, in the XRD pattern, a peak width β 1/4 at a height of 1/4 with respect to the height of the vertex of the (111) peak of the face-centered cubic (fcc) of platinum, and 3 / Find the peak width β 3/4 at 4 heights.

さらに、ＸＲＤパターンが、ガウス関数とローレンツ関数の和で表せると仮定して、上で求めたピーク幅β1/4、及び、ピーク幅β3/4から、それぞれ、ピークの頂点の高さに対する１／２高さに相当するピーク幅（半価幅）β'1/4、及び、β'3/4を求める。 Further, assuming that the XRD pattern can be expressed by the sum of the Gaussian function and the Lorentz function, the peak width β 1/4 and the peak width β 3/4 obtained above are respectively measured with respect to the peak apex height. Peak widths (half widths) β ′ 1/4 and β ′ 3/4 corresponding to ½ height are obtained.

１／４高さでのピーク幅β1/4、及び、３／４高さでのピーク幅β3/4から、それぞれ、１／２高さでのピーク幅β'1/4、及び、β'3/4を求める式は、下記のとおりである。 From the peak width β 1/4 at 1/4 height and the peak width β 3/4 at 3/4 height, respectively, the peak width β ′ 1/4 at 1/2 height, and The formula for obtaining β ′ 3/4 is as follows.

Figure 2012248365
Figure 2012248365

Figure 2012248365
Figure 2012248365

求められた１／２高さでのピーク幅β'1/4、及び、β'3/4から、下記Ｓｃｈｅｒｒｅｒの式で、それぞれ粒子径Ｄ1/2(h/4)、及び、粒子径Ｄ1/2(3h/4)を求める。 From the obtained peak widths β ′ 1/4 and β ′ 3/4 at ½ height, the particle diameter D 1/2 (h / 4) and the particle diameter are obtained by the following Scherrer equation. D 1/2 (3h / 4) is obtained.

Figure 2012248365
Ｄ：結晶子の大きさ（Å）
Ｋ：Ｓｃｈｅｒｒｅｒ定数
λ：Ｘ線管球の波長（Å）
β：結晶子の大きさによる回折線の拡がりの半価幅（Ｒａｄｉａｎ）
θ：回折角 ２θ／２ （ｄｅｇｒｅｅ）
Figure 2012248365
 D: Crystallite size (Å)
K: Scherrer constant λ: wavelength of X-ray tube (Å)
β: Half width of the diffraction line broadening depending on crystallite size (Radian)
θ: diffraction angle 2θ / 2 (degree)

上で求めた２つの粒子径の比Ｄ1/2(h/4)／Ｄ1/2(3h/4)が、粒子径分布の幅を表す指標となる。式３で、それぞれ、粒子径を求めなくても、式１と式２をそれぞれ式３に代入して得られる式を用いて求められる下記式４から、Ｄ1/2(h/4)／Ｄ1/2(3h/4)が直接求められる。 The ratio D 1/2 (h / 4) / D 1/2 (3h / 4) of the two particle sizes obtained above is an index representing the width of the particle size distribution. Even if the particle diameter is not determined in Formula 3, from Formula 4 below obtained using Formulas obtained by substituting Formula 1 and Formula 2 into Formula 3, respectively, D 1/2 (h / 4) / D 1/2 (3h / 4) is directly obtained.

Figure 2012248365
Figure 2012248365

ここで、ピークの頂点での高さに対する１／４高さでのピーク幅β1/4、及び、３／４高さでのピーク幅β3/4から、粒子径Ｄ1/2(h/4)、及び、粒子径Ｄ1/2(3h/4)を、それぞれ見積もる理由は、以下のとおりである。 Here, from the peak width β 1/4 at a height of 1/4 to the height at the peak apex and the peak width β 3/4 at a height of 3/4 , the particle diameter D 1/2 (h / 4) and the particle diameter D 1/2 (3h / 4) are estimated for the following reasons.

２種類のピーク幅を決める２つの高さが１／２に近すぎると、好ましい粒子径分布を持っていない場合（粒子径分布の幅が広い場合）でも、２つの高さでのピーク幅から求めた粒子径がほとんど同じになってしまい、粒子径分布の幅を正確に求めることができない。   If the two heights that determine the two types of peak widths are too close to ½, even if the particle size distribution is not favorable (when the particle size distribution is wide), the peak widths at the two heights The obtained particle sizes are almost the same, and the width of the particle size distribution cannot be obtained accurately.

逆に、２種類のピーク幅を決める２つの高さが１／２から離れすぎている場合、例えば、２種類のピーク幅を決める２つの高さを頂点近くと底辺近くとした場合には、測定や、バックグラウンド除去の誤差の影響で、２つのピーク幅から求められるそれぞれの粒子径の誤差が大きくなるので適切ではない。したがって、２種類のピーク幅を求めるピーク高さを、ピークの頂点での高さに対して、１／４と３／４とした。   Conversely, if the two heights that determine the two types of peak widths are too far from 1/2, for example, if the two heights that determine the two types of peak widths are near the top and the bottom, This is not appropriate because the error in the particle diameters obtained from the two peak widths increases due to the influence of measurement and background removal errors. Therefore, the peak heights for obtaining two types of peak widths were set to 1/4 and 3/4 with respect to the height at the peak apex.

ピーク高さの１／４、及び、３／４におけるピーク幅から、それぞれ２つの半価幅を求め、２種類の粒子径Ｄ1/2(h/4)、及び、Ｄ1/2(3h/4)を算出して比較することが意味するのは、以下のとおりである。 Two half widths are obtained from the peak widths at 1/4 and 3/4 of the peak height, respectively, and two kinds of particle diameters D 1/2 (h / 4) and D 1/2 (3h / 4) is calculated and compared as follows.

粒子径分布を持たない粒子群のＸＲＤパターンは、理想的なピーク形状になる。その結果、ピーク高さ１／４、及び、３／４におけるピーク幅からそれぞれ求めた２つの半価幅より算出される粒子径Ｄ1/2(h/4)、及び、Ｄ1/2(3h/4)は、同じになる。すなわち、Ｄ1/2(h/4)／Ｄ1/2(3h/4)＝１となる。 The XRD pattern of a particle group having no particle size distribution has an ideal peak shape. As a result, the particle diameters D 1/2 (h / 4) and D 1/2 ( D 1/2 ( ) calculated from the two half widths obtained from the peak widths at the peak heights ¼ and 3/4, respectively. 3h / 4) is the same. That is, D 1/2 (h / 4) / D 1/2 (3h / 4) = 1.

しかしながら、粒子径の異なる粒子群によるＸＲＤパターンでは、ピーク形状が理想的なピーク形状からずれる。その結果、ピーク高さの異なるピーク幅から２つの半価幅を求め、前記半価幅からそれぞれ求めた粒子径Ｄ1/2(h/4)、及び、Ｄ1/2(3h/4)に違いが生じる。したがって、粒子径の比Ｄ1/2(h/4)／Ｄ1/2(3h/4)を見ることによって、粒子径分布の幅が判断できる。 However, in the XRD pattern with particle groups having different particle diameters, the peak shape deviates from the ideal peak shape. As a result, two half widths were obtained from the peak widths having different peak heights, and the particle diameters D 1/2 (h / 4) and D 1/2 (3h / 4) obtained from the half widths, respectively. There is a difference. Therefore, the width of the particle size distribution can be determined by looking at the particle size ratio D1 / 2 (h / 4) / D1 / 2 (3h / 4) .

触媒の粒子径分布の幅が狭くて、耐久性に優れた触媒として、好ましい粒子径分布を持つ場合に示すＤ1/2(h/4)／Ｄ1/2(3h/4)の値の範囲は、０．９以上、１．１以下である。すなわち、粒子径分布を持たない理想値１からのずれが、±０．１の範囲内である。 D 1/2 (h / 4) / D 1/2 (3h / 4) values shown when the particle size distribution of the catalyst is narrow and has a preferable particle size distribution as a catalyst having excellent durability. The range is 0.9 or more and 1.1 or less. That is, the deviation from the ideal value 1 having no particle size distribution is within a range of ± 0.1.

さらに、本発明の触媒粒子の粒子径は、３．０〜６．０ｎｍの範囲がより好ましい。上記粒子径は、ＸＲＤパターンにおける白金のｆｃｃの（１１１）ピークの半値幅（１／２高さでのピーク幅）を用いて、上記Ｓｃｈｅｒｒｅｒの式で求めた粒子径Ｄxrdである。 Furthermore, the particle diameter of the catalyst particles of the present invention is more preferably in the range of 3.0 to 6.0 nm. The particle diameter is the particle diameter D xrd obtained by the Scherrer equation using the half width (peak width at 1/2 height) of the (111) peak of platinum fcc in the XRD pattern.

本発明の炭素担体に担持される白金を含む触媒活性成分は、白金のみからなる金属である必要はなく、白金の他にクロム、鉄、コバルト、ニッケル、銅、ロジウム、パラジウム、銀、イリジウム、ルテニウムなどを合金元素として含む金属であっても構わない。   The catalytically active component containing platinum supported on the carbon support of the present invention does not need to be a metal composed of only platinum, but besides platinum, chromium, iron, cobalt, nickel, copper, rhodium, palladium, silver, iridium, A metal containing ruthenium or the like as an alloy element may be used.

電気化学測定には、三極式方式の電解セルを用いる。電解液には、窒素ガス又はアルゴンガス飽和した、硫酸又は過塩素酸を用いる。作用極電極に触媒を載せ、サイクリックボルタンメトリーによって水素脱離波の電気量を求め、平滑多結晶白金の値（２１０μＣ）で除することによって、作用極電極上に載せた触媒の白金表面積を得ることができる。   A three-electrode electrolytic cell is used for electrochemical measurement. As the electrolyte, sulfuric acid or perchloric acid saturated with nitrogen gas or argon gas is used. The catalyst is placed on the working electrode, the amount of electricity of hydrogen desorption wave is obtained by cyclic voltammetry, and divided by the value of smooth polycrystalline platinum (210 μC) to obtain the platinum surface area of the catalyst placed on the working electrode. be able to.

さらに、白金表面積、及び、作用極電極上の白金重量から、白金粒子が球であるとの仮定の下、白金粒子径Ｄecを求める。触媒粒子が凝集し、一部結合している部位があっても、結晶子として分離できれば、ＸＲＤ測定では、１つの粒子として観測される。また、白金粒子表面が高分子保護剤に覆われていたり、酸素還元活性能の低い元素が表面に存在していたりしても、白金粒子の触媒活性は低下するが、ＸＲＤ測定で見積もられる白金粒子径には影響しない。 Further, the platinum particle diameter Dec is obtained from the platinum surface area and the platinum weight on the working electrode under the assumption that the platinum particles are spheres. Even if there are sites where the catalyst particles are aggregated and partially bonded, if they can be separated as crystallites, they are observed as one particle in XRD measurement. Even if the surface of the platinum particle is covered with a polymer protective agent or an element having a low oxygen reduction activity ability is present on the surface, the catalytic activity of the platinum particle is reduced, but platinum estimated by XRD measurement It does not affect the particle size.

一方、電気化学測定によって求められる白金粒子径は、白金表面の水素吸着量から見積もるため、水素吸着を妨げる状態、つまり、触媒粒子の凝集、保護剤の吸着や低活性元素の存在などがある場合には、見積もられる白金表面積が小さくなり、結果として、白金粒子径は大きく見積もられる。   On the other hand, the platinum particle diameter obtained by electrochemical measurement is estimated from the amount of hydrogen adsorption on the platinum surface, so there are conditions that hinder hydrogen adsorption, that is, there is aggregation of catalyst particles, adsorption of protective agents, presence of low active elements, etc. Therefore, the estimated platinum surface area becomes small, and as a result, the platinum particle diameter is estimated to be large.

そのため、ＸＲＤ測定から見積もられる白金粒子径Ｄxrdと、電気化学測定で得られた水素脱離波から見積もられる白金粒子径Ｄecの比Ｄxrd／Ｄecは、白金表面が清浄で、かつ、凝集等がない場合には１に近い値となり、白金表面の活性を低下させる状態では１よりも小さな値となる。 Therefore, the ratio D xrd / D ec of the platinum particle diameter D xrd estimated from the XRD measurement and the platinum particle diameter D ec estimated from the hydrogen desorption wave obtained by the electrochemical measurement is such that the platinum surface is clean, and When there is no aggregation or the like, the value is close to 1, and when the activity on the platinum surface is reduced, the value is less than 1.

触媒活性に優れた触媒として、好ましい触媒表面性状を有する場合に示すＤxrd／Ｄecは、０．６以上、１．４以下である。白金表面が清浄である場合は、Ｄxrd／Ｄecが１に近い値になり、１よりも大幅に大きくなることはない。 As a catalyst having excellent catalytic activity, D xrd / D ec indicated when the catalyst has preferable catalyst surface properties is 0.6 or more and 1.4 or less. When the platinum surface is clean, D xrd / D ec is close to 1 and does not become much larger than 1.

本発明で使用する炭素担体は、特に限定されないが、微粒子を均一に分散させるために、ＢＥＴ法による窒素吸着比表面積が２００ｍ２／ｇ以上であることが好ましい。さらには、５００ｍ２／ｇ以上であることがより望ましい。 The carbon support used in the present invention is not particularly limited, but in order to uniformly disperse the fine particles, the nitrogen adsorption specific surface area by the BET method is preferably 200 m 2 / g or more. Furthermore, it is more desirable that it is 500 m 2 / g or more.

ＢＥＴ法による窒素吸着比表面積が２００ｍ２／ｇ未満であると、特に触媒中に含まれる白金の担持量が５０質量％以上になった場合に、金属元素として白金のみを含む触媒活性成分の炭素担体上での均一分散性が低下することがある。一方、２５００ｍ２／ｇを超えると、炭素材料の電気伝導性が低下して、電極触媒としては不適当になる場合がある。 When the nitrogen adsorption specific surface area by the BET method is less than 200 m 2 / g, particularly when the supported amount of platinum contained in the catalyst is 50% by mass or more, carbon of a catalytically active component containing only platinum as a metal element Uniform dispersibility on the carrier may be reduced. On the other hand, when it exceeds 2500 m 2 / g, the electrical conductivity of the carbon material is lowered, which may be inappropriate as an electrode catalyst.

また、本発明の炭素担体は、非晶質、黒鉛のどちらでもよく、結晶性や黒鉛化度にも限定されない。   The carbon support of the present invention may be either amorphous or graphite, and is not limited to crystallinity or graphitization degree.

本発明において、白金を含む金属の担持量は、触媒活性成分を担持した炭素担体の全質量に対して、金属換算で１０〜８０質量％である。   In the present invention, the amount of platinum-containing metal is 10 to 80% by mass in terms of metal with respect to the total mass of the carbon support on which the catalytically active component is supported.

白金を含む金属の担持量が１０質量％未満では、担持される触媒成分が少なくなるので、触媒層の単位厚みでの出力が減少する。そのため、高出力を得るには触媒層を厚くする必要があり、その結果、生成水の除去が困難になり、電池性能が低下するだけでなく、運転時に触媒層に含まれる水分量が増加して耐久性も低下する。   When the supported amount of the metal containing platinum is less than 10% by mass, the supported catalyst component is reduced, and the output per unit thickness of the catalyst layer is reduced. Therefore, in order to obtain high output, it is necessary to thicken the catalyst layer. As a result, it becomes difficult to remove the generated water, and not only the battery performance decreases, but also the amount of water contained in the catalyst layer increases during operation. Durability is also reduced.

一方、白金を含む金属の担持量が８０質量％を越えると、触媒活性成分を高密度に分散させることが困難で触媒活性が低下し、また、触媒粒子同士が凝集しやすくなって耐久性も低下する。   On the other hand, if the loading amount of the metal containing platinum exceeds 80% by mass, it is difficult to disperse the catalytically active component at a high density and the catalytic activity is lowered. descend.

より好ましい白金を含む金属の担持量は、２０〜８０質量％であり、さらに好ましくは、２０〜７０質量％である。   The more preferable amount of the metal containing platinum is 20 to 80% by mass, and further preferably 20 to 70% by mass.

白金の他に、触媒活性成分として、クロム、鉄、コバルト、ニッケル、銅、ロジウム、パラジウム、銀、イリジウム、ルテニウムから選ばれる１種以上の金属元素を、さらに含有することができる。これらの金属は、白金との複合体であっても、合金であっても構わない。さらには、これらの金属と有機化合物や無機化合物との錯体であっても構わない。   In addition to platinum, the catalyst active component may further contain one or more metal elements selected from chromium, iron, cobalt, nickel, copper, rhodium, palladium, silver, iridium, and ruthenium. These metals may be a complex with platinum or an alloy. Furthermore, it may be a complex of these metals with an organic compound or an inorganic compound.

本発明の固体高分子型燃料電池用触媒は、塩化白金酸等の金属塩化物、金属硝酸塩、金属錯体を水や有機溶媒などの溶媒に溶解した上で、還元剤で還元して、白金を含む触媒活性成分を炭素担体に担持する（液相吸着する）方法で製造することができる。   The solid polymer fuel cell catalyst of the present invention is obtained by dissolving a metal chloride such as chloroplatinic acid, a metal nitrate, and a metal complex in a solvent such as water or an organic solvent, and then reducing the platinum with a reducing agent. It can be produced by a method in which the catalytically active component is supported on a carbon support (liquid phase adsorption).

触媒の粒子径分布の幅は、還元剤を希釈して添加して反応容器全体に均一に拡散させる、溶媒の割合を多くする、界面活性剤を特定の範囲で添加する等によって、狭くすることが可能である。溶媒の割合と界面活性剤の添加量によって、触媒の粒子径分布の幅を狭くする方法が、より再現性よく制御しやすい。溶媒、界面活性剤、還元剤の量は、粒子径分布に大きく影響を与える。   The catalyst particle size distribution width should be narrowed by diluting and adding the reducing agent to allow it to diffuse evenly throughout the reaction vessel, increasing the proportion of the solvent, adding a surfactant within a specific range, etc. Is possible. A method of narrowing the width of the particle size distribution of the catalyst depending on the ratio of the solvent and the amount of the surfactant added is easy to control with good reproducibility. The amount of the solvent, surfactant, and reducing agent greatly affects the particle size distribution.

溶媒量が少なすぎると粒子径が大きくなるので、粒子径のばらつき幅を表す指標であるＤ1/2(h/4)／Ｄ1/2(3h/4)は小さくなり、さらに、触媒粒子の凝集や保護剤被覆の程度を表す指標であるＤxrd／Ｄecが低下し、電池性能、特に、耐久性能が著しく低下する。 If the amount of the solvent is too small, the particle size becomes large, so that D 1/2 (h / 4) / D 1/2 (3h / 4), which is an index representing the variation width of the particle size, becomes small, and further, catalyst particles D xrd / D ec, which is an index indicating the degree of aggregation and protective agent coating, is reduced, and battery performance, particularly durability performance, is significantly reduced.

具体的には、溶媒中の金属前駆体のモル濃度が２０ｍｍｏｌ／Ｌ以下とするのが好ましい。   Specifically, the molar concentration of the metal precursor in the solvent is preferably 20 mmol / L or less.

還元剤としては、例えば、アルコール類、フェノール類、クエン酸類、ケトン類、アルデヒド類、カルボン酸類、エーテル類などが挙げられる。その際に、水酸化ナトリウムや塩酸などを加えてｐＨを調節し、さらに、粒子の凝集を妨げるために、ポリビニルピロリドンなどの界面活性剤を添加するのが好ましい。   Examples of the reducing agent include alcohols, phenols, citric acids, ketones, aldehydes, carboxylic acids, ethers and the like. At that time, it is preferable to add a surfactant such as polyvinyl pyrrolidone in order to adjust pH by adding sodium hydroxide, hydrochloric acid or the like and to prevent aggregation of particles.

還元剤の量が少なすぎると、還元の進行が遅れ、触媒が凝集しやすくなって、凝集の程度を表す指標であるＤxrd／Ｄecが低下して、電池性能と耐久性能が低下する。 If the amount of the reducing agent is too small, the progress of the reduction is delayed, the catalyst becomes easy aggregation is an index representing the degree of aggregation D xrd / D ec is lowered, the battery performance and durability is lowered.

還元剤の量は、金属前駆体に対するモル比で２以上とするのが好ましい。   The amount of the reducing agent is preferably 2 or more in terms of a molar ratio to the metal precursor.

界面活性剤の量が少なすぎると、粒子径分布の幅が大きくなり、電池性能、耐久性能ともに低下する。界面活性剤が多すぎると、粒子径が小さくなり、保護剤被覆の程度を表す指標であるＤxrd／Ｄecが低下して、電池性能と耐久性能が低下する。 If the amount of the surfactant is too small, the width of the particle size distribution becomes large, and both battery performance and durability performance are deteriorated. When the amount of the surfactant is too large, the particle size becomes small, and D xrd / D ec that is an index representing the degree of the protective agent coating is lowered, and the battery performance and the durability performance are lowered.

界面活性剤の量は、金属前駆体に対するモル比で０．２５以上６以下とするのが好ましい。   The amount of the surfactant is preferably from 0.25 to 6 in terms of a molar ratio to the metal precursor.

炭素担体に担持した触媒を、さらに、再還元処理してもよい。再還元処理の方法としては、還元雰囲気、又は、不活性雰囲気の中で、５００℃以下の温度で熱処理を施す方法がある。また、蒸留水中に触媒を分散し、アルコール類、フェノール類、クエン酸類、ケトン類、アルデヒド類、カルボン酸類及びエーテル類から選ばれる還元剤で再還元することもできる。   The catalyst supported on the carbon support may be further subjected to re-reduction treatment. As a method of the re-reduction treatment, there is a method of performing a heat treatment at a temperature of 500 ° C. or less in a reducing atmosphere or an inert atmosphere. Alternatively, the catalyst can be dispersed in distilled water and re-reduced with a reducing agent selected from alcohols, phenols, citric acids, ketones, aldehydes, carboxylic acids and ethers.

本発明の触媒は、電極の構成材料である電解質材料の種類や形態、電極構成に必要なバインダー材料の種類・構造がどのような場合であっても好適に使用でき、電極の構成材料を特に限定するものではない。   The catalyst of the present invention can be suitably used regardless of the type and form of the electrolyte material, which is a constituent material of the electrode, and the type and structure of the binder material necessary for the electrode configuration. It is not limited.

本発明に使用される電解質膜や、触媒層中に使用される電解質材料は、リン酸基、スルホン酸基等を導入した高分子、例えば、パーフルオロスルホン酸ポリマーやベンゼンスルホン酸が導入されたポリマー等を挙げることができる。   The electrolyte membrane used in the present invention or the electrolyte material used in the catalyst layer is a polymer in which a phosphoric acid group, a sulfonic acid group or the like is introduced, such as a perfluorosulfonic acid polymer or benzenesulfonic acid. A polymer etc. can be mentioned.

電解質材料は、高分子に限定するものではなく、無機系材料との複合化膜、無機−有機ハイブリッド系の電解質膜等を使用した燃料電池に使用しても差し支えない。特に好適な作動温度範囲を例示するならば、常温〜１５０℃の範囲内で作動する燃料電池が好ましい。   The electrolyte material is not limited to a polymer, and may be used for a fuel cell using a composite membrane with an inorganic material, an inorganic-organic hybrid electrolyte membrane, or the like. If a particularly preferable operating temperature range is exemplified, a fuel cell that operates within a range of room temperature to 150 ° C. is preferable.

本発明の触媒を用いた燃料電池用電極で、電解質膜を挟み、さらに、ガス拡散層、セパレーター、燃料ガス流路基板、酸素もしくは空気流路基板、ガスマニホールド等を組み合わせて固体高分子型燃料電池とすることができる。   A fuel cell electrode using the catalyst of the present invention, sandwiching an electrolyte membrane, and further combining a gas diffusion layer, a separator, a fuel gas flow path substrate, an oxygen or air flow path substrate, a gas manifold, etc. It can be a battery.

固体高分子型燃料電池用触媒を、以下の方法で作製した。   A polymer electrolyte fuel cell catalyst was produced by the following method.

蒸留水中に０．０３ｍｏｌ／Ｌの塩化白金酸水溶液、０．０３ｍｏｌ／Ｌの塩化コバルト水溶液、０．０３ｍｏｌ／Ｌの塩化クロム水溶液とポリビニルピロリドンを入れ、９０℃で攪拌しながら、水素化ホウ素ナトリウムを蒸留水１０ｍＬに溶かした上で注ぎ、上記金属塩を還元した。   Put 0.03 mol / L chloroplatinic acid aqueous solution, 0.03 mol / L cobalt chloride aqueous solution, 0.03 mol / L chromium chloride aqueous solution and polyvinylpyrrolidone in distilled water and stir at 90 ° C., while stirring sodium borohydride Was dissolved in 10 mL of distilled water and poured to reduce the metal salt.

次いで、その水溶液に触媒担体炭素材料を添加して６０分間撹拌し、その後、濾過、洗浄を行った。得られた固形物を９０℃で真空乾燥した後、粉砕して、続いて、２５０℃の水素雰囲気中で１時間熱処理を施して、触媒を作製した。   Next, the catalyst-supporting carbon material was added to the aqueous solution and stirred for 60 minutes, followed by filtration and washing. The obtained solid was vacuum-dried at 90 ° C. and then pulverized, followed by heat treatment in a hydrogen atmosphere at 250 ° C. for 1 hour to prepare a catalyst.

塩化白金酸量、塩化コバルト量、塩化クロム量、ポリビニルピロリドン量、水素化ホウ素ナトリウム量、触媒担体炭素材料量を表１のように変え、触媒Ｎｏ．１〜２３を得た。   The amounts of chloroplatinic acid, cobalt chloride, chromium chloride, polyvinylpyrrolidone, sodium borohydride, and catalyst carrier carbon material were changed as shown in Table 1, 1-23 were obtained.

得られた触媒Ｎｏ．１〜２３について、ＩＣＰ発光分析によって金属担持量を測定した結果と、ＸＲＤ測定によって触媒粒子径（半価幅から求めたＤxrd）と、ＸＲＤ測定によって求めたＤ1/2(h/4)／Ｄ1/2(3h/4)、さらに、ＸＲＤ測定と電気化学測定で求めた粒子径の比Ｄxrd／Ｄecを、表２に示す。 The resulting catalyst No. For 1 to 23, the result of measuring the metal loading by ICP emission analysis, the catalyst particle diameter (D xrd determined from the half-value width) by XRD measurement, and D 1/2 (h / 4) determined by XRD measurement / D 1/2 (3h / 4) , further, the ratio D xrd / D ec the particle diameter determined by XRD measurement and an electrochemical measurement, shown in Table 2.

触媒Ｎｏ．１〜２３を、それぞれ、アルゴン気流中で、５％ナフィオン溶液（アルドリッチ製）を触媒の質量に対してナフィオン固形分の質量が３倍になるように加え、軽く撹拌した後、超音波で触媒を粉砕し、白金触媒とナフィオンを合わせた固形分濃度が２質量％となるように撹拌しながら酢酸ブチルを加え、各触媒層スラリーを作製した。   Catalyst No. 1 to 23 were added in a stream of argon, 5% Nafion solution (manufactured by Aldrich) so that the mass of Nafion solids was 3 times the mass of the catalyst, and after stirring gently, the catalyst was ultrasonicated. Then, butyl acetate was added with stirring so that the solid content concentration of the platinum catalyst and Nafion was 2% by mass to prepare each catalyst layer slurry.

前記触媒層スラリーをそれぞれガス拡散層の片面にスプレー法で塗布し、８０℃のアルゴン気流中で１時間乾燥し、触媒Ｎｏ．１〜２３を触媒層に含有する固体高分子型燃料電池用電極を得た。   The catalyst layer slurry was applied to one side of each gas diffusion layer by a spray method and dried in an argon stream at 80 ° C. for 1 hour. A polymer electrolyte fuel cell electrode containing 1 to 23 in the catalyst layer was obtained.

それぞれの電極は、白金使用量が０．１０ｍｇ／ｃｍ２となるようにスプレー等の条件を設定した。白金使用量は、スプレー塗布前後の電極の乾燥質量を測定し、その差から求めた。 For each electrode, conditions such as spraying were set so that the amount of platinum used was 0.10 mg / cm 2 . The amount of platinum used was determined by measuring the dry mass of the electrode before and after spray coating and determining the difference.

さらに、得られた固体高分子型燃料電池用電極から、２．５ｃｍ角の大きさで２枚ずつ電極を切り取り、触媒層が電解質膜と接触するように同じ種類の電極２枚で電解質膜（ナフィオン１１２）をはさみ、１３０℃、９０ｋｇ／ｃｍ２で１０分間ホットプレスを施し、アノード及びカソードの触媒層をナフィオン膜に定着させた。 Further, from the obtained electrode for a polymer electrolyte fuel cell, two electrodes having a size of 2.5 cm square are cut out, and the electrolyte membrane (with two electrodes of the same type so that the catalyst layer is in contact with the electrolyte membrane ( The Nafion 112) was sandwiched and hot-pressed at 130 ° C. and 90 kg / cm 2 for 10 minutes to fix the anode and cathode catalyst layers to the Nafion membrane.

さらに、市販のカーボンクロス（ＥｌｅｃｔｒｏＣｈｅｍ社製ＥＣ−ＣＣ１−０６０）を２．５ｃｍ角の大きさに２枚切り取って、ナフィオン膜に定着させたアノードとカソードを挟むようにして１３０℃、５０ｋｇ／ｃｍ２で１０分間ホットプレスを施し、膜／電極接合体（Membrane Electrode Assembly，ＭＥＡ）２３種を作製した（表３のＭＥＡ Ｎｏ．１〜２３）。 Further, two commercially available carbon cloths (EC-CC1-060 manufactured by ElectroChem) were cut into 2.5 cm square sizes, and the anode and cathode fixed on the Nafion membrane were sandwiched at 130 ° C. and 50 kg / cm 2 . Hot pressing was performed for 10 minutes, and 23 types of membrane / electrode assemblies (Membrane Electrode Assembly, MEA) were produced (MEA Nos. 1 to 23 in Table 3).

作製した各ＭＥＡは、それぞれ燃料電池測定装置に組み込み、電池性能測定を行った。電池性能測定は、セル端子間電圧を開放電圧（通常０．９〜１．０Ｖ程度）から０．２Ｖまで段階的に変化させ、セル端子間電圧が０．８Ｖのときに流れる電流密度を測定した。   Each of the produced MEAs was incorporated in a fuel cell measurement device, and battery performance was measured. For battery performance measurement, the cell terminal voltage is changed stepwise from open voltage (usually about 0.9 to 1.0V) to 0.2V, and the current density that flows when the cell terminal voltage is 0.8V is measured. did.

また、耐久試験として、開放電圧に１５秒間保持、セル端子間電圧を０．５Ｖに１５秒間保持のサイクルを４０００回実施し、その後、耐久試験前と同様に電池性能を測定した。   Further, as an endurance test, a cycle of holding the open voltage for 15 seconds and holding the cell terminal voltage at 0.5 V for 15 seconds was performed 4000 times, and then the battery performance was measured as before the endurance test.

ガスは、カソードに空気、アノードに純水素を、利用率がそれぞれ５０％と８０％となるように供給し、それぞれのガス圧は、セルの下流に設けられた背圧弁で０．１ＭＰａに圧力調整した。セル温度は８０℃に設定し、供給する空気と純水素は、それぞれ７５℃と８０℃に保温された蒸留水中でバブリングし、加湿した。   The gas was supplied to the cathode with air and pure hydrogen to the anode so that the utilization rates would be 50% and 80%, respectively, and each gas pressure was reduced to 0.1 MPa by a back pressure valve provided downstream of the cell. It was adjusted. The cell temperature was set to 80 ° C., and the supplied air and pure hydrogen were bubbled and humidified in distilled water kept at 75 ° C. and 80 ° C., respectively.

表３に、各ＭＥＡの電池性能の測定結果と耐久試験後の電池性能を示す。本発明の触媒Ｎｏ．１〜９を用いたＭＥＡは、比較例の触媒Ｎｏ．１０〜２３を用いたＭＥＡに比べて優れた電池性能と耐久性を示した。実施例の中でも、触媒Ｎｏ．１〜４を用いたＭＥＡは、特に優れた電池性能と高い耐久性を示した。   Table 3 shows the measurement results of the battery performance of each MEA and the battery performance after the durability test. The catalyst no. MEAs using Nos. 1 to 9 are catalyst Nos. Of Comparative Examples. Excellent battery performance and durability compared to MEA using 10-23. Among the examples, catalyst no. MEAs using 1-4 showed particularly excellent battery performance and high durability.

このような優れた性能が発揮できるのは、本発明の製造方法によれば、触媒粒子の粒子径分布が狭く、均一分散しているためである。図１に、一例として、触媒Ｎｏ．４のＸ線回折測定で得られた白金の面心立方格子の（１１１）ピークを示す。   The reason why such excellent performance can be exhibited is that according to the production method of the present invention, the particle size distribution of the catalyst particles is narrow and uniformly dispersed. As an example, FIG. 4 shows a (111) peak of a platinum face-centered cubic lattice obtained by X-ray diffraction measurement of No. 4;

本実施例の結果から、本発明の触媒合成法においては、溶媒、界面活性剤、還元剤の量が粒子径分布に大きく影響を与えることが確認できた。   From the results of this Example, it was confirmed that in the catalyst synthesis method of the present invention, the amounts of the solvent, the surfactant and the reducing agent greatly affect the particle size distribution.

Figure 2012248365
Figure 2012248365

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本発明によれば、従来の触媒に比べて、高い触媒活性を持ち、耐久性に優れた固体高分子型燃料電池用触を得ることができる。本発明の触媒を用いた電極を固体高分子型燃料電池に使用すると、エネルギー密度が高い、コンパクトな燃料電池セルスタックが達成でき、携帯用コンピュータ、あるいは、移動用通信機器の電源としても実用できるサイズになる。さらに、高触媒活性であり、耐久性に優れるので、貴金属の使用量を低減でき、大幅な低コスト化を実現できるので、固体高分子型燃料電池の商業的な市場普及を加速することができ、産業上の利用性は大きい。   According to the present invention, it is possible to obtain a solid polymer fuel cell touch having high catalytic activity and excellent durability compared to conventional catalysts. When the electrode using the catalyst of the present invention is used in a polymer electrolyte fuel cell, a high energy density and compact fuel cell stack can be achieved, and it can be used as a power source for portable computers or mobile communication devices. It becomes size. In addition, because it has high catalytic activity and excellent durability, it can reduce the amount of precious metal used and achieve significant cost reductions, which can accelerate the commercial market penetration of polymer electrolyte fuel cells. Industrial applicability is great.

Claims (3)

炭素担体に、白金を含む触媒活性成分を担持した触媒であって、
上記触媒活性成分に含まれる白金を含む金属が、触媒活性成分を担持した炭素担体の全質量に対して、金属換算で１０〜８０質量％であり、
上記触媒のＸ線回折測定で得られた回折パターンからバックグラウンドを削除し、上記回折パターンにおける白金の面心立方格子の（１１１）ピークの高さに対する１／４高さでのピーク幅β1/4、及び、上記（１１１）ピークの高さに対する３／４高さでのピーク幅β3/4を求め、
上記（１１１）ピークをガウス関数とローレンツ関数の和と仮定して、上記β1/4、及び、β3/4からそれぞれ、上記（１１１）ピークの高さに対する１／２の高さでのピーク幅β'1/4、及び、β'3/4を算出し、
上記β'1/4、及び、β'3/4を用いて、Ｓｃｈｅｒｒｅｒの式でそれぞれ算出した白金の粒子径Ｄ1/2(h/4)、及び、Ｄ1/2(3h/4)の比Ｄ1/2(h/4)／Ｄ1/2(3h/4)が、０．９以上、１．１以下であり、かつ、
上記（１１１）ピークの半値幅を用いて、Ｓｃｈｅｒｒｅｒの式で算出した白金の粒子径Ｄxrdと、上記触媒の電気化学測定で得られた水素脱離波から見積もられる白金の粒子径Ｄecの比Ｄxrd／Ｄecが０．６以上、１．４以下である
ことを特徴とする固体高分子型燃料電池用触媒。 A catalyst in which a catalytically active component containing platinum is supported on a carbon support,
The metal containing platinum contained in the catalytically active component is 10 to 80% by mass in terms of metal with respect to the total mass of the carbon support carrying the catalytically active component,
The background is deleted from the diffraction pattern obtained by the X-ray diffraction measurement of the catalyst, and the peak width β 1 at a height of ¼ of the height of the (111) peak of the face-centered cubic lattice of platinum in the diffraction pattern. / 4 and the peak width β 3/4 at 3/4 height relative to the height of the (111) peak,
Assuming that the (111) peak is the sum of a Gaussian function and a Lorentz function, from the above β 1/4 and β 3/4 , the height at half the height of the (111) peak is Calculate the peak widths β ' 1/4 and β' 3/4 ,
Using β ′ 1/4 and β ′ 3/4 , the platinum particle diameters D 1/2 (h / 4) and D 1/2 (3h / 4) calculated by the Scherrer equation, respectively. The ratio D1 / 2 (h / 4) / D1 / 2 (3h / 4) is 0.9 or more and 1.1 or less, and
Using the full width at half maximum of the (111) peak, the platinum particle diameter D xrd calculated by the Scherrer equation and the platinum particle diameter D ec estimated from the hydrogen desorption wave obtained by the electrochemical measurement of the catalyst A catalyst for a polymer electrolyte fuel cell, wherein the ratio D xrd / D ec is 0.6 or more and 1.4 or less. 前記Ｄxrdが、３．０〜６．０ｎｍであることを特徴とする請求項１に記載の固体高分子型燃料電池用触媒。 2. The polymer electrolyte fuel cell catalyst according to claim 1, wherein the Dxrd is 3.0 to 6.0 nm. 前記触媒活性成分に含まれる白金を含む金属が、触媒活性成分を担持した炭素担体の全質量に対して、金属換算で、２０〜８０質量％であることを特徴とする請求項１又は２に記載の固体高分子型燃料電池用触媒。   The metal containing platinum contained in the catalytically active component is 20 to 80% by mass in terms of metal with respect to the total mass of the carbon support carrying the catalytically active component. The catalyst for a solid polymer fuel cell as described.
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015035356A (en) * 2013-08-09 2015-02-19 日産自動車株式会社 Electrode catalyst particle for fuel batteries, electrode catalyst for fuel batteries arranged by use thereof, electrolyte-electrode assembly, fuel battery, and methods for manufacturing catalyst particle and catalyst
KR20170044146A (en) 2014-10-24 2017-04-24 가부시키가이샤 캬타라 Fuel cell electrode catalyst and manufacturing method thereof
DE102018206378A1 (en) 2017-04-28 2018-10-31 Cataler Corporation Electrode catalyst for fuel cells and method for its production
WO2019177060A1 (en) 2018-03-16 2019-09-19 株式会社キャタラー Electrode catalyst for fuel cell, and fuel cell using same

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006016536A1 (en) * 2004-08-09 2006-02-16 Kabushikikaisha Equos Research Fuel cell
JP2009283254A (en) * 2008-05-21 2009-12-03 Nippon Steel Corp Catalyst for polymer electrolyte fuel cell
JP2010506822A (en) * 2006-10-18 2010-03-04 エージェンシー フォー サイエンス，テクノロジー アンド リサーチ Method for functionalizing carbon materials

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006016536A1 (en) * 2004-08-09 2006-02-16 Kabushikikaisha Equos Research Fuel cell
JP2010506822A (en) * 2006-10-18 2010-03-04 エージェンシー フォー サイエンス，テクノロジー アンド リサーチ Method for functionalizing carbon materials
JP2009283254A (en) * 2008-05-21 2009-12-03 Nippon Steel Corp Catalyst for polymer electrolyte fuel cell

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015035356A (en) * 2013-08-09 2015-02-19 日産自動車株式会社 Electrode catalyst particle for fuel batteries, electrode catalyst for fuel batteries arranged by use thereof, electrolyte-electrode assembly, fuel battery, and methods for manufacturing catalyst particle and catalyst
KR20170044146A (en) 2014-10-24 2017-04-24 가부시키가이샤 캬타라 Fuel cell electrode catalyst and manufacturing method thereof
US10950869B2 (en) 2014-10-24 2021-03-16 Cataler Corporation Fuel cell electrode catalyst and method for producing the same
DE102018206378A1 (en) 2017-04-28 2018-10-31 Cataler Corporation Electrode catalyst for fuel cells and method for its production
US11217796B2 (en) 2017-04-28 2022-01-04 Cataler Corporation Electrode catalyst for fuel cell and method of production of same
WO2019177060A1 (en) 2018-03-16 2019-09-19 株式会社キャタラー Electrode catalyst for fuel cell, and fuel cell using same
US11949113B2 (en) 2018-03-16 2024-04-02 Cataler Corporation Electrode catalyst for fuel cell, and fuel cell using same

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