JP2007027096A - Platinum for fuel cell and manufacturing method of platinum-ruthenium alloy catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a high-quality catalyst capable of reducing usage of expensive platinum and ruthenium and suitable for a fuel cell by using a simple method. <P>SOLUTION: Platinum nano-particles produced from platinum cations are reduced and implanted into carbon fine particles by gas bubbles by blowing gaseous hydrogen into an aqueous solution containing a platinum salt and the carbon fine particles. An aqueous solution with a ruthenium salt added therein can be used as well. Carbon black, carbon nanotubes or carbon nanohorns can be used for the carbon fine particles and the manufacturing process of this catalyst is extremely simple. The catalyst is high in catalyst activity because of having a structure where nano-particles of the platinum or platinum-ruthenium alloy low in impurity concentration and high in the degree of activity are highly dispersed on the surfaces of the carbon fine particles, and is used as a catalyst for improving power generation efficiency of a fuel cell even if a supported quantity thereof is small. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a platinum-based catalyst suitable for a fuel cell that is attracting attention as an on-site power source for mobile power sources and cogeneration systems of OA equipment, communication equipment, automobiles, and the like.

  Among various types of fuel cells, polymer electrolyte fuel cells are expected to be a movable or stationary electric energy source in various fields, starting with the power source of automobiles due to the advantages of starting and generating electricity even at low temperatures of about room temperature. . In a polymer electrolyte fuel cell, a catalyst electrode layer is formed on both sides of a polymer ion exchange membrane, and a membrane-electrode assembly sandwiched between porous carbon electrodes is used as a unit, and many membrane-electrode assemblies are stacked. Therefore, the electric power which can be practically used is taken out.

The performance of the fuel cell is greatly influenced by the catalyst used as the catalyst electrode layer. Improvement of catalyst performance is important not only for solid polymer type but also for other types of fuel cells.
A platinum catalyst for a fuel cell is usually produced by a dry method in which a carrier such as carbon black impregnated with a platinum salt-containing liquid is sintered at a high temperature and further reduced with a high-temperature hydrogen stream. In the dry method, the aggregation of platinum particles proceeds at the time of firing, and the specific surface area and thus the catalytic activity tends to decrease. It is also a drawback of the dry method that surface contamination tends to proceed when the catalyst is taken out from a vacuum or reduced pressure atmosphere to an air atmosphere.

Therefore, a method of depositing colloidal platinum on the support surface from a solution containing a metal salt, an organic reducing agent, and a carrier (Patent Document 1), adding a reducing agent to an aqueous dispersion of carbon powder and platinum complex to convert platinum particles into carbon powder. Various wet methods for producing a high-performance catalyst, such as a method for supporting the catalyst on the substrate (Patent Document 2), have been proposed. It is also known that alloy colloidal particles are supported on a powder such as carbon black or activated carbon by blowing hydrogen gas into a solution containing a colloidal metal oxide (Patent Document 3).
JP 2003-320249 A JP 2004-335252 A JP 2002-248350 A

In the method in which platinum particles are supported by reduction of the platinum complex, it is difficult to uniformly deposit platinum particles on fine particles such as carbon black, and as a result, quality stability tends to be lacking. Further performance improvement is required to satisfy the required characteristics as a fuel cell catalyst.
Even in the wet method in which the metal salt of the aqueous solution is reduced to the metal colloid, in order to remove the surfactant molecules from the surface of the generated metal colloid, the aqueous solution containing the support material and the metal salt is separated by filtration, vacuum-sintered, and hydrogen atmosphere It is common to reduce below.

This method involves complicated steps such as sedimentation, filtration, sintering, and reduction, so that the production cost of the electrode catalyst increases. Another disadvantage is that the catalyst particles aggregate during the treatment at high temperature to lower the specific surface area, and when the catalyst is released from vacuum or hydrogen atmosphere to the atmosphere, the catalyst surface is contaminated and the reaction efficiency is lowered.
Even in the method using hydrogen gas blowing (Patent Document 3), the step of forming a colloidal metal oxide by adding an oxidizing agent to a solution containing a plurality of types of metal salts, the colloidal metal oxide reduced colloidal metal oxide A step of supporting the carrier is necessary.

The present inventors have conducted various investigations on platinum deposition methods on the assumption that the crystallinity, distribution state, and surface contamination of platinum deposited on the surface of fine particles of carbon black and the like have a great influence on the quality stability of the catalyst. ·investigated. As a result, it has been found that platinum nanoparticles having good crystallinity and distribution state are supported on the carbon fine particles by a simple operation in which hydrogen gas is directly blown into a solution containing platinum salts and carbon fine particles. In a solution containing ruthenium salt in addition to platinum salt and carbon fine particles, cluster metal platinum and metal ruthenium are generated by blowing hydrogen gas, and are supported on carbon fine particles as platinum ruthenium alloy nanoparticles instead of individual metal nanoparticles. Is done.
Based on this knowledge, the present invention is a very simple method for producing a high-quality catalyst capable of generating a large power generation performance of 30% or more even if the amount of platinum supported is about half that of a conventional catalyst and improving CO resistance. The purpose is to manufacture with.

  In the production method of the present invention, hydrogen gas is blown into an aqueous solution containing platinum salt and carbon fine particles, platinum nanoparticles generated from platinum cations by direct reduction reaction with hydrogen gas are reduced and implanted onto the carbon fine particles, and platinum is deposited. The carbon fine particles are separated by filtration. An aqueous solution containing a ruthenium cation in addition to the platinum cation can also be used. In this case, the platinum ruthenium alloy nanoparticles are reduced and deposited on the carbon fine particles. Prior to the reduction treatment by blowing hydrogen gas, it is preferable to blow in an inert gas such as argon or nitrogen into the aqueous solution to remove dissolved oxygen in the aqueous solution.

  One or more of platinum (II) chloride, hexachloroplatinic (IV) acid, potassium tetrachloroplatinum (II) and potassium hexachloroplatinum (IV) are used as the platinum salt as the source of the platinum cation. The Ruthenium salts include ruthenium (III) chloride. Carbon fine particles include carbon black, carbon nanotube, carbon nanohorn, and the like.

Effects and embodiments of the invention

  In the present invention, platinum cations are directly reduced by hydrogen by bubbling a solution containing platinum salt and carbon fine particles with hydrogen gas. The platinum metal produced by the reduction reaction floats in the form of atoms or metal clusters in the solution, but is attracted to and captured by the carbon fine particles suspended in the solution. Since the formation of metallic platinum and the capture by carbon fine particles are repeated, the carbon fine particles as nanoparticles with a large specific surface area (in other words, a highly dispersed state with high catalytic activity) without growing into a large particle size. It is carried on. It is also considered that the platinum supported on the carbon fine particles is hydrated with water molecules (solvent) and a repulsive force is generated between the solvated nanoparticles to suppress the growth of the platinum nanoparticles.

  Even when a ruthenium salt is used in addition to platinum salt and carbon fine particles, the ruthenium cation is directly reduced to a metallic state by blowing hydrogen gas, and is captured by the carbon fine particles in the same manner as the platinum nanoparticles. Since the ruthenium nanoparticles in the metal state are deposited on the carbon fine particles while maintaining a solid solution state mixed with the platinum nanoparticles at the atomic level, a platinum ruthenium alloy is obtained. In this case as well, a repulsive force is generated between the solvated particles, so that the platinum ruthenium alloy is deposited on the carbon fine particles as nanoparticles without growing greatly. Since ruthenium and platinum atoms have similar atomic sizes, they can achieve a complete solid solution state in which they are completely mixed without any regular arrangement, and become a catalyst excellent in carbon monoxide CO resistance.

When an aqueous solution containing platinum salt, ruthenium salt, and carbon fine particles is bubbled with hydrogen gas, platinum and ruthenium are deposited on the carbon fine particles in a state where platinum and ruthenium are mixed at an atomic level, thereby forming platinum ruthenium alloy nanoparticles. Similar platinum ruthenium alloy nanoparticles are formed even when platinum and ruthenium are successively deposited on carbon fine particles with a time shift instead of an aqueous solution in which platinum salt and ruthenium salt coexist. Specifically, after the reductive implantation of K ₂ PtCl ₄ , RuCl ₃ is introduced into the aqueous solution and the ruthenium is reductively implanted, or the ruthenium and platinum are reductively implanted in the reverse order, A catalyst in which nanoparticles of the same platinum ruthenium alloy are supported on carbon fine particles can be obtained.

As the platinum salt, platinum acid or platinum salt such as PtCl ₂ , K ₂ PtCl ₆ , H ₂ PtCl ₆ can be used, and among them, chloroplatinic acid or its alkali salt is preferable. Ruthenium salts include RuCl ₃ .

  As the carbon fine particles, carbon black such as Vulcan and Ketjen, carbon nanohorn, carbon nanotube and the like are used. The carbon fine particles can be dispersed in an aqueous solution as they are without requiring an activation treatment such as a Pd treatment. Among these, carbon black is suitable as a supporting material because a large number of surface oxides such as CO and COOH are exposed on the surface of fine particles, and a surface state in which nanoparticles of platinum or platinum ruthenium alloy are easily attached. .

  An aqueous solution is prepared by dispersing platinum salt, ruthenium salt and carbon fine particles in pure water, but the concentrations of platinum cation, ruthenium cation and carbon fine particles are not particularly limited. However, excessive addition of platinum salt, ruthenium salt, and carbon fine particles is not preferable because the reduction reaction caused by blowing hydrogen gas is difficult to proceed. In order to deposit an appropriate amount of platinum and ruthenium on the carbon fine particles, addition of a platinum salt or ruthenium salt that is too small or excessive in comparison with the amount of carbon fine particles should be avoided.

  Specifically, the total amount of platinum salt and ruthenium salt added to 100 ml of pure water is 10 to 100 mg, the amount of carbon fine particles added is 10 to 90 mg, (platinum salt + ruthenium salt): the mass ratio of carbon fine particles is 1: Select within the range of (1-9). The composition of the platinum ruthenium alloy can be adjusted by the ratio of platinum salt and ruthenium salt added to pure water. A platinum ruthenium alloy of Pt: Ru = 1: 1 (mass ratio) is preferable for satisfying the required characteristics of the catalyst for fuel cells, and the mass ratio of platinum salt: ruthenium salt is 1: (1-9) according to the target composition. Select within the range.

  Pure water used as a solvent is pure water obtained by repeated distillation or ultrapure water of Mili-Q (18.3 MΩ). Unlike ordinary distilled water or industrial water, pure water or ultrapure water does not contain extra cations, anions, or organic molecules, but carbon dioxide is usually dissolved. Since carbon dioxide gas does not adversely affect the reduction reaction of the platinum salt, there is no problem even if it is not removed. Since it contains carbonic acid, it becomes a slightly acidic solution (pH 6.0 to 6.5), but any neutral, weakly acidic, or weakly alkaline solution can be used as long as the pH is not low or high, which adversely affects the reduction efficiency. is there.

  The aqueous solution containing platinum salt, ruthenium salt, and carbon fine particles is preferably purged with Ar prior to blowing hydrogen gas. Oxygen is dissolved in the aqueous solution. When hydrogen gas is blown into such an aqueous solution and the reduction treatment is performed, the surface of platinum or platinum ruthenium alloy nanoparticles generated by the reduction reaction is contaminated with dissolved oxygen, and the catalytic activity is reduced. Concerned. Contamination of nanoparticles by dissolved oxygen is prevented by removing oxygen dissolved in the aqueous solution by blowing argon gas.

  When hydrogen gas is blown into an aqueous solution containing platinum salt, ruthenium salt, and carbon fine particles, platinum or platinum ruthenium alloy nanoparticles generated by the reduction reaction of the platinum cation and ruthenium cation are deposited on the surface of the carbon fine particles. Since the reduction reaction proceeds in an Ar purged aqueous solution, the produced nanoparticles are kept clean without being contaminated. Further, since the platinum cation and ruthenium cation hydrated in the aqueous solution are directly reduced by hydrogen molecules, the reduction reaction itself easily proceeds.

  The rate at which platinum cations and ruthenium cations are reduced to a metallic state is determined by the frequency of hydrogen molecules colliding with platinum cations and ruthenium cations in an aqueous solution. Little affected by time, blowing speed, liquid temperature, etc. After the hydrogen gas is blown, the aqueous solution may be mechanically stirred for about half a day to advance the nanoparticle implantation. Since collision between hydrogen molecules and platinum cations and ruthenium cations can be expected during stirring, the reduction efficiency to platinum or platinum ruthenium alloy nanoparticles is increased.

  The carbon fine particles on which the platinum or platinum ruthenium alloy nanoparticles are deposited are separated from the aqueous solution by filtration using a glass filter. By washing the obtained platinum or platinum-ruthenium alloy-supported carbon with ultrapure water, a highly pure catalyst (platinum or platinum-ruthenium alloy nanoparticles supported on carbon fine particles) can be obtained. The washed catalyst is dried at a relatively low temperature, but if the drying temperature is too high, the platinum nanoparticles may be fused and grown into particles having a small specific surface area, so the upper limit of the heating temperature is set to 150 ° C. Specifically, drying by heating in the range of 80 to 100 ° C. for 1 hour or more is preferable.

Observation of the dried catalyst by TEM shows that platinum or platinum ruthenium alloy nanoparticles having a particle size of about 2 to 5 nm are highly dispersed on the surface of the carbon fine particles. Platinum or platinum ruthenium alloy nanoparticles have a large specific surface area of 100 to ²⁰⁰ cm ² / mg, and the distance between metal atoms is also reduced.
The shortening of the distance between metal atoms is a unique phenomenon found in platinum or platinum ruthenium alloy catalysts by the hydrogen gas bubble method, which means that the density of metal atoms is increased, and thus contributes to the improvement of the catalyst activity.

In addition to the small particle size of nanometer size, the synthesized catalyst has a large specific surface area and a short interatomic distance. Therefore, as will be apparent from the examples described later, the catalyst has much superior catalytic activity compared to conventional catalysts. Present. The fact that a high-performance catalyst can be obtained by simply operating a platinum salt, ruthenium salt, or carbon fine particle-containing solution simply by bubbling hydrogen gas is an effect that cannot be predicted from the conventional method, and for simplifying the manufacturing process and reducing catalyst costs. Very advantageous.
In addition, the amount of expensive platinum and ruthenium used can be reduced to less than half that of the conventional method without impairing the power generation performance, and even if the carbon monoxide CO concentration as an impurity contained in fuel hydrogen is as high as 500 ppm, the power generation performance is high. It exhibits excellent performance that is not comparable to conventional catalysts, such as no deterioration.

-Production of platinum catalyst-
K ₂ PtCl ₄ : 20 mg, carbon black (primary particle size: 40 to 60 nm): 28 mg was added to ultrapure water: 100 ml and stirred to prepare an aqueous solution containing platinum salt and carbon fine particles.
After argon gas was blown into the aqueous solution at a flow rate of about 0.05 liter / min for 20 minutes, the aqueous solution was kept at room temperature, and hydrogen gas was blown at a flow rate of about 0.2 liter / min. Hydrogen gas blowing was continued for 5 minutes, and then the aqueous solution was allowed to stand for 14 hours. Next, carbon fine particles carrying platinum nanoparticles were separated from the aqueous solution by filtration using a glass filter. The platinum-supported carbon fine particles were heated and dried at 80 ° C. for 3 hours to obtain a platinum catalyst with a platinum yield of 98% by mass.

When the obtained platinum catalyst was observed with a TEM, it was found that platinum nanoparticles having a particle size of about 5 nm were adhered on the carbon black (FIG. 1). As a result of mass spectrometry, the supported amount of platinum nanoparticles was 25% by mass. The specific surface area of the platinum nanoparticles estimated from the potential-current curve was 100 to ²⁰⁰ cm ² / mg, which was about half that of a commercially available platinum catalyst.

-Production of platinum ruthenium alloy catalyst-
K ₂ PtCl ₄ : 18 mg, RuCl ₃ : 9 mg, carbon black (primary particle size: 40-60 nm): 20 mg is added to ultrapure water: 100 ml and stirred to obtain an aqueous solution containing platinum salt, ruthenium salt and carbon fine particles. Was prepared.
The aqueous solution was stirred for 30 minutes while purging with Ar, and then hydrogen gas was blown at a flow rate of 0.2 liter / minute, followed by mechanical stirring for 12 hours. Next, the aqueous solution was filtered, and the carbon fine particles carrying platinum ruthenium alloy nanoparticles were separated from the aqueous solution and dried at 80 ° C. for 3 hours.
The platinum ruthenium alloy catalyst is also highly dispersed in carbon fine particles with a platinum ruthenium alloy (Ru: 50% by mass) nanoparticles (average particle size: 2 nm, specific surface area: 100-200 cm ² / mg) at a supported amount of 36% by mass. It was.

A membrane-electrode assembly was prepared by hot pressing a platinum catalyst together with a fluororesin (Nafion 112) and set in a polymer electrolyte fuel cell. Hydrogen gas: 1.4 liters / minute was sent to the fuel electrode side of the fuel cell heated to 80 ° C., and oxygen gas: 2.6 liters / minute was sent to the oxygen electrode side, and the generated power was measured.
As can be seen from the measurement results in FIG. 2, the power density was as high as 1.24 W / cm ² and the voltage drop accompanying the current rise was slow.

In FIG. 2, the _{K 2 PtCl 6, H 2 PtCl} 4, PtCl 2 with the platinum salt in addition to K ₂ PtCl _4, showing together the power generation performance of the synthesized platinum catalyst in the same manner. Although K ₂ PtCl ₄ shows the best results, it can be seen that the reduction treatment by blowing hydrogen gas can be sufficiently applied to platinum salts such as K ₂ PtCl ₆ , H ₂ PtCl ₄ , and PtCl ₂ .
The membrane-electrode assembly using a catalyst in which platinum ruthenium alloy nanoparticles were supported on carbon fine particles also showed a high power density of 0.82 W / cm ^2, and the voltage drop accompanying the current rise was slow.

In a catalyst in which platinum or platinum ruthenium alloy nanoparticles are reduced and implanted into carbon fine particles with hydrogen gas bubbles, the distance between metal atoms is about 0.4% shorter than that of a catalyst produced by other methods. The distance d _hkl between the metal atomic planes is the Bragg equation (2d _hkl sinθ = λ, λ is the wavelength of the X-ray used, from the value of the diffraction angle 2θ in the X-ray diffraction results (FIGS. 3 and 4). (λ = 0.15418 nm).

Comparing the (111) plane spacing of the platinum catalyst, 0.2266 nm for the commercially available catalyst (particle size: 3 nm, supported amount: 50% by mass) and 0.2257 nm for the electroless catalyst (particle size: 8 nm, supported amount: 50% by mass) In contrast, the platinum catalyst I of the present invention (particle size: 4 nm, supported amount: 24% by mass) was 0.2260 nm, and the platinum catalyst II (particle size: 1 nm, supported amount: 1% by mass) was 0.2252 nm. (Figure 3)
The platinum ruthenium alloy catalyst is 0.2267 nm for a commercially available catalyst (particle size: 4 nm), 0.2262 nm for electroless Pt → Ru catalyst I (particle size: 5 nm), and 0.2260 nm for electroless Pt → Ru catalyst II (particle size: 6 nm). In contrast to nm, the catalyst III of the present invention (particle size: 2 nm) had a (111) plane spacing of 0.2254 nm. (Fig. 4)

The difference in the distance between metal atoms is on the order of 0.001 nm with the (111) plane spacing, but it appears as a clear significant difference in high-precision measurements. The distance between the contracted metal atoms (distance between crystal lattice planes) does not contaminate the metal surface during the catalyst production process, so the surface is reconstructed (the arrangement of the surface atoms that are unsaturated bonds changes to a more stable structure). This is the result of smooth progress. In a commercially available catalyst manufactured by a method other than wet, surface contamination such as oxidation is unavoidable and the distance between crystal lattice planes is not shortened.
As the crystal lattice shrinks, the electron density of metal atoms increases. In particular, in the case of a platinum ruthenium alloy catalyst (FIG. 4), the effect of hydrogen gas bubbles on shortening the distance between metal atoms is remarkable. The increase in electron density brings about a dramatic improvement in oxygen reduction capacity and contributes to the improvement of power generation performance (FIG. 2).

  In addition, when investigating the effects of solvent type and Ar purge on catalyst performance, platinum catalyst and Mili-Q (18.3MΩ) ultrapure water added with platinum salt and carbon black was bubbled with hydrogen gas after Ar purge. The best results were obtained (Figure 5). The results in FIG. 5 indicate that the smaller the impurities in the aqueous solution containing platinum salt and carbon fine particles, the higher the output of the platinum catalyst when used as a fuel cell catalyst. Even with a platinum ruthenium alloy catalyst, a better result is obtained with an aqueous solution having fewer impurities.

  The amount of platinum supported can be adjusted by the concentration of platinum in the aqueous solution and the ratio of platinum concentration / carbon fine particles, but the highest output was obtained when the amount of platinum supported was 25% by mass (FIG. 6). When the amount of platinum supported was too much or too little with 25 mass% as a boundary, the output tended to decrease. Furthermore, when investigating the power generation performance of a fuel cell using a catalyst with a platinum loading of 25% by mass in about half the amount of a commercially available catalyst, it showed a power generation performance superior to that of a commercially available catalyst even with about half the amount used ( Fig. 7).

With the platinum ruthenium alloy catalyst, the highest output was obtained with a catalyst carrying 36 mass% of an alloy of Pt-50 mass% Ru. Moreover, when the relationship between the purity of the hydrogen fuel fed into the fuel cell and the power generation performance was investigated, the output was not significantly reduced even when the impurity CO contained in the hydrogen fuel exceeded 500 ppm (Fig. 8). That is, the platinum ruthenium alloy catalyst is a high CO-tolerant catalyst that does not affect the battery output even if the hydrogen fuel contains carbon monoxide at a concentration of about 500 ppm. Excellent CO resistance is a highly dispersed state in which ruthenium is present around each platinum atom, so that the impurity CO is selectively reduced and removed to CO ₂ by ruthenium, and an active surface free from contaminating CO is maintained constantly. Due to that.

On the other hand, in the case of a commercially available catalyst, the power generation performance was extremely lowered when the impurity CO concentration was 500 ppm or more.
The fact that the power generation efficiency of a fuel cell that consumes hydrogen fuel containing impurity CO does not decrease is not only suitable for a fuel cell using platinum ruthenium alloy nanoparticles as a catalyst, but also for general hydrogen reformed gas. This means that an inexpensive gas fuel can be used without requiring a gas purification (CO gas removal) process.

  As described above, according to the present invention, a catalyst in which platinum or platinum ruthenium alloy nanoparticles are reduced and precipitated can be obtained by a simple operation of simply bubbling a hydrogen gas bubble of an aqueous solution containing platinum salt, ruthenium salt and carbon fine particles. This catalyst has a structure in which platinum or platinum ruthenium alloy nanoparticles are deposited on the surface of carbon fine particles with an extremely high specific surface area, and a fuel cell with high power generation efficiency that cannot be achieved by conventional catalysts is constructed. In addition, the amount of expensive platinum and ruthenium used can be reduced, and long-time reduction and high-temperature heating are not required, so that a high-quality catalyst is produced at a low production cost. Furthermore, a platinum ruthenium alloy catalyst having excellent CO resistance maintains sufficient catalytic activity even in a fuel cell using hydrogen gas containing some impurities CO.

TEM image of platinum-supported carbon fine particles synthesized in Examples Graph comparing power generation performance according to the type of platinum salt Graph showing that the platinum catalyst is X-ray diffracted (λ: 0.15418 nm) and the angle of f.c.c. (111) reflection varies depending on the type of platinum catalyst. Graph showing that the platinum ruthenium alloy catalyst is X-ray diffracted (λ: 0.15418 nm) and the angle of f.c.c. (111) reflection varies depending on the type of platinum ruthenium alloy catalyst. Graph showing the effect of pure water type and Ar purge on power generation performance Graph showing the effect of platinum loading on power generation performance A graph comparing the power generation performance of the catalyst prepared in the example and a commercially available catalyst A graph comparing the CO resistance of platinum ruthenium alloy catalysts produced by the hydrogen gas bubble method with commercial catalysts

Claims (7)

  Hydrogen gas is blown into an aqueous solution containing platinum salt and carbon fine particles, platinum nanoparticles generated from platinum cations by direct reduction reaction with hydrogen gas are reduced and deposited onto carbon fine particles, and the carbon fine particles on which platinum nanoparticles have been deposited are filtered out. A method for producing a platinum catalyst for a fuel cell.   Platinum ruthenium alloy nano particles are formed by reducing and implanting platinum ruthenium alloy nanoparticles generated from platinum cations and ruthenium cations by direct reduction reaction with hydrogen gas into carbon particles. A method for producing a platinum ruthenium alloy catalyst for a fuel cell, comprising filtering carbon fine particles on which the particles are deposited.   The production method according to claim 1 or 2, wherein one or more of platinum (II) chloride, hexachloroplatinic (IV) acid, potassium tetrachloroplatinum (II) and potassium hexachloroplatinum (IV) are used as a platinum cation source. .   The process according to claim 2, wherein ruthenium (III) chloride is used as a ruthenium cation source.   The production method according to claim 1 or 2, wherein one or more of carbon black, carbon nanotube, and carbon nanohorn are used for the carbon fine particles.   The manufacturing method according to claim 1 or 2, wherein an inert gas is blown into the aqueous solution to remove impurities prior to blowing hydrogen gas.   The production method according to claim 1 or 2, wherein the carbon fine particles on which platinum or platinum ruthenium alloy nanoparticles are deposited are filtered and dried at a temperature of 150 ° C or lower.