KR101117066B1 - Synthesis method of Pt alloy/supporter catalysts, catalysts and fuel cell using the same - Google Patents

Abstract

The present invention relates to a method for preparing a platinum alloy / carrier catalyst, comprising the steps of (a) dissolving a water-soluble salt and urea of a metal having catalytic activity in water, dispersing a carrier to prepare a dispersion solution, and (b) the (a) stirring the dispersion solution at a high temperature to precipitate the metal hydroxide particles on the surface of the carrier, and (c) reducing the carrier on which the metal hydroxide particles are precipitated, and the particle size of the alloy catalyst particles And particle size distribution is greatly improved by the use of urea.

In the method for preparing the platinum alloy / carrier catalyst of the present invention, the production of hydroxide ions occurs in a dispersion solution by hydrolysis of urea, and the hydroxide ions and metal salts supplied in a homogeneous phase react with the metal salt to precipitate the catalyst material on the carrier. Platinum alloys of small size and uniform in size distribution can be introduced into the carrier. Due to these features, when the platinum alloy / carrier catalyst of the present invention is used as an electrode catalyst of a fuel cell, it is a catalyst for fuel oxidation reaction of fuels such as methanol and hydrogen and fuel cell polarization performance of the fuel cell. The activity can be greatly increased. In addition, low-cost urea is used as a sedimentation reagent without using expensive surfactants or complex surfactants for the uniform dispersion of catalyst particles such as NaBH _4. It is environmentally friendly and competitive in price.

Description

Synthesis method of Pt alloy / supporter catalysts, catalysts and fuel cell using the same}

The present invention relates to a method for producing a platinum alloy / carrier catalyst, and more particularly, to a method for preparing a platinum alloy / carrier catalyst having improved catalytic activity by improving the particle size and dispersion of the platinum alloy.

Carbon and metal oxides carrying metal nanoparticles have been studied as catalysts and adsorbents for various organic and electrochemical reactions such as epoxy reaction, Heck reaction, fuel cell oxidation, reduction reaction, lithium ion battery and hydrogen storage. In particular, in the case of fuel cells, fuel cells are the next-generation environmentally friendly energy sources. Unlike ordinary batteries, they do not require battery replacement or charging. Instead, fuel cells, such as hydrogen or methanol, are used to supply chemical energy through electrochemical reactions. It is a device that converts energy. Fuel cells have recently been attracting attention as an alternative to eco-friendly vehicles, and in addition, research is being actively conducted as it is likely to be commercialized as a power supply source used in houses or portable devices. The electrode performance of the fuel cell is greatly influenced by the chemical composition, size, distribution, and stability of the electrode catalyst nanoparticles responsible for the oxidation and reduction reactions at the electrode, and also the diffusion of the reactants into the catalyst layer and the discharge of reaction products. It is also greatly influenced by the ease of mass transfer, which is related to the reaction surface area, pore structure, distribution and connectivity of the catalyst layer.

In particular, proton exchange membranes (PEMs) or polymer electrolyte membranes (PEMs) fuel cells are attracting attention as energy sources for automobiles and transportation that require greater power. The principle of the PEM fuel cell is as follows. The fuel cell includes a fuel electrode, an oxygen electrode, and a polymer electrolyte membrane that physically separates them. Hydrogen or alcohols such as ethanol and methanol are supplied to the fuel electrode, and oxygen is supplied to the oxygen electrode. When the electric wires are respectively connected to the fuel electrode and the oxygen electrode (for example, by connecting an external power consumption circuit), the operation of the fuel cell is started. Recently, technology development related to direct methanol fuel cell (DMFC), a kind of PEM fuel cell, has been actively conducted and is expected to be commercialized. However, there are some problems to be solved in order to commercialize the direct methanol fuel cell, and one of them is the high production cost of the fuel cell due to the use of a catalyst based on platinum. In order to solve this problem, efforts have been made to reduce the consumption of platinum by improving the activity of the catalyst.

In general, it is known that the activity of a catalyst supported on a carrier depends largely on the size and dispersion of the metal particles. In order to keep the particle size of the supported platinum or platinum-ruthenium alloy small and improve the degree of dispersion, various methods such as impregnation reduction, colloidal method, microemulsion, ion exchange method, etc. Methods of synthesis of catalysts have been developed. However, most of them fail to properly control the particle size and distribution, have the disadvantage of being a complicated and time-consuming process, and even have the problem of being inefficient in removing residual protective materials. Looking at the representative method for producing a catalyst used in the proton exchange membrane fuel cell in more detail as follows.

The impregnation-reduction method reduces metal precursors in a mixture of a precursor solution of platinum or other metals with a carbon carrier to deposit each metal on the carbon carrier, or first reduce the active metal precursor and impregnate the metal prior to impregnation on the carbon carrier. Deposited metal is deposited on a carbon carrier. At this time, NaBH ₄ , HCHO, HCOOH, HCOONa, N ₂ H ₄ and the like are used as the reducing agent. The related art discloses a method for preparing a PtRuPd / C catalyst using Na ₂ S ₂ O ₃ as a reducing agent.

The colloidal method is a method of preparing a colloidal metal oxide, depositing it on a carbon carrier, and obtaining a catalyst through various other reduction treatments. A related prior art document converts chloroplatinic acid to Na ₆ [Pt (SO ₃ ) ₄ ] and then converts Na ⁺ of Na ₆ [Pt (SO ₃ ) ₄ ] to H ⁺ via ion exchange, _{A method is} disclosed in which ₆ [Pt (SO ₃ ) ₄ ] is heated to separate SO ₃ ^2- and then dried to finally obtain platinum oxide on the colloid. This black colloid can be easily deposited on the carrier by dispersing in water or other solvents. Another prior document has prepared a PtRu / C catalyst using the colloidal method, by converting chloroplatinic acid to Na ₆ [Pt (SO ₃ ) ₄ ] and adding excess H ₂ O ₂ to Na ₆ [Pt (SO ₃ ) ₄ ] is decomposed to a stable colloidal platinum oxide, and a ruthenium compound such as RuCl ₃ is added to the platinum oxide colloid, followed by oxidation of ruthenium with ruthenium oxide, interaction with platinum oxide and the formation of metal clusters. A method is then disclosed for depositing clusters on a carrier and reducing this metal to hydrogen.

Another method is the Bonnemann method, the related literature discloses a method for producing a proton exchange membrane fuel cell electrode catalyst, saturated C ₅ -C ₁₀ hydrocarbons, aromatic hydrocarbons, ethers, esters and ketones, More specifically, a process for preparing a PtRh / C catalyst in n-pentane, hexane, benzene, toluene, THF, diethyl ether acetone, ethyl acetate or mixtures thereof is disclosed.

The above methods can show a relatively small and uniform distribution of catalyst nanoparticles under low loading conditions of 20 to 30% by weight, but when the loading rate is increased, there is a problem in that satisfactory results are not shown in size and distribution. have. In addition, since the synthesis is mainly performed at a high temperature and the solvent used is expensive, there is a problem of an increase in manufacturing cost and environmental pollution, and a complicated manufacturing process consumes a lot of time, and especially in the case of having a high metal loading, control and uniformity of size It is difficult to control the ship. Therefore, in order to improve the physical properties of the catalyst, it is necessary to develop a stable, easy and efficient method for synthesizing a catalyst capable of producing uniformly dispersed platinum or platinum-ruthenium alloy nanoparticles that can be uniformly dispersed and supported in a stoichiometric manner. Is growing.

Accordingly, the first problem to be solved by the present invention is to provide a method for producing a platinum alloy / carrier catalyst having a small catalyst size and uniform dispersion degree of catalyst activity, high environmental activity and simple process. will be.

The second problem to be solved by the present invention is to provide a platinum alloy / carrier catalyst prepared by the above production method.

The third problem to be solved by the present invention is to provide a fuel cell comprising the platinum alloy / carrier catalyst.

In order to achieve the first object, the present invention comprises the steps of dissolving a water-soluble salt and urea of a metal having catalytic activity in water, dispersing a carrier to prepare a dispersion solution, and (b) the step (a) It provides a method of producing a platinum alloy / carrier catalyst comprising the step of stirring the dispersion solution at a high temperature to precipitate the metal hydroxide particles on the surface of the carrier, and (c) reducing the carrier on which the metal hydroxide particles are precipitated.

According to an embodiment of the present invention, the step (a) is a step of preparing a metal-urea solution by dissolving a water-soluble salt and urea of the metal having catalytic activity in water, preparing a carrier dispersion in which the carrier is dispersed in a dispersion. And mixing the metal-urea solution and the carrier dispersion, wherein the carrier dispersion can be adjusted to pH with a predetermined acidity by adding sodium hydroxide.

According to another embodiment of the present invention, the acidity of the dispersion solution prepared in step (a) is preferably in the range of pH 5 to pH 12.

According to another embodiment of the present invention, in the step (a), urea is preferably added in an amount of 5 to 200 times the number of moles of the water-soluble salt of the metal.

According to another embodiment of the present invention, the step (a) comprises the steps of preparing a metal salt aqueous solution by dissolving a water-soluble salt of a metal having catalytic activity in water, and preparing a urea aqueous solution by dissolving urea in water. And, mixing the aqueous metal salt solution and the urea solution, and dispersing the carrier in the mixed solution of the aqueous metal salt solution and the urea solution.

According to another embodiment of the present invention, the water-soluble salt of the metal is platinum, ruthenium, rhodium, molybdenum, osmium, iridium, rhenium, palladium, vanadium, tungsten, cobalt, iron, selenium, nickel, bismuth, tin, It may include at least one metal selected from the group consisting of chromium, copper, titanium, gold and cerium.

According to another embodiment of the present invention, the platinum alloy may be supported by 5 to 95% by weight of the total weight of the catalyst.

According to another embodiment of the present invention, the step (b) is preferably carried out at a temperature of 60 to 120 ℃.

According to another embodiment of the present invention, hydroxide ions for sedimenting the metal hydroxide particles on the surface of the carrier in the step (b) may be generated by hydrolysis of urea.

According to another embodiment of the present invention, the hydroxide ions for sedimenting the metal hydroxide particles on the surface of the carrier in step (b) may be generated by hydrolysis of sodium hydroxide and urea added to the carrier dispersion. .

According to another embodiment of the present invention, the carrier may be a carbon carrier comprising at least one selected from the group consisting of vulcanized carbon, carbon nanotubes, carbon nanowires, double pore structure carbon and carbon capsules.

According to another embodiment of the present invention, the carrier is at least one selected from the group consisting of titanium dioxide, silica, aluminum oxide and manganese dioxide, or at least one selected from the group consisting of titanium dioxide, silica, aluminum oxide and manganese dioxide is carbon It may be made of a complex combined with.

According to another embodiment of the present invention, the reducing agent used in step (c) is NaBH ₄ , LiBH ₄ , HCHO, HCOOH, CH ₃ OH, CH ₃ CH ₂ OH, HCOONa, N ₂ H ₄ , AlBH ₄ aqueous solution And it may be at least one selected from the group consisting of ethylene glycol.

According to another embodiment of the present invention, the step (c) is preferably carried out in a hydrogen atmosphere of 150 to 400 ℃.

According to another embodiment of the present invention, before the step (c) may further comprise the step of separating the carrier precipitated metal hydroxide particles in the dispersion solution.

The present invention includes a carbon carrier and a platinum alloy supported on the carbon carrier, in order to achieve the second object, the size of the supported platinum alloy particles are in the Schiller formula from the platinum 220 peak of the X-ray diffraction pattern It provides a platinum alloy / carrier catalyst, characterized in that calculated by 2.0 to 3.0nm.

According to another embodiment of the present invention, the platinum alloy / carrier catalyst can be prepared by the above production method.

The present invention provides a fuel cell comprising a platinum alloy / carrier catalyst prepared by the above production method in order to achieve the third object.

In the method for preparing a platinum alloy / carrier catalyst of the present invention, the production of hydroxide ions occurs in a dispersion solution by first adjusting the pH to an appropriate pH using an aqueous NaOH solution and hydrolysis of urea and supplying a homogeneous phase. Since ions and metal salts react to precipitate the catalyst material on the carrier, a platinum alloy having a small particle size and a uniform distribution can be introduced into the carrier. Due to these characteristics, when the platinum alloy / carrier catalyst of the present invention is used as an electrode catalyst of a fuel cell, the fuel oxidation reaction and fuel cell polarization performance of fuels such as methanol and hydrogen It can greatly increase the catalytic activity. In addition, the multi-alloy catalyst according to the present invention increases the area in which the metal particles of a very small size (2-3 nm) are uniformly dispersed in the carrier to increase the catalytic reaction, such as epoxy reaction, Heck reaction, lithium ion battery and hydrogen. It can improve the properties of various organic and electrochemical reactions such as storage. In addition, according to the present invention, since the catalyst can be synthesized under mild synthetic conditions in a relatively low temperature aqueous solution, it is possible to provide a method for synthesizing a supported platinum catalyst, which is environmentally friendly and advantageous in terms of cost efficiency.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention comprises the steps of (a) dissolving a water-soluble salt and urea of the metal having a catalytic activity in water, dispersing the carrier to prepare a dispersion solution, and (b) stirring the dispersion solution passed through the step (a) at high temperature It provides a method for producing a platinum alloy / carrier catalyst comprising the steps of: sedimenting the metal hydroxide particles on the surface of the carrier, and (c) reducing the carrier on which the metal hydroxide particles are precipitated.

The present invention uniformly precipitates the metal hydroxide particles on the carrier through the reaction of the hydroxide ions (OH ⁻ ) produced by the hydrolysis of urea and the active metal ions, and the metal hydroxides by an efficient reduction method. By completely reducing the particles, the platinum alloy loading of the platinum alloy / carrier catalyst can be increased, the particle size of the platinum alloy can be kept small, and the distribution of the size can be kept uniform, thereby improving the activity of the catalyst.

Step (a) is a step of preparing a dispersion solution for settling metal hydroxide particles on a carrier by reacting a water-soluble salt of a metal with hydroxide ions produced by hydrolysis of urea. The water-soluble salt of the metal used in the step (a) is platinum (Pt), ruthenium (Ru), rhodium (Rh), molybdenum (Mo), osmium (Os), iridium (Ir), rhenium (Re), palladium (Pd), vanadium (V), tungsten (W), cobalt (Co), iron (Fe), selenium (Se), nickel (Ni), bismuth (Bi), tin (Sn), Cr (chromium), Titanium (Ti), gold (Au), cerium (Ce), copper (Cu), and the like. The molarity of the metal salt, for example in the range of about 0.5 to 2 mM, preferably about 1 mM, is the concentration of the metal salt relative to the total water introduced by the water contained in the metal salt solution and the water contained in the carrier slurry and other sources. Calculate as The dilution of the aqueous solution of the metal salt is to prevent the phenomenon that the metal particles grow by agglomeration and agglomeration of the respective particles when the catalyst metal is precipitated by sedimentation and reduction reactions in the following steps, and for more complete reduction. In addition, the acidity of the aqueous solution before the sedimentation reaction is originally acidity of about pH 3 to pH 4, but in some cases can be adjusted by adding a base solution such as NaOH or NH ₄ OH. These metals can be loaded in an amount of at least 5% of the total weight of the catalyst, as much as 95% by weight, preferably 20% to 80% by weight. The method of the present invention can produce a catalyst in which a metal having a relatively small particle size (2 to 3 nm) is uniformly dispersed on the surface of the carrier, so that expensive precious metals can be efficiently used, which is economically advantageous. In addition, the relative weight of the metal can be widely selected depending on the intended use. The electrode catalyst manufacturing method of the fuel cell, which is an example of the applicability according to the present invention, controls the size and dispersion of the metal catalyst particles in a relatively simple method without undergoing a complicated process, and is a cheap sedimentation reagent without using expensive reagents such as surfactants. Phosphorus urea was added to uniformly disperse the metal hydroxide on the surface of the carbon carrier, and then metal catalyst particles were completely reduced using various reducing agents including hydrogen. This has the advantage of being inexpensive and simple to manufacture, compared to the conventional fuel cell electrode catalyst manufacturing process. The sedimentation reagent urea uses an excess number of moles of 5 times to 200 times the number of moles of the metal salt, preferably about 10 to 100 times.

In the present invention, it is also possible to vary the order in which the water-soluble salts of the metal, urea and carrier are added to water.

One possible method consists of dissolving the water-soluble salts of the metals, dissolving the urea and dispersing the carrier, firstly dissolving the water-soluble salts of the catalytically active metal in water to prepare a metal salt aqueous solution, and then dissolving the urea in water. The aqueous urea solution may be prepared, followed by mixing the aqueous metal salt solution and the aqueous urea solution, and finally dispersing the carrier in the mixed solution of the aqueous metal salt solution and the urea solution. Another method consists of dissolving a water-soluble salt of a metal, dispersing a carrier and dissolving a urea. First, a water-soluble salt of a metal having catalytic activity is dissolved in water to prepare an aqueous metal salt solution, and then the carrier is dispersed in water to support the carrier. The dispersion can be prepared, followed by dissolving urea in the carrier dispersion, and finally mixing the carrier dispersion in which the urea is dissolved with the aqueous metal salt solution. In the above process, stirring may be accompanied for uniform dissolution or dispersion, and through stirring, the water-soluble salt of the metal is evenly penetrated into the pores of the carrier. In some cases, the acidity may be first adjusted to an appropriate pH using an aqueous sodium hydroxide solution before adding a water-soluble salt of a metal having catalytic activity. Thus, by adjusting the pH using an aqueous sodium hydroxide solution, it has the advantage that the acidity of the dispersion solution can be adjusted in a wider pH range than when using only urea, thereby controlling the size distribution of the catalyst more uniformly.

The water-soluble salt of the metal used for this invention can use 2 or more types different from each other. By using a water-soluble salt of a metal containing different metal atoms, it is possible to settle the alloy particles in the carrier. In this case, the amount of the water-soluble salt of the metal is determined stoichiometrically according to the relative amount of the metal to be supported on the carrier, and the concentration dissolved in water may be determined according to the solubility in water according to the type of salt. The water soluble salts of the metals used in the present invention may be hexachloroplatinum (IV) acid and ruthenium chloride. Hydrogen hexachloroplatinum (IV) acid induces the production of platinum hydroxide, ruthenium chloride induces the production of ruthenium hydroxide, and consequently allows the particles of the platinum-ruthenium alloy to be supported on the carrier. The carrier contains many pores on the surface and inside. The pores formed in the carrier maintain a large surface area of the carrier so that a large amount of metal catalyst particles can be supported. The carrier used in the present invention is at least one selected from the group consisting of vulcanized carbon, carbon nanotubes, carbon nanowires, double-porous carbon, and carbon capsules, or at least one selected from the group consisting of titanium dioxide, silica, aluminum oxide and manganese dioxide. It may be made of one, or at least one selected from the group consisting of titanium dioxide, silica, aluminum oxide and manganese dioxide carbon may be composed of a composite combined with carbon.

Step (b) is a step of allowing the metal hydroxide particles to precipitate on the surface of the carrier by heating the dispersion solution of the water-soluble salts, urea and carrier of the metal to react the hydroxide ions produced by hydrolysis of the water-soluble salt of the urea with the metal. Urea contained in the dispersion solution generates hydroxide ions by hydrolysis to maintain a uniform pH in the solution. In some cases, it may also include the step of first adjusting the pH to an appropriate acidity using an aqueous sodium hydroxide solution. In the present invention, since the concentrations of the hydroxide ions and the water-soluble salts of the metals produced in the dispersion solution can be kept constant throughout the dispersion solution, it is possible to prepare the catalyst by the homogeneous sedimentation method.

The preparation of such a catalyst is related to the physical properties of the catalyst. If the pH of the dispersion is high or low in any region, the reaction of the water-soluble salts of the metal with the hydroxide ions can also occur quickly in some regions or slowly in some regions. As such, if the reaction conditions occurring in the dispersion solution are not constant, the size of the metal hydroxide particles produced is not uniform, and the size of the particles cannot be kept small. In addition, since the metal particles after reduction maintain the form of the metal hydroxide particles before reduction to some extent, the metal alloy / carrier catalyst prepared by the homogeneous sedimentation method of the present invention can improve the size and uniformity of the metal particles. The activity of the catalyst can be made excellent. Step (b) is preferably carried out at a temperature of 60 to 120 ℃, because the reaction does not occur well at a temperature below 60 ℃, side reactions may occur at a temperature above 120 ℃.

Taking the hexachloro platinum (IV) acid hydrogen, which is one of the water-soluble salts of the metal used in the present invention, the chemical reaction occurring in step (b) is described as follows.

The supply of hydroxide ions in a homogeneous sedimentation method using urea takes place according to Scheme 1 below. Hydroxide ions are produced by the hydrolysis of urea, and the supply of hydroxide ions occurs in-situ, so that the concentration of hydroxide ions can be maintained uniformly in the solution, and the pH change in the local region You can prevent it from happening suddenly.

Scheme 1

_{CO (NH 2) 2 + 3H} 2 O → 2NH 4 + + CO 2 + 2OH -

Hydrogen hexachloroplatinum (IV) acid, which is dissolved together in a solution in which urea is dissolved, is hydrated and is present in the solution in an ionic state and reacts with the hydroxide ions to produce metal hydroxide particles and settles uniformly on the carrier. At this time, since hydroxide ions are present in a uniform concentration in the solution, the size of the generated hydroxide particles can also be maintained uniformly. Scheme 2 below shows a reaction in which hexachloroplatinum (IV) acid is hydrated, and Scheme 3 shows a reaction in which hydrated platinum ions react with hydroxide ions to generate metal hydroxides.

Scheme 2

[PtCl ₆ ] ^-2 + x H ₂ O ↔ [PtCl _{6 -x} (H ₂ O) _x ] ^{-2 + x + X Cl - (x = 0} , 1, 2)

Scheme 3

_{[PtCl 6 -x (H 2 O} ) x] -2 + x + y OH - ↔ [PtCl _{6 -x} (OH) _y (H ₂ O) _xy ] ^{-2 + xy} + y H ₂ O (x > y)

or

_{[PtCl 6 -x (H 2 O} ) x] -2 + x + z OH - _{↔ [PtCl 6 -xz (OH)} z (H 2 O) x] - 2+ x Z + Cl ^-

Step (c) is a process of reducing the metal hydroxide particles precipitated on the carrier to the metal. In this step, in order to reduce the metal hydroxide particles to the metal completely, the reduction should be carried out under the appropriate reducing conditions, and the reduction may be performed in various ways. It is possible to reduce metal hydroxide particles using liquid reducing agents such as NaBH ₄ , LiBH ₄ , HCHO, HCOOH, CH ₃ OH, CH ₃ CH ₂ OH, HCOONa, N ₂ H ₄ , AlBH ₄ aqueous solution or ethylene glycol. .

In addition, it is also possible to reduce by treating the carrier precipitated metal hydroxide particles in a high-temperature hydrogen atmosphere, the metal hydroxide particles can be effectively reduced when the amount of the metal hydroxide particles supported on the carrier is large as in the present invention. In this case, it is necessary to separate the carrier precipitated metal hydroxide particles from the dispersion solution, and when the reaction of step (b) is completed, the dispersion solution is cooled to room temperature and the solids in the form of slurry are separated and washed with distilled water to retain the remaining chloride. Remove, filter and dry at high temperature. At this time, the heat treatment temperature is preferably 150 to 400 ℃. If the heat treatment temperature is less than 150 ℃ is a reduction rate is not good because the reduction rate, if it exceeds 400 ℃ metal particles can be agglomerated tends to increase the particle size.

As described so far, the platinum alloy / carrier catalyst production method of the present invention can synthesize the catalyst under mild synthesis conditions in an aqueous solution at a lower temperature than the conventional production method, and thus is an environmentally friendly and cost effective catalyst. Provide a synthesis method. In addition, the amount of metal catalyst supported on the platinum alloy / carrier catalyst can be controlled in a wide range of 5 to 95% by weight based on the total weight. In particular, even when the amount of the metal catalyst is high, the size of the metal particles is kept small and the size distribution is uniform. I can keep it. Due to these characteristics, when the platinum alloy / carrier catalyst of the present invention is used as an electrode catalyst of a fuel cell, catalytic activity against fuel oxidation reaction and fuel cell polarization performance of fuel such as methanol and hydrogen is used. Can be greatly increased.

Hereinafter, the present invention will be described in more detail with reference to preferred examples. However, these examples are intended to illustrate the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited thereby.

Example 1-1 ( Preparation of platinum-ruthenium (60 wt.%) / VC catalyst (HD-H ₂ ) at pH 7-8 conditions)

A mole of hexachloroplatinum (IV) acid (manufactured by Kojima) and ruthenium chloride (manufactured by Aldrich) were dissolved in distilled water to prepare a metal salt solution. Vulcan Carbon (hereinafter referred to as VC) was separately dispersed in distilled water and stirred at room temperature for 30 minutes to prepare a VC dispersion. Urea (made by Aldrich) was added to the VC dispersion and stirred until a homogeneous carbon-urea solution was obtained. Subsequently, the metal salt solution was mixed with the carbon-urea solution and stirred, and then the pH was adjusted by adding a little NaOH at room temperature so that the acidity of the entire solution was pH 7-8, and the mixture was stirred for one hour, and then the mixture was brought to 90 ° C. Heated and left to stir for 1 hour. The molar ratio of urea to platinum-ruthenium metal was adjusted to 20: 1. Subsequently, the mixture was cooled to room temperature, the mixed slurry was washed repeatedly with distilled water, filtered to remove excess chloride, and then dried overnight at a temperature of 80 ° C. Subsequently, the dried slurry was placed in a tube furnace and heat-treated at a temperature of 300 ° C. for 1 hour while supplying hydrogen to prepare a platinum-ruthenium / VC catalyst. The platinum-ruthenium loading of the prepared platinum-ruthenium / VC catalyst was 60% by weight.

Example 1-2 ( Preparation of platinum-ruthenium (40 wt.%) / VC catalyst (HD-H ₂ ) at pH 3-4 conditions)

Urea was added to the mixed solution of the metal salt solution and the VC dispersion so that the molar ratio of urea to platinum-ruthenium was 20: 1, and no NaOH solution was added (the acidity of the dispersion solution was pH 3-4), and the amount of platinum-ruthenium supported. A platinum-ruthenium (40 wt%) / VC catalyst (HD-H ₂ ) was prepared in the same manner as in Example 1-1 except that was adjusted to 40 wt%.

Example 1-3 ( Preparation of platinum-ruthenium (40% by weight) / VC catalyst (HD-H ₂ ) at pH ~ 6 conditions)

Urea was added to the mixed solution of the metal salt solution and the VC dispersion so that the molar ratio of urea to platinum-ruthenium was 20: 1, and then NaOH was added so that the acidity of the mixed solution of the dispersion was pH 5-6, and the amount of platinum-ruthenium supported A platinum-ruthenium (40 wt%) / VC catalyst (HD-H ₂ ) was prepared in the same manner as in Example 1-1 except that was adjusted to 40 wt%.

Example 1-4 ( Preparation of platinum-ruthenium (40 wt.%) / VC catalyst (HD-H ₂ ) at pH 7-8 conditions)

Urea was added to the mixed solution of the metal salt solution and the VC dispersion so that the molar ratio of urea to platinum-ruthenium was 20: 1, and then NaOH was added so that the acidity of the mixed solution of the dispersion was pH 7-8, and the amount of platinum-ruthenium supported A platinum-ruthenium (40 wt%) / VC catalyst (HD-H ₂ ) was prepared in the same manner as in Example 1-1 except that was adjusted to 40 wt%.

Example 1-5 ( Preparation of platinum-ruthenium (40% by weight) / VC catalyst (HD-H ₂ ) at pH 9 ~ 10 conditions)

Urea was added to the mixed solution of the metal salt solution and the VC dispersion so that the molar ratio of urea to platinum-ruthenium was 20: 1, and then NaOH was added so that the acidity of the mixed solution of the dispersion was pH9-10, and the amount of platinum-ruthenium supported A platinum-ruthenium (40 wt%) / VC catalyst (HD-H ₂ ) was prepared in the same manner as in Example 1-1 except that was adjusted to 40 wt%.

Example 2 Preparation of Half Battery Using Platinum-Ruthenium (60 wt.%) / VC Catalyst (HD-H ₂ ) of Example 1-1

Half cell, 3-electrode electrolysis with platinum-ruthenium (60 wt.%) / VC catalyst of Example 1-1 to measure the catalytic activity against methanol oxidation of platinum-based catalyst and the electrochemical surface area of platinum Chemical cells). Platinum gauze was used as the counter electrode and Ag / AgCl was used as the reference electrode. The working electrode is a thin film of a Nafion-impregnated catalyst formed on a 3 mm diameter glassy carbon disk, which is immersed in a Teflon cylinder electrolyte with platinum gauze and a counter electrode to undergo an electrochemical reaction. . The working electrode is Appl. Catal. B: Environ. 84 (2008) prepared according to the contents of 100-105. The catalyst loading of the working electrode was 0.2 mg platinum / cm ² .

Example 3-1 (Preparation of single cell using the platinum-ruthenium (60% by weight) / VC catalyst (HD-H ₂ ) of Example 1-1)

Single cell having a catalyst cross-sectional catalyst area of ² cm ^{2 with} the platinum-ruthenium (60 wt.%) / VC catalyst of Example 1-1 to measure the polarization performance of the fuel cell. cell) was prepared. The membrane electrode assembly (MEA) was prepared by hot-pressing (135 ° C., 2000 psi, 5 minutes) both sides of a pre-treated Nafion-115 (manufactured by DuPont) membrane as an anode and a cathode. The positive electrode and the negative electrode were prepared by printing an appropriate amount of supported catalyst ink on Teflon carbon paper (TGPH-090) and drying in an oven at 70 ° C. for 1 hour. The catalyst ink mixed 100 mg of catalyst with 0.763 ml of 5 wt.% Nafion solution and maintained stirring prior to use. The loading of the catalyst was 3.0 mg platinum-ruthenium / cm 2 at the positive electrode and 5.0 mg platinum / cm 2 at the negative electrode (platinum catalyst prepared by Johnson Matthey method). A masterflex liquid micro-pump provides 2.0 M of methanol solution to the anode at a rate of 1.5 ml / min and dried oxygen controlled at a rate of 100 cc / min by a prometer. Supplied to the cathode.

Example 3-2 (Preparation of single cell using platinum-ruthenium (40 wt%) / VC catalyst (HD-H ₂ ) of Example 1-2)

A single cell was manufactured in the same manner as in Example 3-1, except that the platinum-ruthenium (40 wt%) / VC catalyst (HD-H ₂ ) of Example 1-2 was used.

Example 3-3 (Preparation of single cell using platinum-ruthenium (40% by weight) / VC catalyst (HD-H ₂ ) of Example 1-3)

A single cell was prepared in the same manner as in Example 3-1 except for using the platinum-ruthenium (40 wt%) / VC catalyst (HD-H ₂ ) of Example 1-3.

Example 3-4 (Preparation of single cell using the platinum-ruthenium (40% by weight) / VC catalyst (HD-H ₂ ) of Example 1-4)

A single cell was manufactured in the same manner as in Example 3-1, except that the platinum-ruthenium (40 wt%) / VC catalyst (HD-H ₂ ) of Example 1-4 was used.

Example 3-5 (Preparation of single cell using the platinum-ruthenium (40% by weight) / VC catalyst (HD-H ₂ ) of Example 1-5)

A single cell was manufactured in the same manner as in Example 3-1, except that the platinum-ruthenium (40 wt%) / VC catalyst (HD-H ₂ ) of Example 1-5 was used.

Comparative Example 1-1 ( Preparation of platinum-ruthenium (60 wt.%) / VC catalyst (NaBH ₄ ))

A platinum-ruthenium / VC catalyst having the same catalyst loading as in Example 1-1 was prepared using NaBH ₄ as the reducing agent. Specific manufacturing method is Appl. Catal. B: Environ. 84 (2008) 100-105 as described.

Comparative Example 1-2 ( Preparation of Platinum-Ruthenium (40 wt.%) / VC Catalyst (NaBH ₄ ))

A platinum-ruthenium (40 wt%) / VC catalyst (NaBH ₄ ) was prepared in the same manner as in Comparative Example 1-1 except that the catalyst loading was 40 wt%.

Comparative Example 2 (Preparation of half cell using platinum-ruthenium (60 wt.%) / VC catalyst (NaBH ₄ ))

A half cell was manufactured in the same manner as in Example 2, except that platinum-ruthenium (60 wt%) / VC catalyst (NaBH ₄ ) of Comparative Example 1-1 was used as the operating electrode.

Comparative Example 3-1 (Preparation of single cell using platinum-ruthenium (60 wt%) / VC catalyst (NaBH ₄ ))

A single cell was manufactured in the same manner as in Example 3-1, except that platinum-ruthenium (60 wt%) / VC catalyst (NaBH ₄ ) of Comparative Example 1-1 was used for the anode.

Comparative Example 3-2 (Preparation of single cell using platinum-ruthenium (40 wt%) / VC catalyst (NaBH ₄ ))

A single cell was manufactured in the same manner as in Comparative Example 3-1, except that platinum-ruthenium (40 wt%) / VC catalyst (NaBH ₄ ) of Comparative Example 1-2 was used for the anode.

Experimental Example 1 (Surface Observation Using Transmission Electron Microscopy)

The surface of the platinum-ruthenium (60 wt.%) / VC catalyst was observed using transmission electron microscopy (TEM). TEM used a model name FE-2010 manufactured by JEOL, and operated at a voltage of 200 kV to obtain an image.

FIG. 1 shows the distribution of HR-TEM images of Example 1-1 and Comparative Example 1-1 and nanoparticle size of Example 1-1. Referring to (a) of FIG. 1, the platinum-ruthenium (60 wt%) / VC catalyst (HD-H ₂ ) of Example 1-1 has small, spherical and uniform black dots uniformly dispersed in the VC carrier. Is observed. Referring to (c) of FIG. 1, the size of the platinum-ruthenium nanoparticles supported in the platinum-ruthenium (60 wt%) / VC catalyst (HD-H ₂ ) of Example 1-1 has a distribution of 1.7 to 3.3 nm. Was observed, the average size of the particles was 2.6nm. Referring to FIG. 1B, the platinum-ruthenium (60 wt%) / VC catalyst (NaBH ₄ ) of Comparative Example 1-1 has a larger size of the supported platinum-ruthenium particles than that of Example 1-1. The distribution was also bad. The size distribution of the platinum-ruthenium particles was 2.3 to 5.7 nm and the average size was 3.8 nm.

Experimental Example 2 (X-ray diffraction pattern analysis)

The X-ray diffraction patterns (XRD) were analyzed using Cu Kα radiation of Rigaku diffractometer at the scanning speed of 4 ° / min, 40kV, and 20mA. FIG. 2 is an XRD pattern for the platinum-ruthenium (60 wt.%) / VC catalyst of Example 1-1 and Comparative Example 1-1. FIG. Referring to FIG. 2, the peak observed at 24.5 ° is a peak related to the carbon carrier, and (111) of face-centered cubic (fcc) crystalline platinum at positions 2θ values of 39.8, 67.8 and 81.2 °, respectively. , (220) and (311) peaks are observed. These results indicate that the alloy catalyst has a single-phase disordered structure. Compared with bulk platinum, the platinum-ruthenium alloy catalyst moves to a slightly higher 2θ value, and it can be seen that ruthenium atoms are inserted into the platinum to form an alloy. The shifted peaks were observed at 41.0, 68.9, and 83.6 각각, respectively, indicating that an alloy in which platinum and ruthenium coexisted was formed. In addition, the particle size of the metal alloys calculated through the Scherrer formular in the XRD data is 2.7 nm and 3.7 nm in Example 1-1 and Comparative Example 1-1, which is in good agreement with the HR-TEM result of FIG. 1. do.

Experimental Example 3 (thermogravimetric analysis)

Thermogravimetric analysis (TGA) was performed on the platinum-ruthenium (60 wt%) / VC catalysts of Example 1-1 and Comparative Example 1-1. 3 is a thermal decomposition graph with temperature for the catalysts of Example 1-1 and Comparative Example 1-1. In Example 1-1 and Comparative Example 1-1, the alloy content was measured at 60% by weight, and it can be seen that platinum and ruthenium ions were completely reduced to platinum and ruthenium.

Experimental Example 4 (cyclic voltametric measurement)

Cyclic voltammetric measurement was performed using the half cells of Example 2 and Comparative Example 2. The cyclic voltametric measurement was performed at a scan rate of 25 mV / s with 0.5 M sulfuric acid at room temperature, and the electrolyte solution was bubbled by flowing high purity nitrogen for 1 hour prior to each measurement. The stable voltammogram was recorded in 10 cycles. Electrochemical surface area (ESA) is an important factor in determining the intrinsic electrochemical activity of platinum-based catalysts, based on the adsorption charge (0.21 mC / cm ² ) of hydrogen adsorbed as a single layer on platinum polycrystals. For example, it can be calculated from the total charge of the hydrogen adsorption region of the equilibrium cyclic voltamogram at 0.5 MH ₂ SO ₄ ).

4 is a hydrogen electrosorption voltametric curve measured using the half cells of Example 2 and Comparative Example 2. FIG. Referring to FIG. 4, the half cell of Example 2 observed a weak adsorption peak in the potential range of +0.05 to -0.1 V and a strong adsorption peak of -0.1 to -0.2 V in the negative direction potential scan. The peaks represent weakly bound adsorbed hydrogen and strongly bound hydrogen. The electrochemical surface area of Example 2 was measured at 59 m ² / g for platinum, and the electrochemical surface area of Comparative Example 2 was measured at 36 m ² / g for platinum, resulting in a higher electrochemical surface area for Example 2. It was. This indicates that Example 2 has a smaller platinum-ruthenium nanoparticle size than Comparative Example 2 and has a uniform dispersion so that the efficiency is high.

Experimental Example 5 (cyclic voltametric measurement)

Cyclic voltametric measurements were performed using half cells to which Example 2, Comparative Example 2 and VC were applied. FIG. 5 shows cyclic voltammograms showing catalytic activity for methanol oxidation, measured at 1.0 M methanol-0.5 M sulfuric acid. Referring to FIG. 5, the potential corresponding to the point at which the methanol oxidation is initiated is 0.5V based on Ag / AgCl in Example 2, which is lower than 0.1V of Comparative Example 2. In addition, the former catalyst has a much larger peak current in the forward scan and shows a lower peak oxide potential. The ratio of the current density relative to the anode peak of the forward ( I _f ) and reverse ( I _b ) scans is a major factor in evaluating the catalytic performance used to evaluate the carbon monoxide (CO) resistance of the catalyst. A small I _f / I _b value suggests that methanol is not oxidized well to carbon monoxide during the anodic scan and excessive accumulation of carbonaceous material on the catalyst surface leads to large amounts of carbon monoxide contamination. Referring to Table 1 below, Example 2 has a much larger I _f / I _b value than Comparative Example 2, indicating that carbon monoxide resistance is high. For Example 2 the ratio by mass activity measured at 0.4V (mass specific activity) was 335mA / mg _pt, the case of Comparative Example 2 was 165mA / mg _pt. Taken together, it can be seen from Example 2 that the catalytic activity of methanol oxidation is superior to that of Comparative Example 2, which is due to the small size and uniform dispersion of the nanometal particles of the electrode catalyst applied in Example 2. It is thought to be due.

TABLE 1

catalyst ESA
(m ² / g) Onset potential (V) Specific mass activity
(mA / mg _pt ) I _f / I _b Pt-Ru / VC (NaBH ₄ ) 36 0.10 165 2.67 Pt-Ru / VC (HD-H ₂ ) 59 0.05 335 17.11

Experimental Example 6 (Polarity Measurement)

The polar performances of Comparative Examples 3-1, Comparative Example 3-1, and platinum-ruthenium (60% by weight) / VC (E-TEK) were measured. The constant current polarity measurement used the potentiometer (WMPG-1000). FIG. 6 shows the results of a polar performance test under the oxygen condition of Example 3-1, Comparative Example 3-1, and platinum-ruthenium (60 wt%) / VC (E-TEK) unit cell. The fuel cell polarity in the low current density region is due to the slow charge transfer on the electrode surface. The active polarity at 0.5 V is mainly affected by the activity of the catalyst. The unit cell of Example 3-1 showed a current density of 63 mA / cm ² at 60 ° C., 0.5 V, and an oxygen injection mode, and thus, a cell (35 mA /) applied with platinum-ruthenium (60 wt%) / VC (E-TEK) 80% higher than cm ² ), and 91% higher than Comparative Example 3-1 (33 mA / cm ² ). In the case of Example 3-1, an active polarity smaller than that of Comparative Example 3-1 is observed, which means that the methanol oxidation rate is faster in the case of the former. Examples 3-1 represent the maximum power density of 154mW / cm ^2, which is higher than in Comparative Example 3-1 104 mW / cm ² of platinum-ruthenium (60 wt%) / VC cell stage applying (E-TEK) Is higher than 112 mW / cm ² .

Experimental Example 7 (Chroampogram)

Chronoamperograms were measured for Example 3-1 and Comparative Example 3-1. FIG. 7 is a chromatogram result obtained by supplying and measuring oxygen to a cathode at 0.5 V and 30 ^° C. for Example 3-1 and Comparative Example 3-1. In the case of Example 3-1, both the initial and late current responses were high in the entire measured range, which is significantly higher in the case of Example 3-1 than in Comparative Example 3-1. Indicates. Example 3-1 reached equilibrium after about 6 hours, and Comparative Example 3 continuously decreased the current response, indicating that the former was more stable under the same anode operating conditions. In Example 3-1, the reaction current became 260 mA after 8 hours, resulting in an 80% improvement over 150 mA of Comparative Example 3-1, which is much faster than Comparative Example 3-1. It shows that it has a rate of methanol oxidation. This result is due to the fact that Example 3-1 has smaller size and uniform dispersion of platinum-ruthenium alloy nanoparticles than Comparative Example 3-1.

Experimental Example 8 (Surface Observation Using Transmission Electron Microscopy)

The transmission electron microscope observation was performed with respect to the catalysts of Examples 1-2 to Example 1-5 and Comparative Example 1-2 in the same manner as in Experimental Example 1. 8 is an HR-TEM image of the catalyst of Examples 1-2 to Example 1-5 and Comparative Example 1-2. 8, Examples 1-2 (a, f), Examples 1-3 (b, g), Examples 1-4 (c, h), Examples 1-5 (d, i), It is observed that spherical metal particles are supported on a carrier, and Comparative Examples 1-2 (e, j) have a disordered form in which the shape of the metal particles is not spherical. In addition, in the case of Examples, the synthesis of the metal at a high pH resulted in a smaller size of the metal particles, and uniform dispersion of the size was observed.

Experimental Example 9 (Polarity Measurement)

Using the unit cells of Examples 3-2 to 3-5 and Comparative Example 3-2, the performance of the unit cells was measured in the same manner as in Experimental Example 6. The hydrogen oxidation reaction performance of the 40 wt% Pt-Ru alloy catalyst prepared at various pHs was compared with the 40 wt% Pt-Ru alloy catalyst prepared in Comparative Example 3-2, which is a general catalyst manufacturing method, through a single cell performance test. 9 is a performance curve of the unit cells measured under the oxygen conditions of 60 ℃ for the unit cells of Examples 3-2 to 3-5 and Comparative Example 3-2. 9, Examples 3-3 to 3-5 show higher current density and maximum power than Comparative Example 3-2. In other words, it can be seen that the maximum power according to the change in the current density of the catalyst prepared at pH 3-4, 5-6, 7-8, 9-10 has a value of 2.43, 2.58, 2.64, 2.81W, respectively. Based on these results, it was confirmed that as the pH was increased, the size of the catalyst particles decreased and the catalytic activity of the hydrogen fuel cell increased. This is consistent with the smaller catalyst particles, which increases the active area of the catalyst. In addition, it can be seen that the catalyst prepared at pH 9 to 10 shows the maximum power, and it is confirmed to be improved by about 16% compared to the maximum power (2.43W) of the catalyst prepared in Comparative Example 3-2, which is a general catalyst preparation method. . Fig. 10 shows the relationship between the size of the metal particles and the unit cell performance for sizes 2 to 3-5 of the catalyst particles. Referring to FIG. 10, the higher the pH in the synthesis conditions of the catalyst, the smaller the size of the metal particles and the higher the power of the unit cell. In particular, it can be seen that the size of the metal particles is sharply reduced in the region of pH 5 ~ 6, and accordingly the power of the unit cell is also sharply improved.

Figure 1 shows the distribution of HRTEM images of Example 1-1 and Comparative Example 1 and the nanoparticle size of Example 1-1.

FIG. 2 is an XRD pattern for the platinum-ruthenium (60 wt.%) / VC catalyst of Examples 1-1 and Comparative Example 1. FIG.

3 is a thermal decomposition graph with temperature for the catalysts of Example 1-1 and Comparative Example 1. FIG.

4 is a hydrogen electrosorption voltametric curve measured using the half cells of Example 2 and Comparative Example 2. FIG.

FIG. 5 shows cyclic voltammograms showing catalytic activity for methanol oxidation, measured at 1.0 M methanol-0.5 M sulfuric acid.

FIG. 6 shows the results of a polar performance test under the oxygen condition of Example 3-1, Comparative Example 3-1, and platinum-ruthenium (60 wt%) / VC (E-TEK) unit cell.

7 is a chromatogram result obtained by measuring oxygen and supplying oxygen to a cathode at 0.5 V and 30 ^° C. in Example 3-1 and Comparative Example 3-1.

8 is an HR_TEM image of the catalyst of Examples 1-2 to Example 1-5 and Comparative Example 1-2.

9 is a performance curve of the unit cells measured under the oxygen conditions of 60 ℃ for the unit cells of Examples 3-2 to 3-5 and Comparative Example 3-2.

FIG. 10 shows the relationship between the size of metal particles and unit cell performance for Examples 3-2 to 3-5.

Claims (18)

(a) dissolving a water-soluble salt and urea of a metal having catalytic activity in water and dispersing a carrier to prepare a dispersion solution; (a ') by dissolving the urea in water at a rate of 5-200 times the number of moles of the water-soluble salt of the metal, the hydroxy ions produced by the hydrolysis result in constant dispersion of the dispersion solution in the range of 5-12. adjusting pH; (b) hydroxy ions produced by hydrolysis at 60-120 ° C. in the dispersion solution and metal ions produced by hydration of a water-soluble salt of the metal react to form metal hydroxide particles, wherein the dispersion solution is formed. Stirring to precipitate the metal hydroxide particles of a predetermined size formed in the dispersion solution on the surface of the carrier; And (c) reducing the carrier having the metal hydroxide particles precipitated by injecting a reducing agent into the dispersion solution or by separating the carrier containing the precipitated metal hydroxide particles from the dispersion solution and heat-processing at 150-400 ° C. in a hydrogen atmosphere. Platinum alloy / carrier catalyst manufacturing method comprising a. The method of claim 1, Step (a) is a step of dissolving a water-soluble salt and urea of the metal having a catalytic activity in water to prepare a metal-urea solution; Preparing a carrier dispersion in which the carrier is dispersed in the dispersion; And mixing the metal-urea solution and the carrier dispersion. delete delete The method of claim 1, Step (a) comprises the steps of dissolving a water-soluble salt of a metal having a catalytic activity in water to prepare a metal salt aqueous solution; Dissolving urea in water to prepare an aqueous urea solution; Mixing the aqueous metal salt solution and the aqueous urea solution; And dispersing a carrier in a mixed solution of an aqueous metal salt solution and an aqueous urea solution. The method of claim 1, The water-soluble salts of the metals are platinum, ruthenium, rhodium, molybdenum, osmium, iridium, rhenium, palladium, vanadium, tungsten, cobalt, iron, selenium, nickel, bismuth, tin, chromium, copper, titanium, gold and cerium. Method for producing a platinum alloy / carrier catalyst characterized in that it comprises at least one metal selected from the group consisting of. The method of claim 1, Platinum alloy is a method of producing a platinum alloy / carrier catalyst, characterized in that supported by 5 to 95% by weight of the total weight of the catalyst. delete The method of claim 1, The step (a ') further comprises the step of adding sodium hydroxide to the dispersion solution to adjust the pH of the dispersion solution to maintain a constant pH in the range of 5-12, Hydroxide ions for the precipitation of metal hydroxide particles on the surface of the carrier in the step (b) is produced by the hydrolysis of urea in the dispersion solution and the added sodium hydroxide, the method of producing a platinum alloy / carrier catalyst . delete The method of claim 1, Said carrier is a carbon carrier comprising at least one selected from the group consisting of vulcanized carbon, carbon nanotubes, carbon nanowires, double-porous structure carbon and carbon capsules. The method of claim 1, The carrier is made of at least one selected from the group consisting of titanium dioxide, silica, aluminum oxide and manganese dioxide, or at least one selected from the group consisting of titanium dioxide, silica, aluminum oxide and manganese dioxide is characterized in that consisting of a complex bonded with carbon Process for preparing platinum alloy / carrier catalyst. The method of claim 1, The reducing agent used in step (c) is at least one selected from the group consisting of NaBH ₄ , LiBH ₄ , HCHO, HCOOH, CH ₃ OH, CH ₃ CH ₂ OH, HCOONa, N ₂ H ₄ , AlBH ₄ aqueous solution and ethylene glycol Method for producing a platinum alloy / carrier catalyst, characterized in that. delete The method of claim 1, Method for producing a platinum alloy / carrier catalyst characterized in that it further comprises the step of separating the carrier precipitated metal hydroxide particles in the dispersion solution before step (c). delete A platinum alloy / carrier catalyst prepared by the process according to any one of claims 1 to 15. A fuel cell comprising a platinum alloy / carrier catalyst prepared by the method of any one of claims 1 to 15.

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