KR100814840B1 - Cathode catalyst for fuel cell, method for preparing the same, membrane-electrode assembly for fuel cell comprising the same, and fuel cell system comprising the same - Google Patents

Abstract

A cathode catalyst for a fuel cell, a method for manufacturing the cathode catalyst, a membrane-electrode assembly for the fuel cell comprising the cathode catalyst, and a fuel cell system comprising the membrane-electrode assembly are provided to decrease the oxidative reactivity of fuel, thereby reducing the influence due to crossover of fuel. A cathode catalyst(53) for a fuel cell comprises a carbonized aerogel carrier and Me-Ch supported on the carrier, wherein Me element is selected from a group consisting of Rh, Ru, Pd, and a combination thereof, and Ch element is selected from a group consisting of S, Se, and a combination thereof. Me-Ch contains 50-98 atom % of Me and 2-50 atom% of Ch, based on the entire part thereof. Further, 5-75 wt.% of support weight of the Me-Ch is comprised in 100 wt.% of the cathode catalyst.

Description

Cathode catalyst for fuel cell, method for manufacturing the same, membrane-electrode assembly for fuel cell comprising the same, and fuel cell system including the same AND FUEL CELL SYSTEM COMPRISING THE SAME}

1 is a view schematically showing a cross section of a membrane-electrode assembly for a fuel cell according to an embodiment of the present invention.

2 is a view schematically showing the structure of a fuel cell system according to an embodiment of the present invention.

[Industrial use]

The present invention relates to a cathode catalyst for a fuel cell, a method for manufacturing the same, a membrane-electrode assembly for a fuel cell including the same, and a fuel cell system including the same, and more particularly, to reduce the effect of fuel crossover, The present invention relates to a cathode catalyst for a fuel cell having increased loading, a method of manufacturing the same, a membrane-electrode assembly for a fuel cell including the same, and a fuel cell system including the same.

[Prior art]

A fuel cell is a power generation system that directly converts the chemical reaction energy of hydrogen and oxygen contained in hydrocarbon-based materials such as methanol, ethanol and natural gas into electrical energy.

Such a fuel cell is a clean energy source that can replace fossil energy, and has a merit of outputting a wide range of outputs by stacking unit cells, and having an energy density of 4 to 10 times compared to a small lithium battery. It is attracting attention as a compact and mobile portable power source.

Representative examples of the fuel cell include a polymer electrolyte fuel cell (PEMFC) and a direct oxidation fuel cell (Direct Oxidation Fuel Cell). When methanol is used as a fuel in the direct oxidation fuel cell, it is called a direct methanol fuel cell (DMFC).

The polymer electrolyte fuel cell has an advantage of having a high energy density and a high output, but requires attention to handling hydrogen gas and reforms fuel for reforming methane, methanol, natural gas, etc. to produce hydrogen as fuel gas. There is a problem that requires additional equipment such as a device.

On the other hand, the direct oxidation fuel cell has a lower energy density than the polymer electrolyte fuel cell, but it is easy to handle fuel and has a low operating temperature, so that it can be operated at room temperature, in particular, it does not require a fuel reformer.

In such fuel cell systems, the stack that substantially generates electricity comprises several unit cells consisting of a membrane-electrode assembly (MEA) and a separator (also called a bipolar plate). It has a structure laminated to several tens. The membrane-electrode assembly has a structure in which an anode electrode and a cathode electrode are positioned with a polymer electrolyte membrane including a hydrogen ion conductive polymer interposed therebetween.

The principle of generating electricity in a fuel cell is that fuel is supplied to an anode electrode, which is a fuel electrode, adsorbed to a catalyst of the anode electrode, and the fuel is oxidized to generate hydrogen ions and electrons. Reaching the cathode electrode, hydrogen ions pass through the polymer electrolyte membrane and are delivered to the cathode electrode. An oxidant is supplied to the cathode, and the oxidant, hydrogen ions, and electrons react on the catalyst of the cathode to generate electricity while producing water.

An object of the present invention is to provide a cathode catalyst for a fuel cell which is excellent in catalyst efficiency.

Another object of the present invention is to provide a method for producing the cathode catalyst for fuel cells.

Yet another object of the present invention is to provide a membrane-electrode assembly for a fuel cell comprising the cathode catalyst.

It is another object of the present invention to provide a fuel cell system comprising the membrane-electrode assembly.

In order to achieve the above object, the present invention is a carbonized airgel (Carbonized Aerogel) carrier; And Me-Ch supported on this carrier (Me is an element selected from the group consisting of Rh, Pt, Ru, Pd, and combinations thereof, and Ch is a circle selected from the group consisting of S, Se, and combinations thereof. Provided is a cathode catalyst for a fuel cell comprising a).

The Me-Ch preferably contains 50 to 98 atomic% of Me and 2 to 50 atomic% of Ch based on the total Me-Ch.

In the fuel cell cathode catalyst, the amount of Me-Ch supported is preferably 5 to 75% by weight based on the total weight of the catalyst.

The present invention also comprises the steps of gelling an organic acid to prepare an organic gel; Preparing a gel doped with Me by impregnating the organic gel in a Me precursor solution (Me is an element selected from the group consisting of Rh, Pt, Ru, Pd, and combinations thereof); Preparing a carbon aerogel on which Me is carried by supercritical drying the gel doped with Me under high temperature and high pressure; And it provides a method for producing a cathode catalyst for a fuel cell comprising the step of heating the solution prepared by adding the carbon aerogel and Ch precursor on which Me is supported in a solvent.

In the step of preparing the Me-supported carbon aerogel, the gel doped with Me is preferably supercritical dried at a high temperature of 473K to 1273K, and is preferably supercritical dried under a high pressure of 5MPa to 30MPa.

Preferably, the heating is performed at a temperature of 50 to 150 ° C., and the heating is preferably performed for 12 to 36 hours.

The present invention also provides an anode electrode and a cathode electrode positioned opposite each other; And a polymer electrolyte membrane positioned between the anode electrode and the cathode electrode, wherein the cathode electrode includes the cathode catalyst.

The present invention also provides a fuel cell system comprising a membrane-electrode assembly comprising the cathode catalyst and at least one electricity generator, a fuel supply and an oxidant supply.

Hereinafter, the present invention will be described in more detail.

The cathode catalyst for a fuel cell of the present invention includes a carbonized aerogel carrier; And Me-Ch supported on this carrier (Me is an element selected from the group consisting of Rh, Pt, Ru, Pd, and combinations thereof, and Ch is a circle selected from the group consisting of S, Se, and combinations thereof. Post).

The aerogel refers to a gel (powder) obtained by drying under supercritical conditions, and a carbonized aerogel (carbonized aerogel) refers to a gel having large pores and a large surface area obtained by drying carbon under supercritical conditions.

In the present invention, using a carbon aerogel having such a large pore and a large surface area as a carrier, Me-Ch (Me is Rh, Pt, which is difficult to support high oxygen but 20 to 30 times better selectivity for the platinum-based catalyst than the platinum-based catalyst) Element selected from the group consisting of Ru, Pd, and combinations thereof, and Ch is an element selected from the group consisting of S, Se, and combinations thereof. It provides a paper cathode catalyst.

In the cathode catalyst of the present invention, Me-Ch (Me is an element selected from the group consisting of Rh, Pt, Ru, Pd, and combinations thereof, Ch is selected from the group consisting of S, Se, and combinations thereof Of the carrier) is 20 to 75% by weight based on the total weight of the catalyst, which is much higher than about 5 to 20% by weight.

It is preferable that Me is contained in 50 to 98 atomic% and Ch is included in 2 to 50 atomic% with respect to the entire Me-Ch. If Ch is less than 2 atomic%, the selectivity to the fuel oxidation reaction of the oxidant and the reduction of the oxidant is poor, and it is not preferable. If Ch is more than 50 atomic%, the number of active centers is small, and the activity for the reduction reaction of the oxidant is excessively reduced. .

Cathode catalyst for fuel cell having the above configuration can improve the performance degradation due to crossover of fuel because Me-Ch used as active material has 20 to 30 times better selectivity to oxygen reduction reactivity than platinum based catalyst. In addition, it is possible to contribute to the improvement of battery performance by enabling the use of a high concentration of fuel. In addition, since this effect is maximized in a direct oxidation fuel cell using a hydrocarbon fuel, the cathode electrode of the present invention can be more preferably applied to a direct oxidation fuel cell system.

In addition, the present invention comprises the steps of gelling the organic acid to prepare an organic gel; Preparing a gel doped with Me by impregnating the organic gel in a Me precursor solution (Me is an element selected from the group consisting of Rh, Pt, Ru, Pd, and combinations thereof); Preparing a carbon aerogel on which Me is carried by supercritical drying the gel doped with Me under high temperature and high pressure; And it provides a method for producing a cathode catalyst for a fuel cell comprising the step of heating the solution prepared by adding the carbon aerogel and Ch precursor on which Me is supported in a solvent.

First, an organic acid is gelled to prepare an organic gel. The organic acid constituting the organic gel may be preferably used as long as Me can be doped into the gel by ion exchange with a Me precursor. The organic acid constituting the organic gel preferably includes a functional group having an acid, and more preferably further includes a hydroxyl group.

As the organic acid, a C ₆ to C ₃₀ fatty acid can be preferably used, and the fatty acid is more preferably an aromatic fatty acid. Examples of the aromatic fatty acid include benzoic acid, and particularly, 2,4-dihydroxybenzoic acid can be preferably used.

Since the method of gelling the organic acid may be a conventionally known method, detailed description thereof will be omitted. However, according to one embodiment of the present invention, the gelation may be performed by adding the organic acid and the gelling catalyst to the solvent and left at room temperature and atmospheric pressure.

The leaving is preferably performed for 2 to 4 days. If the neglect is less than 2 days, it is not preferable that the gelation is not completed completely, if it is more than 4 days, since the gelation is already completed and waste the process time is not preferable.

It is preferable to use formaldehyde as the solvent, and the gelling catalyst preferably uses a carbonate of an alkali metal of K ₂ CO ₃ .

Me-doped gel is prepared by impregnating Me precursor solution (Me is an element selected from the group consisting of Rh, Pt, Ru, Pd, and combinations thereof). When the organic gel is impregnated into the Me precursor solution, Me is doped into the organic gel by ion exchange between the organic gel and the Me precursor.

The Me precursor solution may be prepared by adding a compound selected from the group consisting of Me chloride, Me acetylacetonite, Me carbonyl, and combinations thereof to a solvent. The solvent may be preferably selected from the group consisting of water, ethanol, acetone, and combinations thereof.

When the Me-doped gel is supercritically dried under high temperature and high pressure, a carbon aerogel bearing Me may be prepared.

The Me-supported carbon aerogel is preferably prepared by supercritical drying under high temperature of 473K to 1273K and high pressure of 5MPa to 30MPa. When the high temperature and high pressure conditions are applied to the gel doped with Me, a supercritical condition capable of supercritical drying may be formed to prepare a carbon aerogel carrying Me. The supercritical drying is preferably CO ₂ supercritical drying.

Me-Ch (Me is Rh, Pt, Ru, Pd, and these supported on a carbonized aerogel carrier) is heated by heating the solution prepared by adding the prepared carbon aerogel and Ch precursor to the solvent. An element selected from the group consisting of combinations, and Ch is an element selected from the group consisting of S, Se, and combinations thereof.

The Ch precursor (Ch is an element selected from the group consisting of S, Se, and combinations thereof) is S powder, Se powder, CH ₃ CSNH ₂ , H ₂ SO ₃ , H ₂ SeO ₃ , and combinations thereof It is preferably selected from the group consisting of. In addition, the solvent is preferably selected from the group consisting of water, ethanol, acetone, benzene, and combinations thereof.

The heating step is a temperature of 50 to 150 ℃, preferably for 12 to 36 hours. When the solution prepared by adding the Me-supported carbon aerogel and the Ch precursor to a second solvent is heated at a temperature of 50 to 150 ° C. for 12 to 36 hours, the Me supported on the carbon aerogel is sulfided or selenized It is preferable to make it possible.

The present invention also provides an anode electrode and a cathode electrode positioned opposite each other; And a polymer electrolyte membrane positioned between the anode electrode and the cathode electrode, wherein the cathode electrode includes the cathode catalyst of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is a view schematically showing a cross section of the membrane-electrode assembly 131 according to an embodiment of the present invention. Hereinafter, the membrane-electrode assembly 131 of the present invention will be described with reference to the drawings.

The membrane-electrode assembly 131 is a portion that generates electricity through oxidation of fuel and reduction of oxidant, and one or several are stacked to form a stack.

A reduction reaction of the oxidant occurs in the catalyst layer 53 of the cathode electrode, and the catalyst layer includes the cathode catalyst for fuel cell of the present invention. The cathode catalyst shows excellent activity and selectivity for the reduction reaction of the oxidant, thereby improving the performance of the cathode electrode 5 and the membrane-electrode assembly 131 including the same.

In the anode layer of the catalyst layer 33, the oxidation reaction of the fuel occurs, and includes a catalyst for promoting the reaction. Participating in the reaction of the fuel cell, anything that can be used as a catalyst can be used, and a representative example thereof is platinum-based Catalysts can be used. The platinum-based catalyst may be platinum, ruthenium, osmium, platinum-ruthenium alloy, platinum-osmium alloy, platinum-palladium alloy or platinum-M alloy (M is Ga, Ti, V, Cr, Mn, Fe, Co, Ni, At least one catalyst selected from the group consisting of Cu, Zn, Sn, Mo, W, Rh, Ru, and mixtures thereof.

As described above, the anode electrode and the cathode electrode may use the same material, but in order to prevent the catalyst poisoning caused by CO generated during the anode electrode reaction in the direct oxidation fuel cell, a platinum-ruthenium alloy catalyst is used as the anode. It is more preferable as an electrode catalyst. Specific examples include Pt, Pt / Ru, Pt / W, Pt / Ni, Pt / Sn, Pt / Mo, Pt / Pd, Pt / Fe, Pt / Cr, Pt / Co, Pt / Ru / W, Pt / Ru At least one selected from the group consisting of / Mo, Pt / Ru / V, Pt / Fe / Co, Pt / Ru / Rh / Ni, Pt / Ru / Sn / W and mixtures thereof may be used.

The catalyst may be used as the catalyst itself (black), or may be supported on a carrier. As the carrier, carbon-based materials such as graphite, denka black, ketjen black, acetylene black, carbon nanotube, carbon nanofiber, carbon nanowire, carbon nanoball, or activated carbon may be used, or alumina, silica, titania Inorganic fine particles such as zirconia and the like may be used, but carbon-based materials are generally used.

Catalyst layers 33 and 53 of the anode electrode and the cathode electrode may include a binder, it is preferable to use a polymer resin having hydrogen ion conductivity as the binder, more preferably sulfonic acid groups, carboxyl in the side chain Any polymer resin having a cation exchange group selected from the group consisting of an acid group, a phosphoric acid group, a phosphonic acid group and derivatives thereof can be used.

Preferably, a fluorine polymer, a benzimidazole polymer, a polyimide polymer, a polyetherimide polymer, a polyphenylene sulfide polymer, a polysulfone polymer, a polyether sulfone polymer, a polyether ketone polymer, a polyether It may include at least one hydrogen ion conductive polymer selected from the group consisting of ether ketone-based polymer, polyphenylquinoxaline-based polymer, and mixtures thereof.

More preferably poly (perfluorosulfonic acid), poly (perfluorocarboxylic acid), copolymers of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid groups, defluorinated sulfided polyether ketones, aryl ketones, Poly (2,2'-m-phenylene) -5,5'-bibenzimidazole (poly (2,2 '-(m-phenylene) -5,5'-bibenzimidazole), poly (2,5- Benzimidazole), and mixtures containing at least one hydrogen ion conductive polymer selected from the group consisting of these can be used.

The binder may be used in the form of a single substance or a mixture, and may also be optionally used with a nonconductive polymer for the purpose of further improving adhesion to the polymer electrolyte membrane. It is preferable to adjust the usage-amount so that it may be suitable for a purpose of use.

Examples of the nonconductive polymer include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro alkylvinyl ether copolymer (PFA), and ethylene / tetrafluoro Ethylene / tetrafluoroethylene (ETFE), ethylenechlorotrifluoro-ethylene copolymer (ECTFE), polyvinylidene fluoride, copolymer of polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), dode It is more preferable that it is at least one selected from the group consisting of silbenzenesulfonic acid, sorbitol, and mixtures thereof.

The electrode substrates 31 and 51 of the anode electrode and the cathode electrode serve to make a reaction source, that is, a fuel and an oxidant, easily accessible to the catalyst layers 31 and 51, and the electrode substrates 31 and 51 are conductive. The surface of a fabric formed of a porous film or polymer fiber composed of carbon paper, carbon cloth, carbon felt or metal cloth (fibrous metal cloth) The metal film is formed on)) may be used, but is not limited thereto.

In addition, it is preferable to use a water-repellent treatment with a fluorine-based resin as the electrode base material because it can prevent the reactant diffusion efficiency from being lowered by water generated when the fuel cell is driven. Examples of the fluorine-based resin include polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonyl fluoride alkoxy vinyl ether, and fluorinated ethylene propylene ( Fluorinated ethylene propylene), polychlorotrifluoroethylene or copolymers thereof can be used.

In addition, a microporous layer may be further included to enhance the reactant diffusion effect in the electrode substrate. The microporous layer is generally a conductive powder having a small particle diameter, for example, carbon powder, carbon black, acetylene black, activated carbon, carbon fiber, fullerene, carbon nanotube, carbon nanowire, carbon nano horn (carbon nano) -horn or carbon nano ring.

The microporous layer is prepared by coating a composition comprising a conductive powder, a binder, and a solvent on the electrode substrate. As the binder, polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonyl fluoride, alkoxy vinyl ether, polyvinyl alcohol, cellulose acetate Or copolymers thereof and the like can be preferably used.

As the solvent, alcohols such as ethanol, isopropyl alcohol, n-propyl alcohol, butyl alcohol, water, dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran, etc. may be preferably used. The coating process may be screen printing, spray coating, or coating using a doctor blade according to the viscosity of the composition, but is not limited thereto.

As the polymer electrolyte membrane 1, a polymer having an ion exchange function of transferring hydrogen ions generated in the catalyst layer 33 of the anode electrode to the catalyst layer 53 of the cathode electrode, and having excellent hydrogen ion conductivity may be used.

Representative examples thereof include a polymer resin having a cation exchange group selected from the group consisting of sulfonic acid groups, carboxylic acid groups, phosphoric acid groups, phosphonic acid groups and derivatives thereof in the side chain.

Representative examples of the polymer resin include a fluorine polymer, a benzimidazole polymer, a polyimide polymer, a polyetherimide polymer, a polyphenylene sulfide polymer, a polysulfone polymer, a polyether sulfone polymer and a polyether ketone At least one selected from the group consisting of a polymer, a polyether-etherketone-based polymer, a polyphenylquinoxaline-based polymer, and a mixture thereof, and more preferably poly (perfluorosulfonic acid), poly (purple) Fluorocarboxylic acid), copolymers of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid groups, defluorinated sulfide polyether ketones, aryl ketones, poly (2,2'-m-phenylene) -5, At least one selected from the group consisting of 5'-bibenzimidazole (poly (2,2 '-(m-phenylene) -5,5'-bibenzimidazole), poly (2,5-benzimidazole) and mixtures thereof One It can be given.

In the hydrogen ion conductive group of the hydrogen ion conductive polymer, H may be substituted with Na, K, Li, Cs or tetrabutylammonium. In the hydrogen ion conducting group of the hydrogen ion conducting polymer, NaOH is substituted when H is replaced with Na, and tetrabutylammonium hydroxide is used when the substituent is substituted with tetrabutylammonium, and K, Li or Cs is also substituted with a suitable compound. It can be substituted using. Since this substitution method is well known in the art, detailed description thereof will be omitted.

The present invention also includes an electricity generation unit including the membrane-electrode assembly for a fuel cell of the present invention, and a separator; A fuel supply unit supplying fuel to the electricity generation unit; And an oxidant supply unit supplying an oxidant to the electricity generation unit.

The electricity generating unit includes a membrane-electrode assembly and a separator (bipolar plate). The electricity generation unit serves to generate electricity through the oxidation reaction of the fuel and the reduction reaction of the oxidant.

The fuel supply unit serves to supply fuel to the electricity generation unit, and the oxidant supply unit serves to supply an oxidant to the electricity generation unit. The fuel means hydrogen or hydrocarbon fuel in gas or liquid state, and typical hydrocarbon fuels include methanol, ethanol, propanol or butanol, and the like. Oxygen is typically used as the oxidant, and may be used by injecting pure oxygen or air. However, the fuel and the oxidant are not limited thereto.

A schematic structure of the fuel cell system 100 is shown in FIG. 2, which will be described in more detail with reference to the following. 2 shows a system for supplying fuel and oxidant to the electricity generation unit 130 using pumps 151 and 171, but the fuel cell membrane-electrode assembly 131 of the present invention is limited to such a structure. Of course, it can be used in a fuel cell system having a structure using a diffusion method without using a pump.

The fuel cell system 100 of the present invention includes a stack 110 having at least one electricity generating unit 130 for generating electrical energy through an oxidation reaction of a fuel and a reduction reaction of an oxidant, and a fuel supplying the fuel. And a supply unit 150 and an oxidant supply unit 170 for supplying an oxidant to the electricity generation unit 130.

The fuel supply unit 150 supplying the fuel includes a fuel tank 153 for storing fuel and a fuel pump 151 connected to the fuel tank 153. The fuel pump 151 serves to discharge the fuel stored in the fuel tank 153 by a predetermined pumping force.

The oxidant supply unit 170 for supplying an oxidant to the electricity generating unit 130 of the stack 110 includes at least one oxidant pump 171 that sucks the oxidant with a predetermined pumping force.

The electricity generating unit 130 is a membrane-electrode assembly 131 for oxidizing and reducing a fuel and an oxidant and a separator (bipolar plate) 133 and 135 for supplying fuel and an oxidant to both sides of the membrane-electrode assembly 131. It is composed of

Hereinafter, preferred examples and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention and the present invention is not limited to the following examples.

(Production of Cathode Catalyst for Fuel Cell)

(Example 1)

1 g of 2,4-dihydroxy benzoic acid and 0.1 g of K ₂ CO ₃ were added to ₂ ml of formaldehyde, and gelled at room temperature and atmospheric pressure for 3 days to prepare an organic gel. The prepared organic gel was impregnated into a solution prepared by adding Rh (NH ₃ ) ₄ Cl ₂ to 0.1M in water to prepare a gel doped with Rh. The Rh-doped gel was CO ₂ supercritical dried under a temperature of 304K and a pressure of 7.6 MPa to obtain a carbon aerogel bearing Rh.

1 g of Rh supported carbon aerogel and 0.06 g of sulfur were added to benzene to form a suspension. The suspension was suspended at 100 ° C. for 24 hours, and then filtered and dried at 80 ° C. to prepare a RhS catalyst supported on a carbonized aerogel. The loading amount of the catalyst was 47% by weight of RhS based on the total catalyst, RhS was 88 atom% and S was 12 atom% in the total RhS.

(Example 2)

A catalyst was prepared in the same manner as in Example 1 except that Se powder was used instead of sulfur.

(Example 3)

A catalyst was prepared in the same manner as in Example 1 except that Pt chloride was used instead of Rh (NH ₃ ) ₄ Cl ₂ .

(Example 4)

A catalyst was prepared in the same manner as in Example 3 except that Se powder was used instead of sulfur.

(Example 5)

A catalyst was prepared in the same manner as in Example 1 except that Ru chloride was used instead of Rh (NH ₃ ) ₄ Cl ₂ .

(Example 6)

A catalyst was prepared in the same manner as in Example 5 except that Se powder was used instead of sulfur.

(Example 7)

A catalyst was prepared in the same manner as in Example 1 except that Pd chloride was used instead of Rh (NH ₃ ) ₄ Cl ₂ .

(Example 8)

A catalyst was prepared in the same manner as in Example 7, except that Se powder was used instead of sulfur.

(Comparative Example 1)

Commercially available Pt black (JM Hispec1000) was used as a catalyst for fuel cells.

(Manufacture of Fuel Cell and Performance Evaluation of Fuel Cell)

A fuel cell system using the catalysts prepared in Examples 1 to 8 as the cathode electrode was manufactured, and performance was compared with the fuel cell system using the platinum-based catalyst of Comparative Example 1 as the cathode electrode. As a result, the fuel cell using the catalysts prepared in Examples 1 to 8 as the cathode electrode had a 20 to 30 times better effect on the selectivity of the methanol oxidation reaction and the oxygen reduction reaction than the fuel cell using the platinum-based catalyst of Comparative Example 1. It was found that the degradation of the battery due to the methanol crossover occurred less.

In addition, by using a carbonized aerogel (Carbonized Aerogel) as a carrier it was possible to increase the loading amount of the catalyst particles, and as a result also increased the oxygen reduction reactivity of the catalyst .

The cathode catalyst for a fuel cell of the present invention has a relatively low fuel oxidation reactivity, thereby reducing the influence of fuel crossover. As a result, the performance of the fuel cell is improved by enabling the use of high concentration fuel. In addition, the cathode catalyst for fuel cells of the present invention can support a large amount of catalyst per unit area, thereby improving the oxygen reduction reactivity of the catalyst.

Claims (18)

Carbonized Aerogel carrier; And Me-Ch supported on the carrier (Me is an element selected from the group consisting of Rh, Ru, Pd, and combinations thereof, and Ch is an element selected from the group consisting of S, Se, and combinations thereof) Cathode catalyst for a fuel cell comprising a. The method of claim 1, Me-Ch (Me is an element selected from the group consisting of Rh, Ru, Pd, and combinations thereof, and Ch is an element selected from the group consisting of S, Se, and combinations thereof). A cathode catalyst for a fuel cell comprising 50 to 98 atomic% of Me and 2 to 50 atomic% of Ch. The method of claim 1, In the fuel cell cathode catalyst, Me-Ch (Me is an element selected from the group consisting of Rh, Ru, Pd, and combinations thereof, Ch is an element selected from the group consisting of S, Se, and combinations thereof) The supported amount is a cathode catalyst for a fuel cell is 5 to 75% by weight based on the total weight of the catalyst. The method of claim 1, Me is Rh, Ch is S cathode catalyst for fuel cells. Gelling the organic acid to prepare an organic gel; Preparing a gel doped with Me by impregnating the organic gel in a Me precursor solution (Me is an element selected from the group consisting of Rh, Ru, Pd, and combinations thereof); Preparing a Me-supported carbon aerogel by supercritical drying the gel doped with Me at a high temperature of 473K to 1273K and a high pressure of 5MPa to 30MPa; And Heating the solution prepared by adding the Me-supported carbon aerogel and Ch precursor to a solvent Method for producing a cathode catalyst for a fuel cell comprising a. The method of claim 5, The organic acid is a method for producing a cathode catalyst for a fuel cell is benzoic acid. The method of claim 5, The Me precursor solution (Me is an element selected from the group consisting of Rh, Ru, Pd, and combinations thereof) is a compound selected from the group consisting of Me chloride, Me acetylacetonite, Me carbonyl, and combinations thereof A method for producing a cathode catalyst for fuel cell, which is prepared by adding to a solvent. The method of claim 7, wherein Wherein said solvent is selected from the group consisting of water, ethanol, acetone, and combinations thereof. delete delete The method of claim 5, The supercritical drying is a method for producing a cathode catalyst for fuel cells that is CO ₂ supercritical drying. The method of claim 5, The Ch precursor (Ch is an element selected from the group consisting of S, Se, and combinations thereof) is S powder, Se powder, CH ₃ CSNH ₂ , H ₂ SO ₃ , H ₂ SeO ₃ , and combinations thereof Method for producing a cathode catalyst for a fuel cell that is selected from the group consisting of. The method of claim 5, Wherein said solvent is selected from the group consisting of water, ethanol, acetone, benzene, and combinations thereof. The method of claim 5, The heating step is a method of producing a cathode catalyst for a fuel cell that is carried out at a temperature of 50 to 150 ℃. The method of claim 5, The heating step is a method for producing a cathode catalyst for a fuel cell will be 12 to 36 hours. An anode electrode and a cathode electrode located opposite each other; And A polymer electrolyte membrane positioned between the anode electrode and the cathode electrode; The cathode-electrode assembly of claim 1, wherein the cathode electrode comprises the cathode catalyst of claim 1. An electricity generating unit including an electrode electrode and a separator including an anode electrode and a cathode electrode positioned opposite to each other, and an electrolyte positioned between the anode electrode and the cathode electrode; A fuel supply unit supplying fuel to the electricity generation unit; And An oxidant supply unit for supplying an oxidant to the electricity generation unit, 5. The fuel cell system of claim 1, wherein the cathode electrode comprises the cathode catalyst of claim 1. The method of claim 17, The fuel cell system is a direct oxidation fuel cell system.

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