KR20070105701A - Cathode catalyst for fuel cell, and membrane-electrode assembly for fuel cell and fuel cell system comprising same - Google Patents

Abstract

A cathodic catalyst for a fuel cell is provided to ensure superior activity and selectivity for a reduction reaction of an oxidant and excellent stability under an acidic atmosphere. A cathodic catalyst for a fuel cell includes a Co-Fe-O-N active material. The active material has a structure represented by the formula 1 of (Co_aFe_b)O_cN_d, wherein 0.1<=a<=0.9, 0.1<=b<=0.9, 0.001<=c<=0.01, and 0.001<=d<=0.2. The active material is carried on a carrier in an amount of 10-80wt% based on the total weight of the catalyst. The carrier is a carbonaceous material selected from the group consisting of graphite, denka black, ketjen black, acetylene black, carbon nanotubes, carbon nanofibers, carbon nanowires, carbon nanoballs, active carbon, and combinations thereof.

Description

Cathode catalyst for fuel cell, and membrane-electrode assembly and fuel cell system for fuel cell including same TECHNICAL FIELD

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 another embodiment of the present invention.

[Industrial use]

The present invention relates to a cathode catalyst for a fuel cell, and a fuel cell membrane-electrode assembly and a fuel cell system including the same, and more particularly, to a fuel cell membrane having excellent activity and selectivity to a reduction reaction of an oxidant. A cathode catalyst capable of improving the performance of an electrode assembly and a fuel cell system, and a membrane-electrode assembly and a fuel cell system for a fuel cell comprising 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.

This fuel cell is a clean energy source that can replace fossil energy, and has the advantage of generating a wide range of outputs by stacking unit cells, and having an energy density of 4-10 times that of 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 the 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 a fuel cell system, the stack that substantially generates electricity is comprised of a number of unit cells consisting of a membrane-electrode assembly (MEA) and a separator (also called a bipolar plate). It has a stacked structure of several tens. The membrane-electrode assembly is called an anode electrode (also called "fuel electrode" or "oxide electrode") and a cathode electrode (also called "air electrode" or "reduction electrode") with a polymer electrolyte membrane including a hydrogen ion conductive polymer therebetween. ) Is located.

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.

It is an object of the present invention to provide a cathode catalyst for a fuel cell having excellent activity and selectivity for the reduction reaction of an oxidant.

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 provides a cathode catalyst for a fuel cell comprising an active material of Co-Fe-O-N.

The present invention also includes an anode electrode and a cathode electrode positioned opposite to each other and a polymer electrolyte membrane positioned between the anode and the cathode electrode, wherein the cathode electrode comprises the cathode catalyst of the present invention- Provide an electrode assembly.

The present invention also provides an electricity generator including the membrane electrode assembly of the present invention and separators located on both sides of the membrane electrode assembly, a fuel supply unit supplying fuel to the electricity generator, and an oxidant to the electricity generator. It provides a fuel cell system comprising an oxidant supply.

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

A fuel cell is a power generation system that obtains electrical energy through oxidation of a fuel and reduction of an oxidant. An oxidation reaction of a fuel occurs at an anode electrode and a reduction reaction of an oxidant occurs at a cathode electrode.

A catalyst capable of promoting the oxidation reaction of the fuel and the reduction reaction of the oxidant is used for the catalyst layers of the anode electrode and the cathode electrode, and platinum-ruthenium is typically used for the catalyst layer of the anode electrode and platinum is used for the catalyst layer of the anode electrode.

However, platinum used as a cathode catalyst has low selectivity for the reduction reaction of the oxidant and is depolarized by the fuel that has passed through the electrolyte membrane to the cathode region in a direct oxidation fuel cell. There is a problem that is deactivated, attention is focused on the catalyst that can replace platinum.

In contrast, the present invention provides a cathode catalyst for a fuel cell comprising an active material of Co-Fe-O-N. The catalyst is excellent in activity and selectivity to the reduction reaction of the oxidizing agent can improve the battery characteristics when applied to the fuel cell.

The metal catalyst forms a bond with the oxidant absorbed on the metal surface in the reduction reaction of the oxidant, and exhibits catalytic activity by the metal providing electrons to the oxidant.

Co and Fe, which are metals used in the cathode catalyst of the present invention, may be used together to form an alloy, thereby increasing activity for the reduction reaction of the oxidant. In addition, Co and Fe may exhibit higher catalytic activity and selectivity for the reduction reaction of the oxidant by forming N, Co-N and Fe-N.

Nitrogen (N) also has lone pairs of electrons, which serve as electron donors and electron reservoirs for providing electrons to metal atoms in the catalyst. Oxygen (O) modifies the surface of the metal to form defects on the metal surface, and the defects thus formed create an active center on the metal surface to further enhance the activity of the catalyst. In addition, oxygen (O) functions to protect the catalyst from the material constituting the electrolyte membrane of the membrane-electrode assembly.

It is preferable that the active material of Co-Fe-O-N has a structure of Formula 1 below.

[Formula 1]

(Co _a Fe _b ) O _c N _d

(Wherein 0.1≤a≤0.9, 0.1≤b≤0.9, 0.001≤c≤0.01, and 0.001≤d≤0.2, more preferably 0.3≤a≤0.6, 0.2≤b≤0.4, 0.006≤c≤0.008 And 0.009 ≦ d ≦ 0.12.)

In Formula 1, a, b, c, and d represent mol% of constituent elements included in the cathode catalyst. If the content of Co in the cathode catalyst is less than 0.1 mol%, alloy formation with Fe is not easy and there is a possibility that the catalytic activity may be lowered. If the content of Co is greater than 0.9 mol%, the catalyst particle size may be increased, which is not preferable. not.

In addition, if the content of Fe is less than 0.1 mol%, alloy formation with Co is not easy and there is a possibility that the catalyst activity may be lowered, and if it is more than 0.9 mol%, there is a possibility that the catalyst particle size may increase, which is not preferable.

If the content of O is less than 0.001 mol%, there is a possibility that the stability of the catalyst may be deteriorated. If the content of O is more than 0.01 mol%, the surface of the catalyst and the active center may be covered by O, which may lower the activity.

If the content of N is less than 0.001 mol%, the stability of the catalyst may be deteriorated, which is not preferable. If the content of N is more than 0.2 mol%, the surface of the catalyst and the active center may be covered by N, which may lower the activity.

The Co-Fe-O-N may be used as a metal catalyst black or may be supported on a carrier. When used on a carrier, the size of the catalyst particles can be reduced, which is more preferable since the reaction surface area of the catalyst can be increased. As the carrier, carbon-based materials such as graphite, denka black, ketjen black, acetylene black, carbon nanotubes, carbon nanofibers, carbon nanowires, carbon nano balls, or activated carbon may be used.

In this case, the supported amount of the Co-Fe-ON active material supported on the carrier is preferably 10 to 80% by weight, and 40 to 60% by weight based on the total weight of the catalyst, in which both the masses of Co-Fe-ON and the carrier are combined. More preferred. If the supported amount is less than 10% by weight, the amount of catalyst is small and there is a possibility that the activity of the catalyst may be lowered, and if it is more than 80% by weight, the catalyst activity may be lowered due to aggregation between particles, which is not preferable.

The cathode catalyst as described above may be prepared by a manufacturing method comprising mixing a Co source, a Fe source, and an N source in a solvent to prepare a mixture, and heat treating the filtrate obtained by filtering the mixture.

As the Co source, a water-soluble salt of Co such as CoCl ₂ .2H ₂ O may be used, and as the source of Fe, a water-soluble salt of Fe such as Fe (NO ₃ ) ₃ .9H ₂ O may be used. In addition, tetramethoxyphenylporphyrin may be used as the N source.

In addition, as the source, a compound including Co, Fe, or N, such as Fe-phthalocyanine and Co-phthalocyanine, may be used as the source.

As the solvent, organic solvents such as benzene and toluene can be used.

The mixing ratio of the source containing each element can be appropriately adjusted in consideration of the content ratio of each element in the final catalyst produced.

When supporting the carrier, a carrier may be further added when the raw material is mixed. As the carrier, the same ones as described above can be used, and the amount of the carrier can also be appropriately adjusted in consideration of the supported amount of the finally obtained cathode catalyst.

The prepared mixture may be filtered, and the resulting filtrate may be heat treated to prepare a cathode catalyst.

It is preferable that the heat processing temperature at the time of heat processing is 450-1150 degreeC, More preferably, it is 800-1000 degreeC. If the heat treatment temperature is less than 450 ° C., the source material is not sufficiently decomposed and is not preferable. If the heat treatment temperature is more than 1150 ° C., the particle size becomes large due to aggregation of the catalyst particles, which is not preferable.

In addition, the heat treatment is preferably performed for 1 to 5 hours. If the heat treatment time is less than 1 hour, the source material is not sufficiently decomposed, and if it is more than 5 hours, the particle size becomes large due to aggregation of the catalyst particles, which is not preferable.

In addition, the heat treatment step is preferably carried out in a mixed gas atmosphere of nitrogen and oxygen. More preferably, the nitrogen and oxygen gas may be mixed in a volume ratio of 1: 0.001 to 1: 0.01. If the volume ratio of oxygen gas to nitrogen is less than 0.001, it cannot be oxidized. If it exceeds 0.01, too much oxide is present on the surface, which is not preferable.

Cathode catalyst prepared by the above production method has excellent activity and selectivity for the reduction reaction of the oxidizing agent can be effectively used as a cathode catalyst for fuel cells.

Specifically, the cathode catalyst for the fuel cell of the present invention may be used in a polymer electrolyte fuel cell (PEMFC), a direct oxidation fuel cell (PEFCC), or the like. In addition, by using a catalyst that selectively acts only on the oxidation reaction of the fuel in the anode catalyst layer and a catalyst that selectively acts only in the reduction reaction of the oxidant in the cathode catalyst layer, even if a mixture of fuel and oxidant is injected into the anode and the cathode catalyst layer In the above, the fuel cell may be employed without limitation in a mixed reactant fuel cell in which only the oxidation reaction of the fuel and only the reduction reaction of the oxidant occurs in the cathode catalyst layer.

 Cathode catalyst of the present invention has excellent selectivity to the oxygen reduction reaction, it can be used more effectively in a direct oxidation fuel cell problem of fuel crossover, and is most suitable for a direct methanol fuel cell (DMFC) Can be used effectively.

The present invention also provides a fuel cell membrane-electrode assembly comprising the cathode catalyst for fuel cell of the present invention.

The membrane-electrode assembly of the present invention includes an anode electrode and a cathode electrode positioned to face each other and a polymer electrolyte membrane positioned between the anode and the cathode electrode, wherein the anode electrode and the cathode electrode are formed of an electrode substrate and a conductive substrate. It includes a catalyst layer formed on the electrode substrate.

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 generates electricity through oxidation of a fuel and reduction of an oxidant, and one or several are stacked and mounted in a stack.

A reduction reaction of the oxidant occurs in the catalyst layer 53 of the cathode electrode, and the catalyst layer includes a cathode catalyst for fuel cells containing Co—Fe—O—N. 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 catalyst layer 33 of the anode electrode, an oxidation reaction of fuel occurs, and a catalyst capable of promoting this may be included. A platinum-based catalyst, which is conventionally used, may be used. As the platinum-based catalyst, platinum, ruthenium, osmium, platinum-ruthenium alloy, platinum-osmium alloy, platinum-palladium alloy, platinum-M alloy (M is Ga, Ti, V, Cr, Mn, Fe, Co, Ni, Transition metal selected from the group consisting of Cu, Zn, Sn, Mo, W, Rh, and combinations thereof), and a catalyst selected from the group consisting of combinations thereof. In the direct oxidation fuel cell, a platinum-ruthenium alloy catalyst is more preferable as the anode electrode catalyst in order to prevent the catalyst poisoning caused by CO generated during the anode electrode reaction. 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 / Mo, Pt / Ru / V, Pt / Fe / Co, Pt / Ru / Rh / Ni, Pt / Ru / Sn / W, and combinations thereof may be used.

In addition, such a metal catalyst may be used as the metal catalyst (black) itself, or may be supported on a carrier. As the carrier, carbonaceous materials such as graphite, denka black, ketjen black, acetylene black, carbon nanotubes, carbon nanofibers, carbon nanowires, carbon nanoballs or activated carbon may be used, or alumina, silica, zirconia, Inorganic fine particles such as titania may be used, but carbon-based materials are generally used.

The catalyst layers 33 and 53 of the anode electrode and the cathode electrode may further include a binder resin to improve adhesion of the catalyst layer and transfer of hydrogen ions.

It is preferable to use a polymer resin having hydrogen ion conductivity as the binder resin, more preferably a cation exchange group selected from the group consisting of sulfonic acid group, carboxylic acid group, phosphoric acid group, phosphonic acid group and derivatives thereof in the side chain. Any polymer resin which has 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 One or more hydrogen ion conductive polymers selected from ether ketone polymers or polyphenylquinoxaline polymers, more preferably poly (perfluorosulfonic acid), poly (perfluorocarboxylic acid), Copolymers of tetrafluoroethylene with fluorovinyl ethers containing sulfonic acid groups, defluorinated polyether ketones, aryl ketones, poly (2,2'-m-phenylene) -5,5'-bibenz Imideazole (poly (2,2 '-(m-phenylene) -5,5'-bibenzimidazole), poly (2,5-benzimidazole) and a combination of hydrogen ion conductive polymer selected from the group consisting of To do It can be used.

The binder resin may be used in the form of a single substance or a mixture, and may also be optionally used with a nonconductive compound 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 non-conductive compound include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro alkyl vinyl ether copolymer (PFA), and ethylene / tetrafluoro Ethylene / tetrafluoroethylene (ETFE), ethylenechlorotrifluoro-ethylene copolymer (ECTFE), polyvinylidene fluoride, copolymer of polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), dode More preferably, it is selected from the group consisting of silbenzenesulfonic acid, sorbitol, and combinations thereof.

The electrode substrates 31 and 51 of the anode electrode and the cathode electrode support the electrode and diffuse the fuel and the oxidant to the catalyst layer, thereby serving to easily access the fuel and the oxidant to the catalyst layer. Conductive substrates are used as the electrode substrates 31 and 51, and representative examples thereof include carbon paper, carbon cloth, carbon felt, or metal cloth (porosity composed of metal cloth in fiber state). The film or the metal film formed on the surface of the cloth formed of polymer fibers (referred to metalized polymer fiber)) may be used, but is not limited thereto.

In addition, it is preferable to use the water repellent treatment of the electrode substrates 31 and 51 with a fluorine-based resin because it prevents 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 (not shown) may be further included to enhance the diffusion effect of the reactants on the electrode substrates 31 and 51. These microporous layers are generally conductive powders having a small particle diameter, such as carbon powder, carbon black, acetylene black, activated carbon, carbon fiber, fullerene, carbon nanotubes, carbon nanowires, and carbon nanohorns. -horn or carbon nano ring, and the like.

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

The polymer electrolyte membrane 1 functions as an ion exchange to move hydrogen ions generated in the catalyst layer 33 of the anode electrode to the catalyst layer 53 of the cathode electrode.

Therefore, generally used as the polymer electrolyte membrane (1) in the fuel cell, anything made of a polymer resin having hydrogen ion conductivity can be used. Representative examples thereof include a polymer resin having a cation exchange group selected from the group consisting of sulfonic acid group, carboxylic acid group, phosphoric acid group, phosphonic acid group 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 Polymers, polyether-etherketone-based polymers, or polyphenylquinoxaline-based polymers, and the like, and more preferably, tetra (fluoro) containing poly (perfluorosulfonic acid), poly (perfluorocarboxylic acid), and sulfonic acid groups. Copolymers of roethylene and fluorovinyl ether, defluorinated sulfide polyether ketones, aryl ketones, poly (2,2'-m-phenylene) -5,5'-bibenzimidazole (poly (2,2 It is preferable to use one selected from the group consisting of '-(m-phenylene) -5,5'-bibenzimidazole), poly (2,5-benzimidazole) and combinations thereof.

In the hydrogen ion conductive group of the hydrogen ion conductive polymer, H may be substituted with Na, K, Li, Cs or tetrabutylammonium. In case of replacing H by Na in the ion-exchange group of the side chain terminal, NaOH is substituted in the preparation of the catalyst composition, and tetrabutylammonium hydroxide is used in the case of using tetrabutylammonium, and K, Li or Cs is also substituted with appropriate compounds. 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 provides a fuel cell system comprising the membrane-electrode assembly of the present invention as described above.

 The fuel cell system of the present invention includes at least one electricity generator, a fuel supply and an oxidant supply.

The electricity generating portion includes a membrane-electrode assembly and a separator (also called bipolar plate). The membrane-electrode assembly includes a polymer electrolyte membrane and cathode and anode electrodes existing on both sides of the polymer electrolyte membrane. 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 such as oxygen or air to the electricity generation unit.

In the present invention, the fuel may include hydrogen or hydrocarbon fuel in gas or liquid state. Representative examples of the hydrocarbon fuel include methanol, ethanol, propanol, butanol or natural gas.

The fuel cell system of the present invention can be employed without limitation in Polymer Electrolyte Membrane Fuel Cell (PEMFC), Direct Oxidation Fuel Cell, and Mixed Reactant Fuel Cell. Can be.

A schematic structure of a fuel cell system 100 according to an embodiment of the present invention 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 membrane-electrode assembly 131 for fuel cells 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 includes a stack 110 having at least one electricity generator 130 for generating electrical energy through an oxidation reaction of a fuel and a reduction reaction of an oxidant, and a fuel supply unit 150 for supplying the fuel. ) 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. ), The electricity generating unit 130 is at least one gather to constitute a stack (110).

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

Example  One

5 g of Fe-phthalocyanine and 7 g of Co-phthalocyanine were added and mixed in 100 ml of benzene, and then 1 g of Ketjen black was further added and stirred at 60 ° C. for 24 hours. The filtrate obtained after the mixture was filtered N ₂ 200ml / min and O ₂ 1ml / min and the mixed air atmosphere, and heat treated at 1000 ℃ for 5 hours supported on Ketjen Black (Co _{0 .5} Fe _{0 .6)} O ₀ to prepare a cathode catalyst of _.008 N _{0 .009.}

The amount of the _{(Co 0 .5 Fe 0 .6)} O 0 N _{0 .009 .008} of active material supported on the Ketjen black was 47 wt%.

Comparative example  One

0.6 g of ruthenium carbonyl, 0.03 g of Se powder, and 1 g of ketjen black were added to 150 ml of toluene, and mixed at 140 ° C. for 24 hours to prepare a mixture. The mixture was filtered to obtain a filtrate, and the obtained filtrate was dried at 80 ° C. to obtain a powder. The powder was heat-treated at 250 ° C. for 3 hours under a hydrogen atmosphere to prepare a cathode catalyst of RuSe supported on Ketjen Black.

At this time, the active material of RuSe in the cathode catalyst comprises 83 mol% of Ru and 17 mol% of Se, and the supporting amount of the active material supported on Ketjen Black was 56% by weight.

Oxygen gas was bubbling for 2 hours in a sulfuric acid solution of 0.5 M concentration to prepare an oxygen saturated sulfuric acid solution, and the catalyst of Example 1 and the catalyst of Comparative Example 1 were each glassy carbon. 3.78 × 10 ⁻³ mg was loaded onto the working electrode, and a platinum mesh was placed in the sulfuric acid solution as a counter electrode, and the current density was measured while changing the voltage.

As a result of the measurement, the catalyst prepared according to Example 1 showed a higher current density than the catalyst of Comparative Example 1. From this, it was confirmed that the catalyst of Example 1 exhibited excellent catalytic activity compared to the catalyst of Comparative Example 1. At this time, the catalyst of Example 1 showed a catalytic activity increased by about 25% compared to that of Comparative Example 1.

Cathode catalyst for fuel cell of the present invention is excellent in activity and selectivity to the reduction reaction of the oxidizing agent, excellent stability even in an acidic atmosphere, and can improve the performance of the fuel cell membrane-electrode assembly and fuel cell system comprising the same There is this.

Claims (13)

A cathode catalyst for a fuel cell comprising the active material of Co-Fe-O-N. The method of claim 1, The active material is a cathode catalyst for a fuel cell having the structure of formula (1). [Formula 1] (Co _a Fe _b ) O _c N _d (Wherein 0.1 ≦ a ≦ 0.9, 0.1 ≦ b ≦ 0.9, 0.001 ≦ c ≦ 0.01, and 0.001 ≦ d ≦ 0.2) The method of claim 1, Wherein the active material is 0.3 ≦ a ≦ 0.6, 0.2 ≦ b ≦ 0.4, 0.006 ≦ c ≦ 0.008, and 0.009 ≦ d ≦ 0.12. The method of claim 1, The active material is a cathode catalyst for a fuel cell that is supported on a carrier. The method of claim 4, wherein The carrier is a carbon-based material selected from the group consisting of graphite, denka black, ketjen black, acetylene black, carbon nanotubes, carbon nanofibers, carbon nanowires, carbon nanoballs, activated carbon, and combinations thereof. Cathode catalyst. The method of claim 4, wherein The active material is a cathode catalyst for a fuel cell that is supported on the carrier in 10 to 80% by weight relative to the total weight of the catalyst. An anode electrode and a cathode electrode located opposite each other; And A polymer electrolyte membrane positioned between the anode and the cathode electrode, 7. The membrane-electrode assembly of a fuel cell, wherein the cathode electrode comprises the cathode catalyst according to any one of claims 1 to 6. The method of claim 7, wherein The polymer electrolyte membrane comprises a polymer resin having a cation exchange group selected from the group consisting of sulfonic acid group, carboxylic acid group, phosphoric acid group, phosphonic acid group and derivatives thereof in the side chain. In claim 8, The polymer resin may be 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 poly A membrane-electrode assembly for a fuel cell, which is a polymer resin selected from the group consisting of ether-ether ketone polymers, polyphenylquinoxaline polymers, and copolymers thereof. The method of claim 7, wherein The anode electrode is platinum, ruthenium, osmium, platinum-ruthenium alloy, platinum-osmium alloy, platinum-palladium alloy, platinum-M alloy (M is Ga, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, A transition metal selected from the group consisting of Zn, Sn, Mo, W, Rh, and combinations thereof), and a catalyst selected from the group consisting of combinations thereof. An electricity generating unit including an anode electrode and a cathode electrode positioned opposite to each other, and a membrane-electrode assembly including a polymer electrolyte membrane positioned between the anode and the cathode and separators disposed on both sides of the membrane-electrode assembly; A fuel supply unit supplying fuel to the electricity generation unit; And An oxidant supply unit for supplying an oxidant to the electricity generating unit, The cathode electrode fuel cell system comprising a cathode catalyst according to any one of claims 1 to 6. The method of claim 11, The fuel cell system is selected from the group consisting of a polymer electrolyte fuel cell, a direct oxidation fuel cell and a mixed injection fuel cell. The method of claim 11, And the fuel cell system is a direct oxidation fuel cell.

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