KR101815248B1 - Method of preparing non-platinum catalyst for fuel cell - Google Patents

Abstract

The present invention relates to a non-platinum catalyst for fuel cells and a method for producing the same, and more particularly, to a non-platinum catalyst for fuel cells comprising iron nitride nanoparticles in a nitrogen-doped carbon- Can be produced by a simple process, can be produced at a low cost with a low production cost, and can be replaced with an expensive platinum catalyst which has been conventionally used as an oxygen reduction electrode catalyst of a fuel cell.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a non-platinum catalyst for fuel cells,

TECHNICAL FIELD The present invention relates to a platinum catalyst for fuel cells applicable to an oxygen reduction electrode of a fuel cell and a method of manufacturing the same.

Since the polymer electrolyte fuel cell is driven at a low temperature, platinum which is a noble metal catalyst should be used for anode and cathode of the fuel cell in order to increase the reaction rate. However, platinum is not only high in price but also has a limited amount of reserves.

For example, in a hydrogen fuel cell vehicle using a polymer electrolyte fuel cell, an amount of platinum used in a fuel cell vehicle is an average of 50 g per unit, and when producing 70 million cars a year, 3,500 tons of platinum is required. However, the current production of platinum is only 180 tons per year, and the estimated amount of platinum is about 36,000 tons, making it difficult to cope with mass production of hydrogen fuel cell vehicles. In terms of price, the platinum price is 65,000 won per g, and the raw material cost of 50 g of platinum is more than 3.25 million won. Furthermore, since platinum is complexed, pyrolyzed, and the like to be processed into ultrafine particles of 2 to 3 nm, the production cost of the platinum catalyst is greatly increased. The most ideal way to solve this problem is the use of non-whitening catalyst materials. In particular, non-platinum based non-precious metal catalysts based on transition metals have been developed over the last decade or more.

Among them, there have been studies to report the possibility of using a transition metal-nitrogen-carbon compound as a non-whitening catalyst having excellent physicochemical and electrical properties. However, there is still a need for a non-whitening catalyst which satisfies both oxygen reduction performance and durability improvement Development has not been reported yet.

Korean Patent Publication No. 10-2012-0098354 Korean Patent No. 10-1305439 Korean Patent No. 10-2013-0134797

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a platinum catalyst for fuel cells exhibiting excellent oxygen reduction reaction (ORR) characteristics and durability.

Another object of the present invention is to provide a redox electrode for a fuel cell comprising a non-platinum catalyst according to various embodiments of the present invention.

It is another object of the present invention to provide a fuel cell including a non-platinum catalyst according to various embodiments of the present invention.

It is another object of the present invention to provide an apparatus comprising a non-platinum catalyst according to various embodiments of the present invention.

It is still another object of the present invention to provide a method for producing a platinum catalyst for fuel cells capable of synthesizing a platinum catalyst for fuel cells according to various embodiments of the present invention at a low cost in a simple process.

One aspect of the present invention relates to a nitrogen-doped carbon-based support (N-doped Carbon, NC); And a nitrided iron nanoparticle supported on the nitrogen-doped carbon-based support (NC).

Another aspect of the present invention relates to a redox electrode for a fuel cell comprising a non-platinum catalyst according to various embodiments of the present invention.

Another aspect of the present invention relates to a fuel cell comprising a non-platinum catalyst according to various embodiments of the present invention.

Another aspect of the invention is an apparatus comprising a non-platinum catalyst according to various embodiments of the present invention, wherein the apparatus is selected from the group consisting of a vehicle, a domestic fuel cell and a portable fuel cell.

Another aspect of the present invention relates to a method for producing a non-platinum catalyst for a fuel cell, comprising the step of heat-treating a mixture of an iron precursor and a carbonaceous carrier in an atmosphere containing a nitrogen-containing active gas.

The non-platinum catalyst for a fuel cell according to the present invention can exhibit excellent oxygen reduction catalyst performance due to its morphological characteristics with high specific surface area by Fe ₃ N nanoparticles among the iron nitride nanoparticles.

In addition, since a non-platinum catalyst for a fuel cell including Fe ₃ N nanoparticles supported on a nitrogen-doped carbon-based support can be produced by a simple process, and the production cost is low and can be obtained in large quantities, It is possible to replace the expensive platinum catalyst used as the electrode catalyst of the fuel cell and has an advantageous effect in terms of cost competitiveness.

Also,

1 is a schematic view showing a process for producing a non-platinum catalyst of Example 1 and Comparative Example 1;
FIG. 2 is a photograph showing TEM (Transmission Electron Microscope) and FFT (Fast Fourier Transform) analysis results of the platinum catalyst prepared in Example 1. FIG.
3 is a graph showing particle size distribution diagrams of the platinum catalysts prepared in Example 1 and Comparative Example 1, respectively.
FIG. 4 is a distribution map of component-based non-platinum catalyst prepared in Example 1 using electron energy loss spectroscopy (EELS).
FIG. 5 is a graph showing the X-ray diffraction (XRD) analysis results obtained by observing phase-crystals of a non-platinum catalyst prepared by different production conditions in order to optimize conditions for producing a non-platinum catalyst in Example 1. FIG.
6 is a graph comparing the initial performance of ORR polarization through a half-cell in a basic atmosphere with respect to a non-platinum catalyst prepared according to the preparation conditions for optimizing conditions for preparing a platinum catalyst of Example 1. (a) to (d) of Comparative Example 1 and a comparative graph (e) of Comparative Example 1. FIG.
7 is a graph showing the Tafel slope versus ORR of the non-platinum catalyst according to the heat treatment temperature in Example 1. FIG.
8 is a graph showing the results of a rotating ring electrode (RRDE) analysis showing the number of electrons transferred per oxygen molecule in the ORR reaction of the non-platinum catalyst prepared in Example 1. FIG.
9 is a graph showing ORR polarization curves of a half-cell using the non-platinum catalyst prepared in Example 1. FIG.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

One aspect of the present invention relates to a nitrogen-doped carbon-based support (N-doped Carbon, NC); And a nitrided iron nanoparticle supported on the nitrogen-doped carbon-based support (NC).

According to one embodiment, the iron nitride nanoparticles may be Fe ₃ N nanoparticles having an average particle size of 1-50 nm.

If the average particle diameter of the iron nitride nanoparticles is less than 1 nm, the durability of the catalyst may be deteriorated. If the average particle diameter is more than 50 nm, the specific surface area of the catalyst may be decreased to lower the catalytic activity.

The iron nitride nanoparticles may be Fe ₃ N nanoparticles, and among the various iron nitride nanoparticles including FeN and Fe ₄ N, the Fe ₃ N nanoparticles may be more advantageous in catalytic activity associated with the oxygen reduction reaction.

According to another embodiment, the iron nitride nanoparticle may have a (111) crystal face, and the (111) crystal face may serve as an active site to improve catalytic activity.

According to another embodiment, the iron nitride nanoparticles may be contained in an amount of 0.5-10 wt% based on the total weight of the non-platinum catalyst for the fuel cell.

If the content of the iron nitride nanoparticles is less than 0.5% by weight, the catalytic activity decreases. If the amount of the iron nitride nanoparticles is more than 10% by weight, the catalytic activity of the resultant catalyst may deteriorate.

According to another embodiment, the carbon-based carrier may be at least one selected from carbon black, carbon nanotube (CNT), and fluorene.

On the other hand, nitrogen doped in the carbon-based carrier can improve the durability of the catalyst. As the number of times of driving the fuel cell increases, carbon wears down and the durability of the catalyst may be lowered. However, the problem of durability degradation of the catalyst due to nitrogen doped in the carbon-based carrier may be compensated.

In order to improve the durability of the catalyst, the weight of doped nitrogen based on the total weight of the nitrogen-doped carbon-based support (NC) may be 5-10 wt%.

If the amount of nitrogen is less than 5% by weight, there is a problem that the ORR activity point is not sufficient. If the amount is more than 10% by weight, there may be a problem of forming N-site which negatively affects the ORR activity.

Another aspect of the present invention relates to a redox electrode for a fuel cell comprising the non-platinum catalyst.

During operation of the fuel cell, the oxygen reduction reaction occurs at the oxygen reduction electrode and H ₂ O is generated, so that the durability may deteriorate with time.

The non-platinum catalyst for fuel cell exhibits excellent oxygen reduction reaction characteristics in an alkaline and acidic atmosphere, so that the oxygen reduction reaction of the oxygen reduction electrode can be promoted.

Another aspect of the present invention relates to a fuel cell comprising the non-platinum catalyst as described above.

Another aspect of the invention relates to an apparatus comprising the non-platinum catalyst. Examples of such a device include, but are not limited to, a fuel cell vehicle, and the like. The present invention is applicable to a vehicle, a forklift, a bus, a scooter, a domestic fuel cell, and a portable fuel cell to which a fuel cell can be applied.

Another aspect of the present invention relates to a method for producing a non-platinum catalyst for a fuel cell, comprising the step of heat-treating a mixture of an iron precursor and a carbon-based carrier in an atmosphere containing a nitrogen-containing active gas.

According to one embodiment, the nitrogen-containing active gas may be at least one selected from the group consisting of ammonia (NH ₃ ) and nitrogen oxides (NO _x ), and the nitrogen oxide may include nitrogen oxides such as NO and NO ₂ Can be used.

Since the nitrogen-containing active gas serves as a nitrogen source of the non-platinum catalyst for the fuel cell, an active gas containing nitrogen can be widely used.

According to another embodiment, the mixture of the iron precursor and the carbon-based carrier may be prepared by mixing 3-7 wt% of the iron precursor and 93-97 wt% of the carbon-based carrier.

The iron precursor and the catalyst activity decreases if it is less than 3% by weight, Fe ₃ N in which the yield has not been nitrided Fe not good to residue, and also decrease the activity of the catalyst even when the 7% excess by weight, Fe ₃ N Together with FeN and Fe.

Wherein if the carbon-based lower than 93% by weight of bodies carrying the catalyst activity is lowered, Fe ₃ N and taken together may include FeN, Fe remainder, 7 and even also decreases the activity of the catalyst if the weight%, Fe ₃ N yields of And the non-nitrided Fe may remain.

According to a further embodiment, the iron precursor is _{Fe (acac) 3 [iron (} III) acetylacetonate], Fe (acac) 2 [iron (II) acetylacetonate], FeCl 3 · 6H 2 O [Iron (III) chloridehexahydrate] , FeSO ₄ .7H ₂ O [Iron (II) sulfateheptahydrate] and Fe (C ₅ H ₅ ) ₂ [ferrocene] can be used.

In the case of using Fe (acac) ₃ [iron (III) acetylacetonate] among the iron precursors, the activity of the oxygen reduction reaction (ORR) of the prepared platinum catalyst for fuel cell can be improved, Fe ₃ N can be obtained without forming unreacted Fe or other kinds of iron nitride.

According to another embodiment, the heat treatment may be performed at 860-940 占 폚 for 1 to 3 hours.

If the heat treatment temperature is less than 860 ° C, the oxygen reduction reaction (ORR) activity of the non-platinum catalyst for fuel cells to be produced is lowered, Fe and Fe ₄ N can be obtained together with Fe ₃ N, (ORR) activity of Fe ₃ N can be lowered and Fe and FeN can be obtained together with Fe ₃ N.

If the heat treatment time is less than 1 hour, the oxygen reduction reaction (ORR) activity of the non-platinum catalyst for fuel cell decreases, Fe and FeN can be obtained together with Fe ₃ N, The oxygen reduction reaction (ORR) activity is lowered and Fe and Fe ₄ N together with Fe ₃ N can be obtained.

In addition, the heat treatment may be performed in three steps to remove residual organic substances after the reaction and to obtain stabilized Fe ₃ N nanoparticles.

Wherein the two-stage heat treatment is performed at a temperature of 860 - 940 캜; An acid leaching step carried out in a 0.5 MH ₂ SO ₄ aqueous solution at 80 ° C; And a second heat treatment step performed at 860 - 940 캜.

If one of the conditions of the first heat treatment, the acid leaching, and the second heat treatment temperature is not satisfied, the organic matter remains after the reaction and the stability of the Fe ₃ N nanoparticles is lowered, which may lower the activity and durability of the produced catalyst .

Therefore, in order to obtain Fe ₃ N nanoparticles which have completely removed organic substances as iron nitride and stabilized, a first heat treatment step performed at a temperature of 860-940 ° C; An acid leaching step carried out in a 0.5 MH ₂ SO ₄ aqueous solution at 80 ° C; And a second heat treatment step performed at 860 - 940 캜.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope and content of the present invention can not be construed to be limited or limited by the following Examples. In addition, it is apparent that, based on the teachings of the present invention including the following examples, those skilled in the art can easily carry out the present invention in which experimental results are not specifically shown.

FIG. 1 is a schematic view showing a process for producing a non-platinum catalyst according to Example 1 and Comparative Example 1, and Example 1 and Comparative Example 1 were carried out in accordance with the above schematic diagrams.

Example 1: Preparation of a non-platinum catalyst (Fe ₃ N / NC)

1 (a), a mixture of 5% by weight of Fe (acac) ₃ (iron (III) acetylacetonate) as an iron precursor and 95% by weight of carbon black as a carbon- Lt; 0 > C for 2 hours to prepare a platinum catalyst.

Comparative Example 1

As shown in Fig. 1 (b), the inside of the reactor containing the 0.05-molar concentration of the metal precursor FeSO ₄ .7H ₂ O aqueous solution is maintained in an argon atmosphere. The potassium borohydride (KBH ₄ ) solution of 1 molar concentration is slowly added to the aqueous solution at room temperature to obtain amorphous iron through a chemical reduction reaction of the metal. The resultant was washed several times with water and ethanol, put in a tube furnace, and heat-treated at 300 ° C for 10 hours in an ammonia atmosphere to obtain Fe ₃ N nanoparticles.

The Fe ₃ N nanoparticles were mixed with carbon black, and then heat-treated at 900 ° C for 1 hour in an ammonia atmosphere to obtain catalyst particles.

Test Example 1: Analysis of structure and shape of catalyst particles

The structure and shape of the catalyst particles prepared in Example 1 and Comparative Example 1 were analyzed.

FIG. 2 is a photograph showing TEM (Transmission Electron Microscope) and FFT (fast fourier transform) analysis results of the platinum catalyst prepared in Example 1. FIG.

Referring to FIG. 2, the non-platinum catalyst prepared in Example 1 has a structure in which Fe ₃ N nanoparticles are supported on N-doped carbon (NC), and the Fe ₃ N nanoparticles have a 111) crystal plane.

3 is a graph showing the size distribution of Fe ₃ N nanoparticles prepared in Example 1 and Comparative Example 1, respectively.

Referring to FIG. 3, the Fe ₃ N nanoparticles prepared in Example 1 were found to have an average particle size of 24 nm and 20.8 nm and that the Fe ₃ N nanoparticles were well dispersed in a nitrogen-doped carbon support (NC) .

On the other hand, the average particle size of the Fe ₃ N nanoparticles prepared in Comparative Example 1 was significantly larger than that of the Fe ₃ N nanoparticles prepared in Example 1 at 195 ㅁ 90.8 nm. From this, in Comparative Example 1 as Fe ₃ N, if the synthesis of the nanoparticles, separately, the size is less Fe ₃ N is difficult that the production of hard large a specific surface area of the catalyst for producing the nanoparticles, while iron in the same manner as in Example 1 When Fe (acac) ₃ (iron (III) acetylacetonate) is used as a precursor to prepare a catalyst by heat treatment with a carbonaceous support, it is possible to synthesize Fe ₃ N nanoparticles of small size to improve the specific surface area of the catalyst .

Test Example 2: Analysis of Component Distribution

EELS mapping test was performed for the analysis of the surface components of the non-platinum catalyst Fe ₃ N / NC prepared in Example 1.

FIG. 4 is a distribution map of component-based non-platinum catalyst prepared in Example 1 using electron energy loss spectroscopy (EELS).

Referring to FIG. 4, it can be seen that Fe ₃ N / NC, which is a non-platinum catalyst prepared in Example 1, has Fe ₃ N nanoparticles supported on carbon (NC) doped with nitrogen uniformly.

Test Example 3: Analysis of components of catalyst according to manufacturing conditions

FIG. 5 is a graph showing the X-ray diffraction (XRD) analysis results obtained by observing phase-crystals of a non-platinum catalyst prepared by different production conditions in order to optimize conditions for producing a non-platinum catalyst in Example 1. FIG.

Figure 5 (a) is a XRD analysis graph of the non-platinum catalyst according to the type of iron precursor, exemplary synthesis was carried out as Example 1, an iron precursor _{Fe (acac) 3, Fe (} acac) 2, FeCl 3 · 6H ₂ O, FeSO ₄ · 7H ₂ O, and Ferrocene, respectively.

5 (b) is a graph of XRD analysis of a non-platinum catalyst according to the weight of the iron precursor, and the same procedure as in Example 1 was carried out except that the weight of the iron precursor Fe (acac) ₃ was 0.5, 1.0, And 7.5 wt%, respectively, based on the XRD analysis results of the non-platinum catalyst.

FIG. 5 (c) is a graph showing XRD analysis results of the non-platinum catalyst according to the heat treatment temperature. As a result, the heat treatment temperature of the mixture of Fe (acac) ₃ and carbon was 800, 850, 900 and 950 Lt; 0 > C.

FIG. 5 (d) is a graph showing XRD analysis results of the non-platinum catalyst according to the heat treatment time, wherein the heat treatment time of the mixture of Fe (acac) ₃ and carbon was set to 2 hours and 4 hours, XRD analysis of the prepared non-platinum catalyst.

5 (a) to 5 (d), a mixture of Fe (acac) ₃ and carbon black was heat-treated at 900 ° C. for 2 hours using Fe (acac) ₃ as an iron precursor in an amount of 5.0 wt% Fe ₃ N was formed in the nonplatinum catalyst, and Fe, FeN, and Fe ₄ N were formed together with Fe ₃ N in the non-platinum catalyst prepared under different conditions.

5 (e) is a graph of XRD analysis results of the platinum catalysts prepared in Example 1 and Comparative Example 1, respectively.

5 (e), Example 1 shows that the ratio of Fe (acac) _{3 prepared} as the iron precursor to the carbon black used as the iron precursor, and the ratio It can be seen that a platinum catalyst containing Fe ₃ N is produced as a platinum catalyst.

In Comparative Example 1, a Fe ₃ N component was detected as a non-platinum catalyst prepared by first synthesizing Fe ₃ N nanoparticles and then heat-treating them together with carbon black.

Test Example 4: Electrochemical Experiment

The electrochemical experiment of the catalyst is usually performed in a rotating disk electrode (RDE) three electrode cell. A 0.1 M KOH solution was used as the electrolyte, and the solution temperature was maintained at 25 ° C. The counter electrode is a platinum plate electrode, and the reference electrode is a saturated calomel electrode (SCE). In the cyclic current method, high purity argon (Ar) gas was purged at a flow rate of 400 cc / min for 30 minutes to remove oxygen in the solution. The argon (Ar) gas atmosphere was maintained at the same flow rate until the end of the experiment. After the circulating current method, the oxygen (O ₂ ) gas was purged for 30 minutes at the same flow rate as the above-mentioned argon (Ar) gas to make the electrolyte solution into the oxygen atmosphere After the quenching, oxygen (O ₂ ) atmosphere was maintained at the same flow rate until the end of the experiment.

10 mg Fe ₃ N / NC catalyst of the platinum catalyst prepared in Example 1 was dispersed by using ultrasonic waves in 1,000 μl of IPA (isopropyl alcohol) solution and 100 μl of Nafion solution (5% by weight solution) . 5 잉크 of the ink was transferred to a glass carbon rotary disc electrode (RDE, 5 mm in diameter) by a micropipette, and was dried. Catalyst ink was prepared by the same method using the non-platinum catalyst prepared in Comparative Example 1 except that 10 μl of ink was used.

4-1. Oxygen reduction reaction (ORR)

ORR experiments were performed at room temperature in an oxygen-saturated 0.1 M KOH solution and 0.1 M KOH solution. The RDE rotational speed is 1600 rpm and the voltage sweep rate is 5 mV / s.

FIG. 6 is a graph comparing the initial performance of ORR polarization through a half-cell in a basic atmosphere with respect to a non-platinum catalyst prepared by varying the production conditions in order to optimize the preparation conditions of the platinum catalyst of Example 1. (a) to (d) of Comparative Example 1 and a comparative graph (e) of Comparative Example 1. FIG.

6 (a) is a graph showing the rotating disk current density versus the ORR characteristics of a non-platinum catalyst according to the kind of iron precursor, and is the same as Example 1 except that Fe (acac) ₃ , Fe acac) ₂ , FeCl ₃ .6H ₂ O, FeSO ₄ .7H ₂ O, and ferrocene, respectively.

Of Figure 6 (b) is a graph showing the rotation disk current density for ORR properties of non-Pt catalysts according to the weight of the iron precursor in Example 1, but the same manner as in each of the weight of the iron precursor, Fe (acac) ₃ 0.5, 1.0, 2.5, 5.0, and 7.5 wt%, respectively.

Of Figure 6 (c) is a graph showing the rotation disk current density for ORR properties of non-Pt catalysts according to the heat treatment temperature in Example 1, but the same manner as the Fe (acac) heat-treating temperature of a mixture of ₃ and a carbon, respectively 800, 850, 900 and 950 < 0 > C, respectively.

Of Figure 6 (d) is a graph showing the rotation disk current density for ORR properties of non-Pt catalysts according to the heat treatment time in Example 1, but the same manner as Fe (acac) a heat treatment time of the mixture of ₃ and a carbon, respectively 2 hours and 4 hours, respectively.

6 (a) to 6 (d), a mixture of Fe (acac) ₃ and carbon was heat-treated at 900 ° C. for 2 hours using 5.0% by weight of Fe (acac) ₃ as an iron precursor It can be seen that the non-platinum catalyst exhibits excellent catalytic activity as compared with the catalysts prepared under other conditions.

6 (e) is a graph showing the rotating disk current density versus ORR characteristics of the non-platinum catalysts prepared in Example 1 and Comparative Example 1, respectively.

6 (e), it can be seen that the non-platinum catalyst prepared in Example 1 exhibits superior catalytic activity as compared with the non-platinum catalyst prepared in Comparative Example 1.

7 is a graph showing the Tafel slope versus ORR of the non-platinum catalyst according to the heat treatment temperature in Example 1. FIG.

Referring to FIG. 7, when the heat treatment temperature is 900 ° C., it shows a low Tafel slope, indicating that the catalyst exhibits a faster ORR than the catalyst prepared under other conditions.

8 is a graph showing the results of a rotating ring electrode (RRDE) analysis showing the number of electrons transferred per oxygen molecule in the ORR reaction of the non-platinum catalyst prepared in Example 1. FIG.

Referring to FIG. 8, it can be seen that the non-platinum catalyst prepared in Example 1 exhibits a favorable 4-electron selectivity for the ORR reaction.

4-2. Accelerated degradation testing (ADT)

CV measurements for the ADT evaluation test consist of 4,000 _cycles at 0.6 to 1.0 V _RHE potential in 0.1 M KOH solution O ₂ purged at room temperature with a scan speed of 50 mV / s.

9 is a graph showing ORR polarization curves of a half-cell using the non-platinum catalyst prepared in Example 1. FIG.

Referring to FIG. 9, when the change in the half-wave potential after 4,000 cycles was measured, it shifted about 33 mV from the initial value, which is almost equivalent to that of the commercial platinum catalyst under equivalent experimental conditions. It can be confirmed that the non-platinum catalyst (Fe ₃ N / NC) prepared in Example 1 exhibits excellent durability.

It will be apparent to those skilled in the art that the present invention is not limited to the embodiments described above and that various changes and modifications may be made without departing from the spirit and scope of the present invention as defined by the appended claims. As shown in FIG.

It will be understood by those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention as defined by the appended claims and their equivalents. .

Claims (13)

delete delete delete delete delete delete delete delete Comprising the step of heat-treating a mixture of an iron precursor and a carbon-based carrier in a nitrogen-containing active gas atmosphere,
And the iron precursor is _{Fe (acac) 3 [iron (} III) acetylacetonate] , and _{Fe (acac) 2 [iron (} II) acetylacetonate] at least one selected from,
The carbon-based carrier is at least one selected from carbon black, carbon nanotubes (CNTs) and fluorenes,
The heat treatment is carried out at 860-940 占 폚 for 1-2 hours,
Wherein the step is performed in one step,
A method for producing a platinum catalyst for fuel cells. 10. The method for producing a platinum catalyst for a fuel cell according to claim 9, wherein the nitrogen-containing active gas is at least one selected from ammonia and nitrogen oxides. The non-platinum catalyst for a fuel cell according to claim 9, wherein the mixture of the iron precursor and the carbon-based carrier is prepared by mixing 3-7 wt% of the iron precursor and 93-97 wt% of the carbon- Gt; delete delete

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