KR20190009584A - Catalyst for fuel cell and method of manufacturing the same, and membrane-electrode assmbly and method of manufacturing the same - Google Patents

Abstract

A catalyst for a fuel cell according to an embodiment of the present invention includes a predetermined metal doped on a platinum-nickel (Pt-Ni) nanoparticle catalyst. The doped predetermined metal may be at least one selected from the group consisting of indium (In), gallium (Ga), tantalum oxide (TaO), ruthenium (Ru), zirconium (Zr), and gadolinium. According to the present invention, a catalyst for a fuel cell and a membrane-electrode assembly excellent in activity and durability against an oxygen reduction reaction can be provided.

Description

TECHNICAL FIELD The present invention relates to a catalyst for a fuel cell, a method for producing the same, a membrane-electrode assembly, and a method for manufacturing the same. BACKGROUND ART [0002]

The present invention relates to a catalyst for a fuel cell and a membrane-electrode assembly, and more particularly, to a catalyst for fuel cell by doping a predetermined metal on platinum-nickel supported on carbon, Electrode assembly.

The polymer electrolyte fuel cell is a high-output fuel cell based on high efficiency and high output, which has a higher current density than other types of fuel cells. It operates at low temperatures and has a simple structure. Also, it has a quick start and response characteristics and is suitable for power source of vehicles and building power. Platinum catalyst (Pt / C) supported on carbon is used as an electrode material of polymer electrolyte fuel cell, and platinum usage should be reduced to reduce the price.

The Pt / C catalyst showed fast hydrogen oxidation reactivity at the cathode, while the slow - oxygen reduction reaction at the anode catalyst showed a large amount of platinum catalyst in the anode. In order to overcome this problem, an attempt has been made to develop a catalyst having a high oxygen reduction activity through the control of the alloy and shape between platinum and transition metal. As a result, a platinum-nickel octahedral catalyst having an oxygen- It has been reported that the reaction activity is very excellent. However, nickel easily dissolves in the fuel cell operating environment and the octahedral structure is deformed into a spherical shape when used for a long period of time, so that the initial performance is excellent but the durability is poor. Also, the eluted nickel may contaminate the Nafion membrane of the Nafion membrane and the Nafion ionomer of the electrode, which may deteriorate the ionic conductivity and deteriorate the performance of the fuel cell. That is, there remains a problem that the durability problem and the activity of the oxygen reduction reaction are low even in the fuel cell driving environment implemented with the catalyst of the platinum-nickel octahedral structure.

In order to overcome the limitations of the conventional platinum catalyst, the present invention provides a catalyst for a fuel cell and a membrane-electrode assembly excellent in activity and durability against an oxygen reduction reaction by preparing a catalyst for a fuel cell doped with a predetermined metal in platinum- .

It is also intended to minimize the elution of nickel in the fuel cell driving environment by doping a predetermined metal, thereby enhancing the stability.

In the case of a membrane-electrode assembly composed of a catalyst for a fuel cell doped with a predetermined metal, a higher initial unit cell performance is exhibited and a higher maximum current density can be generated.

The catalyst for a fuel cell according to an embodiment of the present invention includes a Pt-Ni (Ni) nanoparticle catalyst doped with a predetermined metal, and the doped predetermined metal is indium (In), gallium (Ga) , Tantalum oxide (TaO), ruthenium (Ru), zirconium (Zr), and gadolinium (Gd).

The membrane-electrode assembly for a fuel cell according to an embodiment of the present invention includes a cathode, an anode, and a polymer electrolyte membrane disposed between the cathode and the anode, wherein the anode is formed of a Pt (nano-sized) The anode is made of a platinum (Pt) -nickel (Ni) nanoparticle catalyst doped with a predetermined metal, and the doped predetermined metal is indium (In), gallium (Ga), tantalum oxide (TaO), ruthenium Ru), zirconium (Zr), and gadolinium (Gd).

The method for preparing a catalyst for a fuel cell according to an embodiment of the present invention includes the step of doping a predetermined metal on a Pt-Ni (Ni) nanoparticle catalyst, wherein the doped predetermined metal is indium (In) , Gallium (Ga), tantalum oxide (TaO), ruthenium (Ru), zirconium (Zr), and gadolinium (Gd).

The method for fabricating a membrane-electrode assembly for a fuel cell according to an embodiment of the present invention includes forming a cathode using a platinum (Pt) nanoparticle catalyst, forming a predetermined metal-doped platinum-nickel (Ni) Forming a cathode by a catalyst for a fuel cell, placing a polymer electrolyte membrane between the cathode and the anode, and coating each of the anode and the anode on both sides of the polymer electrolyte membrane, The metal may be one or more selected from the group consisting of indium (In), gallium (Ga), tantalum oxide (TaO), ruthenium (Ru), zirconium (Zr), and gadolinium (Gd).

According to an embodiment of the present invention, a catalyst for a fuel cell doped with a predetermined metal in platinum-nickel is prepared in order to overcome the limitations of the conventional platinum catalyst, -Electrode < / RTI > junction.

Further, by doping a predetermined metal, the dissolution of nickel in the fuel cell driving environment can be minimized and the stability can be further increased.

In the case of a membrane-electrode assembly composed of a catalyst for a fuel cell doped with a predetermined metal, higher initial unit cell performance is obtained and high maximum current density can be produced.

Finally, in the case of a catalyst for a fuel cell doped with a predetermined metal, the reduction rate of the oxygen reduction reaction and the reduction rate of the electrochemically active area are lowered in the durability evaluation.

FIG. 1 is a graph illustrating a doping effect analysis result according to a current-voltage value according to an embodiment of the present invention.
FIG. 2 is a view showing an X-ray diffraction (XRD) analysis result according to an embodiment of the present invention.
3 is a diagram showing a result of a high magnification transmission electron microscope (HR-TEM) analysis according to an embodiment of the present invention.
FIG. 4 is a graph showing the results of evaluating the activity of a reversed electrode according to an embodiment of the present invention.
5 is a graph showing an electrochemical active area (ECSA) change according to an embodiment of the present invention.
FIG. 6 is a graph comparing an oxygen reduction reaction and an electrochemical active area after the durability test according to an embodiment of the present invention.
FIGS. 7 to 9 are views referred to for illustrating analysis of change in chemical composition according to the durability evaluation according to an embodiment of the present invention.
10A is a schematic view showing a membrane electrode assembly (MEA) for a fuel cell according to an embodiment of the present invention.
FIG. 10B is a schematic view showing the overall configuration of a fuel cell according to an embodiment of the present invention. FIG.
10C is an exploded perspective view showing a stack of fuel cells according to an embodiment of the present invention.
FIG. 11 is a diagram for referencing the results of comparing the performance of a unit cell.
12 and 13 are drawings referred to for showing the result of evaluating the durability of the unit cell.

The following detailed description of the invention refers to the accompanying drawings, which illustrate, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It should be understood that the various embodiments of the present invention are different, but need not be mutually exclusive. For example, certain features, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in connection with an embodiment. It is also to be understood that the position or arrangement of the individual components within each disclosed embodiment may be varied without departing from the spirit and scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly explained. In the drawings, like reference numerals refer to the same or similar functions throughout the several views.

Hereinafter, a catalyst for a fuel cell and a membrane-electrode assembly according to an embodiment of the present invention will be described with reference to the accompanying drawings.

The catalyst for a fuel cell according to an embodiment of the present invention includes a Pt-Ni (Ni) nanoparticle catalyst doped with a predetermined metal, and the doped predetermined metal is indium (In), gallium (Ga) , Tantalum oxide (TaO), ruthenium (Ru), zirconium (Zr), and gadolinium (Gd). At this time, the platinum (Pt) -nickel nanoparticle catalyst may be composed of octahedral structure, and the platinum (Pt) -nickel (Ni) Or may be one produced by being carried on a carrier. Although the structure of the platinum (Pt) -nickel (Ni) nanoparticle catalyst according to an embodiment of the present invention is illustrated as an octahedral structure, the present invention is not limited thereto. When the predetermined metal-doped Pt-Ni (Ni) nanoparticle catalyst according to the embodiment of the present invention has an octahedral structure, the edge of the octahedral structure may be about 6.0 + - 0.4 nm. The platinum (Pt) - nickel (Ni) nanoparticle catalyst without metal doping can also have the same size, and the oxygen reduction reaction is more advantageous than the commercial Pt / C catalyst when the particle size is within the above range. Further, platinum may be in the form of spherical dots coexisting with nickel on the surface of nickel particles.

Examples of the support according to an embodiment of the present invention include graphite, denka black, ketjen black, acetylene black, BP2000, carbon nanotubes, carbon nanofibers, carbon nanowires, carbon nanoballs, carbon nanophones, Carbon, or activated carbon may be used. One or more of them may be selected and used. Preferred carbon supports for use in one embodiment of the present invention are HMC, OMC. Specifically, hollow mesoporous carbon (HMC) is a hollow core having a diameter of 50 to 600 nm, a mesopore size of 2 to 5 nm, and a mesoporous shell thickness of 20 to 200 nm. In addition, OMC (ordered mesoporous carbon) is a carbon structure having regular mesopores, and it is synthesized not only in the development mode and structure of mesopores but also in various shapes and sizes. Therefore, mesoporous carbons When the catalyst is supported on a carbon carrier, the size of the catalyst particles can be reduced and the degree of dispersion of the catalyst particles can be increased. Thereby increasing the reaction surface area of the catalyst.

Platinum (Pt) according to one embodiment of the present invention has a total of about 14 +/- 1 wt%, and in one embodiment 14 wt%. When the content of platinum is more than 14 + 1 wt%, platinum may aggregate with each other and the oxygen reduction activity may be lowered. The predetermined doped metal may be composed of 0.2 at% to 2.2 at% of the platinum (Pt) and the nickel (Ni). According to the weight ratio of the platinum and the nickel, regular atomic arrangement can be formed and the oxygen reduction reaction of the catalyst can be increased.

The catalyst for a fuel cell having the above-described structure can be produced by the following process.

A catalyst for a fuel cell can be prepared by doping a predetermined metal on a platinum (Pt) -nickel (Ni) nanoparticle catalyst. The predetermined metal doped is selected from the group consisting of indium (In), gallium (Ga), tantalum oxide ), Ruthenium (Ru), zirconium (Zr), and gadolinium (Gd).

At this time, the platinum (Pt) -nickel (Ni) nanoparticle catalyst can be produced by supporting platinum (Pt) and nickel (Ni) on a carbon carrier.

When the predetermined metal is doped, it may be doped through stirring and thermal reduction at about 170 ° C for 48 hours. According to an embodiment of the present invention, heating can be performed at about 170 DEG C in consideration of the boiling point of a solvent of N, N-dimethylformamide (DMF), and when heating is performed at a temperature lower than the above temperature or less than 48 hours, The reaction may not be successful.

The membrane-electrode assembly for a fuel cell according to an embodiment of the present invention may include a cathode and an anode, and a polymer electrolyte membrane disposed between the cathode and the anode. Wherein the anode comprises a platinum (Pt) nanoparticle catalyst and the anode comprises a predetermined metal doped on a platinum (Pt) -nickel (Ni) nanoparticle catalyst, wherein the doped predetermined metal is indium ), Gallium (Ga), tantalum oxide (TaO), ruthenium (Ru), zirconium (Zr), and gadolinium (Gd).

The membrane-electrode assembly for a fuel cell having the above-described structure can be manufactured by the following process.

A cathode can be constituted of a platinum (Pt) nanoparticle catalyst and a cathode for a fuel cell comprising a predetermined metal doped on a platinum (Pt) -nickel (Ni) nanoparticle catalyst. A polymer electrolyte membrane may be disposed between the cathode and the anode, and the cathode and the anode may be respectively coated on both sides of the polymer electrolyte membrane.

The doped predetermined metal is one or more selected from the group consisting of indium (In), gallium (Ga), tantalum oxide (TaO), ruthenium (Ru), zirconium (Zr), and gadolinium .

At this time, the platinum nanoparticle catalyst formed on the anode can be produced by supporting platinum on a carbon carrier, and the platinum (Pt) -nickel (Ni) nanoparticle catalyst formed on the anode contains platinum (Pt) and nickel ) On a carbon carrier.

When the predetermined metal is doped, it may be doped through stirring and thermal reduction at 170 DEG C for 48 hours.

Comparative Example  A-1: Ni Not combined  Pt catalyst (Pt / C)

Pt / C supported on a carbon support was purchased as a comparative example at a Pt content of 46 wt% as a whole without bonding Ni.

Comparative Example  A-2: Preparation of catalyst for fuel cell Not doped  Not PtNi / C manufactured)

(Platinum (II) acetylacetonate, Pt (acac) 2) which is a platinum precursor, nickel precursor nickel (II) acetylacetonate, Ni (acac) 2) according to an embodiment of the present invention, Then, benzoic acid, a structural control substance, was added with Vulcan Carbon-72R, which is a carbon carrier, and stirred with N, N-dimethylformamide (DMF) as a solvent. The atomic ratio of Pt to Ni was determined to be 1.5: 1 in the preparation of the platinum and nickel precursor mixture. After thoroughly stirring the mixture. And dispersed for 20 minutes by ultrasonic treatment in a static state. The dispersed materials were supported on a carbon carrier by reducing the respective ions of the platinum and nickel precursors by stirring and thermal reaction in a silicone oil bath heated to 160 ^° C. for 12 hours. After completion of the reaction, impurities were removed from the resultant and a mixed solution of ethanol and acetone using a centrifugal separator, and the catalyst material was separated. And completely dried in a vacuum oven to obtain a catalyst (PtNi / C) carrying nano-particles of a platinum nickel octahedral structure on a carbon carrier. At this time, the platinum content was 10 wt% of the whole catalyst.

This process is a very simple, economical and efficient process because the precursor and carrier are synthesized in one solution without any additional process such as heat treatment.

Example  A: Manufacture of catalyst for fuel cell

Example  1: Manufacture of catalysts for fuel cells (In Doped PtNi / C Manufacture: In- PtNi / C)

A small amount of metal indium (In) was added in the solution state of Comparative Example A-2 and dispersed by ultrasonic wave. Then, indium was doped through stirring and thermal reduction at 170 ^° C for 48 hours, 1 < / RTI > to yield an In-PtNi / C catalyst. Specifically, a small amount of metal indium (In) was doped into the mixture of the catalyst (PtNi / C) in which the nanoparticles of the platinum nickel structure on the carbon carrier supported on the carbon support was dissolved, and the resultant was subjected to ultrasonic treatment For about 30 minutes. The dispersed mixture was subjected to stirring and thermal reaction in a silicone oil bath heated at 170 ^° C for 48 hours so that a small amount of metal indium (In) was added to a catalyst (PtNi / C ) Surface. After completion of the reaction, impurities were removed from the mixed solution of ethanol and acetone and the catalyst material was separated using a centrifuge. After drying completely in a vacuum oven, a catalyst (In-PtNi / C) was obtained in which nanoparticles of a platinum nickel octahedral structure doped with a small amount of metal indium (In) were supported on a carbon carrier.

At this time, a catalyst having a platinum content of 14 wt% and doped indium of 1.6 at% was obtained. (In-PtNi / C, 14 wt%)

Example  2: Preparation of Catalyst for Fuel Cell (Ga Doped PtNi / C Manufacture: Ga- PtNi / C)

Ga-PtNi / C was obtained in the same manner as in Example 1, except that a small amount of metallic gallium (Ga) was added in the solution state of Comparative Example A-2. At this time, a catalyst having a platinum content of 14 wt% and doped gallium of 1.4 at% was obtained. (Ga-PtNi / C, 14 wt%)

Example  3: Preparation of catalyst for fuel cell TaO Doped PtNi / C Manufacture: TaO - PtNi / C)

TaO-PtNi / C was obtained in the same manner as in Example 1, except that a small amount of metal tantalum oxide (Tao) was added in the solution state of Comparative Example A-2. At this time, a catalyst having a platinum content of 14 wt% as a whole and a doped tantalum oxide of 2.2 at% was obtained. (TaO-PtNi / C, 14 wt%)

Example  4: Preparation of catalyst for fuel cell Ru Doped PtNi / C Manufacture: Ru - PtNi / C)

Comparative Example A-2 Ru-PtNi / C was obtained in the same manner as in Example 1, except that a small amount of metal ruthenium (Ru) was added in a solution state. At this time, a catalyst having a platinum content of 14 wt% and doped ruthenium of 1.0 at% was obtained. (Ru-PtNi / C, 14 wt%),

Example  5: Preparation of catalyst for fuel cell Zr Doped PtNi / C Manufacture: Zr - PtNi / C)

Zr-PtNi / C was obtained in the same manner as in Example 1, except that a small amount of metal zirconium (Zr) was added in the solution state of Comparative Example A-2.

At this time, a catalyst having platinum content of 14 wt% and doped zirconium of 1.1 at% was obtained. (Zr-PtNi / C, 14 wt%)

Example  6: Preparation of catalyst for fuel cell (Ga Doped PtNi / C Manufacture: Ga- PtNi / C)

Ga-PtNi / C was obtained in the same manner as in Example 1, except that a small amount of metal gadolinium (Ga) was added in the solution state of Comparative Example A-2.

At this time, a catalyst having a platinum content of 14 wt% and a doped gadolinium content of 0.2 at% was obtained. (Ga-PtNi / C, 14 wt%)

The chemical composition (at%) and the platinum content (wt%) of the platinum, nickel, and doping elements for the above-described Examples 1 to 6 and Comparative Examples A-1 and A- Respectively.

[Table 1]

Evaluation example  A-1: current- Voltage value  Doping effect analysis

As shown in FIG. 1, the graph shows the current value according to the voltage change. As the curve approaches to 0.9 V, the oxygen response becomes dominant. For example, it can be seen that the current value for the same 0.9 V is higher than that of Comparative Example A-1 and Comparative Example A-2 in Example 2, have.

Evaluation example  A-2: X-ray diffraction ( XRD ) analysis

From the positions of the Pt peaks of the respective curves shown in Fig. 2, a peak appears near 40 degrees in the case of Pt / C, which is a single platinum catalyst supported on the carbon carrier of Comparative Example A-1, -2 and the peaks of Examples 1 to 6 were shifted to the right, it was found that Comparative Example A-2 and Examples 1 to 6 had better alloy of Pt and Ni than Comparative Example A-1. . In addition, it can be seen that, through the peak positions of Comparative Example A-2 and Examples 1 to 6, the catalyst has an ordered atomic structure and the oxygen reduction reaction is increased.

Evaluation example  A-3: High magnification transmission electron microscope (HR- TEM ) Analysis

FIG. 3 shows that an octahedral structure having an edge of about 6 nm is formed in Comparative Example A-2 and Example 2 synthesized through the above-described process through a high-power transmission electron microscope (HR-TEM) analysis according to an embodiment of the present invention Respectively. Comparative Example A-1 was a commercial Pt / C catalyst, and Pt nanoparticles of about 2-4 nm were evenly distributed in the C carrier. As a result of comparing the catalyst of the PtNi / C octahedral structure not doped with metal formed by Comparative Example A-2 and the Ga-PtNi / C octahedral structure doped with a small amount of Ga according to Example 2, No significant change was observed. The lattice distance analysis between the nanoparticles of Comparative Example A-2 and Example 2 revealed that the (111) surface with good oxygen reduction activity was well exposed.

Evaluation example  A-4: Half  Activity evaluation results

Fig. 4 shows the result of the evaluation of the activity of the reversed electrode according to Comparative Example A and the embodiment of the present invention. FIG. 4 shows the oxygen reduction reaction activity as a voltage vs. current through a linear sweep voltage (LSV) curve. As shown in FIG. 4, it can be seen that the oxygen response is dominant as the curve on the graph approaches 0.9 V. FIG. For example, it can be seen that the current value for the same 0.9 V is higher than that of Comparative Example A-1 and Comparative Example A-2 in Example 2, have.

Evaluation example  A-5: Change in electrochemically active area (ECSA)

FIG. 5 shows the comparison of the electrochemical active area (ECSA) with doping. As a result of comparison between the undoped platinum nickel octahedral structure formed by Comparative Example A-2 and the small amount of gallium-doped catalyst having the best oxygen reduction reaction activity shown in FIG. 4, The effect on the electrochemical active area was found to be insignificant. Thus, Example 2 and Comparative Example A-2 had almost the same electrochemically active area or the same electrochemically active area, but Example 2 had a better effect on oxygen reduction activity than Comparative Example A-2 without metal doping It was confirmed through the electrochemical activity evaluation data of FIGS.

Evaluation example  A-6: Analysis of durability evaluation results

6 compares the oxygen reduction reaction and the electrochemical active area according to the durability evaluation of Comparative Example A-2 and Example 2. Fig. (a) and (b) show changes in the oxygen reduction reaction activity of Comparative Example A-2 and Example 2 according to the cycles, (c) and (d) This is the result of showing the change of chemical active area.

As shown in Fig. 6, in the severe durability evaluation of the oxygen-pumped acidic electrolyte solution environment, the current value after about 30,000 cycles in the initial state of about 0.9 V, about 5 mA In Comparative Example A-2, which is a non-doped platinum nickel octahedron structure, the current value was decreased from about -3.8 mA to about -0.2 mA by about 3.6 mA in the state of 0.9 V . It can be seen that the reduction degree of the current value of Example 2 is lower than that of Comparative Example A-2, and the oxygen reduction reaction is more dominant in the durability evaluation.

In the case of Example 2, even after 30,000 cycles were performed in the initial state, the electrochemically active area showed almost no change of about -10%, whereas in Comparative Example A-2, 43%, and the decrease rate of the electrochemically active area was larger than that of Example 2.

That is, according to FIG. 6, in Example 2 in which the metal was doped, cycles were repeated as compared with Comparative Example A-2 in which the metal was not doped, so that the reduction rate of the oxygen reduction reaction and the reduction rate of the electrochemically active area were lower can confirm.

Evaluation example  7: Analysis of change in chemical composition according to durability evaluation

7 and Fig. 8, the comparison of the atomic content and the distribution through the shape, EDX mapping and line profile scanning analysis before and after the durability evaluation (30,000 cycles) shows that the comparative example A- ), It was found that the octahedral structure collapsed due to a large amount of nickel eluting from 39.8 at% to 19.3 at% in 4000 cycles, and nickel was 9.9 at% after 30,000 cycles in the state where the octahedral structure was collapsed (A-> B). On the other hand, FIG. 8 corresponds to Example 2, and as shown in FIG. 8 and FIG. 9 (b), it was confirmed that a small amount of nickel was eluted from 38.5 at% to 30.4 at% after 30,000 cycles. (The Counts value on the y-axis in Figs. 7 and 8 means a relative Counts value, not an absolute value of each element.) As shown in Fig. 8, in Example 2, a platinum nickel octahedral structure catalyst surface was doped with a small amount of gallium (A-> B). In addition, it was confirmed that the nickel octahedral structure was maintained well after 30,000 cycles.

The results of EDS are shown in FIG. 9 in order to confirm the change of the exact chemical composition according to the durability evaluation. As can be seen from FIG. 9, it can be seen that the catalyst of Example 2 maintains a high nickel content even after the durability evaluation as compared with Comparative Example 2. [

The platinum and nickel eluted by the electrolyte solution-based ICP-MS analysis after the evaluation of the half-cell durability after 30,000 cycles of Comparative Example A-2 and Example 2 were compared and compared with those of Example 2, In the case of Example 2, it was confirmed that much more nickel was eluted. Through this, it was confirmed that a small amount of doped gallium formed a strong bond with nickel, thereby preventing the elution of nickel. The table below shows the elution of each element.

[Table 2] (Unit ppb (μg / kg))

10A is a schematic view showing a membrane electrode assembly (MEA) for a fuel cell according to an embodiment of the present invention.

10A, a membrane electrode assembly (MEA) 20 for a fuel cell according to an embodiment of the present invention includes a polymer electrolyte membrane 25 and a polymer electrolyte membrane 25, (21, 22).

According to an embodiment of the present invention, the anode may be composed of a platinum (Pt) nanoparticle catalyst on a carbon carrier produced by supporting platinum (Pt) on a carbon carrier, and the anode may be formed of platinum (Pt) ) Supported on a carbon carrier, and a predetermined metal doped on the platinum (Pt) -nickel (Ni) nanoparticle catalyst on the carbon support produced by the loading. And the polymer electrolyte membrane 25 may be positioned between the anode and the cathode 21, 22. These positive and negative electrodes 21 and 22 may be coated on both sides of the polymer electrolyte membrane 25, respectively. The polymer electrolyte membrane 25 is a solid polymer electrolyte having a thickness of 10 to 200 탆 and has a function of ion exchange for moving hydrogen ions produced in the catalyst layer of the oxidizing electrode to the catalyst layer of the reducing electrode. The polymer electrolyte membrane 25 is generally used as a polymer electrolyte membrane in a fuel cell, and any polymer electrolyte membrane having hydrogen ion conductivity may be used. Specific examples thereof include a polymer resin having at least one cation-exchange group selected from a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a phosphonic acid group and derivatives thereof in the side chain.

According to an embodiment of the present invention, the predetermined metal doped on the Pt-Ni nanoparticle catalyst may be indium (In), gallium (Ga), tantalum oxide (TaO), ruthenium (Ru) Zirconium (Zr), and gadolinium (Gd).

FIG. 10B is a schematic view showing the overall structure of a fuel cell according to an embodiment of the present invention, and FIG. 10C is an exploded perspective view showing a stack of a fuel cell according to an embodiment of the present invention. FIGS. 10B and 10C are views for explaining the membrane-electrode assembly (MEA, only 20 or less MEAs) of FIG. 10A.

10B and 10C show an example of the fuel cell, but the present invention is not limited thereto.

Referring to FIGS. 10B and 10C, the fuel cell 100 according to an embodiment of the present invention includes a fuel supply unit 110 for supplying a mixed fuel in which fuel and water are mixed, A reforming unit 120 for generating a reforming gas, a stack 130 for generating an electric energy by generating an electrochemical reaction with the reforming gas containing hydrogen gas supplied from the reforming unit with the oxidizing agent, And an oxidant supplier 140 for supplying the oxidant to the stack 130.

The stack 130 includes a plurality of unit cells 131 for generating an electric energy by inducing an oxidizing / reducing reaction of an oxidizing agent supplied from the oxidizing agent supplying unit 140 and a reforming gas containing hydrogen gas supplied from the reforming unit 120 ).

Each unit cell 131 refers to a cell that generates electricity. The unit cell 131 includes a membrane-electrode assembly 132 for oxidizing / reducing a reformed gas containing hydrogen gas and oxygen in an oxidant, (Or a bipolar plate) 133 for supplying a reforming gas and an oxidant to the membrane-electrode assembly 132. The membrane- The separator 133 is disposed on both sides of the membrane-electrode assembly 132 at the center. At this time, the separator located at the outermost side of the stack may be referred to as an end plate. The membrane-electrode assembly 132 is as described above in Fig.

Comparative Example  B: Preparation of membrane-electrode assembly ((-) Pt / C | Pt / C (+))

A membrane-electrode assembly was prepared in the same manner as in Example B, except that both of the positive electrode and the negative electrode were coated with the Pt / C catalyst, Comparative Example A, on both sides of the membrane.

Example  B: Preparation of membrane-electrode assembly ((-) Pt / C | Ga- PtNi / C (+))

Comparative Example A, which is a commercially available Pt / C catalyst, was applied to the cathode through a spraying method, and Example 3, which was a platinum nickel octahedral structure catalyst doped with gallium, was coated on both sides with reference to a Nafion 211 membrane. The electrode area formed by the above manufacturing method corresponds to 5 cm ² for both the positive electrode and the negative electrode, and the amount of platinum loading is also 0.15 mg _pt / cm ² for both sides. After coating, it was dried at room temperature for 24 hours. When the drying is completed, the prepared MEA 20 is positioned between the separators 133. The current collector and the end plate, which are collected by the movement of the electrons generated from the fuel such as hydrogen, are tightened with constant surface pressure of 80 Ib.

Evaluation example  B-1: Performance comparison of unit cell

Fig. 11 shows the results of comparing the performance of the unit cell made of Example B and the unit cell made of Comparative Example B. Fig. The temperature of each unit cell was maintained at 65 ^° C, and humidification conditions were maintained at 100% for both the anode and cathode. 209 mL min ^-1 of hydrogen at the cathode, 663 mL min ^-1 of air at the anode, and no back pressure was applied to both the anode and the cathode. As a result, Example B showed a high polarization curve at low voltage as compared with Comparative Example B, and it was confirmed that the result of the half cell was consistent with the result of high intrinsic activity of the catalyst contained in Example B. 11, the descending curve shows the current density and the rising curve shows the maximum current density. 11, the comparison of the current density at a cell voltage of 0.6 V, which is the reference for comparing the performance of a unit cell, shows that the current density of Example B having a current density of 0.70 Acm ^-2 is higher than that of Comparative Example B having a current density of 0.55 Acm ^-2 . Showed about 27% higher initial unit cell performance. It was also found that Example B produces a maximum current density of about 27% higher than Comparative A at 529 mW / cm ² , compared to Comparative Example B, which can produce a maximum current density of 417 mW / cm ² The maximum current density also showed better performance in Example B.

Evaluation example  B-2: Evaluation of durability of unit cell

Figs. 12 and 13 are the results of evaluating the durability of the unit cell constituted by Example B and the unit cell constituted by Comparative Example B. Fig. The durability test was carried out at a unit cell temperature of 65 ^° C and humidification conditions were maintained at 100% for both the anode and the cathode. Also, the hydrogen in the cathode was maintained at 20 mL min ^-1 , and the nitrogen in the anode was maintained at 100 mL min ^-1 . No back pressure was applied to both the anode and the cathode. The durability evaluation cycle voltage range was 0.6 V to 1.0 V, and the cycle repeated voltage cycling to 3,000, 10,000, 15,000, and 30,000 cycles. After completion of each cycle designated as the durability evaluation standard, the current polarization versus voltage was measured in the same manner as in the evaluation of the unit cell performance of the evaluation example B-1, and the reduction rate of the unit cell performance was compared to determine the durability .

In Figs. 12 and 13, the descending curve shows the current density and the rising curve shows the maximum current density. As a result of the durability evaluation in FIGS. 12 and 13, after 30,000 cycles in the initial state, in Comparative Example B, the current density was reduced by about 56% from 0.55 to 0.24 Acm ^-2 at 0.6 V in FIG. 12, Of Example B had a higher durability than Comparative Example B, with a current density of about 0.70 - > 0.47 Acm < ^-2 > The maximum current density was also decreased to about 49% at a maximum current density of about 417 to 213 mW / cm ² in Comparative Example B of FIG. 12 after 30,000 cycles in the initial state, whereas in Example B of FIG. 13, The maximum current density decreased by about 29% at 371 mW / cm ² , indicating higher durability.

The features, structures, effects and the like described in the embodiments are included in one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects and the like illustrated in the embodiments can be combined and modified by other persons skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (22)

(Pt) -nickel (Ni) nanoparticle catalyst doped with a predetermined metal,
The doped predetermined metal is one or more selected from the group consisting of indium (In), gallium (Ga), tantalum oxide (TaO), ruthenium (Ru), zirconium (Zr), and gadolinium Catalyst for fuel cells.
The method according to claim 1,
Wherein the predetermined metal-doped platinum (Pt) -nickel (Ni) nanoparticle catalyst has an octahedral structure.
The method according to claim 1,
The platinum (Pt) has a total of about 14 +/- 1 wt.%,
Wherein the doped predetermined metal is composed of 0.2 at% to 2.2 at% of the platinum (Pt) and the nickel (Ni).
The method according to claim 1,
The predetermined metal-doped platinum (Pt) -nickel (Ni)
Wherein the catalyst is formed by supporting the platinum (Pt) and the nickel (Ni) on a carbon carrier.
5. The method of claim 4,
Wherein the carbon support is one or more selected from the group consisting of graphite, denka black, methane black, acetylene black, carbon nanowire, carbon nanoballs, HMC, and activated carbon.
A cathode and an anode, and a polymer electrolyte membrane positioned between the cathode and the anode,
The negative electrode is composed of a platinum (Pt) nanoparticle catalyst,
The anode comprises a platinum (Pt) -nickel (Ni) nanoparticle catalyst doped with a predetermined metal,
The doped predetermined metal is one or more selected from the group consisting of indium (In), gallium (Ga), tantalum oxide (TaO), ruthenium (Ru), zirconium (Zr), and gadolinium sign,
Membrane - electrode junction for fuel cell. The method according to claim 6,
Wherein the predetermined metal-doped platinum (Pt) -nickel (Ni) nanoparticle catalyst has an octahedral structure.
The method according to claim 6,
The platinum (Pt) has a total of about 14 +/- 1 wt.%,
Wherein the doped predetermined metal is 0.2 atomic% to 2.2 atomic% of the platinum (Pt) and the nickel (Ni) atom.
The method according to claim 6,
The platinum (Pt) nanoparticle catalyst is produced by carrying the platinum (Pt) on a carbon carrier,
The predetermined metal-doped platinum (Pt) -nickel (Ni)
Wherein the catalyst layer is formed by supporting the platinum (Pt) and the nickel (Ni) on a carbon support.
10. The method of claim 9,
Wherein the carbon support is one or more selected from the group consisting of graphite, denka black, methane black, acetylene black, carbon nanowire, carbon nanoballs, HMC, and activated carbon.
Comprising the step of doping a predetermined metal onto a platinum (Pt) -nickel (Ni) nanoparticle catalyst,
The doped predetermined metal is one or more selected from the group consisting of indium (In), gallium (Ga), tantalum oxide (TaO), ruthenium (Ru), zirconium (Zr), and gadolinium By weight of the catalyst.
12. The method of claim 11,
Wherein the predetermined metal-doped platinum (Pt) -nickel (Ni) nanoparticle catalyst has an octahedral structure.
12. The method of claim 11,
The platinum (Pt) has a total of about 14 +/- 1 wt.%,
Wherein the doped predetermined metal is comprised between 0.2 at% and 2.2 at% based on the platinum (Pt) and the nickel (Ni).
12. The method of claim 11,
Wherein the doping the predetermined metal comprises:
Lt; RTI ID = 0.0 > 170 C < / RTI > for 48 hours through a stirring and thermal reduction reaction.
12. The method of claim 11,
(Ni) nanoparticle catalyst supported on the carbon carrier by supporting the platinum (Pt) and the nickel (Ni) on a carbon carrier to produce a catalyst for a fuel cell Gt;
16. The method of claim 15,
Wherein the carbon carrier is one or more selected from the group consisting of graphite, denka black, methane black, acetylene black, carbon nanowire, carbon nanoballs, HMC, and activated carbon. Forming a cathode with a platinum (Pt) nanoparticle catalyst;
Forming a positive electrode with a catalyst for a fuel cell comprising a predetermined metal-doped platinum (Pt) -nickel (Ni) nanoparticle catalyst;
Placing a polymer electrolyte membrane between the cathode and the anode; And
And coating the negative electrode and the positive electrode on both sides of the polymer electrolyte membrane,
The doped predetermined metal is one or more selected from the group consisting of indium (In), gallium (Ga), tantalum oxide (TaO), ruthenium (Ru), zirconium (Zr), and gadolinium sign,
A method for manufacturing a membrane-electrode assembly for a fuel cell.
18. The method of claim 17,
Wherein the predetermined metal-doped platinum (Pt) -nickel (Ni) nanoparticle catalyst has an octahedral structure.
18. The method of claim 17,
The platinum (Pt) has a total of about 14 +/- 1 wt.%,
Wherein the doped predetermined metal is comprised between 0.2 at% and 2.2 at% based on the platinum (Pt) and the nickel (Ni).
18. The method of claim 17,
The step of constructing the anode with a catalyst for a fuel cell comprising a predetermined metal doped on the platinum (Pt) -nickel (Ni) nanoparticle catalyst,
Wherein the anode is constituted by doping the predetermined metal through stirring and a thermal reduction reaction at 170 DEG C for 48 hours.
18. The method of claim 17,
Supporting the platinum (Pt) on a carbon carrier to produce the platinum (Pt) nanoparticle catalyst; And
Further comprising the step of supporting the platinum (Pt) and the nickel (Ni) on a carbon carrier to produce the platinum (Pt) -nickel (Ni) nanoparticle catalyst.
22. The method of claim 21,
Wherein the carbon support is one or more selected from the group consisting of graphite, denka black, methane black, acetylene black, carbon nanowire, carbon nanoballs, HMC, and activated carbon.

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