KR102213590B1 - Method for fabricating catalyst layer for high durability carbon-based fuel cell, catalyst layer for high durability carbon-based fuel cell fabricated by the method and membrane electrode assembly comprising the same - Google Patents

Abstract

The present invention relates to a method of manufacturing a catalyst layer for a highly durable carbon-based fuel cell, and a membrane electrode assembly for a fuel cell including a catalyst layer for a highly durable carbon-based fuel cell and a catalyst layer for a highly durable carbon-based fuel cell prepared according to the method. A method of manufacturing a catalyst layer for a highly durable carbon-based fuel cell according to an embodiment includes the steps of surface-modifying an aromatic compound on a platinum/carbon catalyst; Preparing a catalyst layer by coating a polymer ionomer on the surface-modified platinum/carbon catalyst; And selectively removing the polymer ionomer coated on the platinum particle surface by applying a potential to the cell in the form of a membrane electrode assembly (MEA) after the catalyst layer is prepared.

Description

METHOD FOR FABRICATING CATALYST LAYER FOR HIGH DURABILITY CARBON, including a method of manufacturing a catalyst layer for a highly durable carbon-based fuel cell and a catalyst layer for a highly durable carbon-based fuel cell manufactured according to the method and a catalyst layer for a highly durable carbon-based fuel cell -BASED FUEL CELL, CATALYST LAYER FOR HIGH DURABILITY CARBON-BASED FUEL CELL FABRICATED BY THE METHOD AND MEMBRANE ELECTRODE ASSEMBLY COMPRISING THE SAME}

The present invention relates to a method of manufacturing a catalyst layer for a highly durable carbon-based fuel cell, and a membrane electrode assembly for a fuel cell including a catalyst layer for a highly durable carbon-based fuel cell and a catalyst layer for a highly durable carbon-based fuel cell prepared according to the method.

Polymer Electrolyte Membrane Fuel Cell (PEMFC) is typically composed of a membrane electrode assembly (MEA) including an anode, a cathode, and a polymer electrolyte membrane disposed between the anode and the cathode. An oxidation reaction of the fuel occurs at the anode to which hydrogen or fuel is supplied, hydrogen ions generated at the anode are conducted to the cathode through the electrolyte membrane, and a reduction reaction of oxygen occurs at the cathode supplied with oxygen, thereby generating electric current.

The anode and cathode of a fuel cell require a catalyst for the redox reaction of the fuel, and a Pt/C or Pt-alloy/C catalyst is generally used. The electrode of the fuel cell includes an ionomer having the same component as the electrolyte membrane so that hydrogen ions generated from the anode can be transferred to the cathode together with the catalyst for redox reaction. This ionomer acts as a hydrogen ion conductor, but also acts as a binder that physically binds the Pt/C catalyst particles constituting the electrode.

However, if the ionomer on the cathode side where the oxygen reduction reaction should take place effectively, if the catalyst layer is excessively coated, oxygen gas is transferred, but the resistance increases, and if it is too thin or not coated, the resistance to transfer hydrogen ions increases. Off relationship exists. Therefore, it is necessary to adjust the amount of ionomer added so that it can be coated on the catalyst layer in an appropriate line. However, the uniform distribution of the ionomer in the catalyst layer has a very difficult problem in the highly durable carbon, which is a carbon having strong graphical properties.

The problem to be solved by the present invention is a method of manufacturing a catalyst layer for a highly durable carbon-based fuel cell with improved performance of a fuel cell by reducing oxygen diffusion resistance at the cathode of a polymer electrolyte fuel cell, and a highly durable carbon-based fuel manufactured according to the method. It is to provide a membrane electrode assembly for a fuel cell including a catalyst layer for a battery and a catalyst layer for a highly durable carbon-based fuel cell.

However, the problem to be solved by the present invention is not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

According to an embodiment of the present invention, the step of surface modification with an aromatic compound on a platinum / carbon catalyst; Preparing a catalyst layer by coating a polymer ionomer on the surface-modified platinum/carbon catalyst; And selectively removing the polymer ionomer coated on the surface of the platinum particles by applying a potential to the cell of the unit cell in the form of a membrane electrode assembly (MEA) after the catalyst layer is prepared; including, highly durable carbon-based It provides a method of manufacturing a catalyst layer for a fuel cell.

According to an embodiment, the carbon may be highly crystalline with a high degree of graphitization.

According to an embodiment, the carbon is, carbon nanotube, carbon nanofiber, carbon nanocoil, carbon nanocage, graphene, and graphene It may include at least one selected from the group consisting of oxides (Graphene oxide).

According to an embodiment, a π-π interaction is formed between the aromatic compound and the carbon, and hydrophilicity may be imparted by the hydrophilic functional group of the aromatic compound.

According to an embodiment, the aromatic compound may include at least one hydrophilic functional group selected from the group consisting of an amine group, a carboxyl group, a sulfone group and a hydroxyl group bonded to a pyrene derivative. .

According to one embodiment, the aromatic compound is aminopyrene (1-Amionpyrene; AP), pyrenebutyric acid, pyrene methylamine, pyrene-boronic acid (Pyrene-1-boronic acid). acid), 1-Pyrenecarboxylic acid (PCA), 1-Pyrenebutyric acid (PBA), 1-pyreneacetic acid, 1-mercaptopyrene (1-mercaptopyrene), 1-pyrenesulfonic acid (1-pyrenesulfonic acid), 1-hydroxypyrene (1-hydroxypyrene), and at least any selected from the group consisting of 6-mercaptobenzopyrene (6-mercaptobenzopyrene) It may contain one.

According to an embodiment, the step of surface modification with an aromatic compound on the platinum/carbon catalyst may include coating the aromatic compound in a single layer on the platinum/carbon catalyst.

According to an embodiment, the polymeric ionomer may include perfluorinated sulfonic acid ionomers (PFSA).

According to one embodiment, the polymeric ionomer is at least one selected from the group consisting of poly(perfluorosulfonic acid), poly(perfluorocarboxylic acid), and a copolymer of tetrafluoroethylene and fluorovinyl ether It may be to include.

According to one embodiment, the polymeric ionomer may include at least any one selected from the group consisting of Nafion, Flemion, aciflex, 3M ionomer, Dow ionomer, Solvay ionomer, and Sumitomo 3M ionomer.

According to one embodiment, the thickness of the catalyst layer prepared by coating a polymer ionomer on the surface-modified platinum/carbon catalyst may be 1 μm to 20 μm.

According to an embodiment, the step of selectively removing the polymer ionomer coated on the surface of the platinum particles by applying a potential to the cell in the form of a membrane electrode assembly (MEA) after the catalyst layer is prepared may be performed at 0 V under hydrogen/nitrogen conditions. It may be to apply a voltage of 1.2 V.

According to an embodiment, the selective removal of the polymer ionomer may be that the polymer ionomer formed on the platinum is mainly removed.

According to an embodiment, by applying the voltage, the aromatic compound and the polymer ionomer are bonded, the polymer ionomer coated on the platinum particle surface is selectively removed, and the ionomer coverage of the carbon surface may be increased.

According to an embodiment, the bonding may be a bonding between the aromatic compound and the sulfonate group of the polymer ionomer.

According to an embodiment, the selective removal of the polymer ionomer may be performed by movement of a bond between the aromatic compound and a sulfonate group of the polymer ionomer located on the platinum.

According to another embodiment of the present invention, a carbon/platinum catalyst; And a polymer ionomer coated on the carbon/platinum catalyst, wherein the polymer ionomer coated on the platinum particle surface is thinner than the polymer ionomer coated on the carbon surface.It provides a catalyst layer for a carbon-based fuel cell.

According to an embodiment, the catalyst layer for a highly durable carbon-based fuel cell may be prepared by a method of manufacturing the catalyst layer for a highly durable carbon-based fuel cell.

According to another embodiment of the present invention, there is provided a membrane electrode assembly for a fuel cell including the catalyst layer for a highly durable carbon-based fuel cell.

The catalyst layer for a carbon-based fuel cell prepared by the method for producing a catalyst layer for a highly durable carbon-based fuel cell according to an embodiment of the present invention covers the surface of the platinum catalyst and thus has a structure in which the polymer ionomer that acts as an oxygen transfer resistance is removed. The diffusion transmission resistance can be reduced, and thus the performance of the fuel cell can be improved.

1 to 4 are conceptual diagrams showing a method of manufacturing a catalyst layer for a highly durable carbon-based fuel cell according to an embodiment of the present invention.
5 is an image before ultrasonic treatment to confirm dispersion of water/hexane of a catalyst according to Examples and Comparative Examples of the present invention.
6 is an image after ultrasonic treatment to confirm dispersion of water/hexane of the catalyst according to Examples and Comparative Examples of the present invention.
7 is data showing platinum active surface area after a catalyst according to an embodiment of the present invention is applied to a cell by manufacturing a unit cell in the form of an MEA.
FIG. 8 is data showing platinum active surface area after a catalyst according to a comparative example of the present invention is applied to a cell by manufacturing a unit cell in the form of an MEA.
9 is a graph showing electrochemical active areas in 1 ^st cycle and 21 ^st cycle according to Examples and Comparative Examples of the present invention.
10 is a graph showing the unit cell performance of the catalyst according to Examples and Comparative Examples of the present invention.
11 is an IV polarization curve graph with corrected ohmic resistance of the catalyst according to Examples and Comparative Examples of the present invention.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. However, since various changes may be made to the embodiments, the scope of the rights of the patent application is not limited or limited by these embodiments. It should be understood that all changes, equivalents, or substitutes to the embodiments are included in the scope of the rights.

The terms used in the examples are used for illustrative purposes only and should not be interpreted as limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, actions, components, parts, or a combination thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiment belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

In addition, in the description with reference to the accompanying drawings, the same reference numerals are assigned to the same components regardless of the reference numerals, and redundant descriptions thereof will be omitted. In describing the embodiments, when it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the embodiments, the detailed description thereof will be omitted.

Hereinafter, an embodiment and a membrane electrode assembly for a fuel cell including a catalyst layer for a highly durable carbon-based fuel cell and a catalyst layer for a highly durable carbon-based fuel cell prepared according to the method for producing a catalyst layer for a highly durable carbon-based fuel cell of the present invention and It will be described in detail with reference to the drawings. However, the present invention is not limited to these examples and drawings.

According to an embodiment of the present invention, the step of surface modification with an aromatic compound on a platinum/carbon (Pt/C) catalyst; Preparing a catalyst layer by coating a polymer ionomer on the surface-modified platinum/carbon catalyst; And selectively removing the polymer ionomer coated on the platinum particle surface by applying a potential to the cell in the form of a membrane electrode assembly (MEA) after the catalyst layer is prepared. It provides a method of manufacturing a catalyst layer for a fuel cell.

1 to 4 are conceptual diagrams showing a method of manufacturing a catalyst layer for a highly durable carbon-based fuel cell according to an embodiment of the present invention. A method of manufacturing a catalyst layer for a highly durable carbon-based fuel cell according to an embodiment of the present invention includes the steps of surface-modifying an aromatic compound on a platinum/carbon catalyst (FIGS. 1 and 2), on a surface-modified platinum/carbon catalyst. Step of preparing a catalyst layer by coating a polymer ionomer (Fig. 3) and after preparing the catalyst layer, a potential is applied to the cell in the form of a membrane electrode assembly (MEA) to select the polymer ionomer coated on the platinum particle surface by applying a potential to the cell. It includes the step of removing (part of) (Fig. 4).

As shown in FIGS. 1 and 2, the surface may be modified with an aromatic compound 130 on the platinum/carbon catalyst 100.

As shown in FIG. 1, the platinum/carbon catalyst 100 may include carbon 110 and platinum particles 120 supported on the carbon 110.

According to an embodiment, the carbon 110 may be highly crystalline with a high degree of graphitization. Carbon with high crystallinity may be intended to give a difference in resistance to oxidation between platinum and carbon.

According to one embodiment, the carbon 110 is, carbon nanotube, carbon nanofiber, carbon nanocoil, carbon nanocage, graphene And graphene oxide (Graphene oxide) may be to include at least one selected from the group consisting of.

According to an embodiment, a π-π interaction is formed between the aromatic compound 130 and the carbon 110, and hydrophilicity may be imparted by the hydrophilic functional group of the aromatic compound. Specifically, the hydrophilic functional groups in the aromatic compound such as carboxyl group (-COOH), thiol group (-SH), hydroxyl group (-OH), amine group (-NH ₂ ), sulfone group (-SO ₃ H), etc. It may be immobilized on the carbon surface to increase the hydrophilicity of the crystalline carbon.

According to an embodiment, the aromatic compound 130 is a pyrene derivative containing at least one hydrophilic functional group selected from the group consisting of an amine group, a carboxyl group, a sulfone group, and a hydroxy group. I can.

According to one embodiment, the aromatic compound 130 is aminopyrene (1-Amionpyrene; AP), pyrenebutyric acid, pyrene methylamine, pyrene-boronic acid (Pyrene- 1-boronic acid), 1-Pyrenecarboxylic acid (PCA), 1-Pyrenebutyric acid (PBA), 1-pyreneacetic acid, 1-mer Selected from the group consisting of captopyrene (1-mercaptopyrene), 1-pyrenesulfonic acid, 1-hydroxypyrene and 6-mercaptobenzopyrene It may include at least any one of.

As shown in FIG. 2, in order to modify the surface of the platinum/carbon catalyst, a solution containing the pyrene derivative may be coated on the platinum/carbon catalyst. The pyrene is adsorbed on the surface of the platinum/carbon catalyst by π-π interaction. That is, the surface modification is performed by adsorbing the pyrene derivative to the platinum/carbon catalyst in the solution. The solvent may be, for example, using dimethylformamide (DMF).

According to an embodiment, the step of surface-modifying the aromatic compound 130 on the platinum/carbon catalyst may include coating the aromatic compound in a single layer on the platinum/carbon catalyst. The coating of the aromatic compound on the platinum/carbon catalyst is difficult to coat with more than a single layer due to the mechanism.

As shown in FIG. 3, a catalyst layer may be prepared by coating a polymer ionomer 140 on the surface-modified platinum/carbon catalyst.

According to an embodiment, the polymeric ionomer 140 may include perfluorinated sulfonic acid ionomers (PFSA). In the drawing of the polymer ionomer 140, what looks like a thread may be a PFSA backbone of the polymer ionomer.

According to one embodiment, the polymeric ionomer 140 is selected from the group consisting of poly(perfluorosulfonic acid), poly(perfluorocarboxylic acid), and a copolymer of tetrafluoroethylene and fluorovinyl ether. It may include at least any one.

According to an embodiment, the polymeric ionomer 140 may include at least one selected from the group consisting of Nafion, Flemion, aciflex, 3M ionomer, Dow ionomer, Solvay ionomer, and Sumitomo 3M ionomer. .

According to one embodiment, the thickness of the catalyst layer prepared by coating the polymer ionomer 140 on the surface-modified platinum/carbon catalyst may be 1 μm to 20 μm. When the thickness of the catalyst layer is less than 1 μm, the formation of a catalyst layer structure for transporting ions and electrons in the catalyst layer may be insufficient, and when the thickness of the catalyst layer exceeds 20 μm, the effects of the present invention may be canceled due to the deepening of the gas diffusion problem.

According to an embodiment, at least one hydrophilic functional group selected from the group consisting of an amine group, a carboxyl group, a sulfone group, and a hydroxyl group of the aromatic compound 130, and a sulfonate group 150 of the polymer ionomer 140 ) May be interactive. For example, when an aminopyrene is used as an aromatic compound and a Nafion ionomer is used as a polymeric ionomer, the interaction between the amine group from the aminopyrene having a partial positive charge and the sulfonate group from the Nafion ionomer having a partial negative charge Because of the action, the platinum/carbon surface is uniformly and completely coated. However, the polymer ionomer on the surface of the platinum particle appears to be thicker than the polymer ionomer on the carbon surface, which may be due to the insufficient amount of the polymer ionomer network on the carbon surface. Since the polymer ionomer film becomes an obstacle in the delivery of the oxygen gas reactant to the platinum particle surface, a polymer ionomer is very thinly coated on the platinum particle surface, and most of the polymer ionomer must be coated on the carbon surface for ion transfer. Therefore, a potential is applied to selectively remove the polymer ionomer coated on the surface of the platinum particles.

As shown in Figure 4, after the catalyst layer is prepared, a potential is applied to the cell in the form of a membrane electrode assembly (MEA) to the unit cell, thereby selectively removing the polymer ionomer coated on the surface of the platinum particles. The term "selective removal" as used herein means "partial removal".

According to an embodiment, the step of selectively removing the polymer ionomer coated on the surface of the platinum particles by applying a potential to the cell in the form of a membrane electrode assembly (MEA) after the catalyst layer is prepared may be performed at 0 V under hydrogen/nitrogen conditions. It may be to apply a voltage of 1.2 V. If it is less than 0 V, there may be an unnecessary side reaction, and if it is more than 1.2 V, there may be a problem of damage to the catalyst layer due to electrochemical carbon corrosion.

According to an embodiment, the application of the potential may be performed by cyclic voltammetry (CV). The application of the potential may be performed under an atmospheric condition including hydrogen, nitrogen and both.

According to one embodiment, the application of the potential is a separate process from proceeding to clean the catalyst surface after MEA preparation.

According to an embodiment, the selective removal of the polymer ionomer may be that the polymer ionomer 140 formed on the platinum particles 120 is mainly removed.

According to an embodiment, by applying the voltage, the aromatic compound and the polymer ionomer are bonded, the polymer ionomer coated on the platinum particle surface is selectively removed, and the ionomer coverage of the carbon surface may be increased. During potential cycling, the aromatic compounds initially attached on the surface of the platinum particles may gradually migrate to the carbon surface. In addition, as the sulfonate group moves through the interaction with the amine according to the displacement, the polymeric ionomer backbone is re-organized. At the end of the cycling process, if the polymer ionomer backbone is re-organized from platinum to the carbon surface, the polymer ionomer coverage is uniformly distributed, thereby reducing the thickness of the polymer ionomer on the platinum and increasing the polymer ionomer coverage on the carbon surface.

According to an embodiment, the bonding may be a bonding between the aromatic compound and the sulfonate group of the polymer ionomer.

According to an embodiment, the selective removal of the polymer ionomer may be due to movement of a bond between the aromatic compound 110 and the sulfonate group of the polymer ionomer located on the platinum particle 120. This is to selectively remove only functional groups on the surface of platinum particles electrochemically.

The catalyst layer for a carbon-based fuel cell prepared by the method for producing a catalyst layer for a highly durable carbon-based fuel cell according to an embodiment of the present invention covers the surface of the platinum catalyst and thus has a structure in which the polymer ionomer that acts as an oxygen transfer resistance is removed. The diffusion transmission resistance can be reduced, and thus the performance of the fuel cell can be improved.

According to another embodiment of the present invention, a carbon/platinum catalyst; And a polymer ionomer coated on the carbon/platinum catalyst, wherein the polymer ionomer coated on the platinum particle surface is thinner than the polymer ionomer coated on the carbon surface.It provides a catalyst layer for a carbon-based fuel cell.

According to an embodiment, the catalyst layer for a highly durable carbon-based fuel cell may be prepared by a method of manufacturing the catalyst layer for a highly durable carbon-based fuel cell.

The catalyst layer for a carbon-based fuel cell according to an embodiment of the present invention has a structure in which the polymer ionomer, which has been acting as an oxygen transfer resistance since it covers the platinum catalyst surface, has a structure, so that the oxygen diffusion transfer resistance can be reduced, thereby improving the performance of the fuel cell. Can be.

According to another embodiment of the present invention, there is provided a membrane electrode assembly for a fuel cell including the catalyst layer for a highly durable carbon-based fuel cell.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, these examples are for illustrative purposes only, and it will not be construed that the scope of the present invention is limited by these examples.

[Example]

Platinum/carbon (Pt/C) surface modification

A catalyst mixture was prepared by mixing 400 ml DI water and 0.8 g of 60 wt% Pt/GC (Johnson Matthey). Then, 80 mg of 1-aminopyrene (AP) was mixed with 160 mL of MetOH to prepare an AP compound. The catalyst mixture and the AP compound mixture were mixed in one beaker glass and sonicated on ice for 10 minutes under medium power. 400 ml of water was added to the mixture, and the mixture was stirred with a magnetic bar at 25° C. and ~350 rpm for about 24 hours. The dispersion was vacuum filtered and washed 3 times with 500 ml of deionized water. It was dried in a vacuum oven at 70° C. overnight (± 12 hours).

Preparation of catalyst ink slurry

0.33 g of Pt/GC-AP (surface-treated catalyst) was mixed with 5.588 g of deionized water and 1.863 g of isopropanol, and then 0.428 g of a fluorine-based ionomer (Aquivion ^β D79, Solvay) having a short-chain structure was added dropwise to obtain an ink slurry. Was prepared. Sonicate on ice for about 10 minutes. Put into a paste slurry mixer and mixed for about 24 hours. Roll milling was performed for the slurry ink using 500 rpm roller rotation. It was put back into the slurry mixer and mixed for 1 to 2 hours until the desired viscosity was obtained. The slurry was coated on a PTFE film to make a ready-decal transfer electrode.

Elemental analysis

The elements of PT/GC-AP (Example), which is PT/GC surface-modified with aminopyrene (AP), and PT/GC without aminopyrene surface treatment (Comparative Example), were analyzed.

Elemental analysis results are shown in Table 1 below. Referring to FIG. 1D, in the catalyst of the comparative example, nitrogen and hydrogen were not detected at all.

Sample name Nitrogen
(wt%) Carbon
(wt%) Hydrogen
(wt%) Example
(PT/GC-AP) 0.35 42.38 0.16 Comparative example
(PT/GC-Ref. (w/o AP)) 0 38.96 0

In the hexane-water mixture (1:1), a water/hexane dispersion test was performed before and after sonication to confirm the physical properties of the AP-surface-treated catalyst and the non-AP-surface-treated catalyst.

5 is an image before ultrasonic treatment for confirming water/hexane dispersion of catalysts according to Examples and Comparative Examples of the present invention, and FIG. 6 is an image confirming water/hexane dispersion of catalysts according to Examples and Comparative Examples of the present invention. It is an image after ultrasonic treatment for doing so. As shown in the image of FIG. 5, it can be seen that the AP-surface-treated catalyst of the embodiment is well dispersed in the water layer, and through this, it can be seen that the hydrophilicity is increased. As shown in the image of FIG. 6, it can be seen that the catalyst of Comparative Example is well dispersed in the hexane layer, which can be confirmed to be hydrophobic. Through this result, it can be confirmed that the AP-surface-treated catalyst of Example has higher hydrophilicity than the AP-surface-treated catalyst of Comparative Example.

Cathodes were prepared using the catalysts of Examples and Comparative Examples. MEA was prepared as follows from the prepared cathode, electrolyte membrane, and anode. Thereafter, a voltage in the range of 0.1 V to 0.25 V was applied under the H ₂ /N₂ condition of the MEA to remove the ionomer on the surface of the platinum catalyst.

Finally, the carbon and platinum catalysts were surrounded by ionomers, but a cathode structure in which the ionomers were not covered only on the platinum catalyst surface could be obtained.

MEA manufacturing

The prepared catalyst ink is coated on a PET film or PTFE film to a thickness of about 100 μm by a doctor blade process. After that, the coated catalyst layer is sufficiently dried at room temperature for 12 hours. The catalyst layer coated on the transfer film is cut into a square with an area of 9.6 cm ² , and a temperature of 120° C. and a pressure of 100 kgf/cm ² are applied for 24 minutes with a Nafion electrolyte membrane (NRE 211, Ion Power) in between. Catalyst layers are formed on both sides of the Nafion electrolyte membrane by a hot pressing process. At this time, one MEA with no AP treatment for both the hydrogen electrode and the air electrode and one MEA with AP treatment for only the air electrode was prepared. The platinum supported amount of the prepared MEA hydrogen electrode was 0.2 mg/cm ² , and the platinum supported amount of the air electrode was 0.15 mg/cm ² .

Unit battery connection

The fuel cell performance evaluation of the prepared MEA was performed in the unit cell. A unit cell consisting of a carbon plate with flow paths formed on both sides of the MEA and a gas diffusion layer (GDL, 10BC, SGL) is connected to set the cell temperature to 80 ℃ and sufficiently humidified hydrogen and air are respectively 350 cc/min and 1500 cc/ First, voltage cycling was performed while flowing at a flow rate of min. At this time, the voltage cycle proceeded 20 times at a scan rate of 50 mV/s in the range of 0 to 1.2 V.

The catalysts according to Examples and Comparative Examples were prepared as MEA-type unit cells, and desorption of functional groups on the surface of platinum by application of a cell potential in an electrochemical treatment process and an increase in the active surface area of platinum due to this were confirmed.

7 is data showing the active surface area of platinum after the catalyst according to an embodiment of the present invention is manufactured in a MEA form and a potential is applied to the cell, and FIG. 8 is a unit in MEA form of the catalyst according to the present invention. This is data showing the active surface area of platinum after manufacturing a battery and applying a potential to the cell. As shown in FIG. 7, in the case of using the catalyst of the embodiment, the hydrogen adsorption and desorption current at the platinum surface occurring in the range of 0.1 V to 0.25 V in the case of 1 ^st cycle vs. 21 ^st cycle according to cell voltage application is voltage application cycle As (cycle) increases, it tends to increase. Therefore, it is shown that the aromatic compounds adsorbed on the platinum surface are desorbed during the cell voltage application process. As shown in FIG. 8, in the case of using the catalyst of the comparative example, the hydrogen adsorption and desorption current at the platinum surface occurring in the range of 0.1 V to 0.25 V in the case of 1 ^st cycle vs. 21 ^st cycle according to the cell voltage application is voltage applied. There is little change as the cycle increases.

The electrochemically active surface area (ECSA) in the 1 ^st cycle and the 21 ^st cycle of the cyclic voltammetry (CV) was measured.

9 is a graph showing electrochemical active areas in 1 ^st cycle and 21 ^st cycle according to Examples and Comparative Examples of the present invention. As shown in FIG. 9, it can be clearly confirmed that the effective active area of the catalyst measured through the CV experiment increased significantly after the cycle when the catalyst of the Example was used compared to the Comparative Example, and was relatively large at the 21 ^st cycle.

The unit cell performance of the catalysts of Examples and Comparative Examples according to the surface modification was confirmed.

10 is a graph showing the unit cell performance of the catalyst according to Examples and Comparative Examples of the present invention. As shown in FIG. 10, it can be seen that the unit cell performance of the MEA using the catalyst surface-modified by the AP shows higher unit cell performance in the entire current range compared to the MEA using the catalyst that is not surface-modified. In addition, even in the comparison of HFR (High Frequency Resistance) values that mainly reflect the interface resistance between the electrode and the film, the resistance value of the MEA surface-modified with AP shows a relatively low value, so that the effect of surface modification can be confirmed.

11 is a graph of IV polarization curves in which HFR contact resistance of catalysts according to Examples and Comparative Examples of the present invention is corrected. Even in the I-V result with corrected contact resistance, the unit cell performance of the surface-modified catalyst-based MEA was higher than that of the sample-based unit cell that did not. Therefore, it can be seen that the surface modification is effective in terms of the reaction of the fuel cell.

Through this, the cathode for a fuel cell using the AP-surface-treated example catalyst has a structure having a uniform distribution on both the platinum and carbon surfaces of the Nafion ionomer, which covered the surface of the platinum catalyst and acts as an oxygen transfer resistance. It affects the reduction of diffusion resistance. Optimal conditions for diffusion of reactive gases as well as proton conduction can help to improve the performance of the fuel cell. In addition, it can be seen that oxygen transfer is smoothly performed in the cathode due to the improvement of the platinum utilization rate, and thus it can be seen that it has an effect of increasing the amount of platinum participating in the catalytic reaction.

As described above, although the embodiments have been described by the limited drawings, a person of ordinary skill in the art can apply various technical modifications and variations based on the above. For example, even if the described techniques are performed in a different order from the described method, and/or the described components are combined or combined in a form different from the described method, or are replaced or substituted by other components or equivalents. Appropriate results can be achieved.

Therefore, other implementations, other embodiments and claims and equivalents fall within the scope of the following claims.

100: platinum/carbon catalyst
110: carbon
120: platinum particles
130: aromatic compound
140: polymer ionomer
150: sulfonate group

Claims (19)

Surface modification with an aromatic compound on a platinum/carbon catalyst;
Preparing a catalyst layer by coating a polymer ionomer on the surface-modified platinum/carbon catalyst; And
After the catalyst layer is prepared, a voltage of 0.1 V to 1.2 V is applied to the cells of the unit cell in the form of a membrane electrode assembly (MEA) under hydrogen/nitrogen conditions to selectively remove the polymer ionomer coated on the surface of the platinum particles. step;
Including,
The selective removal of the polymer ionomer is that the polymer ionomer formed on the platinum is mainly removed,
By applying the voltage, the aromatic compound and the polymer ionomer are bonded, and the polymer ionomer coated on the platinum particle surface is selectively removed to increase the ionomer coverage of the carbon surface,
The bond is a bond between the aromatic compound and the sulfonate group of the polymer ionomer,
The selective removal of the polymer ionomer is that the polymer ionomer located on the platinum is electrochemically desorbed,
Method for producing a catalyst layer for a highly durable carbon-based fuel cell.
The method of claim 1,
The carbon is highly crystalline with a high degree of graphitization,
Method for producing a catalyst layer for a highly durable carbon-based fuel cell.
The method of claim 1,
The carbon is a carbon nanotube, carbon nanofiber, carbon nanocoil, carbon nanocage, graphene, and graphene oxide. It includes at least any one selected from the group consisting of,
Method for producing a catalyst layer for a highly durable carbon-based fuel cell.
The method of claim 1,
Forming a π-π interaction between the aromatic compound and the carbon, and hydrophilicity is imparted by the hydrophilic functional group of the aromatic compound,
Method for producing a catalyst layer for a highly durable carbon-based fuel cell.
The method of claim 1,
The aromatic compound includes at least one hydrophilic functional group selected from the group consisting of an amine group, a carboxyl group, a sulfone group and a hydroxyl group bonded to a pyrene derivative,
Method for producing a catalyst layer for a highly durable carbon-based fuel cell.
◈ Claim 6 was abandoned upon payment of the set registration fee. The method of claim 1,
The aromatic compound is aminopyrene (1-Amionpyrene; AP), pyrenebutyric acid, pyrene methylamine, pyrene-1-boronic acid, 1-pi 1-Pyrenecarboxylic acid (PCA), 1-Pyrenebutyric acid (PBA), 1-pyreneacetic acid, 1-mercaptopyrene, 1-pyrenesulfonic acid (1-pyrenesulfonic acid), 1-hydroxypyrene (1-hydroxypyrene) and 6-mercapto benzopyrene (6-mercaptobenzopyrene) containing at least any one selected from the group consisting of ,
Method for producing a catalyst layer for a highly durable carbon-based fuel cell.
The method of claim 1,
The step of surface modification with an aromatic compound on the platinum/carbon catalyst,
The aromatic compound is coated in a single layer on the platinum/carbon catalyst,
Method for producing a catalyst layer for a highly durable carbon-based fuel cell.
The method of claim 1,
The polymeric ionomer is a method of producing a catalyst layer for a highly durable carbon-based fuel cell that includes perfluorinated sulfonic acid ionomers (PFSA).
The method of claim 1,
The polymeric ionomer includes at least any one selected from the group consisting of poly(perfluorosulfonic acid), poly(perfluorocarboxylic acid), and a copolymer of tetrafluoroethylene and fluorovinyl ether,
Method for producing a catalyst layer for a highly durable carbon-based fuel cell.
◈ Claim 10 was abandoned upon payment of the set registration fee. The method of claim 1,
The polymeric ionomer comprises at least any one selected from the group consisting of Nafion, Flemion, Aciplex, 3M ionomer, Dow ionomer, Solvay ionomer, and Sumitomo 3M ionomer,
Method for producing a catalyst layer for a highly durable carbon-based fuel cell.
◈ Claim 11 was abandoned upon payment of the set registration fee. The method of claim 1,
The thickness of the catalyst layer prepared by coating a polymer ionomer on the surface-modified platinum/carbon catalyst is 1 μm to 20 μm,
Method for producing a catalyst layer for a highly durable carbon-based fuel cell.
delete delete delete delete delete Carbon/platinum catalyst; And
A polymer ionomer coated on the carbon/platinum catalyst;
Including,
The polymer ionomer coated on the platinum particle surface is thinner than the polymer ionomer coated on the carbon surface,
Any one of claims 1 to 11 prepared by the method for producing a catalyst layer for a highly durable carbon-based fuel cell,
High durability carbon-based fuel cell catalyst layer
delete A membrane electrode assembly for a fuel cell comprising the catalyst layer for a highly durable carbon-based fuel cell of claim 17.

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