JP2012015090A - Apparatus and method for producing fuel cell catalyst layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell capable of stably providing higher output under a slightly humidified environment or an non-humidified environment.SOLUTION: An apparatus for producing a fuel cell catalyst layer according to the present invention includes: a catalyst modification means 10; an ultrasonic homogenizer 20; a rotation/revolution-type centrifugal mixer 30; and a screen printer 40. The catalyst modification means 10 modifies platinum as catalyst metal microparticles with a nitric acid group, which is a modifying group having hydrophilicity, to produce a treated catalyst. The rotation/revolution-type centrifugal mixer 30 mixes a pre-paste together with a solution of a polymer electrolyte 2 to prepare a catalyst paste.

Description

  The present invention relates to a fuel cell catalyst layer manufacturing apparatus and a fuel cell catalyst layer manufacturing method.

  A cell of a fuel cell includes an electrolyte layer, a cathode electrode joined to one surface of the electrolyte layer and supplied with air, and an anode electrode joined to the other surface of the electrolyte layer and supplied with fuel. The cathode electrode and the anode electrode have a catalyst layer. The catalyst layer contains innumerable catalysts in which catalytic metal fine particles such as platinum are supported on a conductive carrier such as carbon black, and a polymer electrolyte.

  As a conventional method for producing a catalyst layer, for example, Patent Document 1 discloses an invention of a production method by the inventors of the present invention. In this production method, first, a countless catalyst after pulverization is mixed with water to obtain a pre-paste. During this time, by adopting a centrifugal stirring method using a large amount of water, bubbles that may exist between the respective catalysts are suitably removed. Next, the pre-paste is mixed with the polymer electrolyte solution to form a catalyst paste. And a catalyst layer is obtained with a catalyst paste. For example, the catalyst paste is printed on a substrate having gas permeability such as carbon cloth, and the catalyst paste is dried together with the substrate. Thereby, the electrode used as the cathode electrode or anode electrode in which the catalyst layer was formed on the base material is obtained.

  In the catalyst layer thus obtained, the hydrophilic functional groups of the polymer electrolyte are oriented on the catalyst side, and a continuous hydrophilic layer is formed between each catalyst and the polymer electrolyte. This catalyst layer is referred to as having a PFF (Proton Film Flow) structure. When the electrode having the catalyst layer having the PFF structure is used as a cathode electrode and an anode electrode and these are provided on both surfaces of the electrolyte layer, a membrane electrode assembly (MEA) is obtained. According to the test results of the inventor, in the fuel cell using this membrane electrode assembly as a cell, protons move favorably, and high output is obtained while being lightly humidified or non-humidified.

JP 2006-140062 JP

  By the way, there is a demand for a fuel cell that can stably exhibit higher output under light humidification or no humidification. For this, it has become clear from the research by the inventors of the present invention that it is effective to hydrophilize the support of the catalyst layer.

  As a method for hydrophilizing the carrier, “Carbon” (Kim Kinoshita; John Wiley & Sons 1988), page 199 and JP-A-7-134995, the carrier and catalyst are boiled with an aqueous acid solution such as an aqueous nitric acid solution. To obtain a treated catalyst. This treated catalyst has a hydroxyl group on the surface and is considered to improve hydrophilicity. For this reason, if a catalyst layer is manufactured with this treated catalyst, protons are likely to move in the obtained catalyst layer, and high output can be obtained.

  However, according to the test by the inventors of the present invention, if the carrier or catalyst is boiled with an aqueous acid solution, the catalyst or carrier is oxidized and deteriorated. For this reason, high activity cannot be stably expected with this treated catalyst.

  Therefore, the present invention has been made in view of the above-described conventional situation, and it is an issue to be solved to provide a fuel cell that can stably exhibit higher output under light humidification or non-humidification. Yes.

The fuel cell catalyst layer production apparatus of the present invention is a fuel cell catalyst layer production apparatus for forming a catalyst layer from a catalyst paste.
A catalyst modifying means for producing a treated catalyst by modifying catalytic metal fine particles with a modifying group having hydrophilicity;
Pre-paste preparation means for preparing the pre-paste by mixing the treated catalyst with water;
And a catalyst paste preparation means for preparing a catalyst paste by mixing the pre-paste together with a polymer electrolyte solution (claim 1).

  In the production apparatus of the present invention, first, the catalyst modifying means binds a metal complex that is the same or the same kind as the catalyst metal fine particles and includes a modifying group to the catalyst metal fine particles. At this time, by using the complex, it is possible to obtain a treated catalyst obtained by modifying the catalytic metal fine particles with a hydrophilic modifying group without giving any stress to the structure of the catalyst.

  Since this treated catalyst is not a product obtained by boiling the support or catalyst with an aqueous acid solution, the catalyst or support is not oxidized and does not deteriorate. According to the inventors' tests, the treated catalyst may contain 2400-7800 μg / g of modifying groups per weight of catalyst and 5200-14000 μg / g of weight per weight of support.

As the complex solution, platinum chloride (IV) acid hydrate aqueous solution (H ₂ PtCl ₆ .nH ₂ O / H ₂ O sol.), Platinum chloride (IV) hydrochloride acid solution (H ₂ PtCl ₆ / HCl sol.) , Platinum chloride (IV) ammonium aqueous solution ((NH ₄ ) ₂ PtCl ₆ / H ₂ O sol.), Dinitrodiamine platinum (II) aqueous solution (cis- [Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] / H ₂ O sol.), Dinitrodiamine platinum (II) nitric acid solution (cis- [Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] / HNO ₃ sol.), Dinitrodiamine platinum (II) sulfuric acid solution (cis- [Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] / H ₂ SO ₄ sol.), Potassium tetracurl platinum (II) acid aqueous solution (K ₂ PtCl ₄ ) / H ₂ O sol. ), Platinum (II) chloride aqueous solution (PtCl ₂ / H ₂ O sol.), Platinum (IV) chloride aqueous solution (PtCl ₄ / H ₂ O sol.), Tetraamine platinum (II) dichloride hydrate aqueous solution ([Pt (NH ₃ ) ₄ ] Cl ₂ .H ₂ O / H ₂ O sol.), Tetraamine platinum (II) hydroxide aqueous solution ([Pt (NH ₃ ) ₄ ] (OH) ₂ / H ₂ O sol. .), Hexaamine platinum (IV) dichloride aqueous solution ([Pt (NH ₃ ) ₆ ] Cl ₂ / H ₂ O sol.), Hexaamine platinum (IV) hydroxide aqueous solution ([Pt (NH ₃ ) ₆ ] (OH) ₂ / H ₂ O sol.), Hexahydroxoplatinum (IV) acid aqueous solution (H ₂ [Pt (OH) ₆ ] / H ₂ O sol.), Hexahydroxoplatinum (IV) acid nitric acid solution (H ₂ [Pt ( _{OH) 6] / HNO 3 sol} .), hexahydroxoplatinum IV) acid sulfuric acid solution _{(H 2 [Pt (OH)} 6] / H 2 SO 4 sol.), Ethanolamine platinum solution _{(H 2 [Pt (OH)} 6] / H 2 NCH 2 CH 2 OH sol.) , Etc. Can be adopted. Among these, a complex solution containing chlorine is not so preferable because chlorine is considered to deteriorate platinum. Here, only the metal species in the complex is platinum, but it is not necessarily limited thereto.

According to the inventor's knowledge, as the complex solution, dinitrodiamineplatinum (II) nitric acid solution (cis- [Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] / HNO ₃ sol having NO ₃ ⁻ as a ligand) is used. .), hexahydroxoplatinum (IV) acid nitric acid solution _{((H 2 Pt (OH)} 6) / HNO 3 sol.), hexahydroxoplatinate SO ₄ ^2-a a ligand source of platinum (IV) acid sulfate solution (( _{H 2 Pt (OH) 6)} / H 2 SO 4 sol.), NH 4 + a tetraamine platinum (II) hydroxide aqueous solution having a ligand _{([Pt (NH 3) 4} (OH) 2] / H ₂ O sln.) Or the like can be employed.

  Next, the pre-paste preparation means mixes the treated catalyst with water to form a pre-paste. At this time, since the hydrophilic modifying group is adsorbed on the treated catalyst, the surface of each treated catalyst is more reliably covered with water. Further, by adopting a centrifugal stirring method using a large amount of water, bubbles that may exist between the respective catalysts are suitably removed.

  Then, the catalyst paste preparation means mixes the pre-paste together with the polymer electrolyte solution to obtain a catalyst paste. At this time, since each treated catalyst has wettability to water, the polymer electrolyte orients the hydrophilic functional group of the side chain of the polymer electrolyte on the treated catalyst side. Thus, a catalyst paste is obtained in which hydrophilic layers that are continuous with each other are formed with water between the treated catalyst and the polymer electrolyte that are in contact with each other.

  Thereafter, a catalyst layer is obtained with a catalyst paste. For this reason, if a catalyst layer is manufactured using this catalyst paste, the catalyst layer has a PFF structure more reliably.

  For this reason, in the fuel cell having this catalyst layer, since the hydrophilic layer is continuously formed in the catalyst layer, protons easily move along this. Further, since the polymer electrolyte has the hydrophilic functional group of the side chain of the polymer electrolyte oriented on the hydrophilic layer side, the hydrophilic layer is effectively used for proton transfer. For this reason, the amount of water necessary for the movement of protons is retained in the water channel and moves well in the water channel.

  Therefore, according to the manufacturing apparatus of the present invention, a fuel cell capable of stably exhibiting higher output under light humidification or no humidification can be obtained.

  As the pre-paste preparation means and the catalyst paste preparation means, for example, a ball mill, a stirrer, a bead mill and a roll mill, a rotation / revolution centrifugal stirrer having a chamber, and the like can be employed. The same thing can be employ | adopted by a pre paste preparation means and a catalyst paste preparation means.

  The pre-paste preparation means may be a wet jet mill. In this case, it is considered that a more suitable pre-paste can be obtained.

  The catalyst paste preparation means may be a wet jet mill. In this case, it is considered that a more suitable catalyst paste can be obtained.

The method for producing a fuel cell catalyst layer according to the present invention includes a fuel cell catalyst layer production apparatus for forming a catalyst layer from a catalyst paste.
A catalyst modification step for producing a treated catalyst by modifying catalytic metal fine particles with a modifying group having hydrophilicity;
A pre-paste preparation step of preparing the pre-paste by mixing the treated catalyst with water;
And a catalyst paste preparation step of preparing a catalyst paste by mixing the pre-paste together with the polymer electrolyte solution (claim 4).

  According to the production method of the present invention, it is possible to obtain a fuel cell catalyst layer having the above characteristics.

  Therefore, according to the manufacturing method of the present invention, it is possible to obtain a fuel cell that can stably exhibit higher output under light humidification or non-humidification.

  The modifying group is preferably at least one selected from nitric acid group, amino group, sulfonic acid group, hydroxyl group and halogen group. The inventor has confirmed the effect of the present invention when the modifying group is a nitrate group.

  In the production method of the present invention, it is preferable to pulverize the treated catalyst in water in the pre-paste preparation step. And it is preferable that this grinding | pulverization process is performed with an ultrasonic homogenizer (Claim 7). If the pulverization process is performed with an ultrasonic homogenizer, the order or size of the catalyst particles can be reduced, and large pores of 0.1 μm or more can be reduced. For this reason, useless spaces (pores) cannot be formed in the catalyst layer, the resistance value of the catalyst layer is reduced, and the fuel cell exhibits high output.

It is a block diagram which shows the manufacturing apparatus of the catalyst layer for fuel cells of an Example. It is a flowchart which shows the manufacturing process regarding the manufacturing apparatus of the catalyst layer for fuel cells of an Example. 4 is a graph showing a relationship among cell temperature, voltage, and resistance in the fuel cells of Sample 1 and Comparative Examples 1 and 2 in connection with Test 1. 3 is a schematic cross-sectional view showing a part of a fuel cell catalyst layer in Sample 1. FIG. 4 is a graph showing a relationship among cell temperature, voltage, and resistance in the fuel cell of Sample 2 and Comparative Examples 1 and 2 in connection with Test 2. 6 is a graph showing a relationship among cell temperature, voltage, and resistance in the fuel cell of Sample 3 and Comparative Examples 1 and 2 in connection with Test 3. It is a graph which shows the XPS analysis result in the processed catalyst in the test 2, the sample 3-1, the sample 3-2, and the sample 4 under N1s superposition. It is a graph which shows the XPS analysis result in the processed catalyst in Sample 2, Sample 3-1, Sample 3-2 and Sample 4 under the superposition of S2p in connection with Test 4. 4 is a photomicrograph of a magnification of 5000 times showing a cross section of an electrode of Sample 4 according to Test 5. 4 is a photomicrograph at 5000 times showing a cross section of an electrode of Comparative Example 3 according to Test 5. 6 is a graph showing pore distributions of Sample 4, a catalyst layer, and a catalyst layer of Comparative Example 3 according to Test 5. 10 is a graph showing the relationship between current density and voltage in fuel cells of Sample 5 and Comparative Example 4 in connection with Test 6. 10 is a graph showing the relationship between current density and voltage in fuel cells of Samples 6-1, 6-2 and Comparative Example 5 according to Test 6.

(Example)
As shown in FIG. 1, the apparatus for producing a catalyst layer for a fuel cell according to the example comprises a catalyst modifying means 10, an ultrasonic homogenizer 20 for performing a wet pulverization process, a pre-paste preparation means, and a rotation / A revolving centrifugal stirrer 30 and a known screen printer 40 are provided. The ultrasonic homogenizer 20 is a public article. In addition, as the rotation / revolution centrifugal stirrer 30, a product name “Hybrid Mixer HM-500” manufactured by Keyence Corporation is adopted. The rotation / revolution centrifugal stirrer 30 has a chamber (not shown).

  In this manufacturing apparatus, the fuel cell catalyst layer can be obtained through the manufacturing process shown in FIG.

  First, an assembly consisting of a myriad of catalysts was purchased. The catalyst support type is Ketjen Black EC600JD and the catalyst type is Pt / Co. Each catalyst has platinum and cobalt supported on a carrier made of carbon in a loading amount of 60% by mass. In step S1 shown in FIG. 2, the aggregate was pulverized using a blade mill.

  Next, the treated catalyst is obtained by the catalyst modifying means 10. This treated catalyst is a catalyst that has adsorbed nitrate groups. Specifically, a treated catalyst is obtained by performing a catalyst modification step with a stirrer and a heating device (both not shown) of the catalyst modification means 10 as shown in step S2. That is, a complex solution was prepared, and the pulverized catalyst was added to the complex solution.

As the complex solution, dinitrodiamine platinum (II) nitric acid solution (cis- [Pt (NH ₃ ) ₂ (NO ₂ ) ₂ ] / HNO ₃ sol.) (Pt 0.05 g / 150 mL, nitric acid concentration 0.07% (0 .01M)).

  The catalyst was added to the complex solution and stirred with a stirrer for 5 hours. Thereby, it is thought that the nitrate group which exists around the dinitrodiamine platinum is adsorbed on the platinum of the catalyst. The complex solution after the treatment was filtered, the residue was dried at 60 ° C. for 2 hours, and heat-treated at 150 ° C. for 2 hours in nitrogen gas. The reason why the treated catalyst is heat-treated is to remove impurities on the surface of each treated catalyst as much as possible. Thus, 1.012 g (Pt yield 84.3%) of the treated catalyst was obtained from 1 g of the catalyst.

  Thereafter, in step S3, the treated catalyst was subjected to a pre-paste preparation process. First, in step S31, 100 mL of water was added to 1 g of the treated catalyst, and water immersion was performed.

  Next, in step S32, the ultrasonic homogenizer 20 was inserted into the water in which the treated catalyst was immersed, and ultrasonic waves with a frequency of 20 kHz were added for 10 minutes to perform a wet pulverization process as a pulverization process.

  Further, in Step S33, the centrifugal stirring method was executed by the rotation / revolution centrifugal stirrer 30. At this time, the treated catalyst and water reduced to 8 times equivalent to the treated catalyst were accommodated in the chamber of the stirrer. Thereafter, while applying centrifugal force to the mixture by revolving the chamber, the mixture was stirred by its own weight by rotating the chamber to obtain a pre-paste. During this time, since the nitrate group is adsorbed on the treated catalyst, the surface of each treated catalyst is more reliably covered with water. In addition, about a pre-paste preparation means, it can replace with the autorotation / revolution type | formula centrifugal stirrer 30, and can also employ | adopt a wet jet mill.

  Next, in step S4, a catalyst paste preparation process is performed. In the catalyst paste preparation step, the pre-paste and the polymer electrolyte solution are accommodated in the rotation / revolution centrifugal stirrer 30, and the catalyst paste is obtained by executing the centrifugal stirring method. During this time, since each treated catalyst has wettability to water, the polymer electrolyte orients the hydrophilic functional group of the side chain of the polymer electrolyte on the treated catalyst side. A hydrophilic layer that is continuous with water is formed between the treated catalyst and the polymer electrolyte that are in contact with each other. In addition, about a catalyst paste preparation means, it can replace with the autorotation / revolution type | formula centrifugal stirrer 30, and can also employ | adopt a wet jet mill.

  Thereafter, as a final process of step S5, a catalyst layer is obtained from the catalyst paste obtained by the manufacturing apparatus. First, carbon cloth was prepared as a base material having gas permeability. A diffusion layer having a carbon cloth as a base material and a water repellent layer made of a mixture of carbon black and PTFE on both sides was prepared. Thereafter, in step S51, screen printing by the screen printer 40 was performed on the cathode catalyst layer and the anode catalyst layer using the catalyst paste. Thus, the fuel cell catalyst layer is obtained by the manufacturing apparatus of the example.

{Verification}
<Test 1>
Further, in step S52, the substrate after printing was rapidly dried to obtain a cathode electrode and an anode electrode. These were provided on both surfaces of the electrolyte layer to obtain a membrane electrode assembly. Using this membrane electrode assembly as a cell, the fuel cell of Sample 1 was assembled. The catalyst layer of the fuel cell of Sample 1 has Pt of 0.1 mg / cm ² .

As Comparative Example 1, a catalyst paste was obtained by a conventional manufacturing method in which the catalyst modification step S2 and the homogenization treatment S32 were not performed, and a similar fuel cell was assembled using this catalyst paste. The catalyst layer of the fuel cell of Comparative Example 1 has a Pt of 0.1 mg / cm ² .

Further, as in Comparative Example 1, the fuel cell of Comparative Example 2 was assembled. The catalyst layer of the fuel cell of Comparative Example 2 has Pt of 0.4 mg / cm ² .

In these fuel cells, the humidification temperature is 60 ° C., the supply amount of H ₂ is 0.8 L / min (0.1 MPa-G), the supply amount of air is 3.0 L / min (0.1 MPa-G), conditions of electrode area 45mm × 45mm (20.25cm ^2), to generate electricity of a constant current, was determined and the cell temperature (° C), and voltage (V), and the relationship between the resistance (Ω · cm ²⁾ . The results are shown in FIG.

  FIG. 3 shows that the fuel cell of Sample 1 can stably exhibit higher output under light humidification than the fuel cell of Comparative Example 1. The performance of the fuel cell of Sample 1 is the same as that of Comparative Example 2 in which the platinum amount is four times. For this reason, in the fuel cell of the sample 1, even if it reduces platinum amount, it turns out that a high output can be exhibited stably under light humidification. As shown in FIG. 4, the catalyst layer of the fuel cell of Sample 1 contains an infinite number of catalysts 1 in which catalytic metal fine particles 1b are supported on a carrier 1a and a polymer electrolyte 2. In this catalyst layer, The hydrophilic functional group of the side chain 101 of the polymer electrolyte 2 is oriented to the catalyst 1 so that the hydrophilic layer 3 is formed on the catalyst 1 (PFF structure). Thereby, in the catalyst layer of the fuel cell of Sample 1, the hydrophilic layer 3 that is continuous with each other is reliably formed between each catalyst 1 and the polymer electrolyte 2.

<Test 2>
The complex solution was a hexahydroxoplatinum (IV) acid nitric acid solution ((H ₂ Pt (OH) ₆ ) / HNO ₃ sol.), And the fuel cell of Sample 2 was assembled. Other conditions are the same as those of Sample 1. The catalyst layer of the fuel cell of Sample 2 has Pt of 0.1 mg / cm ² .

In the fuel cell of Sample 2 and Comparative Examples 1 and ² , the relationship between the cell temperature (° C), the voltage (V), and the resistance (Ω · cm ² ) was obtained under the same conditions as in Test 1. The results are shown in FIG.

  From FIG. 5, it can be seen that the fuel cell of Sample 2 can stably exhibit a high output under light humidification as in Sample 1.

<Test 3>
The complex solution was tetraamine platinum (II) hydroxide aqueous solution ([Pt (NH ₃ ) ₄ (OH) ₂ ] / H ₂ O sln.), And the fuel cell of Sample 3 was assembled. Other conditions are the same as those of Sample 1. The catalyst layer of the fuel cell of Sample 3 has Pt of 0.1 mg / cm ² .

  In the fuel cell of Sample 3 and Comparative Examples 1 and 2, the relationship among the cell temperature (° C.), voltage (V), and resistance (mΩ) was determined under the same conditions as in Test 1. The results are shown in FIG.

  From FIG. 6, it can be seen that the fuel cell of Sample 3 can stably exhibit high output under light humidification as in Samples 1 and 2.

<Test 4>
Hexahydroxoplatinum (IV) acid sulfuric acid solution ((H ₂ Pt (OH) ₆ ) / H ₂ SO ₄ sol.) Was used as the complex solution, and a treated catalyst in sample 4 was obtained.

  XPS analysis of the treated catalyst in samples 2-4 was performed. The results were obtained with two types of treatment supernatant catalysts of Sample 3 (Sample 3-1 and Sample 3-2). FIG. 7 shows the result of N1s superposition, and FIG. 8 shows the result of S2p superposition.

As shown in FIG. 7, the processing supernatant catalyst of each sample has an organic nitrogen, ammonium salt, or NO component of amine or amide. For this reason, it turns out that these have adsorbed NO ₃ ⁻ or NH ₄ ⁺ in the catalyst.

<Test 5>
FIG. 9 shows a cross section of the electrode of Sample 4 manufactured in the same manner as Sample 1, and FIG. 10 shows a cross section of the electrode of Comparative Example 3 manufactured in the same manner as Comparative Example 1. The catalyst layer of the electrode of Sample 4 and Comparative Example 3 was screen-printed under the same conditions. The catalyst layers of Sample 4 and Comparative Example 3 have Pt of 0.11 mg / cm ² . 9 and 10 are photomicrographs of each electrode magnified 5000 times.

  Further, the pore distributions of the catalyst layer of Sample 4 and the catalyst layer of Comparative Example 3 were determined. The results are shown in FIG. As shown in FIG. 11, the pores of about 0.04 to 0.1 μm are not so different between the catalyst layer of Sample 4 and the catalyst layer of Comparative Example 3. On the other hand, it can be seen that the pores of 0.1 μm or more are reduced by the wet pulverization treatment.

  Further, as shown in FIGS. 9 and 10, the electrode of Sample 4 has a catalyst layer thickness of about 2 μm, the catalyst layer is dense, and no pores are present in the catalyst layer. The electrode of No. 3 has a catalyst layer thickness of about 5 μm, and pores are conspicuous in the catalyst layer. This difference is caused by whether or not wet pulverization is performed on the treated catalyst in water in the pre-paste preparation process.

  If the catalyst layer is thin like the electrode of sample 4, it is preferable that generated water is easily removed even if generated water is generated at a position close to the electrolyte layer under high temperature and low humidification conditions. In addition, the absence of pores in the catalyst layer as in the electrode of Sample 4 indicates that the resistance value is low, which is also preferable.

  Therefore, in the production apparatus of the present invention, in the pre-paste preparation process, it is preferable to perform a wet pulverization treatment with the ultrasonic homogenizer 20 on the treated catalyst in water.

(Test 6)
A fuel cell of Sample 5 using a treated catalyst prepared in the same manner as Sample 1 and containing only 2 μg / g of nitrate groups, and a catalyst manufactured in the same manner as Comparative Example 1 and containing only 2 μg / g of nitrate groups. With respect to the fuel cell of Comparative Example 4 used, the relationship between the current density (A / cm ² ) and the voltage (V) under conditions of 50 ° C., normal pressure, and full humidification was determined. The results are shown in FIG.

On the other hand, the fuel cell of sample 6 using the treated catalyst containing nitrate group 4700 μg / g manufactured in the same manner as sample 1 and the catalyst containing nitrate group 4700 μg / g manufactured using Comparative Example 1 were used. For the fuel cell of Comparative Example 5, the relationship between current density (A / cm ² ) and voltage (V) under the same conditions was determined. Results were obtained for two types of treatment supernatant catalysts of Sample 6 (Sample 6-1 and Sample 6-2). The results are shown in FIG.

  As shown in FIG. 12, the effect of the pulverization process (wet pulverization process) does not appear in the treated catalyst having a small number of nitrate groups. However, as shown in FIG. 13, the effect of the wet pulverization treatment is remarkable in the treated catalyst having many nitrate groups.

  In the above, the present invention has been described with reference to Examples and Tests 1 to 6. However, the present invention is not limited to the above Examples and Tests 1 to 6, and may be appropriately changed without departing from the spirit of the present invention. Needless to say, this is applicable.

  The present invention can be used for a moving power source for an electric vehicle or the like, or a stationary power source.

1b ... catalyst metal fine particles 10 ... catalyst modification means 1 ... catalyst 30 ... rotation / revolution centrifugal stirrer (pre-paste preparation means, catalyst paste preparation means)
2 ... polymer electrolyte S2 ... catalyst modification step S3 ... pre-paste preparation step S4 ... catalyst paste preparation step S32 ... wet grinding treatment (grinding treatment)
20 ... Ultrasonic homogenizer

Claims (7)

In a fuel cell catalyst layer manufacturing apparatus for forming a catalyst layer from a catalyst paste,
A catalyst modifying means for producing a treated catalyst by modifying catalytic metal fine particles with a modifying group having hydrophilicity;
Pre-paste preparation means for preparing the pre-paste by mixing the treated catalyst with water;
An apparatus for producing a catalyst layer for a fuel cell, comprising: catalyst paste preparation means for preparing a catalyst paste by mixing the pre-paste together with a polymer electrolyte solution.   The apparatus for producing a catalyst layer for a fuel cell according to claim 1, wherein the pre-paste preparation means is a wet jet mill.   The apparatus for producing a catalyst layer for a fuel cell according to claim 1 or 2, wherein the catalyst paste preparation means is a wet jet mill. In a fuel cell catalyst layer manufacturing apparatus for forming a catalyst layer from a catalyst paste,
A catalyst modification step for producing a treated catalyst by modifying catalytic metal fine particles with a modifying group having hydrophilicity;
A pre-paste preparation step of preparing the pre-paste by mixing the treated catalyst with water;
And a catalyst paste preparation step of preparing a catalyst paste by mixing the pre-paste together with the polymer electrolyte solution.   The method for producing a fuel cell catalyst layer according to claim 4, wherein the modifying group is at least one selected from a nitric acid group, an amino group, a sulfonic acid group, a hydroxyl group, and a halogen group.   The method for producing a fuel cell catalyst layer according to claim 4 or 5, wherein in the pre-paste preparation step, the treated catalyst in water is pulverized.   The method for producing a fuel cell catalyst layer according to claim 6, wherein the pulverization is performed by an ultrasonic homogenizer.

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