JP5436059B2 - Method for producing platinum particle-supported carbon black catalyst - Google Patents

Description

  The present invention relates to a method for producing a platinum particle-supported carbon black catalyst.

In recent years, global environmental problems have been greatly highlighted. A fuel cell not only has high energy conversion efficiency but also contributes to the reduction of CO ₂ emissions, and is also a clean cell that emits almost no NOx, SOx, dust, etc. that cause acid rain and air pollution. It is. Furthermore, there is an advantage that silence is also high. Therefore, some fuel cells are being put into practical use as an energy conversion device that is optimal for the 21st century. In particular, a polymer electrolyte fuel cell (PEFC) among fuel cells has an advantage that it can be miniaturized because of its low operating temperature and high output density.

FIG. 13 is a cross-sectional view showing an example of a polymer electrolyte fuel cell.
The polymer electrolyte fuel cell has a structure in which a polymer solid electrolyte membrane 1 is sandwiched between an oxygen electrode 2 and a hydrogen electrode 3. The polymer solid electrolyte membrane 1 is an ion exchange membrane obtained by, for example, applying a slurry containing a polymer solid electrolyte on a carbon fiber porous cloth substrate and then baking the slurry.
The central portion outside the oxygen electrode 2 is carried by the current collector 6, and the central portion outside the hydrogen electrode 3 is carried by the current collector 7. The current collector 6 is made of a material having good electrical conductivity and corrosion resistance, and is usually formed of graphite, titanium, stainless steel or the like.

The outer peripheral edge of the oxygen electrode 2 is in contact with the inside of the frame-shaped gasket 4, and the outer periphery of the gasket 4 is in contact with the protruding peripheral edge of the inner side of the frame 8 having a plurality of recesses at the inner central part. doing. Thus, a plurality of oxygen electrode chambers 9 are formed between the inside of the frame 8 and the outside of the oxygen electrode 2 so as to correspond to the plurality of recesses. The frame 8 includes an oxygen gas supply port 12 connected to the oxygen electrode chamber 9 so as to penetrate the inside and outside, an unreacted oxygen gas connected to the oxygen electrode chamber 9 so as to penetrate the inside and outside, and And a generated water outlet 13.
On the other hand, the outer peripheral edge of the hydrogen electrode 3 is in contact with the inner side of the frame-shaped gasket 5, and the outer peripheral edge of the gasket 5 is a protruding peripheral edge on the inner side of the frame 10 having a plurality of recesses at the inner central part. Are in contact. Thus, a plurality of hydrogen electrode chambers 11 are formed between the inside of the frame 10 and the outside of the hydrogen electrode 3 so as to correspond to the plurality of recesses. The frame 10 has a hydrogen gas supply port 14 connected to the hydrogen electrode chamber 11 so as to penetrate the inside and the outside, and an unreacted hydrogen gas intake connected to the hydrogen electrode chamber 11 so as to penetrate the inside and the outside. And an outlet 15.

For the oxygen electrode 2 and the hydrogen electrode 3, a catalyst in which platinum fine particles exhibiting high catalytic activity are supported on a carrier is usually used. Examples of the method for producing platinum fine particles include various methods such as electrodeposition, sputtering, platinum complex impregnation-reduction thermal decomposition, alcohol reduction, borohydride reduction, and oxide gas phase reduction. Can be mentioned.
By the way, as one factor that hinders the spread of such polymer electrolyte fuel cells, it is cited that the price is high. In particular, platinum used for the oxygen electrode 2 and the hydrogen electrode 3 is extremely expensive.

Therefore, platinum fine particles having an average particle diameter of 3 nm are used in the oxygen electrode 2 and the hydrogen electrode 3 of the polymer electrolyte fuel cell, but it is known that platinum contributing to the reaction is only the surface layer. Therefore, the specific surface area is increased by reducing the particle size. In addition, by designing a platinum thin film of several atomic layers on a substrate, a catalyst design aiming at reducing platinum while maintaining the catalytic activity of platinum has been performed.
Specifically, as a method for producing a thin platinum film, an adjustment step in which a platinum carbonyl complex is dissolved in an organic solvent to obtain a platinum carbonyl complex solution, and the platinum carbonyl complex solution is applied onto a metal substrate having a large ionization tendency. Then, the process of obtaining the metal base | substrate with which the platinum thin film was formed by removing an organic solvent is included (for example, refer patent document 1).
As a method for producing a platinum carbonyl complex, a platinum compound represented by the chemical formula (1) or (2) is dissolved in an aqueous solution to prepare a sample solution, and then CO is bubbled into the sample solution. A platinum carbonyl complex solution is being prepared.
M ₂ PtX ₆ (1)
M ₂ PtX ₄ (2)
Here, M is an alkali metal, an ammonium group or hydrogen, and X is a halogen atom.

JP 2008-10366 A

However, in the method for producing a thin platinum film as described above, an electrodeposition method, a sputtering method, a platinum complex impregnation-reduction thermal decomposition method, an alcohol reduction method, a borohydride reduction method, an oxide vapor phase reduction method, etc. Although it is possible to obtain a platinum thin film having a thinner film thickness than the above various methods, there is a problem that the film thickness of the platinum thin film cannot be controlled.
On the other hand, a platinum particle-supporting carbon black catalyst in which finely divided platinum is supported on the ketjen black surface is also manufactured. By applying such a platinum particle-supporting carbon black catalyst on a substrate, the amount of unexposed platinum is reduced as much as possible.

Therefore, the present inventors can use a platinum carbonyl complex solution as described above to support a fine platinum compound having a small particle diameter and a narrow distribution width on the ketjen black surface. I found.
However, the average particle size of the platinum compound supported on the ketjen black surface could not be controlled. Therefore, even if platinum particles are supported on the substrate, a thin platinum film can be obtained, but the thickness of the platinum thin film cannot be controlled.

Therefore, in order to solve the above problems, the present inventors have studied a method for producing a platinum particle-supporting carbon black catalyst that can control the average particle diameter of fine platinum particles supported on the carbon surface. First, in the manufacturing method as described above, the sample solution is prepared by dissolving the compound represented by the chemical formula (1) or (2) in the aqueous solution. However, instead of the aqueous solution, mixing of water and acetonitrile is performed. Sample solutions were prepared using a solvent, ethanol, butanol, and hexanol, respectively. And when each sample solution produced in this way was used, it turned out that the average particle diameters of the particulate platinum carry | supported on the carbon surface differ, respectively.
2 to 4 are a transmission electron microscope (TEM) photograph of a platinum particle-supported carbon black catalyst and a graph of particle size distribution. 2 shows the case where ethanol is used, FIG. 3 shows the case where butanol is used, and FIG. 4 shows the case where hexanol is used. The black circles are Pt particles, and the light gray ones are carbon black (KB).
As shown in FIG. 2, when ethanol is selected, the average particle diameter of fine platinum particles is 2.02 ± 0.35 nm. When butanol is selected as shown in FIG. 3, the average particle diameter of fine particle platinum is Was 2.28 ± 0.31 nm. As shown in FIG. 4, when hexanol was selected, the average particle size of fine platinum particles was 2.24 ± 0.25 nm.
As a result, it was found that the average particle size of fine platinum particles supported on the carbon surface can be controlled by selecting a solvent when preparing the sample solution.

Further, in the manufacturing method as described above, while the sample solution is heated at a predetermined temperature, CO is bubbled into the sample solution to produce a platinum carbonyl complex solution. However, the predetermined temperature is 30 ° C. or 50 ° C. Platinum carbonyl complex solutions were prepared at 70 ° C. and 70 ° C., respectively. And when each platinum carbonyl complex solution produced in this way was used, it turned out that the average particle diameters of the particulate platinum supported on the carbon surface differ, respectively.
6 to 8 are diagrams showing transmission electron micrographs and graphs of particle size distribution of platinum particle-supported carbon black catalysts. 6 is performed at 30 ° C., FIG. 7 is performed at 50 ° C., and FIG. 8 is performed at 70 ° C.
As shown in FIG. 6, when 30 ° C. is selected, the average particle diameter of the fine platinum particles becomes 1.81 ± 0.30 nm. When 50 ° C. is selected as shown in FIG. The particle diameter was 2.30 ± 0.36 nm. As shown in FIG. 8, when 70 ° C. was selected, fine-particle platinum aggregates were formed.
As a result, it was found that the average particle size of fine platinum particles supported on the carbon surface can be controlled by selecting the temperature when preparing the platinum carbonyl complex solution.

That is, the method for producing a platinum particle-supported carbon black catalyst of the present invention includes a chemical formula (1) or a chemical formula in one solvent selected from the group consisting of a mixed solvent of water and acetonitrile, ethanol, and butanol or hexanol. A sample solution preparation step for preparing a sample solution by dissolving the platinum compound shown in (2), and bubbling carbon monoxide into the sample solution while heating the sample solution at 30 ° C. to 40 ° C. A platinum carbonyl complex solution preparation step for preparing a carbonyl complex solution, and a mixing step of mixing the platinum carbonyl complex solution in a carbon particle dispersion in which carbon particles are dispersed in one type of solvent selected in the sample solution preparation step wherein the door is taken to obtain without firing the platinum particles supported carbon black catalyst.
M ₂ PtX ₆ (1)
M ₂ PtX ₄ (2)
Here, M is an alkali metal, an ammonium group or hydrogen, and X is a halogen atom.

  According to the method for producing a platinum particle-supported carbon black catalyst of the present invention, when ethanol is selected when preparing a sample solution, fine platinum particles having an average particle diameter of 2.00 ± 0.35 nm are supported on the carbon surface. If butanol or hexanol is selected, fine particles of platinum with an average particle size of 2.30 ± 0.35 nm can be supported on the carbon surface, and if a mixed solvent of water and acetonitrile is selected, the average Fine platinum having a particle diameter of 1.80 ± 0.35 nm can be supported on the carbon surface.

  As described above, according to the method for producing a platinum particle-supporting carbon black catalyst of the present invention, the average particle diameter of fine platinum particles supported on the carbon surface can be controlled.

(Means and effects for solving other problems)
Moreover, the method for producing a platinum particle-supported carbon black catalyst of the present invention comprises preparing a sample solution by dissolving a platinum compound represented by chemical formula (1) or chemical formula (2) in a mixed solvent of water and acetonitrile. A platinum carbonyl complex solution for producing a platinum carbonyl complex solution by bubbling carbon monoxide in the sample solution while heating the sample solution at a predetermined temperature selected from a step and a temperature range of 25 ° C. to 65 ° C. Including a preparation step and a mixing step of mixing the platinum carbonyl complex solution in a carbon particle dispersion in which carbon particles are dispersed in a 1: 1 mixed solvent of water and acetonitrile, and firing the platinum particle-supported carbon black catalyst. Trying to get without.
M ₂ PtX ₆ (1)
M ₂ PtX ₄ (2)
Here, M is an alkali metal, an ammonium group or hydrogen, and X is a halogen atom.

Here, the “predetermined temperature” means an arbitrary temperature T ° C., and may be a selected temperature range T ± 2 ° C.
According to the method for producing a platinum particle-supported carbon black catalyst of the present invention, when 30 ° C. is selected when preparing a platinum carbonyl complex solution, fine platinum particles having an average particle size of 1.80 ± 0.35 nm are carbonized. If it can be supported on the surface and 50 ° C. is selected, fine platinum having an average particle size of 2.30 ± 0.35 nm can be supported on the carbon surface.
As described above, according to the method for producing a platinum particle-supporting carbon black catalyst of the present invention, the average particle diameter of fine platinum particles supported on the carbon surface can be controlled.

In the method for producing a platinum particle-supported carbon black catalyst of the present invention, the carbon particles may be ketjen black.
Furthermore, in the method for producing a platinum particle-supported carbon black catalyst of the present invention, in the mixing step, the platinum carbonyl complex solution may be mixed with the carbon particle dispersion while performing ultrasonic treatment.

It is a graph which shows the ultraviolet visible absorption spectrum of the platinum carbonyl complex solution obtained in 1st embodiment. It is a figure which shows the transmission electron micrograph of a platinum particle carrying | support carbon black catalyst "Pt-et / CB", and the graph of a particle size distribution. It is a figure which shows the transmission electron micrograph of a platinum particle carrying | support carbon black catalyst "Pt-but / CB", and the graph of a particle size distribution. It is a figure which shows the transmission electron micrograph of a platinum particle carrying | support carbon black catalyst "Pt-hex / CB", and the graph of a particle size distribution. It is a graph which shows the ultraviolet visible absorption spectrum of the platinum carbonyl complex solution obtained in 2nd embodiment. It is a figure which shows the transmission electron micrograph of a platinum particle carrying | support carbon black catalyst "Pt-30 / CB", and the graph of a particle size distribution. It is a figure which shows the transmission electron micrograph of a platinum particle carrying | support carbon black catalyst "Pt-50 / CB", and the graph of a particle size distribution. It is a figure which shows the transmission electron micrograph of a platinum particle carrying | support carbon black catalyst "Pt-70 / CB", and the graph of a particle size distribution. It is a figure which shows the transmission electron micrograph of a platinum particle carrying | support carbon black catalyst "Pt / CB-TKK", and the graph of a particle size distribution. It is a figure which shows the measurement cell for rotating electrodes. It is a figure which shows a Tafel plot. It is a figure which shows a Tafel plot. It is sectional drawing which shows an example of a polymer electrolyte fuel cell.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments described below, and it goes without saying that various aspects are included without departing from the spirit of the present invention.

<First embodiment>
The method for producing a platinum particle-supported carbon black catalyst according to the first embodiment includes a sample solution preparation step (A) for preparing a sample solution, a platinum carbonyl complex solution preparation step (B) for preparing a platinum carbonyl complex solution, A mixing step (C) for obtaining a Pt / CB solution by mixing a platinum carbonyl complex solution with a carbon particle dispersion, a filtration step (D) for obtaining a platinum particle-supporting carbon black catalyst, and a platinum particle-supporting carbon black catalyst on the substrate. And an electrode manufacturing step (E) to be applied.

(A) Sample solution preparation step A platinum compound represented by the chemical formula (1) or the chemical formula (2) is dissolved in one kind of solvent selected from the group consisting of a mixed solvent of water and acetonitrile, ethanol, and butanol or hexanol. To prepare a sample solution.
M ₂ PtX ₆ (1)
M ₂ PtX ₄ (2)
Here, M is an alkali metal, an ammonium group or hydrogen, and X is a halogen atom.

Examples of the platinum compound represented by the chemical formula (1) include H ₂ PtCl ₆ , K ₂ PtCl ₆ , Na ₂ PtCl ₆ , K ₂ PtBr ₆ , K ₂ PtBr ₆ , (NH ₄ ) ₂ PtCl ₆ , (NH ₄ ). ₂ PtBr _{6 and the} like.
Examples of the platinum compound represented by the chemical formula (2) include H ₂ PtCl ₄ , K ₂ PtCl ₄ , Na ₂ PtCl ₄ , K ₂ PtBr ₄ , K ₂ PtBr ₄ , (NH ₄ ) ₂ PtCl ₄ , (NH ₄ ). ₂ PtBr ₄ or the like.

The mixed solvent of water and acetonitrile is preferably water: acetonitrile = 1: 1 by volume ratio.
The butanol is preferably 1-butanol, and the hexanol is preferably 1-hexanol.
And the density | concentration of the platinum compound in the sample solution produced at a sample solution preparation process is not specifically limited, It is preferable that they are 0.1 mmol / L or more and 10 mmol / L or less.

(B) Platinum carbonyl complex solution preparation process While heating a sample solution at 30 degreeC or more and 40 degrees C or less, CO is bubbled through a sample solution, Then, a platinum carbonyl complex solution is produced by stirring.
The time for bubbling CO is preferably 1 hour or more and 5 hours or less.
The stirring time is preferably from 30 minutes to 50 hours.
In addition, it is preferable that a platinum carbonyl complex is a compound shown by Chemical formula (3).
[Pt ₃ (CO) ₃ (μ-CO) ₃ ] _n ^2- (3)

Here, FIG. 1 is a graph showing ultraviolet-visible absorption spectra of the platinum carbonyl complex solution before and after the reaction.
As shown in FIG. 1 (a), when ethanol is selected, the peak values in the UV-visible absorption spectrum after the reaction are 420 and 795 nm, that is, n in the chemical formula (3) is determined according to literature (420 and 820 nm). A platinum carbonyl complex of 6 is formed. And as shown in FIG.1 (b), when butanol is selected, the peak value in the ultraviolet visible absorption spectrum after reaction is 423,824 nm, that is, in the chemical formula (3) according to the literature etc. (421,825 nm). A platinum carbonyl complex in which n is 7 or more is formed. Furthermore, as shown in FIG. 1 (c), when hexanol is selected, the peak values in the UV-visible absorption spectrum after the reaction are 425 and 840 nm, that is, in the chemical formula (3) according to literatures (423 and 845 nm). A platinum carbonyl complex in which n is 8 or more is formed.

(C) Mixing step A platinum carbonyl complex solution is mixed with a carbon particle dispersion in which carbon particles are dispersed in one type of solvent selected in the sample solution preparation step to obtain a Pt / CB solution.
At this time, it is preferable to mix the carbon particle dispersion and the platinum carbonyl complex solution while performing ultrasonic treatment. The time for mixing the carbon particle dispersion and the platinum carbonyl complex solution is preferably from 30 minutes to 90 minutes.
Examples of the carbon particles include ketjen black.
And the density | concentration of the carbon particle in a carbon particle dispersion liquid is not specifically limited, It is preferable that they are 0.1 mmol / L or more and 10 mmol / L or less.
Here, FIGS. 2 to 4 are diagrams showing a transmission electron micrograph and a graph of particle size distribution of the platinum particle-supported carbon black catalyst.
As shown in FIG. 2, when ethanol is selected, fine particles of platinum having an average particle size of 2.00 ± 0.35 nm can be supported on the carbon surface. As shown in FIGS. 3 and 4, butanol or When hexanol is selected, fine particles of platinum having an average particle diameter of 2.30 ± 0.35 nm can be supported on the carbon surface.

(D) Filtration process Platinum particle carrying | support carbon black catalyst is obtained by filtering Pt / CB solution.
(E) Electrode preparation step A platinum particle-supported carbon black catalyst is dispersed in ethanol to obtain a suspension, and the suspension is applied to a substrate and dried to obtain an electrode.

<Second Embodiment>
The method for producing a platinum particle-supported carbon black catalyst according to the second embodiment includes a sample solution preparation step (A) for preparing a sample solution, a platinum carbonyl complex solution preparation step (B) for preparing a platinum carbonyl complex solution, A mixing step (C) for obtaining a Pt / CB solution by mixing a platinum carbonyl complex solution with a carbon particle dispersion, a filtration step (D) for obtaining a platinum particle-supporting carbon black catalyst, and a platinum particle-supporting carbon black catalyst on the substrate. And an electrode manufacturing step (E) to be applied. In addition, description is abbreviate | omitted about the thing similar to 1st embodiment mentioned above.

(A) Sample solution preparation process The platinum compound shown by Chemical formula (1) or Chemical formula (2) is dissolved in the mixed solvent of water and acetonitrile, and a sample solution is produced.
The mixed solvent of water and acetonitrile is preferably water: acetonitrile = 1: 1 by volume ratio.
And the density | concentration of the platinum compound in the sample solution produced at a sample solution preparation process is not specifically limited, It is preferable that they are 0.1 mmol / L or more and 10 mmol / L or less.

(B) Platinum carbonyl complex solution preparation step While heating the sample solution at a predetermined temperature selected from a temperature range of 25 ° C. or higher and 65 ° C. or lower, CO is bubbled into the sample solution, and then stirred to obtain platinum. Make a carbonyl complex solution.
The predetermined temperature is preferably 30 ° C, 40 ° C, 50 ° C or 60 ° C.
The time for bubbling CO is preferably 1 hour or more and 5 hours or less.
The stirring time is preferably from 30 minutes to 50 hours.
In addition, it is preferable that a platinum carbonyl complex is a compound shown by Chemical formula (3).

Here, FIG. 5 is a graph showing an ultraviolet-visible absorption spectrum of the platinum carbonyl complex solution obtained in the second embodiment.
As shown in FIG. 5A, when 30 ° C. is selected, the peak value in the UV-visible absorption spectrum after the reaction is 540 nm, that is, n in the chemical formula (3) is 3 according to the literature (365, 545 nm). A platinum carbonyl complex is formed. Further, as shown in FIG. 5B, when 40 ° C. is selected, the peak value in the UV-visible absorption spectrum after the reaction is 490 nm, and when 50 ° C. is selected as shown in FIG. 5C. The peak value in the UV-visible absorption spectrum after the reaction is 470 nm. As shown in FIG. 5D, when 60 ° C. is selected, the peak value in the UV-visible absorption spectrum after the reaction is 420, 700 nm, As shown in FIG. 5 (e), when 70 ° C. is selected, the peak values in the UV-visible absorption spectrum after the reaction are 405 and 700 nm.

Here, FIGS. 6 to 8 are diagrams showing transmission electron micrographs and graphs of particle size distribution of the platinum particle-supported carbon black catalyst.
Thereby, as shown in FIG. 6, when 30 ° C. is selected, fine particles of platinum having an average particle diameter of 1.80 ± 0.35 nm can be supported on the carbon surface, and as shown in FIG. When the temperature is selected, fine particles of platinum having an average particle diameter of 2.30 ± 0.35 nm can be supported on the carbon surface. As shown in FIG. 8, when 70 ° C. was selected, fine-particle platinum aggregates were formed.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
<Example 1>
(A) to the sample solution preparation step ethanol to prepare a sample solution obtained by dissolving H ₂ PtCl ₆ · 6H ₂ O of 0.5 mmol / L.
(B) Step of preparing platinum carbonyl complex solution While heating the sample solution at 35 ° C., bubbling Ar gas into the sample solution for 20 minutes, then bubbling CO for 4 hours, and then stirring for 32 hours, platinum carbonyl A complex solution was prepared.

(C) Mixing step A carbon particle dispersion in which 0.39 mg of ketjen black was dispersed in 4 ml of ethanol and a platinum carbonyl complex solution were mixed while performing ultrasonic treatment for 1 hour to obtain a Pt / CB solution. .
(D) Filtration Step By filtering the Pt / CB solution, a platinum particle-supported carbon black catalyst (hereinafter also referred to as “Pt-et / CB”) according to Example 1 was obtained.
(E) Electrode preparation step The platinum particle-supported carbon black catalyst according to Example 1 was dispersed in 1.1 ml of ethanol to obtain a suspension, and 20 μl of the suspension was made into a glassy carbon cylinder having a diameter of 5 mm with a micropipette. The electrode according to Example 1 was obtained by dropping on the upper surface of the body and drying.

<Example 2>
In the sample solution preparation step and the platinum carbonyl complex solution preparation step, butanol was used instead of ethanol, and the stirring time in the platinum carbonyl complex solution preparation step was set to 42 hours. A platinum particle-supported carbon black catalyst (hereinafter also referred to as “Pt-but / CB”) and an electrode according to Example 2 were obtained.
<Example 3>
In the sample solution preparation step and the platinum carbonyl complex solution preparation step, hexanol was used instead of ethanol, and the stirring time in the platinum carbonyl complex solution preparation step was 40 hours, as in Example 1, A platinum particle-supported carbon black catalyst (hereinafter also referred to as “Pt-hex / CB”) and an electrode according to Example 3 were obtained.

<Example 4>
(A) Sample Solution Preparation Step A sample solution was prepared by dissolving 0.5 mmol / L H ₂ PtCl ₆ .6H ₂ O in a 1: 1 mixed solvent of water and acetonitrile.
(B) Step of preparing platinum carbonyl complex solution While heating the sample solution at 30 ° C., Ar gas was bubbled into the sample solution for 20 minutes, then CO was bubbled for 4 hours, and then stirred for 4 hours, thereby producing platinum carbonyl. A complex solution was prepared.

(C) Mixing step A carbon particle dispersion obtained by dispersing 0.39 mg of Ketjen Black in 4 ml of a 1: 1 mixed solvent of water and acetonitrile and a platinum carbonyl complex solution are mixed while performing ultrasonic treatment for 1 hour. Thus, a Pt / CB solution was obtained.
(D) Filtration process By filtering the Pt / CB solution, a platinum particle-supporting carbon black catalyst (hereinafter also referred to as “Pt-30 / CB”) according to Example 4 was obtained.
(E) Electrode preparation step The platinum particle-supported carbon black catalyst according to Example 4 was dispersed in 1.1 ml of ethanol to obtain a suspension, and 20 μl of the suspension was made into a glassy carbon cylinder having a diameter of 5 mm with a micropipette. The electrode which concerns on Example 4 was obtained by dripping on the upper surface of a body and making it dry.

<Example 5>
The platinum particle-supported carbon black catalyst (hereinafter referred to as “Pt-50 / Pt”) according to Example 5 was used in the same manner as in Example 4 except that the mixture was heated at 50 ° C. in the platinum carbonyl complex solution preparation step and then stirred for 90 minutes. CB ”) and an electrode.

<Comparative Example 1>
A platinum particle-supported carbon black catalyst (hereinafter also referred to as “Pt / CB-TKK”) according to Comparative Example 1 was used as a Pt / CB catalyst (manufactured by Tanaka Kikinzoku, trade name “TEC10E50E”). Moreover, the electrode which concerns on the comparative example 1 was obtained.
<Comparative example 2>
The platinum particle-supported carbon black catalyst according to Comparative Example 2 (hereinafter referred to as “Pt-70 /”), except that the platinum carbonyl complex solution was heated at 70 ° C. and then stirred for 1 hour in the same manner as in Example 4. CB ”) and an electrode.

<Physical property evaluation>
(1) Electrolytic emission transmission electron microscope photograph A TEM photograph was taken using an electrolytic emission transmission electron microscope (FE-TEM) (manufactured by Hitachi, Ltd., "HF-2000", acceleration voltage 200 kV).
FIGS. 2 to 4 and FIGS. 6 to 9 show TEM photographs and graphs of particle size distribution of the platinum particle-supported carbon black catalysts according to Examples 1 to 5 and Comparative Examples 1 and 2. FIG.
As a result, the platinum particle-supported carbon black catalyst according to Comparative Example 1 supported fine platinum particles having an average particle diameter of 3.19 ± 0.68 nm on the carbon surface. That is, it carries fine platinum having a large particle size and a wide distribution width.

<Performance evaluation>
(2) Tafel plot The measurement cell for rotating electrodes was used to measure the convection voltammogram for calculating the Tafel plot. Here, FIG. 10 is a diagram showing a measurement cell for a rotating electrode.
The rotating electrode measurement cell is arranged in the first water tank 31, the second water tank 32, the working electrode 21 arranged in the upper part in the first water tank 31, and the lower part in the first water tank 31. A counter electrode 22, a reference electrode (RHE) 23 disposed at an upper portion in the second water tank 32, a capillary 24 that connects the first water tank 31 and the second water tank 32, and the first water tank 31. The oxygen gas supply port 25 and the oxygen gas discharge port 26 connected to the inside, the electrode support 30 to which the working electrode 21 is attached at the bottom, the motor 27 for rotating the electrode support 30, and the measurement cell for the rotating electrode are controlled. And a potentiostat 28.

The potentiostat 28 is, for example, a computer-controlled potentiostat “BASCV-50W” or the like.
As the working electrode 21, the electrodes according to Examples 1 to 5 and Comparative Examples 1 and 2 were used. At this time, the working electrode 21 was attached to the lower part of the electrode support 30 using a heat-shrinkable tube and silver paste so that the upper surface of the glassy carbon cylinder was on the lower side. Further, an acetone solution of methyl methacrylate polymer (“138-02735” manufactured by Wako Pure Chemical Industries, Ltd.) was applied to the side surface of the working electrode 21, and then the acetone was removed, so that the side surface of the working electrode 21 was methyl methacrylate. Coated with polymer.

The counter electrode 22 was formed of a circular platinum plate, and the reference electrode 23 was formed of an Hg / Hg ₂ SO ₄ electrode. In the first water tank 31 and the second water tank 32, 0.1 mol / L HClO ₄ was put as the electrolyte solution 29.
During the measurement, the electrolytic solution 29 is kept at 25 ° C., and the oxygen gas is introduced from the oxygen gas supply port 25 at a flow rate of 20 ml / min, and the positive potential direction is 0.05 to 1.0 V (vs. RHE). Scanning was performed.
Then, the measurement current i and the electrode potential E obtained when the motor 27 was rotated at each rotation speed (0, 1600 rpm) were measured five times.

As a result, a convection voltammogram was obtained by subtracting the average value of the result of 0 rpm from the average value of the result of 1600 rpm. And Pt real area _Spt was computed using Formula (1). Furthermore, the activation dominant current _ik was calculated from the convection voltammogram using the equation (2), and a Tafel plot was drawn from the relationship between the activation dominant current _ik and the electrode potential E. 11 and 12 show Tafel plots of the electrodes according to Examples 1 to 5 and Comparative Example 1. FIG.
S _pt = Q / 210 (1)
i _k = i _l × i / (i _l −i) (2)
Here, Q is the amount of electricity desorbed from hydrogen, i _l is the diffusion limit current, and i is the measurement current.

  The present invention can be used for the production of platinum particle-supported carbon black catalysts.

DESCRIPTION OF SYMBOLS 1 Polymer solid electrolyte membrane 2 Oxygen electrode 3 Hydrogen electrode 4, 5 Gasket 6, 7 Current collector 8, 10 Frame 9 Oxygen electrode chamber 11 Hydrogen electrode chamber 12 Oxygen gas supply port 13 Unreacted oxygen gas and generated water outlet 14 Hydrogen gas supply port 15 Unreacted hydrogen gas outlet 21 Working electrode 22 Counter electrode 23 Reference electrode 24 Capillary 25 Oxygen gas supply port 26 Oxygen gas discharge port 27 Motor 28 Potentiostat 30 Electrode support

Claims (4)

A platinum compound represented by chemical formula (1) or chemical formula (2) is dissolved in one kind of solvent selected from the group consisting of a mixed solvent of water and acetonitrile, ethanol, and butanol or hexanol to prepare a sample solution. A sample solution preparation process;
A step of preparing a platinum carbonyl complex solution by bubbling carbon monoxide to the sample solution while heating the sample solution at 30 ° C. or higher and 40 ° C. or lower;
Wherein the sample solution preparation step of carbon particle dispersion obtained by dispersing carbon particles into one solvent selected in, and a mixing step of mixing the platinum carbonyl complex solution,
A method for producing a platinum particle-supported carbon black catalyst, characterized in that the platinum particle-supported carbon black catalyst can be obtained without firing.
M ₂ PtX ₆ (1)
M ₂ PtX ₄ (2)
Here, M is an alkali metal, an ammonium group or hydrogen, and X is a halogen atom. A sample solution preparation step of preparing a sample solution by dissolving a platinum compound represented by chemical formula (1) or chemical formula (2) in a mixed solvent of water and acetonitrile;
A platinum carbonyl complex solution preparation step of preparing a platinum carbonyl complex solution by bubbling carbon monoxide to the sample solution while heating the sample solution at a predetermined temperature selected from a temperature range of 25 ° C. to 65 ° C. ,
The carbon particle dispersion obtained by dispersing carbon particles in a mixed solvent of water and acetonitrile, and a mixing step of mixing the platinum carbonyl complex solution,
A method for producing a platinum particle-supported carbon black catalyst, characterized in that the platinum particle-supported carbon black catalyst can be obtained without firing.
M ₂ PtX ₆ (1)
M ₂ PtX ₄ (2)
Here, M is an alkali metal, an ammonium group or hydrogen, and X is a halogen atom.   The method for producing a platinum particle-supported carbon black catalyst according to claim 1 or 2, wherein the carbon particles are ketjen black.   The platinum particle-supporting carbon black catalyst according to any one of claims 1 to 3, wherein in the mixing step, the platinum carbonyl complex solution is mixed with the carbon particle dispersion while performing ultrasonic treatment. Manufacturing method.