KR102416422B1 - Method for producing a platinum-based alloy catalyst for fuel cell - Google Patents

Abstract

The present invention relates to a method of manufacturing a method for manufacturing a platinum-based alloy catalyst for a fuel cell, and is intended to simplify the manufacturing process by omitting the process of preparing a transition metal precursor solution. The present invention comprises the steps of dispersing a carbon-based catalyst support in a polyol to prepare a carbon-based catalyst support solution; preparing a mixed solution by adding a platinum solution and a transition metal precursor powder to a carbon-based catalyst carrier solution and mixing at 40 to 100° C.; reducing the platinum-based alloy by adding a reducing agent to the mixed solution; and washing and drying the mixture solution containing the platinum-based alloy; provides a method for producing a platinum-based alloy catalyst for a fuel cell comprising a.

Description

Method for producing a platinum-based alloy catalyst for fuel cell

The present invention relates to a method for producing a platinum-based alloy catalyst, and more particularly, to a method for producing a platinum-based alloy catalyst for a fuel cell using a transition metal precursor powder directly for catalyst synthesis.

A fuel cell is a device that converts chemical energy into electrical energy through an electrochemical reaction by supplying gas or liquid fuel from the outside, rather than having reactants and products inside the cell like normal cells (primary and secondary). to be. Fuel cells are highly efficient, eco-friendly, and use a variety of fuels. Fuel cells have the advantage that they can be manufactured for various industrial fields depending on the type. Because of these advantages, fuel cells can be applied to various industries, from portable power sources for portable devices, etc., to transportation power sources for automobiles, and distributed power sources available for home and power plant business.

There are various types of such fuel cells according to the types of fuels and electrolytes used. For example, the fuel cell, depending on the type of fuel, a polymer electrolyte fuel cell (PEMFC), a direct methanol fuel cell (DMFC), a phosphoric acid fuel cell (Phosphoric Acid Fuel Cell: PAFC), solid oxide fuel cell (SOFC), alkaline electrolyte fuel cell (AFC), and the like.

Since the efficiency of such a fuel cell is greatly affected by the rate of electrode reaction, a nano-sized catalyst is used as an electrode material. Electrode catalysts used in fuel cells have a disadvantage in that their manufacturing cost is high because platinum (Pt)-based noble metals have been the mainstream until now. As described above, the conventional fuel cell using the platinum-based electrode catalyst has no choice but to increase the economic burden, and the commercialization stage is delayed due to the limited reserves and the use of very expensive platinum. Moreover, it has been reported that in order for fuel cell vehicles to be commercialized, the amount of platinum used per kW should be reduced to 0.2 g or less.

In order to solve this problem, research on non-platinum-based catalysts is being actively conducted. However, it is true that it is difficult to apply the non-platinum-based catalyst to an electrode for an actual fuel cell.

Therefore, apart from the development of the above-described non-platinum catalyst material, research and development of platinum-based alloy catalyst materials with reduced platinum usage are being actively conducted, and these platinum-based alloy catalyst materials use a smaller amount of platinum than pure platinum materials. It is possible to manufacture a high-performance catalytic electrode with improved catalytic activity while still doing so. For example, Korean Patent Publication No. 10-1340984 discloses a method for producing a platinum-based alloy catalyst. According to the disclosed method for producing a platinum-based alloy catalyst, a transition metal is first supported on a carbon-based catalyst carrier, and platinum is sequentially supported by preparing according to a liquid phase reduction method, thereby controlling the particle size of the transition metal, and then the size of the platinum nanoparticles can be controlled and supported, and a platinum alloy catalyst with reduced amount of platinum can be prepared while increasing the activity of the catalyst.

However, when the transition metal is supported on the carbon-based catalyst carrier, the transition metal precursor is mixed with a solvent to prepare a transition metal precursor solution, and after preparing the carbon-based catalyst carrier solution, the transition metal precursor solution and the carbon-based catalyst carrier solution are mixed. Use the mixing method.

For this reason, it is necessary to separately prepare a transition metal precursor solution by calculating the transition metal precursor in a volume ratio and mixing it with a solvent. And since it is mixed with the carbon-based catalyst carrier solution in the form of a transition metal precursor solution, there is a limit in accurately controlling the amount of the transition metal precursor supported on the carbon-based catalyst carrier.

Registered Patent Publication No. 10-1340984 (2013.12.12. Announcement)

Accordingly, an object of the present invention is to provide a method for manufacturing a platinum-based alloy catalyst for a fuel cell, which can simplify the manufacturing process by omitting the process of preparing a transition metal precursor solution.

Another object of the present invention is to provide a method for preparing a platinum-based alloy catalyst for a fuel cell that can more easily and accurately control the amount of a transition metal precursor supported on a carbon-based catalyst carrier.

In order to achieve the above object, the present invention comprises the steps of dispersing a carbon-based catalyst support in a polyol to prepare a carbon-based catalyst support solution; preparing a mixed solution by adding a platinum solution and a transition metal precursor powder to the carbon-based catalyst carrier solution and mixing at 40 to 100° C.; reducing the platinum-based alloy by adding a reducing agent to the mixed solution; and washing and drying the mixed solution containing the platinum-based alloy.

The polyol is at least one selected from the group consisting of ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), tetraethylene glycol (TTEG), propylene glycol (PG) and butylene glycol (BG). include

The carbon-based catalyst carrier includes at least one selected from the group consisting of activated carbon, carbon black, Ketjen black, carbon nanotubes, carbon nanofibers, graphite, graphene, and graphene oxide.

The transition metal precursor includes at least one selected from the group consisting of a nickel precursor, a palladium precursor, a ruthenium precursor, a cobalt precursor, a copper precursor, an iridium precursor, and an iron precursor.

The reducing agent includes at least one selected from the group consisting of sodium hydroxide, sodium borohydride, hydrazine and formaldehyde.

The method for producing a platinum-based alloy catalyst for a fuel cell according to the present invention comprises 130 to 180 of a mixture containing the platinum-based alloy reduced to pH 9 to 12, which is performed between the reducing step and the washing and drying step. It further includes; stirring at °C for 2 to 7 hours.

In the step of preparing the mixed solution, the volume ratio of the carbon-based catalyst carrier solution, the platinum solution, and the transition metal precursor powder may be 40 to 80: 20 to 60: 3 to 10.

The platinum-based alloy catalyst prepared in the washing and drying step includes the carbon-based catalyst support and a platinum-based alloy supported on the carbon-based catalyst support. The platinum-based alloy includes 67 to 95% by weight of platinum, and 5 to 33% by weight of a transition metal.

And the present invention, dispersing the carbon-based catalyst carrier in ethylene glycol (EG) to prepare a carbon-based catalyst carrier solution; preparing a mixed solution by adding a platinum solution and a nickel precursor powder to the carbon-based catalyst carrier solution and mixing at 40 to 100° C.; reducing the platinum-based alloy by adding 0.1 to 1M NaOH to the mixture to adjust the pH to 9 to 12; stirring the reduced mixture containing the platinum-based alloy at 130 to 180° C. for 2 to 7 hours; and washing and drying the mixed solution containing the platinum-based alloy to obtain a platinum-based alloy catalyst.

According to the present invention, since the platinum-based alloy catalyst for a fuel cell is manufactured by directly injecting the transition metal precursor powder into the carbon-based catalyst carrier solution, the manufacturing process can be simplified by omitting the process of preparing the existing transition metal precursor solution. . At this time, when the transition metal precursor powder is directly added to the carbon-based catalyst carrier solution and mixed, the temperature of the mixed solution is maintained at 40 to 100 ° C. can be stored as

Since the transition metal precursor powder is directly injected into the carbon-based catalyst carrier solution, the amount of transition metal particles supported on the carbon-based catalyst carrier can be more easily and accurately adjusted.

And the present invention comprises the steps of dispersing the reduced carbon-based catalyst carrier in ethylene glycol (EG) to prepare a carbon-based catalyst carrier solution; preparing a mixed solution by adding a platinum solution and a nickel precursor powder to the carbon-based catalyst carrier solution and mixing at 40 to 100° C.; reducing the platinum-based alloy by adding 0.1 to 1M NaOH to the mixture to adjust the pH to 9 to 12; stirring the reduced mixture containing the platinum-based alloy at 130 to 180° C. for 2 to 7 hours; and washing and drying the mixed solution containing the platinum-based alloy to obtain a platinum-based alloy catalyst.

1 is a flowchart according to a method of manufacturing a platinum-based alloy catalyst for a fuel cell using the transition metal precursor powder according to the present invention directly for catalyst synthesis.
FIG. 2 is a table showing TEM images and EDX analysis results of platinum-based alloy catalysts for fuel cells prepared according to Examples.
3 is a table showing a TEM photograph and an EDX analysis result of a platinum-based alloy catalyst for a fuel cell prepared according to a comparative example.

It should be noted that, in the following description, only parts necessary for understanding the embodiments of the present invention will be described, and descriptions of other parts will be omitted without departing from the gist of the present invention.

The terms or words used in the present specification and claims described below should not be construed as being limited to their ordinary or dictionary meanings, and the inventors have appropriate concepts of terms to describe their invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined in Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only preferred embodiments of the present invention, and do not represent all of the technical spirit of the present invention, so various equivalents that can be substituted for them at the time of the present application It should be understood that there may be variations and variations.

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

1 is a flowchart according to a method of manufacturing a platinum-based alloy catalyst for a fuel cell using the transition metal precursor powder according to the present invention directly for catalyst synthesis.

1, the method for preparing a platinum-based alloy catalyst for a fuel cell (hereinafter referred to as 'platinum-based alloy catalyst') according to the present invention comprises the steps of dispersing a carbon-based catalyst carrier in a polyol to prepare a carbon-based catalyst carrier solution ( S10), adding a platinum solution and a transition metal precursor powder to a carbon-based catalyst carrier solution and mixing at 40 to 100° C. to prepare a mixed solution (S20), adding a reducing agent to the mixed solution to reduce the platinum-based alloy ( S30), and washing and drying the mixture containing the platinum-based alloy (S50).

In addition, the method for producing a platinum-based alloy catalyst according to the present invention is performed between the reducing step (S30) and the washing and drying step (S50), stirring the mixed solution containing the reduced platinum-based alloy (S40) may further include.

Each step according to the method for producing a platinum-based alloy catalyst according to the present invention will be described in detail as follows.

First, a carbon-based catalyst carrier solution is prepared by dispersing the carbon-based catalyst carrier in a polyol in step S10.

Here, the carbon-based catalyst carrier may include at least one selected from the group consisting of activated carbon, carbon black, Ketjen black, carbon nanotubes, carbon nanofibers, graphite, graphene, and graphene oxide.

The polyol contains at least one selected from the group consisting of ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), tetraethylene glycol (TTEG), propylene glycol (PG), and butylene glycol (BG) can do.

The carbon-based catalyst carrier solution includes 40 to 80% by weight of the carbon-based catalyst carrier and 20 to 60% by weight of a polyol.

Next, in step S20, the platinum solution and the transition metal precursor powder are added to the carbon-based catalyst carrier solution, and then mixed at 40 to 100° C. to prepare a mixed solution.

Here, the mixed solution may be prepared by mixing a carbon-based catalyst carrier solution, a platinum solution, and a transition metal precursor powder at a synthesis ratio (volume ratio) of 40 to 80: 20 to 60: 3 to 10.

The platinum solution may contain 5 to 20% by weight of platinum.

The transition metal precursor may include at least one selected from the group consisting of a nickel precursor, a palladium precursor, a ruthenium precursor, a cobalt precursor, a copper precursor, an iridium precursor, and an iron precursor. Here, as a nickel precursor, nickel acetate, Ni(acac) ₂ , nickel chloride (NiCl ₂ ), nickel nitrate (Ni(NO ₃ ) ₂ ), nickel chloride hydrate (NiCl ₂ oxH ₂ O), nickel nitrate hydrate ( Ni(NO ₃ ) ₂ oxH ₂ O), nickel sulfate (NiSO ₄ ), and nickel sulfate hydrate (NiSO ₄ oxH ₂ O) may include at least one selected from the group consisting of.

Conventionally, when preparing a mixed solution, a transition metal precursor powder was mixed in a separate solvent to prepare a transition metal precursor solution, and then a carbon-based catalyst carrier solution, a platinum solution, and a transition metal precursor solution were mixed.

On the other hand, in the present invention, since the mixture solution can be prepared by adding the transition metal precursor powder to the carbon-based catalyst carrier solution and the platinum solution, the manufacturing process can be simplified by omitting the process of preparing the existing transition metal precursor solution.

And, so that the transition metal precursor powder can be well dissolved by being put into the carbon-based catalyst carrier solution and the platinum solution, it is preferable that step S20 be performed at 40 to 100°C. There may be a problem that the transition metal precursor powder is not well dissolved at 40° C. or less. Conversely, when it exceeds 100° C., a side reaction other than mixing may occur between the transition metal precursor powder, the carbon-based catalyst carrier solution, and the platinum solution.

Next, a reducing agent is added to the mixed solution in step S30 to reduce the platinum-based alloy. That is, the platinum-based alloy is reduced while adjusting the pH to 9 to 12 using a reducing agent in the mixed solution. By adjusting the pH using a reducing agent, the size of the reduced platinum-based alloy can be adjusted.

Here, the reducing agent may include at least one selected from the group consisting of sodium hydroxide, sodium borohydride, hydrazine and formaldehyde. For example, 0.1M to 1M sodium hydroxide may be used as a reducing agent.

Then, the mixture containing the platinum-based alloy reduced in step S40 is stirred. That is, the mixture containing the reduced platinum-based alloy is stirred at 130 to 180° C. for 2 to 7 hours. The stirring speed may be 300 to 600 rpm. In this temperature range, stirring time, and stirring speed range, the transition metal particles can be smoothly dispersed in the carbon-based catalyst carrier.

And by washing and drying the mixture containing the platinum-based alloy in step S50, it is possible to obtain a platinum-based alloy catalyst according to the present invention. That is, washing may be performed using ethanol, distilled water, or a mixture thereof. Drying may be performed at 60 to 100° C. for 6 to 24 hours.

As described above, the platinum-based alloy catalyst prepared by the manufacturing method according to the present invention includes a carbon-based catalyst support and a platinum-based alloy supported on the carbon-based catalyst support. Here, the platinum-based alloy may include 67 to 95% by weight of platinum and 5 to 33% by weight of a transition metal. In the platinum-based alloy catalyst, the content of the transition metal can be controlled by controlling the synthesis ratio of the mixed solution in step S20 and the temperature applied to the mixed solution.

According to the present invention, since the platinum-based alloy catalyst is prepared by directly injecting the transition metal precursor powder into the carbon-based catalyst carrier solution, the manufacturing process can be simplified by omitting the process of preparing the existing transition metal precursor solution. At this time, when the transition metal precursor powder is directly added to the carbon-based catalyst carrier solution and mixed, the temperature of the mixture is maintained at 40 to 100 ° C. can hold

And since the transition metal precursor powder is directly injected into the carbon-based catalyst carrier solution, the amount of the transition metal particles supported on the carbon-based catalyst carrier can be more easily and accurately adjusted.

[Examples and Comparative Examples]

With respect to the method for manufacturing the platinum-based alloy catalyst according to the present invention, the content of the transition metal included in the platinum-based alloy catalyst was confirmed through Examples and Comparative Examples.

First, 50 wt% of carbon black was dispersed in ethylene glycol (EG) to prepare a carbon-based catalyst carrier solution. Next, a mixture of the carbon-based catalyst carrier solution, the platinum solution, and the nickel precursor powder was prepared in a synthesis ratio (volume ratio) of 50:45:5. The platinum solution contains 10% by weight platinum. Nickel acetate powder was used as the nickel precursor powder.

At this time, in the Example, the mixture was mixed at 50 ° C. for 5 minutes, and in the Comparative Example, the mixture was prepared by mixing at room temperature for 5 minutes.

Next, 1M NaOH was added to the mixture to reduce the pH to 11, and the mixture was stirred at 160° C. for 3 hours.

And after washing the mixed solution containing the reduced platinum-based alloy was dried at 80 ℃ 12 hours to prepare a platinum-based alloy catalyst according to Examples and Comparative Examples.

FIG. 2 is a table showing TEM images and EDX analysis results of platinum-based alloy catalysts prepared according to Examples. And Figure 3 is a table showing the TEM photograph and EDX analysis results of the platinum-based alloy catalyst prepared according to Comparative Example. Here, the composition ratio of the platinum-based alloy supported on the carbon-based catalyst carrier is shown in FIGS. 2 and 3 . That is, the composition ratio of the platinum-based alloy excluding the carbon-based catalyst carrier in the platinum-based alloy catalyst is indicated.

2 and 3, the platinum-based alloy of the platinum-based alloy catalyst according to the comparative example contains 0.08 wt% of nickel, but the platinum-based alloy of the platinum-based alloy catalyst according to the embodiment contains 10.90 wt% of nickel . That is, when the nickel precursor powder is directly added to the carbon-based catalyst carrier solution and mixed, the temperature of the mixture is maintained at 50° C., so that even if the nickel precursor powder is used, the nickel particles can be stably supported on the carbon-based catalyst carrier.

On the other hand, the embodiments disclosed in the present specification and drawings are merely presented as specific examples to aid understanding, and are not intended to limit the scope of the present invention. It is apparent to those of ordinary skill in the art to which the present invention pertains that other modifications based on the technical spirit of the present invention can be implemented in addition to the embodiments disclosed herein.

Claims (9)

preparing a carbon-based catalyst carrier solution by dispersing the carbon-based catalyst carrier in a polyol;
preparing a mixed solution by adding a platinum solution and a transition metal precursor powder to the carbon-based catalyst carrier solution and mixing at 40 to 100° C.;
reducing the platinum-based alloy while adjusting the pH to 9 to 12 by adding a reducing agent to the mixed solution;
stirring the reduced mixture containing the platinum-based alloy at 130 to 180° C. for 2 to 7 hours; and
washing and drying the mixture containing the platinum-based alloy;
A method for producing a platinum-based alloy catalyst for a fuel cell comprising a. The method of claim 1,
The polyol is at least one selected from the group consisting of ethylene glycol (EG), diethylene glycol (DEG), triethylene glycol (TEG), tetraethylene glycol (TTEG), propylene glycol (PG) and butylene glycol (BG). A method for producing a platinum-based alloy catalyst for a fuel cell, comprising: The method of claim 1,
The carbon-based catalyst carrier is a platinum-based alloy catalyst for fuel cells, characterized in that it comprises at least one selected from the group consisting of activated carbon, carbon black, Ketjen black, carbon nanotubes, carbon nanofibers, graphite, graphene and graphene oxide. manufacturing method. The method of claim 1,
The transition metal precursor includes at least one selected from the group consisting of a nickel precursor, a palladium precursor, a ruthenium precursor, a cobalt precursor, a copper precursor, an iridium precursor, and an iron precursor. The method of claim 1,
The reducing agent is a method for producing a platinum-based alloy catalyst for a fuel cell, characterized in that it comprises at least one selected from the group consisting of sodium hydroxide, sodium borohydride, hydrazine and formaldehyde. The method of claim 1,
The reducing agent is 0.1M to 1M sodium hydroxide,
In the stirring step, the stirring speed is a method for producing a platinum-based alloy catalyst for a fuel cell, characterized in that 300 to 600 rpm. According to claim 1, In the step of preparing the mixture,
The volume ratio of the carbon-based catalyst carrier solution, the platinum solution, and the transition metal precursor powder is 40-80: 20-60: 3-10. According to claim 1, wherein the platinum-based alloy catalyst prepared in the washing and drying step,
and a platinum-based alloy supported on the carbon-based catalyst support and the carbon-based catalyst support,
The platinum-based alloy is a method for producing a platinum-based alloy catalyst for a fuel cell, characterized in that it comprises 67 to 95% by weight of platinum and 5 to 33% by weight of a transition metal. Dispersing the carbon-based catalyst carrier in ethylene glycol (EG) to prepare a carbon-based catalyst carrier solution;
preparing a mixed solution by adding a platinum solution and a nickel precursor powder to the carbon-based catalyst carrier solution and mixing at 40 to 100° C.;
reducing the platinum-based alloy by adding 0.1 to 1M NaOH to the mixture to adjust the pH to 9 to 12;
stirring the reduced mixture containing the platinum-based alloy at 130 to 180° C. for 2 to 7 hours; and
washing and drying the mixture containing the platinum-based alloy to obtain a platinum-based alloy catalyst;
A method for producing a platinum-based alloy catalyst for a fuel cell comprising a.

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