KR20200001064A - The platinum-transition metal composite supported on carbon and method for preparing the same - Google Patents

Abstract

The present invention provides a platinum-transition metal complex supported on a carbon support which comprises the carbon support and platinum-transition metal nanoparticles supported on the carbon support. According to the platinum-transition metal complex supported on the carbon support and a manufacturing method thereof according to the present invention, the platinum-transition metal complex can be utilized as an electrochemical oxygen reduction catalyst having higher activity by introducing cobalt, and can be manufactured by a simple method.

Description

Platinum-transition metal composite supported on carbon support and its manufacturing method {TH PLATINUM-TRANSITION METAL COMPOSITE SUPPORTED ON CARBON AND METHOD FOR PREPARING THE SAME}

The present invention relates to a platinum-transition metal complex supported on a carbon support and a method for producing the same, more particularly, by introducing cobalt, platinum supported on a carbon support usable as an electrochemical oxygen reduction catalyst having high activity- It relates to a transition metal composite and a method for producing the same.

The polymer electrolyte fuel cell reaction consists of hydrogen oxidation of the anode and oxygen reduction of the cathode. Due to the slow oxygen reduction reaction compared to the fast hydrogen oxidation reaction, a large amount of platinum is used to act as an obstacle to commercialization of fuel cells. Therefore, when driving the device, a catalyst for an oxygen reduction reaction (ORR) at the cathode is required. These catalysts have been mainly used platinum (Pt) catalyst, but the price is very expensive and there is a problem in the stability to moisture or methanol. To overcome this, new catalyst systems have been studied. Examples are as follows.

Pt-less alloys using small amounts of platinum, precious metals other than platinum, nano-carbons that do not contain metals, and catalytic systems composed of non-noble metals (iron, cobalt, etc.) and nano-carbons (MNC) There is). Although much research is still being conducted on such catalyst systems, the development of new catalyst systems of high activity, low cost, and high stability is a very important task for practical application in industry. In particular, catalyst systems using platinum or alloys using other precious metals other than platinum still have a disadvantage in that the price of the catalyst is high. Nano-carbon-based metals have a problem in that the activity of the catalyst is low but the price is low.

On the other hand, the catalyst system (M-N-C) using nano carbon, such as iron (Fe), cobalt (Co), etc., which are inexpensive transition metals, is relatively inexpensive and has a high possibility of being used in an actual industry as a catalyst system that can show good activity. However, in the case of the previously reported M-N-C catalyst system, a heat treatment process at a temperature of several hundred degrees or more is essential, which is another problem of increasing the production cost. In addition, since it is difficult to control the active species of the catalyst during this heat treatment process, there is a problem in the practical application of the catalyst.

An object of the present invention is to solve the above problems, by introducing cobalt in the platinum-transition metal alloy, to provide a platinum-transition metal complex supported on a carbon support that can be utilized as an electrochemical oxygen reduction catalyst having a higher activity It is.

In addition, to provide a method for producing a platinum-transition metal composite supported on a carbon support that can be produced by a simple method.

According to an aspect of the present invention, a carbon support: and platinum-transition metal nanoparticles supported on the carbon support; Provided is a platinum-transition metal complex supported on a carbon support comprising a.

The platinum-transition metal nanoparticles may include one or more selected from platinum-zinc (Pt-Zn) nanoparticles and platinum-cobalt-zinc (Pt-Co-Zn) nanoparticles.

The platinum-transition metal nanoparticles may be platinum-cobalt-zinc (Pt-Co-Zn) nanoparticles.

The carbon support may be a carbon support (NC) doped with nitrogen.

The carbon support is selected from carbon black, Ketjen black, carbon nano tube, carbon nano fiber, graphite carbon, graphene and graphene oxide. It may include one or more.

The platinum-transition metal complex supported on the carbon support may be an intermetallic phase.

Platinum-transition metal complex supported on the carbon support may have a diameter of 1 to 10nm.

The platinum-transition metal composite supported on the carbon support may be a catalyst for oxygen reduction of a fuel cell.

According to another aspect of the present invention, a fuel cell including a cathode, a cathode and a separator positioned between the anode and the cathode, wherein the anode or the cathode comprises a platinum-transition metal complex supported on the carbon support Phosphorus, fuel cells are provided.

According to another aspect of the invention, (a) mixing the platinum precursor, zinc precursor, cobalt precursor and the carbon support to prepare a mixture; And (b) heat treating the mixture to synthesize a platinum-transition metal composite supported on a carbon support. Provided is a method of preparing a platinum-transition metal composite supported on a carbon support comprising a.

The manufacturing method may use a wet impregnation method.

The platinum precursor may include at least one selected from chloroplatinic acid hydrate, sodium hexachloroplatinate hexahydrate, and potassium hexachloroplatinate.

The zinc precursor is zinc nitrate hexahydrate (Zn (NO ₃ ) ₃ 9H ₂ O), zinc chloride (ZnCl ₂ ), zinc sulfate (ZnSO ₄ ), zinc hydroxide (Zn (OH) ₂ ) and zinc acetate (Zn (CH) It may include one or more selected from ₃ CO ₂ ) ₂ ).

The cobalt precursor may include at least one selected from cobalt chloride hexahydrate (CoCl ₂ 6H ₂ O) or cobalt nitrate hexahydrate (Co (NO ₃ ) ₂ 6H ₂ O).

The carbon support may be a carbon support doped with nitrogen dispersed in ethanol.

The carbon support is selected from carbon black, Ketjen black, carbon nano tube, carbon nano fiber, graphite carbon, graphene and graphene oxide. It may include one or more.

Step (a) may be performed via sonication.

Step (b) (b-1) the first heat treatment at 200 ℃ to 400 ℃; And (b-2) second heat treatment at 600 ° C. to 800 ° C .;

The platinum-transition metal complex supported on the carbon support according to the present invention has an effect that can be utilized as an electrochemical oxygen reduction catalyst having higher activity by introducing cobalt.

In addition, the manufacturing method of the platinum-transition metal composite supported on the carbon support according to the present invention has an effect that can be produced by a simple method.

FIG. 1A is a transmission electron microscope (TEM) image of Example 1, and FIG. 1B is an enlarged image of FIG. 1A.
2 is a graph of crystal structure analysis by X-ray diffraction of Example 1. FIG.
3A is a Cyclic voltammetry graph of Example 1 and Comparative Examples 1 and 2, and FIG. 3B is a linear sweep voltammetry graph of Example 1 and Comparative Examples 1 and 2. FIG.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, terms including ordinal numbers such as first and second to be used below may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

In addition, when a component is referred to as being “formed” or “laminated” on another component, it may be directly attached to, or laminated to, the front or one side on the surface of the other component, It will be understood that other components may exist in the.

Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Hereinafter, the platinum-transition metal composite supported on the carbon support of the present invention will be described.

The present invention provides a carbon support: and platinum-transition metal nanoparticles supported on the carbon support; It provides a platinum-transition metal complex supported on a carbon support comprising a.

The platinum-transition metal nanoparticles may include one or more selected from platinum-zinc (Pt-Zn) nanoparticles and platinum-cobalt-zinc (Pt-Co-Zn) nanoparticles.

The platinum-transition metal nanoparticles may be platinum-cobalt-zinc (Pt-Co-Zn) nanoparticles.

The carbon support may be a carbon support (NC) doped with nitrogen.

The carbon support is selected from carbon black, Ketjen black, carbon nano tube, carbon nano fiber, graphite carbon, graphene and graphene oxide. It may include one or more.

The platinum-transition metal complex supported on the carbon support may be an intermetallic phase.

Platinum-transition metal complex supported on the carbon support may have a diameter of 1 to 10nm.

The platinum-transition metal composite supported on the carbon support may be a catalyst for oxygen reduction of a fuel cell.

The present invention provides a fuel cell comprising a cathode, a cathode, and a separator positioned between the anode and the cathode, wherein the anode or the cathode includes a platinum-transition metal composite supported on the carbon support. do.

In addition, the method of preparing a platinum-transition metal composite supported on the carbon support of the present invention will be described in detail.

The method of preparing the platinum-transition metal composite supported on the carbon support may be a wet impregnation method.

First, a platinum precursor, zinc precursor, cobalt precursor and carbon support are mixed to prepare a mixture (step a).

The platinum precursor may include at least one selected from chloroplatinic acid hydrate, sodium hexachloroplatinate hexahydrate, and potassium hexachloroplatinate.

The zinc precursor is zinc nitrate hexahydrate (Zn (NO ₃ ) ₃ 9H ₂ O), zinc chloride (ZnCl ₂ ), zinc sulfate (ZnSO ₄ ), zinc hydroxide (Zn (OH) ₂ ) and zinc acetate (Zn (CH) It may include one or more selected from ₃ CO ₂ ) ₂ ).

The cobalt precursor may include at least one selected from cobalt chloride hexahydrate (CoCl ₂ 6H ₂ O) or cobalt nitrate hexahydrate (Co (NO ₃ ) ₂ 6H ₂ O).

The carbon support may be a carbon support doped with nitrogen dispersed in ethanol.

The carbon support is selected from carbon black, Ketjen black, carbon nano tube, carbon nano fiber, graphite carbon, graphene and graphene oxide. It may include one or more.

Step (a) may be performed via sonication.

Next, the mixture is heat treated to a carbon support Supported  Synthesize the platinum-transition metal complex (step b).

Step (b) (b-1) the first heat treatment at 200 ℃ to 400 ℃; And (b-2) performing a second heat treatment at 600 ° C. to 800 ° C., and preferably, may include a first heat treatment at 300 ° C. and a second heat treatment at 750 ° C. FIG.

After impregnating the precursor by wet impregnation method, Pt-Zn / C can be synthesized in a relatively simple manner through heat treatment. However, wet impregnation has a disadvantage in that the particle size cannot be precisely controlled. The use of doped carbon (NC) has the effect of simplifying the high dispersion and synthesis of the particles.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, this is for illustrative purposes and the scope of the present invention is not limited thereby.

EXAMPLE

Preparation Example 1 N-doped Vulcan-XC

1 g of Vulcan-XC (Cabot corporation) and 1.5 g urea (Urea) were ground for 15 minutes in a mortar and then mixed with Vulcan-XC and urea at 150 ° C. for 2 hours, followed by 2 hours at 300 ° C. Heat treatment for Subsequently, it was sufficiently washed with water and ethanol to prepare a nitrogen-doped carbon support (N-doped Vulcan-XC).

Example 1 Platinum-Cobalt-Zinc Composite Supported on Carbon Support (Pt-Co-Zn / NC)

1 mL aqueous H ₂ PtCl ₆ 6H ₂ O solution (0.14 mg / mL), 1 mL Zn (NO ₃ ) ₂ 6H ₂ O aqueous solution (0.214 mg / mL), 1.7 mL CoCl ₂ 6H ₂ O aqueous solution (0.064 mg / mL) And nitrogen-doped carbon support (N-doped Vulcan-XC) dispersed in ethanol prepared according to Preparation Example 1 in a three-necked flask, sonicated for 20 minutes, and solvent ethanol was evaporated to obtain a powder.

The powder was heat-treated at 300 ° C. for 1 hour and then heat-treated at 750 ° C. for 2 hours to prepare a platinum-cobalt-zinc composite (Pt-Co-Zn / NC) supported on a carbon support.

Comparative Example 1: Platinum-Zinc Composite Supported on Carbon Support (Pt-Zn / NC)

In Example 1 1 mL of H ₂ PtCl ₆ 6H ₂ O aqueous solution (0.14 mg / mL), 1 mL of Zn (NO ₃ ) ₂ 6H ₂ O aqueous solution (0.214 mg / mL), 1.7 mL CoCl ₂ 6H ₂ O aqueous solution (0.064 mg / mL) and 1 mL of H ₂ PtCl ₆ 6H ₂ O aqueous solution (0.14 mg / mL) instead of using a nitrogen-doped carbon support (N-doped Vulcan-XC) dispersed in ethanol prepared according to Preparation Example 1 ), 1 mL of Zn (NO ₃ ) ₂ 6H ₂ O aqueous solution (0.214 mg / mL) and a nitrogen-doped carbon support (N-doped Vulcan-XC) dispersed in ethanol prepared according to Preparation Example 1 Except that was prepared in the same manner as in Example 1.

Comparative Example 2: Platinum-Cobalt Composite (Pt-Co / NC) Supported on Carbon Support

In Example 1 1 mL of H ₂ PtCl ₆ 6H ₂ O aqueous solution (0.14 mg / mL), 1 mL of Zn (NO ₃ ) ₂ 6H ₂ O aqueous solution (0.214 mg / mL), 1.7 mL CoCl ₂ 6H ₂ O aqueous solution (0.064 mg / mL) and 1 mL of H ₂ PtCl ₆ 6H ₂ O aqueous solution (0.14 mg / mL) instead of using a nitrogen-doped carbon support (N-doped Vulcan-XC) dispersed in ethanol prepared according to Preparation Example 1 ), Except that a 1 mL CoCl ₂ 6H ₂ O aqueous solution (0.064 mg / mL) and a nitrogen-doped carbon support (N-doped Vulcan-XC) dispersed in ethanol prepared according to Preparation Example 1 were used. It prepared in the same manner as in Example 1.

[Test Example]

Test Example  1: on carbon support Supported  Transmission Electron Microscope (TEM) image analysis of platinum-cobalt-zinc complex (Pt-Co-Zn / NC)

FIG. 1A is a TEM analysis image of Example 1, and FIG. 1B is an enlarged image of FIG. 1A.

1A and 1B, it can be seen that Pt-Co-Zn / NC (Example 1) having an average size of 5 nm was prepared.

Test Example 2 Analysis of Crystal Structure through X-ray Diffraction

Figure 2 is a graph showing the X-ray diffraction pattern of Example 1, Table 1 shows a comparison of the XRD peak of Comparative Example 1 (PDF card # 00-006-0604) and the value of the XRD peak of Example 1 It was.

Plane 2θ in Comparative Example 1 (Pt-Zn / NC) 2θ of Example 1 (Pt-Co-Zn / NC) 001 25.4 25.5 110 31.1 31.4 111 40.8 40.9 200 44.8 45.0 002 52.2 52.45 112 62.2 62.49

2, the crystal structure of Pt-Co-Zn / NC prepared according to Example 1 was confirmed by X-ray diffraction analysis. Two phases were identified as the XRD phase, the Pt-Zn intermetallic phase and the Pt-Co intermetallic phase.

Also, referring to Table 1, the peak of Example 1 (Pt-Co-Zn / NC) shifts slightly to the right from the reference peak of Comparative Example 1 (Pt-Zn / NC, PDF card # 00-006-0604). It was confirmed that this was caused by the introduction of Co into the Pt-Zn intermetallic structure, the compressive strain (compressive strain) is generated.

Test Example 3: Analysis of Electrochemical Activity of Catalyst

Figure 3a is a cyclic voltammetry graph (0.1 M HClO ₄ ) of Example 1 and Comparative Examples 1 and 2. 3b is a linear sweep voltammetry graph (20 mV / s, 0.1 M HClO ₄ ) of Example 1 and Comparative Examples 1 and 2; In addition, the electrochemical characteristics when using Example 1 and Comparative Examples 1 to 2 as a catalyst are shown in Table 2 below.

In order to measure cyclic voltammetry, a trielectrode was constructed using a platinum electrode as a counter electrode, an Ag / AgCl electrode as a reference electrode, and a glass carbon electrode as a working electrode. 0.1 M HClO ₄ was used as the electrolyte, and after argon gas purging for 20 minutes, cyclic voltammetry was measured at a rate of 50 mV / s.

Oxygen gas was purged with 0.1 M HClO ₄ for 20 minutes to measure linear sweep voltammetry, and linear sweep voltammetry was measured at a speed of 20 mV / s while rotating the working electrode at 1,600 rpm.

Examples 1 and Comparative Examples 1 to 1 were added to a solution in which a water: 2-propanol: nafion ionomer solution was mixed at a ratio of 4/1 / 0.05 (v / v) to measure an electrochemical surface area (ECSA). 2 is mixed at a concentration of 2 mg / mL and sonicated at 40 DEG C or lower for 1 hour. The sonicated solution is dropped on a glass carbon electrode and dried. At this time, the loading of platinum rising to the electrode was 3.0 μg / cm ² .

ECSA
(m ² / g _Pt ) Active per mass
(A / mg _Pt ) Specific activity
(mA / cm ² _Pt ) Example 1 36.6 0.514 1.4 Comparative Example 1 56 0.38 0.62 Comparative Example 2 31.6 0.23 0.73

Referring to Figures 3a, 3b and Table 2, by measuring the cyclic voltammetry Example 1 (Pt-Co-Zn / NC), Comparative Example 1 (Pt-Zn / NC) and Comparative Example 2 (Pt-Co / NC ) Has an ECSA value of 36.6 m ² / g _Pt , 56 m ² / g _Pt and 31.6 m ² / g _Pt , respectively.

In addition, the activity per mass and specific activity in the RHE 0.9 V was analyzed, the specific activity is an indicator showing how high the activity of the active point of Example 1 and Comparative Examples 1 and 2. Example 1 (Pt-Co-Zn / NC) is shown as a specific activity of 1.4 mA / cm ² Pt specific activity of the existing Pt / C (0.159 mA / cm ² Pt, Source: RSC Adv. 2016, 6, 88255) It was confirmed that Example 1 (Pt-Co-Zn / NC) actually showed high activity in the oxygen reduction reaction with an improved value about 8 times compared with that of the present invention. And synergistic effect between Zn and Co, since the activity of Example 1 (Pt-Co-Zn / NC) is greater than that of Comparative Example 1 (Pt-Zn / NC) and Comparative Example 2 (Pt-Co / NC) It was found that existed.

Although preferred embodiments of the present invention have been described above, those of ordinary skill in the art may add, change, delete, or eliminate the elements within the scope not departing from the spirit of the present invention described in the claims. The present invention may be variously modified and changed by addition, etc., which will also be included within the scope of the present invention. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form. The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Claims (17)

Carbon support: and
Platinum-transition metal nanoparticles supported on the carbon support; To
Platinum-transition metal complex supported on a carbon support comprising. The method of claim 1,
The platinum-transition metal composite supported on the carbon support, characterized in that the platinum-transition metal nanoparticles are platinum-cobalt-zinc (Pt-Co-Zn) nanoparticles. The method of claim 1,
Platinum-transition metal composite supported on a carbon support, characterized in that the carbon support is nitrogen-doped carbon support (NC). The method of claim 1,
The carbon support is selected from carbon black, Ketjen black, carbon nano tube, carbon nano fiber, graphite carbon, graphene and graphene oxide. Platinum-transition metal composite supported on a carbon support, characterized in that it comprises one or more. The method of claim 1,
Platinum-transition metal composite supported on the carbon support, characterized in that the platinum-transition metal complex supported on the carbon support is an intermetallic phase. The method of claim 1,
Platinum-transition metal composite supported on the carbon support, characterized in that the platinum-transition metal complex supported on the carbon support is 1 to 10nm in diameter. The method of claim 1,
Platinum-transition metal composite supported on the carbon support, characterized in that the platinum-transition metal complex supported on the carbon support is a catalyst for oxygen reduction reaction of the fuel cell. In a fuel cell comprising a cathode, a cathode and a separator positioned between the anode and the cathode,
The anode or cathode is a fuel cell comprising a platinum-transition metal composite supported on the carbon support according to claim 1. (a) preparing a mixture comprising a platinum precursor, a zinc precursor, a cobalt precursor and a carbon support; And
(b) heat treating the mixture to synthesize a platinum-transition metal composite supported on a carbon support; To
Method for producing a platinum-transition metal composite supported on a carbon support comprising. The method of claim 9,
Method for producing a platinum-transition metal composite supported on a carbon support, characterized in that the manufacturing method uses a wet impregnation method. The method of claim 9,
The platinum precursor comprises at least one selected from chloroplatinic acid hydrate, sodium hexachloroplatinate hexahydrate, and potassium hexachloroplatinate. Method for producing a platinum-transition metal composite supported on a carbon support. The method of claim 9,
The zinc precursor is zinc nitrate hexahydrate (Zn (NO ₃ ) ₃ 9H ₂ O), zinc chloride (ZnCl ₂ ), zinc sulfate (ZnSO ₄ ), zinc hydroxide (Zn (OH) ₂ ) and zinc acetate (Zn (CH) ₃ CO ₂ ) A method for producing a platinum-transition metal composite supported on a carbon support comprising at least one selected from ₂ ). The method of claim 9,
Platinum supported on a carbon support, characterized in that the cobalt precursor comprises at least one selected from cobalt chloride hexahydrate (CoCl ₂ 6H ₂ O) or cobalt hexahydrate (Co (NO ₃ ) ₂ 6H ₂ O) Method for producing a transition metal composite. The method of claim 9,
The carbon support of step (a) is a method for producing a platinum-transition metal composite supported on a carbon support, characterized in that the carbon support doped with nitrogen dispersed in ethanol. The method of claim 9,
The carbon support of step (a) is carbon black, Ketjen black, carbon nanotube, carbon nanofiber, graphite carbon, graphene and Method of producing a platinum-transition metal composite supported on a carbon support, characterized in that it comprises at least one selected from graphene oxide. The method of claim 9,
Step (a) is carried out by sonication (sonication), the method of producing a platinum-transition metal composite supported on a carbon support. The method of claim 9,
Step (b)
(b-1) first heat treatment at 200 ° C to 400 ° C; And
(b-2) secondary heat treatment at 600 ° C. to 800 ° C .;
Method for producing a platinum-transition metal composite supported on a carbon support comprising a.

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