KR101311745B1 - Catalysis for Fuel Cell and the Fabrication Method Thereof - Google Patents

Abstract

) 지지체를 포함하는 특징이 있으며, 우수한 전기전도도를 가지며, 부식 저항성이 높고, 연장된 촉매 수명을 가지며, 기체 확산 저항이 낮은 특징이 있다.The present invention relates to a catalyst for a fuel cell and a method for manufacturing the same. In detail, the catalyst for a fuel cell according to the present invention is a magellitic titanium oxide carrying at least 15% by weight of an active metal for electrocatalyst (

) Has a feature of including a support, has excellent electrical conductivity, high corrosion resistance, extended catalyst life, and low gas diffusion resistance.

Description

Catalyst for Fuel Cell and Manufacturing Method Thereof {Catalysis for Fuel Cell and the Fabrication Method Thereof}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst for a fuel cell and a method for manufacturing the same, and more particularly, to a catalyst for a fuel cell and a method for manufacturing the same, which support a large amount of catalyst metal, have excellent electrical conductivity, and have high corrosion resistance.

The demand for energy is increasing globally due to industrial development and population growth, but the production of oil and natural gas, the main energy sources, is expected to decrease gradually from about 2020. With the depletion of fossil fuels, there is an urgent need for research and development on alternative clean energy sources that do not pollute the environment.

In addition, the Kyoto Protocol was adopted in 1997 to ratify GHG emissions, which has been ratified by 119 countries, including Korea.

The technology that uses various natural resources such as solar heat, wind power and hydrogen energy as the energy source is being researched and developed, but unlike the existing thermal power generation, the thermodynamic limitation (Carnot efficiency) is not limited to the direct power generation without the combustion process or mechanical work. It does not receive power, has high power generation efficiency, does not emit air pollutants (NOx), sulfur compounds (SOx), etc., and can reduce CO ₂ emissions. Type power generation method is available, medium and large power generation system of 100 발전 ~ 10㎾ class, small power generation system of 1㎾ ~ 10㎾ class, auxiliary power source for automobile, and mobile power source of several W ~ ㎾ class Fuel cell technology has been spotlighted as an alternative clean energy by lighting that can easily adjust power generation capacity.

A fuel cell is a device for directly converting chemical energy into electrical energy by reacting fuel gas such as hydrogen (H ₂ ) with oxygen (O ₂ ), and a fuel electrode and an air electrode are generally formed.

In the anode, hydrogen cations and electrons are generated by a catalytic reaction, and the hydrogen cations generated therein move through the electrolyte to the cathode, and electrons move from the anode to the cathode along an external circuit. In addition, in the cathode, water is generated by the reaction of hydrogen cations that have passed through the electrolyte and electrons that have moved along the external circuit with oxygen. At this time, a predetermined potential difference occurs between the fuel electrode and the air electrode.

Such fuel cells can be classified into various types according to the type of electrolyte used and operating temperature, but can obtain a high current density at a relatively low temperature of 100 ° C. or lower, and has an excellent energy conversion efficiency compared to other fuel cells. Polymer Electrolyte Membrane Fuel Cells (PEMFCs), which use hydrogen as a direct fuel, are attracting attention as power sources for automobiles, household power generation, and mobile devices.

However, the biggest problem in commercializing such a polymer electrolyte fuel cell is that the performance of the catalyst gradually decreases with a long time operation or start / stop repetition, thereby degrading the performance of the polymer electrolyte fuel cell. Such a decrease in performance is reported to be due to the decrease in the surface area of the platinum catalyst with the operation of the fuel cell.

In general, the polymer electrolyte fuel cell catalyst uses a form of Pt / C, which is formed of nano-sized platinum on a carbon support having a high active area.

However, the polymer electrolyte fuel cell operates under conditions where carbon corrosion is likely to occur, such as high anode potential, low pH, and high oxygen concentration. Accordingly, in the case of the carbon-based support, while the polymer electrolyte fuel cell is operated, carbon is oxidized in the form of CO or CO ₂ to cause corrosion of the carbon supporting the catalyst, thereby reducing the active area of platinum. The problem of deterioration of fuel cell life due to deterioration of performance and reduction of durability occurs.

 The active metal for the electrocatalyst may be used alone or in the form of two or more alloys of a noble metal and a transition metal such as Pt, Ru, Pd, Ir, Co, Mo, Fe, Ce, and La.

)을 촉매 지지체로 사용하고자 하는 연구(T. Ioroi, Z. Siroma, N. Fujiwara, S. Yamazaki, K. Yasuda, Electrochem. commun. 7 (2005) 183.; T. Ioroi, H. Senoh, S. Yamazaki, Z. Siroma, N. Fujiwara, K. Yasuda, J. Electrochem. Soc. 155 (2008) B321.)가 시도되고 있다.In addition, as a new support to replace a variety of carbon, studies on graphitized carbon, metal oxide-based support has been attempted, and among them, the magnetic phase titanium oxide having better electrical conductivity than carbon and high durability even at high voltage operation (

) As a catalyst support (T. Ioroi, Z. Siroma, N. Fujiwara, S. Yamazaki, K. Yasuda, Electrochem. Commun. 7 (2005) 183 .; T. Ioroi, H. Senoh, S Yamazaki, Z. Siroma, N. Fujiwara, K. Yasuda, J. Electrochem. Soc. 155 (2008) B321.) Have been tried.

However, in the case of the magnetellitic titanium oxide support, there is a difficulty in supporting a large amount of catalyst on the support due to the small surface area. The maximum catalyst metal loading reported so far is less than 10wt%, and the catalyst layer becomes relatively thick and the gas inlet diffusion distance becomes longer when using a catalyst of low loading amount, resulting in decreased performance and durability due to increased gas diffusion resistance. As a result, there are still problems with technical limitations that are still not applicable to fuel cells.

T. Ioroi, Z. Siroma, N. Fujiwara, S. Yamazaki, K. Yasuda, Electrochem. commun. 7 (2005) 183. T. Ioroi, H. Senoh, S. Yamazaki, Z. Siroma, N. Fujiwara, K. Yasuda, J. Electrochem. Soc. 155 (2008) B321.

The present invention has been made to solve the above-described problems, in detail, the object of the present invention is to carry a large amount of active metal for the electrocatalyst, has excellent electrical conductivity, high corrosion resistance, durability is increased, gas diffusion It is to provide a catalyst for a low resistance fuel cell and a method of manufacturing the same.

The catalyst for a fuel cell according to the present invention is characterized in that it comprises a magnetite-type titanium oxide support on which an active metal for electrocatalyst is loaded, wherein the supported amount of active metal on the support is 15 to 60% by weight. Even more characteristically is 35 to 60% by weight.

The active metal is a nanoparticle having an average size of 1.5nm to 7nm, the active metal satisfies the following relation 1 and is characterized in that dispersed in the support.

(Relational expression 1)

1 * 10 ¹⁶ / 1m ² ≤ electroactive metal dispersion density ≤1 10 * ¹⁸ for one catalyst / 1m ²

The present invention provides a polymer electrolyte fuel cell equipped with the catalyst for fuel cells described above.

) 및 탈이온수를 혼합하여 혼합액을 제조하고, 상기 혼합액에 환원제가 용해된 환원용액을 투입 및 교반하여 전극촉매용 활성금속이 담지된 매그넬리상 타이타늄 산화물을 제조한다.A method for preparing a catalyst for a fuel cell according to the present invention includes an active metal precursor for an electrocatalyst and a magnetellitic titanium oxide (

) And deionized water are mixed to prepare a mixed solution, and a reducing solution in which a reducing agent is dissolved is added to the mixed solution and stirred to prepare a magnetellitic titanium oxide carrying active metal for electrocatalyst.

The mixed solution contains 0.040 to 0.160 molar concentration of active metal precursor, and the mixed solution preferably contains 1.0 to 3.0% by weight of the magnesium phase titanium oxide.

The reducing agent is preferably one or two or more selected from NaBH ₄ , KBH ₄ , ethylene glycol and hydrazine, and includes borohydride containing NaBH ₄ or KBH ₄ for bulk loading of the active metal. The reducing solution in which the hydride-based reducing agent is dissolved is added and stirred so as to satisfy the following Equation 2 to prepare a magnetellitic titanium oxide on which the active metal for the electrocatalyst is supported.

(Relational expression 2)

2 mol / minute feed rate ≤ ([BH ₄ ^-] / min) ≤ 6 mol / min.

The feed rate is number of moles [BH ₄ ^-] of the borohydride ion is added to the mixture per minute is.

In the production method according to the present invention, when the reducing solution is added to the mixed solution, the mixed solution is characterized in that the stirring at 500 to 1500 rpm.

The reducing solution is characterized by containing the reducing agent of 0.1 to 1.0 molarity,

When the reducing solution is added to the mixed solution, the reducing solution is introduced such that the molar ratio of the active metal precursor: the reducing agent is 1: 8.3 to 33.3.

The mixed solution is prepared by mixing and stirring an active metal precursor, magnesium phase titanium oxide and deionized water at 500 to 1500 rpm for 12 to 36 hours.

The electrocatalyst active metal may be a precious metal including platinum (Pt), ruthenium (Ru), palladium (Pd), and iridium (Ir); And transition metals including cobalt (Co), molybdenum (Mo), iron (Fe), cesium (Ce), and lanthanum (La); or a single or two or more alloys thereof.

The active metal precursor is a noble metal described above; And a transition metal; halide of one or two or more selected metals. In detail, the halide includes fluoride, chloride, bromide or iodide.

According to the present invention, a method for preparing a fuel cell catalyst is prepared by adding and stirring a reducing solution into the mixed solution, and recovering the prepared catalyst using filtration; And washing the recovered catalyst and drying it at 90 to 100 ° C.

The fuel cell catalyst according to the present invention is characterized in that an active metal for electrocatalyst 15 wt% or more is evenly dispersed and supported in the form of nanoparticles on a magnesium phase titanium oxide support, and has excellent electrical conductivity and excellent durability at high voltage. It is characterized by high corrosion resistance under oxygen conditions.

1 is a transmission electron micrograph of the catalyst prepared in the embodiment of the present invention,
2 is a transmission electron micrograph of the catalyst prepared in Comparative Example of the present invention,
3 is a view showing a result of measuring the performance of a cell equipped with a catalyst according to the present invention,
4 is a view showing an accelerated stress test result of an electrode equipped with a catalyst according to the present invention,
5 is a view showing an accelerated stress test result of an electrode equipped with a commercial Pt-C catalyst.
6 is a view showing CVs results measured after accelerated stress test results of an electrode equipped with a catalyst according to the present invention.
FIG. 7 shows CVs results measured after accelerated stress test results of an electrode equipped with a commercial Pt-C catalyst.
8 is a transmission electron micrograph after the accelerated stress test results of the electrode equipped with a catalyst according to the present invention,
9 is a transmission electron micrograph taken after the accelerated stress test results of the electrode equipped with a commercial Pt-C catalyst.

Hereinafter, the catalyst of the present invention and a preparation method thereof will be described in detail. Hereinafter, the technical and scientific terms used herein will be understood by those skilled in the art without departing from the scope of the present invention. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

) 지지체를 포함하는 특징이 있으며, 보다 특징적으로 본 발명에 따른 연료전지용 촉매는 상기 지지체상의 전극촉매용 활성금속 담지량이 15 내지 60 중량%인 특징이 있으며, 보다 더 특징적으로 상기 지지체상의 활성금속 담지량이 35 내지 60 중량%인 특징이 있다. Catalyst for fuel cell according to the present invention, preferably the catalyst for the polymer electrolyte fuel cell (polymer electrolyte fuel cell) is a magnesium oxide titanium oxide carrying an active metal for electrocatalyst at least 15% by weight (

A fuel cell catalyst according to the present invention is characterized in that the amount of active metal supported on the support on the support is 15 to 60% by weight, and more particularly the amount of active metal supported on the support. It is characterized by 35 to 60% by weight.

In the present invention, the magnetic phase titanium oxide is a titanium sub oxide (titanium sub oxide), means Ti _n O _2n-1 (4≤n≤10), Ti ₄ O ₇ based on Ti ₄ O ₇ , Commercially available ebonex in which Ti ₅ O ₉ , Ti ₆ O ₁₁ , Ti ₇ O ₁₃ and Ti ₈ O ₁₅ coexist.

The electrocatalyst active metal may be a precious metal including platinum (Pt), ruthenium (Ru), palladium (Pd), and iridium (Ir); And transition metals including cobalt (Co), molybdenum (Mo), iron (Fe), cesium (Ce), and lanthanum (La); or a single or two or more alloys thereof. In view of good catalytic activity, the active metal preferably comprises platinum.

In detail, the electrocatalyst active metal is a nanoparticle having an average size of 2nm to 5nm, the electrocatalyst active metal satisfies the following relation 1 and is characterized in that it is dispersed in the support.

(Relational expression 1)

1 * 10 ¹⁶ / 1m ² ≤ electroactive metal dispersion density ≤1 10 * ¹⁸ for one catalyst / 1m ²

In the relation 1, the active metal dispersion density for the electrocatalyst is the number of active metal particles supported per unit area (1 m ² ) of the magnetellitic titanium oxide support.

The supported amount of the active metal for electrocatalyst supported on the magnetite-type titanium oxide, the dispersion density of the active metal for electrocatalyst, and the particle size of the active metal for electrocatalyst are defined in the conventional carbon-based support. It is equivalent to or more than supported.

Accordingly, the catalyst of the present invention solves the problem of low corrosion resistance under the oxygen conditions of the active metal-carbon-based support for the conventional electrode catalyst used in the conventional polymer electrolyte fuel cell, while the active metal-carbon-based support for the conventional electrode catalyst Can be effectively replaced.

Furthermore, the polymer electrolyte fuel cell equipped with the catalyst according to the present invention has excellent electrical conductivity, excellent durability at high voltage, and high oxygen conditions, as the active metal for electrocatalyst is supported on the support of magneto-type titanium oxide. It is characterized by having corrosion resistance. In addition, more than 15% by weight of the active metal for the electrocatalyst is evenly dispersed and supported in the form of nanoparticles to enable the production of a thin catalyst layer is characterized by preventing the increase in gas diffusion resistance.

Hereinafter, a method for preparing a catalyst according to the present invention will be described in detail. Applicant, in preparing a catalyst for a fuel cell by supporting an active metal for an electrocatalyst on a magnetite-type titanium oxide support, examines in detail the substance of a reducing agent, an input condition of a reducing agent, and a reducing condition when supporting an active metal for an electrocatalyst. As a result, in the case where the active metal material for electrocatalyst is reduced and supported on the support under specific conditions and methods, the amount of loading is remarkably increased, confirming that the size and dispersibility of the supported particles are extremely excellent and completing the present invention. It became.

) 및 탈이온수를 혼합하여 혼합액을 제조하고, 상기 혼합액에 NaBH₄, KBH₄, 에틸렌글리콜(ethylene glycol) 및 히드라진(Hydrazine)에서 하나 또는 둘 이상 선택된 환원제가 용해된 환원용액을 투입 및 교반하여 전극촉매용 활성금속이 담지된 매그넬리상 타이타늄 산화물을 제조하는 특징이 있다.The method for preparing a catalyst for a fuel cell, preferably a polymer electrolyte fuel cell, according to the present invention is an active metal precursor for an electrocatalyst, a magnetite-type titanium oxide (

) And deionized water are mixed to prepare a mixed solution, and a reducing solution in which one or two or more reducing agents are dissolved in NaBH ₄ , KBH ₄ , ethylene glycol, and hydrazine is added and stirred to the mixed solution. It is characterized in that the magnetellitic titanium oxide carrying the active metal for the catalyst is prepared.

For uniform mass loading of the active metal, the reducing agent is preferably a borohydride-based reducing agent including NaBH ₄ , KBH ₄ , or a mixture thereof, and a reducing solution in which the borohydride-based reducing agent is dissolved in the mixed solution. Injecting and stirring so as to satisfy the following relation 2, it is characterized in that the magnetellitic titanium oxide on which the active metal for the electrocatalyst is supported.

(Relational expression 2)

2 mol / minute feed rate ≤ ([BH ₄ ^-] / min) ≤ 6 mol / min.

The feed rate is number of moles [BH4 ^-] of the borohydride ion is added to the mixture per minute it is.

In the production method according to the present invention, a borohydride-based reducing agent for reducing the active metal precursor is dissolved in a mixed solution of the magnetellitic titanium oxide, which is a support on which the active metal precursor and the active metal are supported, as shown in Equation 2 above. The reducing solution is characterized in that a large amount of input in a very short time.

When the reducing solution is added, very fast reduction occurs between the reducing agent and the support. The borohydride-based reducing agent is added according to the above Equation 2, so that the active metal for the electrode catalyst can be supported on the support very evenly and uniformly. In addition, the amount of active metal supported for the electrocatalyst on the support can be significantly increased.

More specifically, when the loading rate is slower than 2 mol / min, it is difficult to obtain an active metal carrying amount for the electrocatalyst of 15% by weight or more, and when the loading rate is faster than 6 mol / min, local excessive reduction occurs and is uniform. It is difficult to support the active metal for the electrocatalyst in the form of nanoparticles so distributed.

 As described above, the method for preparing a catalyst according to the present invention is to control the reduction of the active metal for the electrocatalyst by the input conditions of the reducing solution 15% by weight or more, more specifically 15 to 60% by weight for the electrode catalyst A magnetellitic titanium oxide in which the active metal is evenly supported in the form of nanoparticles is prepared.

The reduction of the active metal for the electrocatalyst is most controlled by the addition of the above-mentioned reducing solution, but is also affected by the stirring conditions of the mixed solution, the reducing agent concentration of the reducing solution, and the amount of the reducing solution added.

The next factor that affects the loading amount and the loading state of the reducing solution is the stirring condition when the reducing solution is added, and in the manufacturing method of the present invention, when the reducing solution is added to the mixed solution, the mixed solution is 500 It is characterized by being stirred at 1500 rpm.

 When the stirring rate of the mixed solution at the time of the introduction of the reducing solution is too slow at less than 500 rpm or too fast at more than 1500 rpm, there is a risk that the loading amount of the active metal for the electrocatalyst supported on the support decreases.

Preferably, in the present invention, a reducing solution is added according to the above Equation 2, and when the reducing solution is added, the mixed solution is stirred at 500 to 1500 rpm, so that at least 15 wt% of the active metal for the electrocatalyst is in the form of nanoparticles. An evenly supported magnetellitic titanium oxide is prepared.

The reducing solution preferably contains the reducing agent in a concentration of 0.1 to 1.0 molar. As described above, the reducing agent is preferably a borohydride-based reducing agent, and the borohydride-based reducing agent is preferably NaBH ₄ , KBH ₄ , or a mixture thereof, and more preferably NaBH ₄ .

In more detail, when the reducing solution is added to the mixed solution, the reducing solution is added such that the molar ratio of the active metal precursor: the borohydride reducing agent is 1: 8.3 to 33.3.

Along with the relation 2, the molarity of the reducing solution and the amount of the reducing solution added according to the molar ratio of the active metal precursor for the electrocatalyst and the borohydride-based reducing agent are uniform while supporting the catalyst metal on the support by an extremely fast reduction reaction. It is a condition that can be supported.

The mixed solution is preferably prepared by mixing and stirring the active metal precursor for electrocatalyst, magnesium phase titanium oxide and deionized water at 500 to 1500 rpm for 12 to 36 hours.

The active metal precursor may be a precious metal including platinum (Pt), ruthenium (Ru), palladium (Pd) and iridium (Ir); And a transition metal including cobalt (Co), molybdenum (Mo), iron (Fe), cesium (Ce), and lanthanum (La); halides of one or two or more metals selected from above. Halides include fluoride, chloride, bromide or iodide.

Preferably, the active metal precursor is chloride, and platinum is one example. The chloride is platinum chloride including hexachloroplatinum, potassium tetrachloroplatinate, tetraamine platinum chloride, and tetramethyl platinum. chloride), or mixtures thereof. In order to have a catalyst metal loading of 15% by weight to 60% by weight, the mixed solution preferably contains an active metal precursor of 0.04 to 0.16 molar concentration.

The magellitic titanium oxide is a titanium suboxide of Ti _n O _2n-1 (4 ≦ _n ≦ 10), and Ti ₄ O ₇ , Ti ₅ O ₉ , Ti ₆ O ₁₁ , Ti ₇ O ₁₃ , Ti ₈ O _{15 ,} Ti ₉ O ₁₇ and Ti ₁₀ O _19, and one or two or more selected materials, the magneto Marinelli phase titanium oxide is Ti ₄ to O ₇ based on Ti ₄ O _7, Ti ₅ O _9, Ti ₆ O _11, Ti ₇ O Commercially available ebonex in which ₁₃ and Ti ₈ O ₁₅ coexist.

The magneto-type titanium oxide contained in the mixed solution is preferably in the form of a powder having an average particle size of 200 to 800 nm, and the mixed solution preferably contains 1 to 3% by weight of the magnetic-type titanium oxide.

As described above, a reduction solution is added to the mixed solution to prepare a fuel cell catalyst (magnetitic titanium oxide carrying an active metal for electrode catalyst), and thereafter recovering the catalyst produced by filtration; And washing the recovered catalyst to dry at 90 to 100 ° C.

At this time, the recovering step of the catalyst can recover the fuel cell catalyst prepared by the solid / liquid separation using a conventional filter (filter) or centrifugation, after mixing the deionized water and the recovered fuel cell catalyst again The catalyst can be washed by filtration.

Drying of the washed catalyst is preferably carried out at 90 to 100 ℃, to ensure the removal of moisture and impurities on the surface of the synthetic catalyst.

(Example)

)을 혼합하고 1500 rpm으로 24시간 동안 교반하여 혼합액을 제조하였다. 제조된 혼합액을 1500 rpm으로 교반하며 0.5몰 농도의 NaBH₄ 수용액 1000g을 BH₄ ^- 이온의 투입 속도가 3 mol/분이 되도록 투입하고, 1500 rpm의 속도로 24시간 교반하였다. 이후, 여과지를 이용하여 제조된 촉매를 회수하고, 탈이온수로 세척한 후, 100 ℃에서 24시간 건조하여 전극촉매용 활성금속이 담지된 매그넬리 타이타늄 산화물인 촉매를 제조하였다.
10.17 g H ₂ PtCl ₆ and 6 g Ti ₄ O ₇ powder in 500 ml of deionized water (Atraverda,

) Was mixed and stirred at 1500 rpm for 24 hours to prepare a mixed solution. The prepared liquid mixture was stirred at 1500 rpm, and 1000 g of an aqueous NaBH ₄ solution having a concentration of 0.5 mol was added at a rate of 3 mol / min for BH ₄ ^- ions, followed by stirring at a speed of 1500 rpm for 24 hours. Subsequently, the catalyst prepared using the filter paper was recovered, washed with deionized water, and dried at 100 ° C. for 24 hours to prepare a catalyst which is a magnetite titanium oxide carrying active metal for electrocatalyst.

(Comparative Example)

) 6g을 혼합한 후, 24시간 동안 1500 rpm으로 교반하였다. 이후, 여과지를 이용하여 제조된 촉매를 회수하고, 탈이온수로 세척한 후, 100 ℃에서 24시간 건조하여 촉매를 제조하였다.The catalyst was prepared by the polyol method. In detail, 10.17 g of H ₂ PtCl ₆ was mixed with 1000 ml of ethylene glycol, and then the pH was adjusted to 11 by adding 0.1 M NaOH solution. The pH-controlled mixture was stirred at 1500 rpm for 3 hours at 160 ° C., and then cooled to 60 ° C., and Ti ₄ O ₇ powder (Atraverda,

6g) and then stirred at 1500 rpm for 24 hours. Thereafter, the catalyst prepared using the filter paper was recovered, washed with deionized water, and dried at 100 ° C. for 24 hours to prepare a catalyst.

As a result of ICP-AES analysis of the catalysts prepared in Examples and Preparation Examples, when the catalyst was prepared according to the present invention, the supported amount of the active metal for the electrocatalyst had a very high loading amount of 36% by weight, whereas a conventional polyol When the catalyst is prepared by the method, it can be seen that the supported amount is only 14% by weight. As a result of calculating the actual amount of active metal supported as a yield when 100% of the active metal precursor for the electrocatalyst added for supporting the electrocatalyst active metal was supported, the yield of the manufacturing method according to the present invention was 90%. In the comparative example, the yield was found to be only 38%.

1 is a transmission electron micrograph of the catalyst prepared in the above Example according to the present invention, Figure 2 is a transmission electron micrograph of the catalyst prepared in the comparative example. As can be seen in Figures 1 and 2, the catalyst according to the present invention can be seen that the platinum particles having a diameter of 2 to 3nm is extremely uniformly supported on the magnetellitic titanium oxide support, 2.1 * 10 per support area of 1 m ² gae ¹⁷ ~ 8.4 * 10 it can be seen that the ¹⁷ platinum particles are dispersed.

However, in the case of using a conventional polyol method as in the comparative example, the size of the platinum particles is large, 5 to 7 nm, the platinum particles are agglomerated with each other, and the dispersibility is also very low. In addition, it can be seen that the size and dispersion of platinum particles are greatly improved.

In order to evaluate the electrochemical properties of the prepared catalyst, the catalyst prepared in each of Examples and Comparative Examples was subjected to conventional spray-drying methods (YG Yoon, GG Park, TH Yang, JN Han, WY Lee, CS Kim, Int. Hydrogen Energy 28 (2003) 657.) was used to prepare a cathode, and a membrane electrode composite (electrode area 50 cm ² ) was prepared using a commercial Pt-C catalyst (Johnson Matthey HiSPEC 4000) as an anode. It was. At this time, as the electrolyte material, a Nafion membrane having a water ion exchange characteristic was used, and the platinum loading of each electrode was adjusted to 0.4 mgPt / cm ² .

The prepared membrane electrode composite was used as a single cell, and electrochemical characteristics were analyzed using a Solartron 1480A Prtentiostat / Galvanostat device.

Oxygen or air was used as reactant on the cathode side of the cell and pure hydrogen was used as anode side reactant on the cell. All feed gases were supplied at 100% water saturation using a humidifier. The cell was tested at 70 ° C., atmospheric pressure, and during the voltage-current (I-V) test, the hydrogen utilization was adjusted to 75% and the air utilization (or oxygen utilization) was adjusted to 50%.

3 is a cell performance measurement result measured as a single cell membrane electrode composite equipped with the anode (cathode) containing the catalyst according to the invention and the anode of a commercial Pt-C catalyst (Johnson Matthey HiSPEC 4000) . As can be seen from the results in FIG. 3, it can be seen that when the reactants are oxygen or air, they have increased efficiency over all current ranges tested.

If 5% by weight platinum is supported on the support, the electrode should be made to a thickness of up to about 20 μm in order for the electrode to load platinum at 0.24 mg Pt / cm ² . On the other hand, the catalyst prepared in Example according to the present invention was loaded with 36% by weight of platinum on a support, so that the thickness of the electrode for loading the platinum at 0.4 mg Pt / cm ² was only about 3 μm. Therefore, it can be seen that the diffusion distance of oxygen is very short and the movement distance of electrons has excellent efficiency as shown in FIG. 3.

The durability of the electrode with catalyst according to the invention was tested according to the accelerated stress test technique. In the durability test, an electrode equipped with a commercial Pt-C catalyst (Johnson Matthey HiSPEC 4000) was also tested as a comparative group. To clarify the reason for the decrease in performance, the CVs (Cyclic Voltammograms) of the electrodes were measured before and after the accelerated stress test.

4 is a performance curve of an electrode equipped with a catalyst (example catalyst) according to the present invention measured by repeatedly cycling a voltage range of 0.9 to 1.3 (voltage scan rate: 100 mV / s) in which carbon corrosion occurs under fuel cell operating conditions. It is shown. At this time, the performance curve was measured every 1,000 cycles during the 10,000 cycles.

FIG. 5 shows a performance curve of a cell equipped with a commercial Pt-C catalyst measured by repeatedly cycling a voltage range of 0.9 to 1.3 where carbon corrosion occurs, similar to FIG. 3.

As can be seen in FIGS. 4 and 5, the electrode containing the catalyst according to the present invention maintains its initial performance during 10,000 cycles, while the current density decreases continuously for the Pt-C catalyst of the comparative group. Able to know. Through this, it can be confirmed that the durability of the catalyst of the present invention is very excellent.

6 and 7 show the results of CVs of the electrode with the catalyst and the electrode with the commercial Pt-C catalyst according to the present invention. From the results of FIGS. 6 and 7, the performance decrease as shown in FIG. Was confirmed to be due to a change in the electrochemical reaction area of the catalyst provided in the electrode.

8 and 9 are transmission electron micrographs of the catalyst (FIG. 8) and the commercial Pt-C catalyst (FIG. 9) according to the present invention after the accelerated stress test. As can be seen in Figures 8 and 9, both catalysts were agglomerated by the test, but the amount of catalyst remaining on the support using ECSA was found to be the most common platinum (94%) for commercial Pt-C catalysts. Above) was lost by carbon corrosion, and it was confirmed that more than 96% of platinum remained in the catalyst according to the present invention.

In the catalyst according to the present invention from the results of FIGS. 4 and 8 and the ECSA results, the corrosion resistance of the support is high and the bonding strength with the active metal for the electrocatalyst is high, so that the platinum disappears hardly, and thus the platinum agglomerates. Even if this occurs, the accelerated stress test shows little performance loss.

Claims (15)

15% by weight or more of the active metal for the electrocatalyst is supported on the magellitic titanium oxide support, and the electrocatalyst active metal satisfies the following relation 1 and is dispersed in the magellinium titanium oxide support. .
(Relational expression 1)
1 * 10 ¹⁶ / 1m ² ≤ electroactive metal dispersion density ≤1 10 * ¹⁸ for one catalyst / 1m ² The method of claim 1,
The electrocatalyst active metal may be a precious metal including platinum (Pt), ruthenium (Ru), palladium (Pd), and iridium (Ir); And transition metals including cobalt (Co), molybdenum (Mo), iron (Fe), cesium (Ce), and lanthanum (La); a fuel selected from the group consisting of two or more alloys thereof. Battery catalyst. The method of claim 1,
The active metal for the electrocatalyst is a fuel cell catalyst, characterized in that the nanoparticles having an average size of 1.5 nm to 7 nm. delete A mixed solution was prepared by mixing an active metal precursor for electrocatalyst, magenta-type titanium oxide, and deionized water, and adding and stirring a reducing solution in which the borohydride-based reducing agent was dissolved in the mixed solution so as to satisfy the following Equation 2. A method for producing a catalyst for a fuel cell, which manufactures magnesium-type titanium oxide on which an active metal for a catalyst is supported.
(Relational expression 2)
2 mol / minute feed rate ≤ ([BH ₄ ^-] / min) ≤ 6 mol / min.
(The feed rate is number of moles [BH ₄ ^-] of the borohydride ion is added to the mixture per minute is.) 6. The method of claim 5,
Method of producing a catalyst for a fuel cell, characterized in that when the reducing solution is added to the mixed solution, the mixed solution is stirred at 500 to 1500 rpm. 6. The method of claim 5,
The reducing solution is a method for producing a catalyst for a fuel cell, characterized in that containing the reducing agent of 0.1 to 1.0 molar concentration. The method according to any one of claims 5 to 7, wherein
When the reducing solution is added to the mixed solution, the method for producing a catalyst for a fuel cell, characterized in that the reducing solution is added so that the molar ratio of the active metal precursor for the electrocatalyst: the reducing agent 1: 8.3 to 33.3. The method of claim 8,
The mixed solution is a method for producing a catalyst for a fuel cell, characterized in that it contains an active metal precursor for electrode catalyst of 0.04 to 0.16 molarity. 6. The method of claim 5,
The fuel cell catalyst is a method for producing a catalyst for a fuel cell, characterized in that at least 15% by weight of the active metal for the electrocatalyst supported on the magnesium phase titanium oxide. 6. The method of claim 5,
The electrocatalyst active metal precursor may be a precious metal including platinum (Pt), ruthenium (Ru), palladium (Pd), and iridium (Ir); And a transition metal including cobalt (Co), molybdenum (Mo), iron (Fe), cesium (Ce), and lanthanum (La); a halide of one or more selected metals. Manufacturing method. 8. The method of claim 7,
The borohydride-based reducing agent is a method for producing a catalyst for a fuel cell, characterized in that NaBH ₄ , KBH ₄ , or a mixture thereof. 6. The method of claim 5,
The mixed solution is a method for producing a catalyst for a fuel cell, characterized in that prepared by mixing and stirring the active metal precursor for electrocatalyst, magnesium phase titanium oxide and deionized water at 500 to 1500rpm for 12 to 36 hours. 6. The method of claim 5,
Preparing a fuel cell catalyst by injecting and stirring a reducing solution into the mixed solution, and recovering the prepared catalyst using filtration; And washing the recovered catalyst and drying it at 90 to 100 ° C. A polymer electrolyte fuel cell comprising the catalyst for fuel cell of any one of claims 1 to 3.

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