KR101423754B1 - Preparation method of nanoporous carbon for fuel cell catalyst support using rice hull, and direct methanol and polymer electrolyte fuel cell comprising the same - Google Patents

Abstract

The present invention relates to a porous carbon catalyst support for a fuel cell, and more specifically, to a method for preparing a nanoporous carbon catalyst support for a fuel cell, the method including: a first step of washing, with distilled water, and drying a rice plant or a soksaegwa plant; a second step of grinding the rice plant or the soksaegwa plant dried in the first step with a grinder; a third step of heat treating the rice plant or the soksaegwa plant ground in the second step; a fourth step of carbonizing the rice plant or the soksaegwa plant heat-treated in the third step to prepare a silica/carbon composite; a fifth step of primarily acid-treating the silica/carbon composite prepared in the fourth step; and sixth step of secondarily acid-treating the silica/carbon composite primarily acid-treated in the fifth step to prepare a carbon catalyst support from which silica is extracted. A nanoporous carbon catalyst support for a fuel cell, prepared as described above, has a structure in which meso-porous pore is formed to have a characteristic of an excellent catalyst support and to improve fuel oxidation and oxygen reduction performance. According to the present invention, a platinum/ruthenium catalyst or a platinum catalyst forms a dispersed nanopore to obtain excellent fuel cell performance and long-term durability, since a portion in which inorganic silica is dispersed in a nanostructure inside a plant cell of a rice hull is removed by an acid treatment. Further, since an agricultural by-product is used, mass production is facilitated through low costs.

Description

The present invention relates to a method for preparing a nano-porous carbonaceous catalyst carrier for a fuel cell using a rice husk, a direct methanol and a polymer electrolyte fuel cell comprising the same, a preparation method of nanoporous carbon for fuel cell catalyst using rice hull, and a direct methanol and polymer electrolyte fuel cell the same}

The present invention relates to a nano-porous carbonaceous catalyst carrier for fuel cells using a rice husk, and more particularly to a nano-porous carbonaceous catalyst carrier for fuel cells capable of improving catalyst supporting properties and fuel oxidation and oxygen reduction performance. And a direct methanol and a polymer electrolyte fuel cell comprising the same.

Fuel cells belonging to the renewable energy technology include a solid polymer electrolyte fuel cell (PEMFC) that directly supplies the gaseous hydrogen fuel to the fuel cell stack and a liquid fuel such as methanol directly supplied to the fuel cell stack Direct methanol fuel cell (DMFC).

Polymer electrolyte fuel cells (PEFCs), which use hydrogen as a fuel, have the advantages of high energy density and high output. However, attention has to be paid to the handling of hydrogen gas. Methane, methanol and natural gas And a fuel reforming device for reforming the fuel and the like.

Direct Methanol Fuel Cell (DMFC) uses almost the same hydrogen ion conductive polymer membrane as a polymer electrolyte fuel cell, but it differs from a polymer electrolyte fuel cell in that liquid methanol is used directly as a fuel. Direct methanol fuel cells are capable of starting at room temperature without a fuel reformer and operate at operating temperatures below 100 ° C, making them suitable for portable or small fuel cells.

Direct methanol fuel cells are attracting attention as energy conversion devices that have the advantages of high energy density, low temperature operation, and miniaturization of the system. However, the direct methanol fuel cell has a disadvantage in that it uses much expensive noble metal catalyst due to the low reactivity of liquid methanol and crossover (permeates) from the fuel electrode to the air electrode to degrade the performance of the fuel cell. To overcome these disadvantages, catalyst abatement technology and high performance polymer membrane synthesis technology have been studied extensively.

The basic structure of a direct methanol fuel cell is composed of a fuel electrode (oxidizing electrode) and an air electrode (reducing electrode) attached to a porous carbon paper on both sides of a polymer electrolyte membrane composed of a Nafion membrane, The collector or separator plate is located.

Direct methanol fuel cells use solid polymer membranes such as nepion, which are solid electrolytes. Researches on solid polymer type direct methanol fuel cells, which mainly use hydrogen ion exchange polymer membranes as electrolytes, are the mainstream.

Direct methanol fuel cells use hydrogen ion exchange polymer membranes that transfer hydrogen ions to the electrolyte. The polymer membrane serves as a carrier of hydrogen ions between the fuel electrode and the air electrode, and serves as a separator for separating fuel and oxygen from each other. Therefore, the polymer electrolyte membrane should have high hydrogen ion conductivity, low electron conductivity, less reactive gas or fuel transfer, and high mechanical and chemical stability.

Conventional studies to improve the performance of direct methanol fuel cell include development of coating technology of carbon-supported high activity platinum catalyst (Pt / C, PtRu / C), high conductivity proton conductive polymer membrane and electrode slurry for electrode performance improvement It is progressing.

Membrane / Electrode Assembly (hereinafter referred to as MEA), which is a core component of a stack in which electricity is generated, among various components constituting the fuel cell, is generally bonded to an electrolyte polymer membrane having three layers, an air electrode and a fuel electrode have. Among them, the air electrode and the fuel electrode are important core materials that determine the performance of the PEFC.

The catalyst carrier is used for dispersing the catalyst, increasing the catalyst utilization rate, and stabilizing the catalyst. As the catalyst supporting body, carbon material is used most frequently because it has excellent acid base stability, excellent electric conductivity and high specific surface area. That is, the specific surface area, porosity, shape, surface functional group, electron conductivity and corrosion resistance of the catalyst carrier should be appropriate.

As such a carbon-based catalyst supporting body, materials such as carbon black (Ketjen black), acetylene black (acetylene black) and the like, which are produced by incomplete combustion of oil or gas, are mainly used.

Here, carbon black is most widely used as a support for a fuel cell electrode catalyst, and representative examples thereof include Vaulcan XC-72 carbon black and the like.

When producing the catalyst carrier, pore size and distribution should be uniformly produced. When the metal catalyst nanoparticles enter the micropores of the carbon in the catalyst impregnation process, the activity becomes low. Therefore, the microporous size of the catalyst carrier should be smaller than the size of the platinum nanoparticles.

In order to overcome such disadvantages, recently, nanomaterials such as carbon nanotubes and carbon nanofibers have been developed. However, such a material is very excellent in electric conductivity, but a technique for uniformly dispersing catalyst nanoparticles by modifying the surface characteristics of a carrier for supporting the catalyst is required, and it is particularly developed to enable mass production.

In addition, since these materials have an excessively long aspect ratio, the coating surface is irregular at the time of electrode coating, so that the length of the carrier is controlled. Thus, there are few cases of commercialization as a fuel cell catalyst carrier.

Currently, research and development is being actively carried out to utilize plant resources as a biomass energy source in Korea. Unlike fossil fuel resources, which have limited reserves, plant resources are advantageous because they can sustain resource production, are easy to regenerate and recover, and are cheap.

The present inventors produced nanoporous catalyst carriers by carbonizing rice or haploid plants massively produced as domestic agricultural by-products and forming nanoporous structures inherent in plant cells to form mesopores.

The present invention has a mesoporous pore structure superior to that of a conventional carbon black catalyst carrier used in a fuel cell and has a better catalyst carrying property and fuel oxidation and oxygen reduction performance than a carbon black catalyst carrier. .

In consideration of the problems of the prior art described above, the present invention provides a method of carbonizing a rice or haploid plant, which is a by-product of agriculture, so that a nanoporous structure inherent in a plant cell forms mesopores and a portion in which inorganic silica is dispersed in a nanostructure The present invention provides a nano-porous carbonaceous catalyst carrier having nano-dispersed pores formed thereon by acid treatment and having excellent catalyst supporting properties and improved fuel oxidation and coral reduction performance.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, A second step of crushing the rice or horsetail plants dried in the first step with a crusher; A third step of heat treating the rice or horsetail plant pulverized in the second step; A fourth step of carbonizing the rice or horsetail plants thermally treated in the third step to produce a silica / carbon composite; A fifth step of subjecting the silica / carbon composite prepared in the fourth step to primary acid treatment; And a sixth step of subjecting the silica / carbon composite subjected to the first acid treatment in the fourth step to a second acid treatment to produce a carbon-based catalyst carrier containing silica extracted therefrom. to provide.

The method may further include activating the carbon-based catalyst carrier with carbon dioxide (CO ₂ ) gas.

The activation is preferably performed at a temperature of 900 to 1100 DEG C for 1 to 5 hours.

In the first step, drying is preferably performed at 110 DEG C for 10 to 24 hours.

In the second step, it is preferable that the rice or horsetail plants are ground to a particle size of 0.1 to 5 탆.

In the third step, the heat treatment is preferably performed at 200 to 300 ° C for 1 to 5 hours.

In the fourth step, the carbonization treatment is preferably performed at 500 to 800 ° C for 1 to 5 hours.

In the fifth step, the silica / carbon composite may be subjected to primary acid treatment with hydrofluoric acid (hydrofluoric acid). The primary acid treatment is preferably carried out at a temperature of 50 to 80 캜 for 1 to 5 hours.

The primary acid-treated silica / carbon composite may be selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid and subjected to secondary acid treatment. The secondary acid treatment is preferably carried out at a temperature of 50 to 80 DEG C for 1 to 5 hours.

Wherein the paddy plant is selected from the group consisting of rice, bamboo, reeds, water bodies, strips, blood, grasses, saddle grass, grass, string, millet, sorghum, sugarcane, corn, wheat, barley, oats, The plant may be selected from the group consisting of horsetail and horsetail.

More preferably, the rice plant can be selected from rice hulls.

The present invention also provides a nanoporous carbon-based catalyst carrier for a fuel cell manufactured by employing the method for manufacturing a nanoporous carbon-based catalyst carrier.

The present invention also provides a fuel cell comprising: a fuel electrode; Air pole; Polymer Electrolyte Membrane; And a separation plate, wherein the fuel electrode comprises a platinum catalyst or a platinum / ruthenium catalyst, and the air electrode comprises a platinum catalyst or a platinum alloy catalyst supported on a carbon-based porous catalyst support for a fuel cell, Thereby providing an electrolyte fuel cell.

The amount of platinum contained in the fuel electrode is preferably 20 to 50 parts by weight, and the content of platinum or platinum-based alloy carried on the air electrode is preferably 20 to 50 parts by weight.

The present invention also provides a fuel cell comprising: a fuel electrode; Air pole; Polymer Electrolyte Membrane; And a separation plate, wherein the fuel electrode is supported on a platinum / ruthenium catalyst, and the air electrode is supported on a carbon-based porous catalyst support for a fuel cell, Lt; / RTI >

The content of platinum / ruthenium contained in the fuel electrode is preferably 40 to 85 parts by weight, and the content of platinum or platinum based alloy carried on the air electrode is preferably 40 to 85 parts by weight.

The present invention relates to a method for producing a nanocomposite carbon-based catalyst support for a fuel cell, which comprises preparing a silica / carbon composite by treating a rice or haploid plant with carbonization treatment, and subjecting the silica / carbon composite to acid treatment with hydrofluoric acid and sulfuric acid. The nanoporous carbonaceous catalyst carrier for fuel cell manufactured by the above method has a mesoporous pore structure and has excellent catalyst supporting properties and can improve fuel oxidation and oxygen reduction performance.

In addition, it is easy to mass-produce by using agricultural by-products.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a manufacturing process diagram showing a manufacturing process of a carbon-based porous catalyst carrier for a fuel cell using rice hulls. FIG.
FIG. 2 is a schematic view showing a process of manufacturing three kinds of carbon-based porous catalyst carriers for fuel cells using rice hulls.
Fig. 3 is a graph showing the results of (1) raw rice husk without heat treatment, (2) rice husk obtained by oxidation at 700 캜 in air, and (3) carbonaceous porous catalyst carrier As a scanning electron microscope.
Fig. 4 is a graph showing the results of a comparison between the raw rice husk (RH 700), the rice husks (RH 260) heat-treated at 260 ° C in air and the rice husks (RH 700HF) obtained by hydrofluoric acid treatment and sulfuric acid treatment, The rice husks heat-treated at 700 ℃ in nitrogen atmosphere were activated by CO ₂ gas at 900-1100 ℃ for 1-5 hours and then treated with hydrofluoric acid and sulfuric acid at 50-80 ℃ for 1-5 hours to obtain rice husk (RH 900CO2) Surface area and volume of mesopores and micropores, and pore size.
FIG. 5 is an X-ray diffraction diagram of a rice husk-supported platinum / ruthenium catalyst (PtRu / RH 700HF) obtained by hydrofluoric acid treatment and sulfuric acid treatment of rice husks heat treated at 700 ° C. in a nitrogen atmosphere. to be.
6 is a view showing a case where a rice husk platinum / ruthenium catalyst (PtRu / RH 700HF) obtained by hydrofluoric acid treatment and sulfuric acid treatment of (1) a commercially available carbon supported platinum / ruthenium catalyst (Com.) And (2) (SE) and transmission (TE) photographs taken with a high resolution scanning microscope (UHR SEM).
7 is a graph showing the results of a comparison between a platinum / ruthenium catalyst (PtRu / RH 700HF) obtained by hydrofluoric acid treatment and sulfuric acid treatment of rice husks heat treated at 700 ° C in (A) a commercial carbon supported platinum / ruthenium catalyst (Com.) And (B) , An IV curve, an output density curve, and an anode polarization curve of a unit cell measured with 2M methanol.
Fig. 8 is a graph showing the results of (A) comparison of the ratio of PtRu / XC (Com.) And Pt (ruthenium) catalysts obtained by hydrofluoric acid treatment and sulfuric acid treatment to rice hulls heat treated at 700 캜 in a nitrogen atmosphere of commercial carbon- (1, 2, 3, 5, and 10 M) of the MEA prepared by using the MEA (MW / RH 700HF).

Hereinafter, the present invention will be described in detail. In the following description of the present invention, a detailed description of known configurations and functions will be omitted.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and should be construed in accordance with the technical meanings and concepts of the present invention.

The embodiments described in the present specification and the configurations shown in the drawings are preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention and thus various equivalents and modifications Can be.

The present invention provides a nanoporous carbon-based catalyst support for a fuel cell having improved fuel oxidation and oxygen reduction performance by carbonizing agricultural byproducts such as rice or horsetail plants to form mesopores of a plant cell-specific nanoporous structure.

As a method for manufacturing the nanoporous carbon-based catalyst carrier for a fuel cell, rice or horsetail plants are washed with distilled water and dried. The drying is preferably performed at 110 DEG C for 10 to 24 hours.

When the drying time is below the lower limit of the above range, there is a problem that distilled water remains. When the drying time exceeds the upper limit of the above range, the plant is excessively dried and the carbonization process can not proceed smoothly Which is undesirable.

The dried rice or horsetail plants are crushed by a crusher. Preferably, the plants are ground to a particle size of 0.1 to 5 mu m.

If the particle size is below the lower limit of the above range, there is a problem that the catalyst loading area becomes small after carbonization. If the particle size exceeds the upper limit of the above range, there arises a problem that the catalyst loading surface area becomes low.

Next, the pulverized rice or Haploid plants are heat-treated as described above. The heat treatment is preferably performed at 200 to 300 ° C for 1 to 5 hours.

The heat treatment is a process for removing water and volatile substances present inside and on the fiber structure of the rice hull, which is a raw material of biomass, so that the thermal decomposition of the fiber structure of the rice husk is easily performed in the carbonization process. When the temperature of the heat treatment is below the lower limit of the above range, there is a problem that moisture or volatile substances can not be completely removed. When the upper limit of the above range is exceeded, the combustion of carbon components proceeds and the content of fixed carbon is lowered, Which is difficult to obtain.

The heat-treated rice or haploid plants are carbonized to produce a silica / carbon composite. The carbonization treatment is preferably performed at 500 to 800 ° C for 1 to 5 hours.

In the carbonization process, the physical properties such as the degree of carbonization of the carbide, the fixed carbon content, and the pore structure may be varied depending on the temperature and time of carbonization in the pyrolysis step in which the basic structure of the rice husk carbon is formed. If the carbonization temperature is below the lower limit of the above range, there is a problem such that the carbonization degree is lowered. If it exceeds the upper limit of the above range, problems such as collapse of the pore structure and reduction of the specific surface area are undesirable.

The silica / carbon composite prepared above is subjected to primary acid treatment. The acid used in the primary acid treatment may be hydrofluoric acid. The primary acid treatment is preferably carried out at a temperature of 50 to 80 캜 for 1 to 5 hours.

When the acid treatment temperature is below the lower limit of the above range, the acid treatment time may be excessively required or the acid treatment may not be completed. If the acid treatment temperature is above the upper limit of the above range, the disintegration of the pore structure or poisoning Gas generation and the like occur, which is not preferable.

The first acid-treated silica / carbon composite is subjected to secondary acid treatment to prepare a nanoporous carbon-based catalyst carrier for silica-extracted fuel cells. The acid used in the secondary acid treatment may be selected from the group consisting of sulfuric acid, nitric acid and hydrochloric acid. The secondary acid treatment is preferably performed at 50 to 80 ° C for 1 to 5 hours.

When the acid treatment temperature is below the lower limit of the above range, the acid treatment time may be excessively required or the acid treatment may not be completed. If the acid treatment temperature is above the upper limit of the above range, the disintegration of the pore structure or poisoning Gas generation and the like occur, which is not preferable.

Finally, the method may further include activating the carbon-based catalyst carrier with carbon dioxide (CO ₂ ) gas.

The activation is preferably performed at a temperature of 900 to 1100 DEG C for 1 to 5 hours.

If the activation temperature is below the lower limit of the above range, the pore development may not be completed due to low activation, and if it exceeds the upper limit of the above range, problems such as disintegration of the pore structure or excessive pore may occur, which is not preferable .

Wherein the paddy plant is selected from the group consisting of rice, bamboo, reeds, water bodies, strips, blood, grasses, saddle grass, grass, string, millet, sorghum, sugarcane, corn, wheat, barley, oats, The plant may be selected from the group consisting of horsetail and horsetail. More preferably, the rice plant may be rice hulls.

The present invention also includes a polymer electrolyte fuel cell employing the above-described nano-porous carbonaceous catalyst carrier for a fuel cell.

The polymer electrolyte fuel cell includes a fuel electrode; Air pole; Polymer Electrolyte Membrane; And the separation plate, wherein the fuel electrode is supported on a platinum catalyst or a platinum / ruthenium catalyst, and the air electrode is supported on a carbon-based porous catalyst support for a fuel cell manufactured by the platinum catalyst or the platinum alloy catalyst, respectively.

Here, the amount of platinum contained in the anode is preferably 20 to 50 parts by weight based on 100 parts by weight of the supported catalyst composed of the carbon support and the catalyst, and the content of the platinum or platinum-based alloy supported on the cathode is preferably 20 to 50 parts by weight Do.

When the content of the platinum catalyst is less than the lower limit of the above range, there arises a problem that the electrochemical catalytic activity of the electrode is lowered. When the content exceeds the upper limit of the above range, the amount of catalyst used becomes excessively high, which is not preferable .

In addition, the present invention includes a direct methanol fuel cell employing the above-described nano-porous carbonaceous catalyst carrier for a fuel cell.

The direct methanol fuel cell includes a fuel electrode; Air pole; Polymer Electrolyte Membrane; And a separation plate, wherein the fuel electrode is supported on a platinum / ruthenium catalyst, and the air electrode is supported on a carbon-based porous catalyst support for a fuel cell, . ≪ / RTI >

Here, the content of platinum / ruthenium contained in the fuel electrode is preferably 40 to 85 parts by weight based on 100 parts by weight of the supported catalyst composed of the carbon support and the catalyst, and the content of the platinum or platinum based alloy carried on the air electrode is 40 to 85 wt% Addition is preferable.

If the amount of the platinum catalyst is below the lower limit of the range, there is a problem that the electrochemical catalytic activity of the electrode is lowered. If the upper limit of the above range is exceeded, the amount of catalyst used becomes excessively high, which is not preferable .

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are only for describing the present invention in more detail and that the scope of the present invention is not limited by these embodiments in accordance with the gist of the present invention .

Example  1: Nanoporous for fuel cell using rice husk Carbon system  catalyst Carrier  Produce

A manufacturing process of a carbon-based porous catalyst carrier for a fuel cell using rice hulls is shown in Fig. The carbonaceous catalyst carrier for a rice hull-use fuel cell produced in this embodiment is obtained by washing rice hulls with distilled water and drying at 110 ° C for 10-24 hours, followed by pulverizing to a size of 0.1-5 μm by a pulverizer, After the carburization for 5 hours, it was pyrolyzed and carbonized at 500-800 ℃ for 1-5 hours to prepare a silica / carbon composite.

The silica / carbon composite prepared above was treated with hydrofluoric acid and sulfuric acid to prepare a carbon-based porous catalyst carrier for a fuel cell.

The silica / carbon composite is treated with hydrofluoric acid and sulfuric acid at 50-80 ° C for 1-5 hours and then activated with carbon dioxide (CO ₂ ) gas at 900-1100 ° C for 1-5 hours to obtain activated carbon porous catalyst bed A step of producing retardation was carried out.

The above process of producing a carbon-based porous catalyst carrier for a fuel cell using rice hulls is schematically shown in FIG. 2 for easy understanding. The silica / carbon composite catalyst for fuel cell is prepared by etching pyrolysis of the rice husks to remove organic substances and carbonization, and the silica / carbon composite is treated with hydrofluoric acid and sulfuric acid to remove the silica. A catalyst supporting body is obtained and activated again with carbon dioxide (CO ₂ ) gas at 900-1100 ° C for 1-5 hours to obtain an activated carbon porous catalyst supporting body for a fuel cell.

It can be seen that small projections are formed on the surface of the raw rice husk not subjected to the heat treatment (Fig. 3 (1)). The rice hulls obtained by oxidizing the rice hulls at 700 ° C. for 2 hours in the air are mostly composed of silica, and the size of these silica particles is about 20-100 nm (FIG. 3 (2)). The results of X-ray fluorescence analysis (XRF) of silica / carbon porous catalyst carrier treated with sulfuric acid in nitrogen atmosphere at 700 ℃ showed 66.5 weight ratio of carbon and 29.3 weight ratio of silica.

The rice husks obtained by heat treatment of rice hulls at 700 ° C in a nitrogen atmosphere with hydrofluoric acid and sulfuric acid were found to consist of roughened carbon particles (FIG. 3 (3)).

Raw rice without heat treatment (RH Raw), rice husk (RH 260air) heat-treated at 260 ° C in air, rice husk (RH 700HF) obtained by hydrofluoric acid treatment and sulfuric acid treatment at 700 ° C in a nitrogen atmosphere, measuring the nitrogen adsorption-desorption isotherms and the resulting heat-treated rice hull to 700 ℃ at 50-80 ℃ treatment 1-5 hours hydrofluoric acid and sulfuric acid and activated with CO ₂ gas for 1-5 hours at 900-1100 ℃ rice hulls (RH 900CO2) obtained And the pore distribution was measured. The surface area, volume, and pore size of the mesopores and micropores obtained using the measurement values obtained by the above method are shown in FIG.

It can be seen in FIG. 3 that the BET surface areas of the four types of treated rice hulls, namely RH Raw, RH 260air, RH 700HF and RH 900CO2, increase to 1.3, 19.6, 393.3 and 1569 m ² / g and increase in total pore volume, respectively have.

Example  2: Preparation of catalyst for fuel cell using rice husk

A platinum / ruthenium catalyst, a platinum catalyst or a platinum alloy catalyst is supported on the nano-porous carbonaceous catalyst carrier for fuel cell according to the present invention manufactured using rice hulls. Using the prepared catalyst carrier, platinum chloride hydrate (H ₂ PtCl ₆ ) ₅ · 6H ₂ O (Aldrich)) and ruthenium chloride hydrate (RuCl ₃ ) 3H ₂ O (Aldrich)). More specifically, a solution prepared by dispersing porous carbon in distilled water and dispersing with an ultrasonic dispersing apparatus and a solution prepared by dissolving chloroplatinic hydrate or ruthenium chloride hydrate in distilled water were mixed and stirred for 24 hours, and 0.1-1 M NaBH ₄ solution was used as a reducing agent The Pt, Ru, or Pt-Ru metal was reacted for 20-60 minutes to be liquid-reduced on the support. The supported catalyst was filtered with a filter paper, washed with distilled water for 3 hours (25-50 ° C) and dried in a vacuum dryer at 60-85 ° C for 5-15 hours to prepare a catalyst. The supported platinum, ruthenium or platinum / ruthenium loading was adjusted to a weight ratio of 40-85.

A commercially available carbon supported platinum / ruthenium catalyst A (Com.) And a catalyst prepared by the above method according to the present invention, that is, a rice husk carrying platinum / ruthenium catalyst B obtained by treating hydrocarbons heat treated at 700 ° C. with hydrofluoric acid and sulfuric acid in a nitrogen atmosphere (PtRu / RH 700HF) is shown in Fig. The diffraction peaks shown in FIG. 5 represent (111), (200), (220) and (311) planes, which represent platinum crystal planes of a faced-centered cubic structure. Catalyst Com. And PtRu / RH 700HF were 2.1 and 2.3 nm, respectively. The results are also in agreement with the UHR-SEM analysis results shown in FIG. 6, and the particle size of the catalyst prepared by using rice husk is similar to the crystal size of the commercial catalyst of H Company H of 2.1 nm .

The size of the catalyst crystal grains was calculated by the following Scherrer equation as the peak of the platinum (220) plane.

L = (0.9? _Kal ) / (B ₂ ? _Cos ? _Max )

Where L is the crystal size, λ is the wavelength of the Kα line, θ is the Bragg angle, and B is the half-width (radian).

6 (1)), and a catalyst prepared by the above method according to the present invention, that is, a catalyst obtained by hydrofluoric acid treatment and sulfuric acid treatment of rice husk heat-treated at 700 ° C in a nitrogen atmosphere (SE) (left photograph) and transmission (TE) (right photograph) photographed by high resolution scanning microscope (UHR-SEM) of platinum / ruthenium catalyst B (PtRu / RH 700HF) Is shown in Fig. 6, platinum / ruthenium metal catalyst having a size of 2-4 nm is supported on the carbon surface of about 20-40 nm in size. 6 (1)) and the catalyst (FIG. 6 (2)) supported on the commercial catalyst of H Company of foreign countries are compared with the metal particles carried on the surface of the catalyst according to the present invention (2) of FIG. 6) are distributed in a very uniform manner, and the metal catalyst supported on the surface of the commercial catalyst carrier catalyst (FIG. 6 (1) It can be seen that there are a considerable number of carriers. That is, it can be seen that the metal catalyst supported on the catalyst carrier according to the present invention is more uniformly supported.

Example  3: Catalyst for fuel cell using rice husk Carrier  evaluation

A catalyst, distilled water and Nafion solution (20 weight ratio based on catalyst weight) were mixed and dispersed with an ultrasonic disperser to prepare a catalyst slurry for evaluating the performance of the prepared catalyst. The amount of platinum supported on the carbon substrate diffusion layer (GDL) was 1.5-2 mg Pt / cm ² . After coating, only the polymer electrolyte membrane was hot-pressed at a temperature of 120-150 ° C and a pressure of 2-5 MPa. Finally, a membrane / electrode assembly was fabricated using coated polymer membrane and gas diffusion layer. As the gas diffusion layer, water repellent treated anode and Toray 060 and SGL 25BC for air electrode were used, respectively.

The MEA was prepared by using platinum / ruthenium catalyst B (PtRu / RH 700HF), a commercially available carbon supported platinum / ruthenium catalyst A (Com.) And a rice husk supported platinum / ruthenium catalyst B obtained by hydrofluoric acid treatment and sulfuric acid treatment of rice husk heat- The IV curves, the output density curves and the anode polarization curves of the unit cells were measured at 1, 2, 3, 5, and 10 M methanol. An IV curve, an output density curve and an anode polarization curve of the unit cell measured at 2 M methanol are shown in FIG. 7 representatively. 7, the unit cell using the catalyst B (PtRu / RH 700HF) according to the present invention had a rated output (0.4 V) and a maximum output of 111 mW / cm ² and 134 (104 mW / cm ² ) (0.295 V) And showed higher output than Catalyst A (Com.). That is, it was confirmed that the platinum / ruthenium catalyst B (PtRu / RH 700HF) using the rice husk according to the present invention had better output characteristics than the commercial catalyst.

The changes in the characteristics of the unit cell according to the methanol concentration using the above catalyst according to the present invention were evaluated and compared with the commercial catalyst, two commercial catalysts A (Com.) And Catalyst B (PtRu / RH 700HF) One unit cell was measured for IV curves, power density and anode polarization curves at five different methanol concentrations (1, 2, 3, 5, and 10 M methanol). The maximum power density according to the methanol concentration (1, 2, 3, 5, 10 M) of the unit cell manufactured using the two catalysts is shown in FIG. 8, it was found that the maximum power density of the unit cell using the catalyst B (PtRu / RH 700HF) according to the present invention exhibited a higher maximum power density at almost all the methanol concentrations than that of the commercial catalyst A (Com.). That is, it was confirmed that the platinum / ruthenium catalyst B (PtRu / RH 700HF) using the rice husk according to the present invention had better output characteristics than the commercial catalyst A (Com.).

As described above, preferred embodiments of the present invention have been disclosed in the present specification and drawings, and although specific terms have been used, they have been used only in a general sense to easily describe the technical contents of the present invention and to facilitate understanding of the invention , And are not intended to limit the scope of the present invention.

It is to be understood by those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

Claims (18)

Washing the rice or haploid plants with distilled water and drying them;
A second step of crushing the rice or horsetail plants dried in the first step with a crusher;
A third step of heat treating the rice or horsetail plant pulverized in the second step;
A fourth step of carbonizing the rice or horsetail plants thermally treated in the third step to produce a silica / carbon composite;
A fifth step of subjecting the silica / carbon composite prepared in the fourth step to primary acid treatment; And a sixth step of subjecting the silica / carbon composite subjected to the first acid treatment in the fourth step to a second acid treatment to produce a carbon-based catalyst carrier from which the silica is extracted. (Method for producing catalyst carrier).
The method according to claim 1,
Further comprising the step of activating the carbon-based catalyst carrier with carbon dioxide (CO ₂ ) gas.
3. The method of claim 2,
Wherein the activation is performed at a temperature of 900 to 1100 DEG C for 1 to 5 hours.
The method according to claim 1,
Wherein the drying in the first step is performed at 110 ° C for 10 to 24 hours.
The method according to claim 1,
Wherein the rice or horsetail plants are ground to a particle size of 0.1 to 5 占 퐉 in the second step.
The method according to claim 1,
Wherein the heat treatment is performed at 200 to 300 ° C for 1 to 5 hours in the third step.
The method according to claim 1,
Wherein the carbonization treatment is performed at 500 to 800 ° C for 1 to 5 hours in the fourth step.
The method according to claim 1,
Wherein the silica / carbon composite is subjected to primary acid treatment with hydrofluoric acid in the fifth step.
The method according to claim 1,
Wherein the primary acid treatment is carried out at a temperature of 50 to 80 캜 for 1 to 5 hours.
The method according to claim 1,
Wherein the silica / carbon composite subjected to the first acid treatment in the fifth step is selected from the group consisting of sulfuric acid, nitric acid, and hydrochloric acid and subjected to a secondary acid treatment.
The method according to claim 1,
Wherein the secondary acid treatment is carried out at a temperature of 50 to 80 캜 for 1 to 5 hours.
The method according to claim 1,
Wherein the paddy plant is selected from the group consisting of rice, bamboo, reeds, water bodies, strips, blood, grasses, saddle grass, grass, string, millet, sorghum, sugarcane, corn, wheat, barley, oats, Wherein the plant is selected from the group consisting of horseshoe crab and beetle.
The method according to claim 1,
Wherein the rice plant is rice hull. ≪ RTI ID = 0.0 > 8. < / RTI >
A nano-porous carbonaceous catalyst carrier for a fuel cell produced by employing the production method of any one of claims 1 to 13.
Fuel electrode;
Air pole;
Polymer Electrolyte Membrane; And a separation plate,
The anode may be a platinum catalyst or a platinum / ruthenium catalyst,
Wherein the air electrode comprises a platinum catalyst or a platinum based alloy catalyst supported on the carbon-based porous catalyst carrier for a fuel cell according to claim 14, respectively.
16. The method of claim 15,
Wherein the content of the platinum contained in the fuel electrode is 20 to 50 parts by weight, and the content of the platinum or platinum-based alloy carried on the air electrode is 20 to 50 parts by weight.
Fuel electrode;
Air pole;
Polymer Electrolyte Membrane; And a separation plate,
The fuel electrode may be a platinum / ruthenium catalyst,
Wherein the air electrode comprises a platinum catalyst or a platinum based alloy catalyst supported on the carbon-based porous catalyst carrier for a fuel cell according to claim 14, respectively.
18. The method of claim 17,
Wherein the content of platinum / ruthenium in the fuel electrode is 40 to 85 parts by weight, and the content of platinum or platinum-based alloy carried on the cathode is 40 to 85 parts by weight.

Images