Porous carbon support, method of manufacturing a porous carbon support, and fuel cell catalyst using the same

Abstract

The present invention provides a porous carbon support, a method of manufacturing the porous carbon support, and a fuel cell catalyst having platinum-containing metal particles supported on the porous carbon support. In the porous carbon support, the surface area of pores having a size of 0 nm (inclusive of the lower limit) to 2 nm (inclusive of the upper limit) is 100 m 2 / g to 300 m 2 / g; and the surface area of pores having a size of 2 nm to 5 nm is 100 m 2 / g to 800 m 2 / g, as obtained from an adsorption isotherm using a Barrett-Joyner-Halenda (BJH) desorption method based on the Harkins-Jura equation.

Description

TECHNICAL FIELD

[0001] The present application relates to a porous carbon support, a method of manufacturing a porous carbon support, and a fuel cell catalyst using the same, and more particularly, to a porous carbon support capable of effectively supporting metal particles including platinum (Pt) due to its high porosity and crystallinity, a method of manufacturing a porous carbon support, and a fuel cell catalyst having improved stability and durability by including the same.

[0002] Two national projects related to the present application supported by the government will be described below.

[0003] Project Unique Number: 1711160139

[0004] Project serial number: 2021M3H4A1A02049886

[0005] Government agency: Ministry of Science and Information Technology

[0006] Project management professional agency: Korea National Research Foundation

[0007] Research business name: Core technology development project / Nano and material technology development project / Future technology research center / Pioneer

[0008] Project name: Development of synthesis technology of high-crystalline porous carbon support based on low-temperature processing

[0009] Contribution rate: 1 / 2

[0010] Guiding agency: Carbon Studio Co., Ltd.

[0011] Research period: January 1, 2022-December 31, 2022

[0012] Project Unique Number: 1415178031

[0013] Project serial number: 20011473

[0014] Government agency: Ministry of Trade, Industry and Energy

[0015] Project management professional agency: Korea Institute of Industrial Technology Planning Evaluation

[0016] Research business name: Material parts technology development project / Material parts heterogeneous technology fusion

[0017] Project name: Core technology development of production of carbon support for electrode catalyst for fuel cell to realize Hydrogen Society

[0018] Contribution rate: 1 / 2

[0019] Guiding organization: Carbon Studio Co., Ltd.

[0020] Research period: January 1, 2022 - December 31, 2022 BACKGROUND

[0021] A polymer electrolyte membrane fuel cell (PEMFC) is a power generation system that generates electricity by a catalytic mediator of an electrochemical reaction of hydrogen and oxygen. The PEMFC has a structure in which a cation exchange membrane is located between an oxidation electrode (hereinafter, a negative electrode) and a reduction electrode (hereinafter, a positive electrode). Since such a PEMFC is suitable for transportation vehicles, it is expected to have a high demand in the future.

[0022] A catalyst is a key element that determines the performance of a fuel cell. A conventional PEMFC catalyst uses an amorphous carbon support to load metal particles including platinum, but there are many problems.

[0023] For example, when a transportation fuel cell having a platinum-based catalyst is driven, at the start of operation, the positive electrode is affected by a high voltage applied thereto, oxidation and irreversible deterioration occur on the positive electrode, and the negative electrode suffers from a sharp voltage rise due to intermittent lack of hydrogen in the fuel cell stack unit. The voltage rise deteriorates the carbon support of the catalyst. This in turn causes platinum nanoparticles to detach from the surface of the carbon support and reduce the active surface area of the platinum particles, thereby reducing the stability and durability of the fuel cell as a whole.

[0024] To solve this problem, recent research has been conducted to improve the dispersion of platinum particles by forming additional pores in the carbon support to increase catalytic activity. However, when a chemical reaction is forcibly induced to form pores in carbon as in the conventional steam activation method, the reaction proceeds randomly on the surface of carbon, making it difficult to control the size distribution of the formed pores. In addition, there is no distinction between the crystalline and amorphous regions of carbon during the activation reaction and the formation of pores, so the overall crystallinity decreases after the formation of pores. Therefore, such processing exhibits a trade off relationship between porosity and crystallinity. In other words, even when the porosity and dispersion of platinum particles are improved by the activation process, there is a disadvantage that the stability and durability of the fuel cell operation are reduced due to the decrease in crystallinity. SUMMARY

[0025] TECHNICAL PROBLEM

[0026] An object of the present application is to provide a porous carbon support having high crystallinity and micropores capable of efficiently supporting metal particles including platinum, and a manufacturing method thereof.

[0027] Another object of the present application is to provide a fuel cell catalyst having improved stability and durability by using the porous carbon support.

[0028] However, technical subjects of the present application are not limited to the above, and the following description includes other matters that can be clearly understood by those skilled in the art.

[0029] Technical Solution

[0030] The present application provides a porous carbon support having pores with a specific surface area defined as follows: a surface area of pores in the size range of greater than 0 nm to less than 2 nm obtained by t-plot method based on Harkins-Jura equation in adsorption isotherm analysis in the thickness (t) range of 0.35 nm to 0.4 nm in the porous carbon support is 100 m 2 / g to 300 m 2 / g, a surface area of pores in the size range of 2 nm or more to 5 nm or less obtained by Barrett-Joyner-Halenda (BJH) desorption method based on Harkins-Jura equation in adsorption isotherm analysis is 100 m 2 / g to 800 m 2 / g.

[0031] The ratio of the surface area of pores in the size range of 2 nm or more to 5 nm or less obtained by BJH desorption method based on Harkins-Jura equation in adsorption isotherm analysis to the total specific surface area based on BET in the porous carbon support can range from 0.2 to 1.

[0032] The surface area of pores in the size range of 2 nm or more to 100 nm or less obtained from the porous carbon support by BJH desorption method based on Harkins-Jura equation can range from 200 m 2 / g to 2000 m 2 / g.

[0033] The ratio of the surface area of pores in the size range of 2 nm or more to 100 nm or less obtained by BJH desorption method based on Harkins-Jura equation in adsorption isotherm analysis to the total specific surface area based on BET in the porous carbon support can range from 0.5 to 2.

[0034] The tap density of the porous carbon support can range from 0.05 g / cm 3 to 0.5 g / cm 3 .

[0035] The true density of the porous carbon support can range from 2.1 g / cm 3 -4 g / cm 3 .

[0036] The average size of the primary particles of the porous carbon support can range from 10 nm to 30 nm.

[0037] The porous carbon support can have a layered structure.

[0038] The average interlayer spacing (d 002 ) of the porous carbon support measured by X-ray diffraction can range from 0.335 nm to 0.355 nm, and the a-axis lattice constant (La) can range from 4 nm to 10 nm.

[0039] The average number of graphene layers of the porous carbon support can be 6 to 20 layers.

[0040] The mass reduction rate of the porous carbon support measured by thermogravimetric analysis (TGA) at a temperature range of 500℃ to 700℃ can range from 0% to 30%.

[0041] The lowest temperature of the porous carbon support obtained by derivative thermogravimetric analysis (DTG) analysis can range from 740℃ to 850℃.

[0042] Further, the present application provides a method of manufacturing a porous carbon support, the method comprising:

[0043] (a) heat-treating a carbon material at a temperature range of 1500℃ to 3000℃ to remove impurities and crystallize the carbon material;

[0044] (b) pretreating the resulting crystallized carbon material in an atmosphere containing at least one heteroatom selected from the group consisting of boron, carbon, nitrogen, oxygen, phosphorus, and sulfur to introduce activated sites doped with the heteroatom into the crystallized carbon material;

[0045] (c) mixing the carbon material having the activated sites with an additive including an organic surfactant, and then heat-treating the mixture to remove the heteroatom and activate the carbon material;

[0046] (d) washing and drying the activated carbon material.

[0047] Further, the present application provides a fuel cell catalyst having metal particles including platinum supported on a porous carbon support.

[0048] Advantages

[0049] The porous carbon support of the present invention has a highly porous structure suitable for loading metal particles including platinum and exhibits high crystallinity, which makes the porous carbon support exhibit excellent stability and durability, as well as high efficiency and cost efficiency when used as a fuel cell catalyst.

[0050] According to the manufacturing method of the present invention, the crystallinity and porosity can be simultaneously improved by introducing heteroatoms into the carbon material and then removing the heteroatoms. Therefore, porous carbon supports with high crystallinity and porosity can be obtained in high yield.

[0051] The fuel cell catalyst of the present invention has platinum-containing metal particles of suitable size to be effectively dispersed within the pores of a porous carbon support, which enhances catalyst activity. Therefore, the characteristics of fuel cells using the same catalyst of the present invention can be improved.

[0052] However, the effects of the present invention are not limited thereto, and even when the expected effects are not directly described below, the expected effects derived from the technical features of the present invention may be included. Attached Figure Description

[0053] Figure 1 (a) to (e) are SEM (scanning electron microscope) images of porous carbon supports according to Examples 1-1 to 1-2 or Comparative Examples 1-1 to 1-3, respectively.

[0054] Figure 2 (a) to (e) are TEM (transmission electron microscopy) images of porous carbon supports according to Examples 1-1 to 1-2 or Comparative Examples 1-1 to 1-3, respectively.

[0055] Figure 3 (a) to (e) are XRD patterns of porous carbon supports according to Examples 1-1 to 1-2 or Comparative Examples 1-1 to 1-3, respectively;

[0056] Figure 4 (a) is a TGA diagram of the porous carbon support according to Examples 1-1 to 1-2 and Comparative Examples 1-1 to 1-3. Figure 4 (b) is a DTG diagram of the porous carbon support according to Examples 1-1 to 1-2 and Comparative Examples 1-1 to 1-3;

[0057] Figure 5 (a) to (e) are TEM images of catalysts for fuel cells according to Examples 2-1 to 2-2 and Comparative Examples 2-1 to 2-3, respectively. Detailed Implementation

[0058] The present invention provides a porous carbon support in which the surface area of pores ranging from greater than 0 nm to less than 2 nm in size, obtained through analysis of adsorption isotherms in a thickness (t) range of 0.35 nm to 0.4 nm by the t-plot method based on the Harkins-Jura equation, ranges from 100 m 2 / g to 300 m 2 / g. The surface area of pores ranging from 2 nm or more to 5 nm or less, obtained through analysis of adsorption isotherms by the Barrett-Joyner-Halenda (BJH) desorption method based on the Harkins-Jura equation, ranges from 100 m 2 / g to 800 m 2 / g.

[0059] The porous carbon support of the present invention has a highly porous structure suitable for loading platinum particles, and exhibits high crystallinity, so that in the case of using the carbon support as a fuel cell catalyst, stability and durability are improved, while high efficiency, low cost effects can be achieved.

[0060] The term "isothermal adsorption by the t-plot method based on the Harkins-Jura equation" in the present invention refers to a method well known in the art for calculating the surface area of pores in a porous carbon support. Specifically, the relative pressure (P / Po) on the x-axis of nitrogen adsorption isotherms is converted into the thickness of a gas adsorption layer based on the Harkins-Jura equation to obtain a t-plot formula, and the surface area of pores is calculated by determining the y-intercept of a trend line with respect to a specific thickness range on the x-axis using the obtained t-plot formula (Harkins-Jura equation: t = [13.99 / {0.034-log(P / Po)} 0.5 , P / Po: relative pressure, t: gas adsorption thickness).

[0061] The "isothermal adsorption by the t-plot method based on the Harkins-Jura equation" can calculate the surface area of pores that can take a negative value depending on the gas adsorption thickness (t), so it is important to select an appropriate thickness range depending on the adsorption characteristics of the material. Whether the thickness range is appropriate can be verified based on whether the surface area of the pores is positive and based on the correlation coefficient (Removal of Pharmaceuticals and Personal Care Products from Aqueous Solutions with Metal-Organic Frameworks, Isil Akpinar, UCL, 2017, pp. 55 and 83).

[0062] The correlation coefficient here indicates the degree to which the corresponding index reflects the original data, and can be obtained by applying the calculation method of the Pearson Correlation Coefficient (PCC) in the trend line. When the calculated surface area of the pores is a positive value, the determination result is reliable. When the calculated correlation coefficient in the process is a value closer to 1, it is determined that the trend line of the t-plot formula can well reflect the original data (The dual capture of AsV and AsIII by UiO-66 and analogues, Cornelius O. Audu etc., The Royal Society of Chemistry 2016, p. 1), (Hierarchically Porous Organic Polymers: Highly Enhanced Gas Uptake and Transport through TEM templated Synthesis, Sanjiban Chakraborty, ESI for Chem, 2014, p. 2).

[0063] When the surface area of the micropores with a size range of greater than 0 nm to less than 2 nm is calculated, the t-plot method can be easily used. The porous carbon carrier of the present application can have micropores with a size range of greater than 0 nm to less than 2 nm. The pores of this size range connect the mesopores or macropores with a size range greater than 2 nm, serving as a bridge for the entire pore network inside the porous carbon. According to the calculation of the t-plot method based on the Harkins-Jura equation, it was found that the surface area of the micropores with a size range of greater than 0 nm to less than 2 nm obtained in the range of a gas adsorption thickness (t) of 0.35 nm-0.4 nm has a positive value.

[0064] In addition, when the micropores with a size range of greater than 0 nm to less than 2 nm of the porous carbon carrier are studied based on the t-plot method in the thickness (t) range of 0.35 nm-0.4 nm, the value of the correlation coefficient is 0.9990 or more, closer to the value of 1, and can be considered to be almost consistent with the true value.

[0065] The term "isothermal adsorption of BJH desorption method based on Harkins-Jura equation" in the present invention is another method of calculating the surface area of pores in the porous carbon support, in which the nitrogen desorption isotherm is converted into a BJH desorption curve based on the Harkins-Jura equation, which is well known in the art, and thus the details of the method are not described herein. The BJH desorption method can be used to calculate the surface area of pores having a size range of 2 nm or more. In one example of catalyst synthesis, pores having a size range of 2 nm to 5 nm among pores having a size range of 2 nm or more are the portion for loading platinum particles, wherein the characteristics of the loaded platinum particles are determined by the high porosity of the pores in this size range.

[0066] The surface area of pores having a size range of greater than 0 nm to less than 2 nm of the porous carbon support of the present invention according to the t-plot method based on the Harkins-Jura equation obtained in a thickness (t) range of 0.35 nm to 0.4 nm can range from 100 m 2 / g to 300 m 2 / g. In the case of pores smaller than the above size, there is an insufficient amount of micropores connecting mesopores or macropores, and thus gas is not easily transported during the operation of a fuel cell. However, micropores of this size only serve as a bridge between mesopores or macropores, and are not the portion for loading platinum particles, and thus the specific surface area of pores capable of loading platinum particles can be insufficient when the pores are larger than the micropores. That is, it is necessary to maintain a suitable specific surface area within the above range.

[0067] Specifically, the range can be 100 m 2 / g to 250 m 2 / g, or 100 m 2 / g to 200 m 2 / g, or 120 m 2 / g to 190 m 2 / g, or 135 m 2 / g to 155 m 2 / g, or 165 m 2 / g to 185 m 2 / g.

[0068] The surface area of pores having a size range of 2 nm or more to 5 nm or less of the porous carbon support of the present invention according to the BJH desorption method based on the Harkins-Jura equation can range from 100 m 2 / g to 800 m 2 / g. In the case where the surface area is less than the above range, the specific surface area capable of being loaded is insufficient, so that the metal particles including platinum are not loaded on the surface or are loaded in an agglomerated manner, which decreases the catalyst performance or makes it difficult to maintain the morphology, and eventually leads to stability and durability problems. Therefore, this is undesirable. In addition, in the case where the surface area exceeds the above range, the specific surface area of the pores capable of loading the metal particles is excessively large, so that platinum particles having a size range of less than 3 nm can be loaded. That is, it is necessary to maintain a proper specific surface area within the above range.

[0069] Specifically, the range of the area can be 100 m 2 / g-600 m 2 / g, or 200 m 2 / g-500 m 2 / g, or 200 m 2 / g-250 m 2 / g, or 200 m 2 / g-230 m 2 / g, or 400 m 2 / g-480 m 2 / g, or 440 m 2 / g-480 m 2 / g.

[0070] According to an embodiment of the present application, the ratio of the surface area of the pores having a size range of 2 nm or more to 5 nm or less, obtained from the adsorption isotherm analysis based on the BJH desorption method based on the Harkins-Jura equation, to the total specific surface area based on BET, of the porous carbon support, can be in the range of 0.2-1. Accordingly, the present application allows the occupied total specific surface area based on BET to reach a large level, and can effectively load platinum particles having a size range of 3 nm-4 nm suitable for a fuel cell.

[0071] Specifically, the ratio can be in the range of 0.2-0.8, or 0.3-0.7, or 0.35-0.65, or 0.35-0.4 or 0.6-0.65.

[0072] The porous carbon support of the present application has a pore network structure in which mesopores or macropores are connected through micropores. In addition to the pores having a size range of 2 nm-5 nm for effective loading of platinum particles, pores having a size range of 2 nm-100 nm also serve as a passage for water drainage in the operation of a fuel cell, and the pores within these ranges are technically helpful for the performance of a fuel cell.

[0073] According to an embodiment of the present application, the range of the surface area of the pores having a size range of 2 nm or more to 100 nm or less, obtained from the adsorption isotherm analysis based on the BJH desorption method based on the Harkins-Jura equation, can be 200 m2 / g-2000m 2 / g. In a case where the range is exceeded, product water generated in the operation of the fuel cell cannot be smoothly discharged using a carbon support having a pore outside the range, and thus the characteristics of the fuel cell cannot be well utilized, which is undesirable.

[0074] Specifically, the range can be 500m 2 / g-1500m 2 / g, or 600m 2 / g-1000m 2 / g, or 600m 2 / g-650m 2 / g or 900m 2 / g-1000m 2 / g.

[0075] According to an embodiment of the present application, the ratio of the surface area of pores having a size of 2 nm or more to 100 nm or less obtained by the analysis of the adsorption isotherm by the BJH desorption method based on the Harkins-Jura equation can be in the range of 0.5-2. In a case where the range is exceeded, product water generated in the operation of the fuel cell cannot be smoothly discharged using a carbon support having a pore outside the range, and thus the characteristics of the fuel cell cannot be well utilized, which is undesirable.

[0076] Specifically, the ratio can be in the range of 0.8-1.8, or 1.0-1.5, or 1.1-1.2 or 1.0-1.2.

[0077] In the present application, the term "tap density" refers to the density of the total volume of the porous carbon support. The term "true density" refers to the density of the volume occupied only by the material in the porous carbon support, which refers to the density of the remaining volume other than the air gap volume in the total volume, which can be measured based on ASTM D8176.

[0078] According to an embodiment of the present application, the tap density can be in the range of 0.05 g / cm 3 -0.5 g / cm 3 , and the true density can be in the range of 2.1 g / cm 3 -4 g / cm 3 . In a case where the range of the tap density or the true density is exceeded, there can be a great difference in the porosity. The difference in the porosity can cause a difference in the oil absorption amount in the preparation of a slurry for the manufacture of a fuel cell. In this case, the manufacturing conditions need to be changed, which can result in low manufacturing efficiency, which is undesirable.

[0079] Specifically, the tap density can be in the range of 0.08 g / cm3 -0.4 g / cm 3 , or 0.08 g / cm 3 -0.3 g / cm 3 , or 0.08 g / cm 3 -0.2 g / cm 3 , or 0.08 g / cm 3 -0.15 g / cm 3 . Specifically, the true density can range from 2.2 g / cm 3 -3.5 g / cm 3 , or 2.6 g / cm 3 -3.1 g / cm 3 , or 2.3 g / cm 3 -2.6 g / cm 3 .

[0080] The average size of the primary particles of the porous carbon support can range from 10 nm to 30 nm. In cases outside of this range, slurry for fuel cell manufacturing is difficult to form a uniform dispersion, for example, agglomerate formation occurs, so that the catalyst performance is reduced, or it is difficult to maintain the catalyst morphology, so that the electrochemical stability can be reduced, which is undesirable. Specifically, the size range can be 15 nm to 30 nm or 20 nm to 30 nm. The average size of the primary particles can be measured based on ASTM D3849.

[0081] Graphite is a crystal form in a hexagonal close-packed structure in which regular hexagonal planes are stacked in parallel, and the average interlayer spacing (d 002 ) is smaller, the a-axis lattice constant (La) is larger, the average number of graphene layers in the structure is more, and the crystallinity of the graphite is higher. The average interlayer spacing (d 002 ), the a-axis lattice constant (La), and the average number of graphene layers can be measured based on ASTM D5187 using X-ray diffraction.

[0082] According to one embodiment of the present application, the average interlayer spacing (d 002 ) measured by X-ray diffraction can range from 0.335 nm to 0.355 nm, the a-axis lattice constant (La) can range from 4 nm to 10 nm, and the average number of graphene layers can range from 6 to 20. Such a porous carbon support tends to have a very narrow interlayer spacing, a large number of stacked graphites, and a thicker graphite thickness, and the average width of the graphite is larger than that of ordinary graphite, so the crystallinity is significantly improved, which means that the carbon support has oxidation resistance and minimizes degradation during fuel cell operation. In cases outside of this range, the desired effects of the present application can not be obtained, which is undesirable.

[0083] In the porous carbon support of the present application, more specifically, the average interlayer spacing (d 002 ) measured by using X-ray diffraction can range from 0.340 nm to 0.352 nm, or from 0.342 nm to 0.350 nm, or from 0.342 nm to 0.347 nm or from 0.348 nm to 0.350 nm. Specifically, the a-axis lattice constant (La) can range from 6 nm to 9 nm, or from 7 nm to 9 nm, or from 7 nm to 8 nm or from 8 nm to 9 nm. Specifically, the average number of layers of the graphene layer can range from 7 to 15 or from 7.5 to 12 or from 8 to 9 or from 10 to 11.

[0084] The term "Thermogravimetric Analysis (TGA)" in the present application means measuring the rate of mass change of a sample as a function of temperature or time under the action of temperature. The oxidation resistance of carbon can be determined by TGA under an oxidizing gas atmosphere. The slower the mass reduction in a high temperature range means the better the oxidation resistance. Derivative Thermogravimetric Analysis (DTG) can be performed by TGA, and the results can be measured based on ASTM E1131.

[0085] According to one embodiment of the present application, the porous carbon support has a mass reduction rate in the temperature range of 500°C to 700°C of 0% to 30% measured by TGA, which means that the carbon support has excellent oxidation resistance so that carbon deterioration can be minimized when the carbon support is used as a catalyst for a fuel cell, and ultimately stability and durability can be achieved. More specifically, the mass reduction rate in the temperature range of 500°C to 700°C can range from 2% to 28% or from 10% to 28% or from 15% to 25% or from 18% to 20% or from 21% to 23%.

[0086] According to one embodiment of the present application, the temperature at which the mass of the carbon material is found to be reduced by 30% from the total amount is in the high temperature range of 700°C to 740°C by TGA. The experimental carbon support exhibits excellent oxidation resistance, so that carbon deterioration can be minimized when used as a catalyst for a fuel cell, and ultimately stability and durability can be achieved. More specifically, the temperature range in which the mass of the carbon material is found to be reduced by 30% from the total amount can range from 705°C to 730°C or from 710°C to 715°C or from 715°C to 725°C.

[0087] According to one embodiment of the present application, the minimum temperature of the porous carbon support obtained by DTG is in the range of 740°C to 850°C, which means that the carbon support has excellent oxidation resistance so that heat generation of carbon can be minimized when the carbon support is used as a catalyst for a fuel cell, and ultimately stability and durability can be achieved. Specifically, the temperature range can be 750°C to 820°C or 750°C to 780°C or 750°C to 760°C or 770°C to 780°C.

[0088] Meanwhile, the present application provides a catalyst for a fuel cell, in which a porous carbon support is used as a catalyst support for a fuel cell, and metal particles including platinum particles are supported on the porous carbon support.

[0089] The catalyst for a fuel cell of the present application is formed by effectively dispersing metal particles including platinum of a suitable size into the pores of a porous carbon support, which improves the catalyst activity, thereby improving the characteristics of a fuel cell using the catalyst.

[0090] According to one embodiment of the present application, the metal particles can be any one selected from the group consisting of Pt, Ru, Sn, Pd, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Mo, Se, W, Ir, Os, Rh, Nb, Ta, Zr, and Pb, or a mixture of two or more metals.

[0091] Specifically, the catalyst for a fuel cell of the present application can be an electrocatalyst for a fuel cell. The electrode can be a cathode or an anode, and preferably can be an anode.

[0092] According to one embodiment of the present application, the fuel cell can be a polymer electrolyte fuel cell, but is not limited thereto.

[0093] Meanwhile, the present application provides a method, the method comprising:

[0094] (a) heat-treating a carbon material at a temperature range of 1500°C to 3000°C to remove impurities and crystallize the material;

[0095] (b) pre-treating the resulting crystallized carbon material in an atmosphere containing at least one heteroatom selected from the group consisting of boron, carbon, nitrogen, oxygen, phosphorus, and sulfur, to introduce activated sites doped with the heteroatom into the crystallized carbon material;

[0096] (c) mixing the carbon material having the activated sites with an additive including an organic surfactant, and then heat-treating the mixture to remove the heteroatom and activate the carbon material;

[0097] (d) washing and drying the activated carbon material.

[0098] In the manufacturing method of the present application, the substitution of heteroatoms in the molecular structure of carbon makes the substitution sites relatively unstable, and subsequently when a chemical reaction such as an activation process is performed, a relatively high activation reaction occurrence rate can be induced at the unstable sites, and thus not only crystallinity but also a higher yield can be achieved. These sites where the heteroatoms are introduced also serve as sites for micropore formation. Thus, a porous carbon support can be manufactured in which the carbon support has a high porosity structure suitable for loading platinum particles and also exhibits high crystallinity, and thus when the carbon support is used as a catalyst for a fuel cell, the stability and durability of the catalyst are improved, and at the same time, a high efficiency, low cost effect can be achieved.

[0099] Step (a) is a step of heat-treating a carbon material, removing impurities from the material, and crystallizing the material. Through this step, heteroatoms can be effectively penetrated into the internal structure of the carbon material (step (b)). Here, the impurities are substances other than carbon present on the surface or inside of the carbon material, and examples of the impurities can be petroleum residues or other functional groups, but are not limited thereto. In step (a), as the lattice constant of the carbon material increases, partial or complete crystallization can be performed.

[0100] In one embodiment of the present application, the carbon material can be amorphous carbon, such as hard carbon (cellulose, phenol resin, and isotropic pitch) and soft carbon (mesophase pitch and needle coke; for example, crystalline carbon such as artificial graphite and natural graphite, specifically, amorphous carbon, and more specifically, soft carbon. Soft carbon exhibits relatively stronger anisotropy than hard carbon, and the planar layers of carbon are arranged in parallel, so that crystallization, that is, graphitization, can be easily performed by heat treatment at 1500°C or higher. In some cases, the result can be CNT (carbon nano tube) or CNF (carbon nano fiber).

[0101] In one embodiment of the present application, step (a) can be performed at a temperature range of 1500°C to 3000°C for 10 minutes or more under vacuum or a nitrogen atmosphere or under an atmosphere of a noble gas such as argon, neon, and helium. These conditions are designed to crystallize the carbon material and remove impurities other than carbon present in the carbon material, and when the conditions are exceeded, the object of the present application can not be achieved, which is undesirable. Specifically, the step can be performed at a temperature range of 1500°C to 2000°C for 10 minutes to 100 minutes under vacuum or a nitrogen atmosphere or under a noble gas atmosphere, and more specifically, the step can be performed at a temperature range of 1500°C to 2000°C or 2100°C to 2500°C for 10 minutes to 50 minutes under vacuum or a nitrogen atmosphere or under a noble gas atmosphere.

[0102] In one embodiment of the present application, the impurities are elements other than carbon present in the carbon material, and examples of the impurities can be boron, carbon, nitrogen, oxygen, phosphorus, and sulfur, but are not limited thereto.

[0103] Step (b) is a step of introducing a predetermined heteroatom into the crystallized carbon material after removing the impurities, and in the process, the carbon is selectively substituted with the heteroatom according to the crystallinity in the carbon material, from low crystallinity to high crystallinity. The heteroatom introduction site serves as a starting point of the reaction in the subsequent activation process, and also serves as a place where micropores are formed. In some cases, by adjusting the heteroatom introduction site or frequency, micropores of a desired size can be obtained in a desired portion, so that the pores can be induced to be dispersed in a desired form.

[0104] In one embodiment of the present application, the pre-treatment refers to a heat treatment at a temperature in the range of 400°C to 1200°C for 30 minutes to 600 minutes under an atmosphere containing at least one heteroatom selected from boron, carbon, nitrogen, oxygen, phosphorus, and sulfur supplied at a flow rate in the range of 100 seem to 800 seem or 10 Nm 3 / hour to 100 Nm 3 / hour. In the case of exceeding this condition range, it can be impossible to sufficiently form pores of a desired form at a desired site of the carbon material, so that the intended effect of the present application can not be obtained, which is not desirable. Specifically, the heat treatment can be performed at a temperature in the range of 500°C to 1000°C for 60 minutes to 600 minutes at a flow rate in the range of 100 seem to 600 seem.

[0105] In one embodiment of the present application, the heteroatom can be at least one selected from boron, carbon, nitrogen, oxygen, phosphorus, and sulfur.

[0106] Step (c) is a step of forming micropores after the heteroatom introduced in the pre-treatment serves as a starting point of the reaction, and the heteroatom reacts with an additive at a high temperature, and the reaction thereof can form a microporous structure suitable for a fuel cell. Through the activation process, the heteroatom doped in the portion of the carbon material having low crystallinity is removed. This process can increase the crystallinity and cause the formation of pores of a desired size, and finally a carbon support having high porosity and a crystalline structure can be formed.

[0107] In one embodiment of the present application, based on 100 parts by weight of the carbon material having the activated sites introduced by the pre-treatment, the additive can contain 0.1-10 parts by weight of the inorganic surfactant or the organic surfactant, 0.1-10 parts by weight of the alkali metal hydroxide, and 1-10 parts by weight of the neutralization water. In the case of beyond the range, it can be impossible to obtain the intended effect, which is undesirable. Specifically, based on 100 parts by weight of the carbon material having the activated sites introduced by the pre-treatment, the additive can contain 0.5-5 parts by weight of the organic surfactant, 0.5-5 parts by weight of the alkali metal hydroxide, and 1-8 parts by weight of the neutralization water.

[0108] In one embodiment of the present application, the alkali metal hydroxide can be any one or more selected from the group consisting of LiOH, NaOH, KOH, RbOH, and CsOH, but is not limited thereto.

[0109] In one embodiment of the present application, the organic surfactant can be at least any one selected from the group consisting of SDBS, SDS, LDS, CTAB, DTAB, PVP, Triton X series, Brij series, Tween series, poly(acrylic acid), and polyvinyl alcohol, but is not limited thereto.

[0110] In one embodiment of the present application, the heat treatment can be performed at a temperature range of 500-1000°C for 10-100 minutes under a rare gas atmosphere. In the case of beyond the range of the conditions, it can be impossible to sufficiently form the pores of the desired size at the desired sites, so that it can be impossible to obtain the intended effect of the present application, which is undesirable. Specifically, the step can be performed at a temperature range of 600-900°C for 10-60 minutes or at a temperature range of 600-800°C for 20-40 minutes.

[0111] In step (d), the activated carbon material is washed and dried.

[0112] In one embodiment of the present application, the washing can be performed at a pH condition range of pH 5-pH 9, specifically, at a pH condition range of pH 6-pH 8. In the case of beyond the range, there can be an alkaline material or an acidic material in the carbon material, which has a significant influence on the subsequent loading of the catalyst and the operation of the MEA, which is undesirable.

[0113] In one embodiment of the present application, drying can be performed at a temperature range of 70°C to 120°C under atmospheric pressure for 10 to 20 hours, and then at a temperature range of 80°C to 150°C under vacuum for 1 to 5 hours. In case of exceeding the above conditions, moisture can exist in the carbon material, and the residual moisture can cause inaccuracy in carbon content at the time of synthesizing a catalyst. The step can be performed at a temperature range of 70°C to 100°C under atmospheric pressure for 10 to 15 hours, and then at a temperature range of 80°C to 120°C under vacuum for 1 to 3 hours.

[0114] Hereinafter, an embodiment of the present application is described in detail. However, the following examples are illustrative of the present application, and the description of the present application is not limited to the following examples.

[0115] Example 1-1: Production of a porous carbon support

[0116] (a) The carbon material (KETJENBLACK 600JD) was heated at a temperature range of 2100°C to 2500°C (b) for 10 to 50 minutes under an argon atmosphere and crystallized. Then, the crystallized carbon material was pretreated by heat-treating at a temperature range of 500°C to 1000°C for 1 to 10 hours under an atmosphere of oxygen and nitrogen supplied at a flow rate range of 100 seem to 600 seem. After the pretreatment, the organic surfactant and the neutralizing water were added in the amounts of each weight part described above, respectively, based on 100 parts by weight of the pretreated carbon material, and then the sample was stirred for more than 30 minutes and hot-air dried. The sample was heated at a temperature of more than 600°C for more than 30 minutes under a rare gas atmosphere, and then recovered. After adding hydrochloric acid, ammonia water, and neutralizing water to the sample, the recovered sample was stirred for more than 30 minutes, respectively, and then washed by vacuum filtration. The addition of the hydrochloric acid and the ammonia water was performed once, respectively, and the weight ratio of the hydrochloric acid to the potassium hydroxide was in the range of 1 to 5, and the weight ratio of the ammonia water to the hydrochloric acid was in the range of 1 to 5. The neutralizing water was repeatedly added while stirring until the pH of the solution reached a pH range of pH 6 to pH 8. When the pH reached the desired pH, the sample was dried at a temperature of more than 80°C under atmospheric pressure for more than 12 hours, and then dried at a temperature of more than 100°C under vacuum for more than 1 hour, and then recovered.

[0117] Example 1-2 and Comparative Examples 1-1 to 1-3: Production of a porous carbon support

[0118] The porous carbon supports of Examples 1-2 were manufactured in the same manner as shown in Example 1-1, except for the condition changes between Example 1-1 and Example 1-2 as shown in Table 1. Comparative Example Examples 1-1 toComparative Example 1-3 Each of the carbon materials proposed in Table 1 was used as a porous carbon support.

[0119] [Table 1]

[0120]

[0121] Example 2-1: Production of a catalyst for a fuel cell

[0122] 0.75 g of the porous carbon support manufactured according to Example 1-1 was dispersed in a mixed solution of ethylene glycol (EG) and water. The weight ratio of water to ethylene glycol (EG) in this process was 1. A platinum precursor and a stabilizer were sequentially added to the dispersed solution. In this process, the concentration of the platinum precursor ranged from 10 wt% to 50 wt%, and the weight ranged from 2 g to 10 g, and the concentration of the stabilizer ranged from 10 wt% to 50 wt%, and the weight ranged from 2 g to 10 g. Then, the mixed solution was heated to a temperature range of 90°C to 160°C for 1 hour to 5 hours to allow the platinum particles to be loaded on the surface of the porous carbon support. Thereafter, the mixed solution was cooled to room temperature, the porous carbon support on which the platinum particles were loaded was filtered out, washed sufficiently with purified water, and dried in a vacuum dryer at a temperature of 250°C, and then a catalyst for a fuel cell was manufactured.

[0123] Example 2-2 and Comparative Examples 2-1 to 2-3: Production of a catalyst for a fuel cell

[0124] Example 2-2 and Comparative Examples 2-1 to Comparative Example 2-3 were manufactured in the same method as shown in Example 2-1, except that the porous carbon supports according to Examples 1-1 to 1-2 and Comparative Examples 1-1 to 1-3 were used.

[0125] Experimental Example 1

[0126] According to Examples 1-1 to 1-2 and Comparative Examples 1-1 to 1-3, photographs of the porous carbon supports obtained by using SEM (scanning electron microscope) are shown in (a) to (e) of Figure 1 According to Examples 1-1 to 1-2 and Comparative Examples 1-1 to 1-3, photographs of the porous carbon supports obtained by using TEM (transmission electron microscope) are shown in (a) to (e) of Figure 2 In summary, Comparative Example 1-1 (as shown in (c) of

[0127] In summary, Comparative Example 1-1 (as shown in (c) of Figure 1 In summary, Comparative Example 1-1 (as shown in (c) of Figure 2 In summary, Comparative Example 1-1 (as shown in (c) of Figure 1 In summary, Comparative Example 1-1 (as shown in (c) of Figure 2of (d) and Comparative Examples 1-3 Figure 1 of (e) and Figure 2 of (e) and Comparative Example 1-1 Figure 1 of (a) and Figure 2 of (a) and Comparative Example 1-2 Figure 1 of (b) and Figure 2 of (b) and Comparative Example 1-3 In contrast to Comparative Examples 1-1 to 1-3 (as shown in (a) and (b) of FIG. 1), a thick and clear crystalline layer was not observed, and most of the carbon structure was found to be amorphous. At the same time, in Examples 1-1 to 1-2, both the catalyst-specific thick and clear crystalline layer of carbon and the hollow high-porosity structure of carbon were found to exist. Specifically, inside the carbon, most of the thick and clear crystalline layer was formed inside the carbon, and very low degrees of amorphous structure could be identified in the SEM and TEM photographs.

[0128] Experimental Example 2

[0129] The porous carbon supports of Examples 1-1 to 1-2 and Comparative Examples 1-1 to 1-3 were respectively subjected to pre-treatment and analysis using BET (Brunauer, Emmett, Teller). In the pre-treatment using BET, the carbon support was heated at a temperature of 200°C for 12 hours or more under vacuum conditions, and then impurities including moisture in the carbon support were removed. Then, by using a device for BET analysis to hold a test tube in which the sample was loaded, nitrogen gas was gradually introduced into the inside of the test tube under temperature conditions of 77.35 K, so that the nitrogen gas was adsorbed and desorbed from the surface of the sample. In this process

[0130] In this process, by using the volume of nitrogen gas adsorbed into the sample and the relative pressure inside the tube, an isotherm called the "isotherm of nitrogen adsorption and desorption" was obtained, and then based on this curve, the following values regarding porosity were calculated.

[0131] The surface area of pores ranging in size from 0 nm to 2 nm (SSA, (i)) was calculated for the porous carbon supports of Example 1-1 to Example 1-2 and Comparative Example 1-1 to Comparative Example 1-3 according to the t-plot method based on the Harkins-Jura equation in the thickness (t) range of 0.35 nm to 0.4 nm. The surface area of pores ranging in size from 2 nm to 5 nm (SSA, (ii)) and the surface area of pores ranging in size from 2 nm to 100 nm (SSA, (iii)) were calculated according to the BJH desorption method based on the Harkins-Jura equation. In addition, the BET (Brunauer, Emmett, Teller) specific surface area (total SSA, (iv)) was calculated based on the BET method in the relative pressure range of 0.05 to 0.30 for the porous carbon supports obtained in Example 1-1 to Example 1-2 and Comparative Example 1-1 to Comparative Example 1-3. The ratio of the surface area of pores ranging in size from 2 nm to 5 nm to the total BET specific surface area (v) and the ratio of the surface area of pores ranging in size from 2 nm to 100 nm to the total BET specific surface area (vi) were calculated according to the BJH desorption method based on the Harkins-Jura equation, and the ratios are shown in Table 2.

[0132] [Table 2]

[0133]

[0134] In general, it is known that the suitable size of platinum particles for fuel cells in a carbon support ranges from 3 nm to 4 nm, and the size of pores for effectively loading the platinum particles ranges from 2 nm to 5 nm, and thus it is very important to adjust the specific surface area with respect to the size of the pores. According to Table 2, the surface area of pores ranging in size from 2 nm to 5 nm as shown in Example 1-1 to Example 1-2 was 213.80 m 2 / g, 464.85 m 2nm-5 nm, so that sufficient platinum particles cannot be loaded on the support, and the surface area is relatively very large in Comparative Example 1-2, so that the average size of the platinum particles can be small relative to the pore size, which is undesirable. In addition to the pores in the size range of 2 nm-5 nm, which are effective in loading platinum particles, it is also known that pores in the size range of 2 nm-100 nm can be used as a drainage passage in the operation of a fuel cell, which means that the respective portion of the porosity is also important. Therefore, it can be expected that the higher the ratio of the surface area of the pores in the size range of 2 nm-100 nm to the simple total specific surface area means better drainage (water is a product in the operation of a fuel cell). According to Table 2, a high ratio of 1.00 or more is shown in Examples 1-1 to 1-2, and a ratio of less than 1.00 is shown in Comparative Examples 1-1 to 1-3. The results indicate that in Examples 1-1 to 1-2, the proportion of pores in the size range of 2 nm-100 nm is very high, which means that there is a great opportunity for better drainage in the later operation of a fuel cell compared to Comparative Examples 1-1 to 1-3.

[0135] Comparative Example 3

[0136] The surface area of pores in the size range of greater than 0 nm to less than 2 nm was calculated with the porous carbon supports in Examples 1-1 to 1-2 and Comparative Examples 1-1 to 1-3 as obtained from the adsorption isotherm analysis in the thickness (t) range of 0.35 nm-0.5 nm by the t-plot method based on the Harkins-Jura equation, and the above-obtained surface area was compared with the value obtained in the thickness (t) range of 0.35 nm-0.4 nm, and the results are shown in Table 3. When a trend line is drawn based on linear regression, each correlation coefficient is calculated in each range of the trend line. PV (pore volume (0 nm-2 nm)) was calculated in the thickness (t) range of 0.35 nm-0.5 nm based on the BJH desorption method based on the Harkins-Jura equation. The correlation coefficient was obtained by using the calculation method of the Pearson correlation coefficient (PCC) in the trend line.

[0137] [Table 3]

[0138]

[0139]

[0140] According to Table 3, since a negative number was obtained in the thickness (t) range of 0.35 nm to 0.5 nm in Example 1-1 to Example 1-2, it was difficult to obtain the surface area (SSA) and PV of the pores having a size range of greater than 0 nm to less than 2 nm in an accurate manner. In order to find out the difference in the calculation of the surface area of the pores having a size range of greater than 0 nm to less than 2 nm between the two cases (the thickness (t) range of 0.35 nm-0.5 nm and the thickness (t) range of 0.35 nm-0.4 nm), the correlation coefficient was obtained in each range. The corresponding correlation coefficient serves as an index of the degree to which the trend line reflects the original data, and the closer the coefficient is to 1, the better it reflects. This explains why it is necessary to perform a BET-based analysis in the thickness range to obtain a correlation coefficient closer to 1. Therefore, in Example 1-1 to Example 1-2, a correlation coefficient closer to 1 could be obtained in the thickness (t) range of 0.35 nm-0.4 nm compared to the thickness range of 0.35 nm-0.5 nm. In general, a greater increase in the correlation coefficient could be determined in the thickness (t) range of 0.35 nm-0.4 nm compared to the case of the comparative example.

[0141] Experimental Example 4

[0142] The tap density and true density were obtained by using ASTM D8176 (Standard Test Method for Mechanical Tap Density of Activated Carbon (Powder and Fine Mesh)) with the porous carbon supports in Example 1-1 to Example 1-2 and Comparative Example 1-1 to Comparative Example 1-3. Specifically, the tap density is the average value after 3 measurements using a tap density meter, and the true density is the average value after 3 measurements using a helium pycnometer. In addition, the average size of the primary particles was obtained using TEM data by using ASTM D3849 (Standard Test Method for Carbon Black - Morphological Characterization of Carbon Black Using Electron Microscopy), and is shown in Table 4.

[0143] [Table 4]

[0144]

[0145] The tap density of close to 0.1, the true density in the range of 2.0-3.0, and the average size of primary particles in the size range of 20-30 nm were obtained in the porous carbon supports in Examples 1-1 to 1-2 of Table 4. The results were determined to be very suitable for the loading of metal catalysts. However, the true density and average size of primary particles in Comparative Example 1-1 and the true density in Comparative Example 1-3 exceeded the suitable range for the loading of metal catalysts, which can have an influence on the oil uptake in slurry preparation and the dispersion of metal particles in the slurry state. This can be another reason for the low performance of the fuel cell. The tap density, true density, and average size of primary particles in Comparative Example 1-2 were very similar to the preferred values, and thus the oil uptake and dispersion in slurry preparation were expected to be almost no problem, but finally, as shown in Table 3, the sample had the disadvantage that the appropriate pore surface area required for the fuel cell was too large. That is, the tap density, true density, and average size of primary particles in Comparative Example 1-2 were similar to the preferred values, but the porosity of the carbon support was not suitable for use as a carrier for a fuel cell. Therefore, when all the requirements for the respective physical properties are satisfied at the same time, the performance of the fuel cell can be maximized.

[0146] Experimental Example 5

[0147] The average interlayer spacing (d 002 ), a-axis lattice constant (La), and average number of layers of graphene layers were obtained by using ASTM D5187 (Standard Test Method for Determining Grain Size in Calcined Petroleum Coke by X-Ray Diffraction) with the porous carbon supports in Examples 1-1 to 1-2 and Comparative Examples 1-1 to 1-3. Specifically, the carbon support samples were uniformly stacked on an XRD substrate at a constant thickness, irradiated with Cu K-alpha X-rays (wavelength: 0.154 nm), and the X-ray diffraction intensity depending on 2 theta was measured. The subsequent XRD pattern is shown in (a) to (e) of FIG. 1. Figure 3 In (a) to (e) of FIG. 1, the specific results of carbon in the graph drawn by X-ray diffraction were measured with the values of peaks 002 and 100 based on the Bragg equation and the Scherrer equation, and then the average number of layers of graphene layers (Lc / (d 002 )+1) was obtained and shown in Table 5. Here, the average interlayer spacing (d 002 ) is the average distance between graphite layers, and the average number of layers of graphene layers is the average number of layers of graphene layers in the structure. The a-axis lattice constant (La) is the lateral dimension, i.e., the crystal size in the a-axis direction, which is approximately the size of the graphite structure.

[0148] Further, the oxidation resistance was identified by using TGA analysis of the porous carbon supports in Examples 1-1 to 1-2 and Comparative Examples 1-1 to 1-3 using ASTM E1131 (Standard Test Method for Constituent Analysis by Thermogravimetry). Specifically, the sample was loaded into the inside of TGA, and heated at a rate of 20℃ / min or less with an oxidizing gas such as air at a flow rate of 200 sccm or less. A DTG (derivative thermogravimetry) graph was obtained by TGA (thermogravimetric analysis), and then the minimum temperature of DTG was obtained. The TGA and DTG graphs showed that the minimum temperature of DTG was higher in Examples 1-1 to 1-2 than in Comparative Examples 1-1 to 1-3. Figure 4 (a) to (b) of Table 5.

[0149] [Table 5]

[0150]

[0151] According to Table 5, the carbon supports in Examples 1-1 to 1-2 had a smaller average interlayer spacing (d 002 ) and a larger a-axis lattice constant than the carbon supports in Comparative Examples 1-1 to 1-3, which means that the carbon supports in Examples 1-1 to 1-2 had a narrower interlayer spacing of graphite, an average more number of stacked layers of graphite, a larger thickness of graphite, and a larger average width of graphite. Thus, the carbon supports were highly porous and crystalline. According to (a) to (b) of Table 5 and Figure 4 , the carbon supports in Examples 1-1 to 1-2 had a lower mass reduction rate (%) and a higher DTG minimum temperature in the temperature range of 500℃-700℃ than Comparative Examples 1-1 to 1-3, so that the porous carbon supports of Examples 1-1 to 1-2 were determined to face mass reduction at high temperature. In addition, it was found that the DTG minimum value in Examples 1-1 to 1-2 was greater than that in Comparative Examples 1-1 to 1-3. The results indicate that the mass reduction due to oxidation was also relatively slow. Overall, Examples 1-1 to 1-2 indicate that the higher the temperature, the slower the mass reduction in TGA, which means high oxidation resistance. Thus, it can be concluded that the high crystallinity in Examples 1-1 to 1-2 leads to high oxidation resistance.

[0152] Experimental Example 6

[0153] The TEM photos of the fuel cell catalysts according to Examples 2-1 to 2-2 and Comparative Examples 2-1 to 2-3 are shown in (a) to (e) of Table 6, respectively. Then, the Pt content, the average size of the supported Pt, as obtained in Examples 2-1 to 2-2 and Comparative Examples 2-1 to 2-3, were obtained. In addition, a half-cell potential test was performed to evaluate the electrochemical reaction, and the results are shown in Table 6. Figure 5

[0154] ​The Pt content was measured using an XRF device. Standard signal data, dependent on the loading rate, was obtained by measuring the Pt signal of a standard sample with a known Pt loading. The Pt signals measured from the samples obtained in Examples 2-1 to 2-2 and Comparative Examples 2-1 to 2-3 were substituted into the standard data to calculate the Pt loading.

[0155] The average size of the loaded Pt particles was measured by using ImageJ software to identify the diameter of the Pt particles in the TEM images, and at least 50 Pt particles in the TEM images were studied to calculate the mean and standard deviation.

[0156] Electrochemical experiments were conducted in a rotating disk electrode (RDE) three-electrode cell using 0.1 M HClO4 solution as the electrolyte. The reference electrode was Ag / AgCl (saturated KCl, 3 M), and the other electrode was a platinum wire. To prepare the catalyst ink, the catalyst was placed in distilled water, Nafion (5 wt%), and isopropanol (IPA) and ultrasonically dispersed. The prepared ink was pipetted at 100 μg / cm³ using a micropipette. 2 The platinum area was loaded onto a glassy carbon RDE (5 mm) and the ink was dried. After purging with high-purity nitrogen for 30 minutes, it was then heated at 0.05V. RHE -1.05V RHE Measurements were performed using cyclic voltammetry (CV) at a scan rate of 20 mV / s within the voltage range. This was achieved using a voltage range of 0.05 V. RHE -0.4V RHE The electrochemical surface area (ECSA) was calculated from the hydrogen desorption area. After purging with high-purity oxygen for 30 minutes, the surface area was measured at 0.05 V. RHE -1.05V RHE The redox reaction (ORR) was carried out at a RED torque speed of 1600 rpm and a scan rate of 5 mV / s within the voltage range.

[0157] Pt loading (μg / cm) in this article 2 Electrochemical surface area (ECSA) is an indicator of the number of Pt particles loaded per unit area of ​​an electrode. 2 ECSA (mA / gpt) represents the surface area of ​​the platinum particles participating in the electrochemical reaction, where a higher ECSA indicates higher hydrogen activity. MA (Mass Activity) (mA / gpt) represents oxygen activity, where a higher MA generally indicates a higher current density, and MA is calculated from the catalyst loading density. Half-wave potential (V) is the potential when the current is halved. Again, a higher potential indicates higher oxygen activity.

[0158] [Table 6]

[0159]

[0160] According to Table 6, the fuel cells fabricated using the fuel cell catalysts according to Examples 2-1 to 2-2 generally exhibited excellent ECSA, MA, and half-wave potential (V). In particular, although the amount (%) of Pt loaded and the Pt loading per unit area in Examples 2-1 to 2-2 were almost identical to those in Comparative Examples 2-1 to 2-3, the ECSA, MA, and half-wave potential (V) in Examples 2-1 to 2-2 were generally considered very large. This result implies that despite the similar amount of Pt loaded, the carbon used in Examples 2-1 to 2-2 has a porosity suitable for fuel cells, leading to most of the electrochemical activity and excellent oxygen reduction reaction. This high performance of the fuel cells is driven by the surface area of ​​pores with sizes ranging from 2 nm to 5 nm, as previously determined in Example 1. The specific surface area in Examples 1-1 to 1-2 is suitable for loading platinum particles. After loading, as... Figure 5 As shown in (a) to (b), the average size range of the spherical platinum particles can be determined to be 3 nm-4 nm, and the platinum particles have uniform size and shape. However, as Figure 5 Comparative Example 2-1, shown in (c), has a small specific surface area, resulting in a relatively large average size of platinum particles, reaching 5.30 nm. Therefore, the ECSA is considered relatively small. Conversely, as... Figure 5 Comparative Example 2-2, shown in (d), has a large specific surface area, resulting in a smaller average size of 2.51 nm for the platinum particles. Therefore, it is determined that the ECSA is larger but the MA is smaller. Furthermore, as... Figure 5 The small specific surface area of ​​Comparative Examples 2-3 shown in (e) resulted in some particles being unevenly dispersed or not spherically loaded, thus the average size was 4.77 nm with a standard deviation of 2.81 nm, which is very high. Similarly, the measured ECSA was small.

Claims

1. A porous carbon support comprising: pores having a size ranging from greater than 0 nm to less than 2 nm, said pores having a surface area ranging from 100 m 2 / g to 300 m 2 / g. and pores having a size ranging from above 2 nm to below 5 nm, said pores having a surface area ranging from 100 m 2 / g to 800 m 2 / g, wherein the porous carbon support has an average interlayer spacing d in the range of 0.335 nm - 0.355 nm as measured by X-ray diffraction 002 , and an a-axis lattice constant L in the range of 4 nm - 10 nm a , wherein the porous carbon support comprises, on average, 6-20 graphene layers.

2. The porous carbon support according to claim 1, wherein, The ratio of the surface area of pores having a size ranging from more than 2 nm to less than 5 nm obtained from adsorption isotherm analysis of the porous carbon support by BJH desorption based on the Harkins-Jura equation to the total specific surface area based on BET ranges from 0.2-1.

3. The porous carbon support according to claim 1, wherein, The surface area of the pores ranging from 2 nm or more to 100 nm or less obtained by the analysis of the adsorption isotherm by the BJH desorption method based on the Harkins-Jura equation ranges from 200 m2 / g to 1000 m2 / g 2 / g-2000 m 2 / g.

4. The porous carbon support according to claim 1, wherein, The ratio of the surface area of pores having a size ranging from more than 2 nm to less than 100 nm obtained from adsorption isotherm analysis of the porous carbon support by BJH desorption based on the Harkins-Jura equation to the total specific surface area based on BET ranges from 0.5-2.

5. The porous carbon support of claim 1, wherein the tap density of the porous carbon support ranges from 0.05 g / cm3 to 0.5 g / cm3. 3 -0.5 g / cm3 3 .

6. The porous carbon support of claim 1, wherein the porous carbon support has a true density ranging from 2.1 g / cm3 3 -4 g / cm3 3 .

7. The porous carbon support of claim 1, wherein the average size of the primary particles of the porous carbon support ranges from 10 nm-30 nm.

8. The porous carbon support of claim 1, wherein the porous carbon support has a layered structure.

9. The porous carbon support of claim 1, wherein the mass reduction rate in the temperature range of 500°C-700°C by thermogravimetric analysis (TGA) ranges from 0%-30%.

10. The porous carbon support of claim 1, wherein the lowest temperature by derivative thermogravimetric analysis (DTG) of the porous carbon support ranges from 740°C-850°C.

11. A method of manufacturing a porous carbon support, the method comprising: (a) heat-treating a carbon material in the temperature range of 1500°C-3000°C to remove impurities and crystallize the carbon material; (b) pretreating the crystallized carbon material in an atmosphere containing at least one heteroatom selected from boron, carbon, nitrogen, oxygen, phosphorus, and sulfur to introduce activated sites doped with the heteroatom; and (c) mixing the carbon material having the activated sites with an additive comprising an organic surfactant, and then heat-treating the mixture to remove the heteroatom and activate the carbon material; and (d) washing and drying the activated carbon material.

12. A fuel cell catalyst comprising: metallic particles comprising platinum particles supported on the porous carbon support of claim 1.

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