Carbon material for catalyst support, method for preparing the same, catalyst, and fuel cell

Abstract

The application discloses a carbon material for a catalyst carrier and a preparation method thereof, a catalyst and a fuel cell, and relates to the technical field of batteries. 002 The carbon material for the catalyst carrier has a graphite crystallite structure, the interplanar spacing d of the graphite crystallite is less than 0.355 nm, the grain size La of the graphite crystallite is 2 nm to 14 nm, the longitudinal stacking height Lc of the graphite crystallite is 1.5 nm to 13 nm, the specific surface area S of the carbon material is 100 m BET 2 / g to 1200 m 2 / g, and the carbon material satisfies 30%<=Phi<=95%; Phi is the grain gap degree of the carbon material. The application can solve the problem that the existing carbon material for the catalyst carrier cannot effectively balance high specific surface area and high order degree.​

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fuel cell technology, in particular to a carbon material for catalyst carrier, a preparation method thereof, a catalyst and a fuel cell. BACKGROUND

[0002] Proton Exchange Membrane Fuel Cell (PEMFC) is a device that converts chemical energy into electrical energy and heat energy through the electrochemical reaction of hydrogen and oxygen. Its core components include proton exchange membrane, catalyst layer, gas diffusion layer and bipolar plate.

[0003] The catalyst layer includes carbon material loaded with catalyst, ion conductor and other possible added components. In order to promote the electron transmission between electrode materials and optimize the performance of the battery, carbon material with high specific surface area and abundant pores is often selected as catalyst carrier. Among them, carbon black materials such as acetylene black, Vulcan XC-72R (Chinese name: Cabot XC-72R) and Ketjen black (Chinese name: Ketjen black) are widely used, with specific surface area ranging from 50 to 1200 m 2 / g, which has high conductivity and suitable pore structure, and can make platinum particles uniformly dispersed on its surface. However, due to the low degree of order of the carbon layer of carbon black material, there is a high risk of carbon corrosion during long-term operation, which negatively affects the electrochemical stability. Although the traditional graphite material has a high degree of order, its specific surface area is <50 m² / g, which cannot provide enough active sites. In addition, although graphene obtained by metal intercalation or carbon nanotubes prepared by high-temperature metal catalysis has a relatively high degree of order and high specific surface area, it has a high metal content, which can easily damage the proton membrane. SUMMARY

[0004] The main purpose of the present application is to provide a carbon material and a preparation method thereof, a fuel cell catalyst and a fuel cell, which aims to solve the problem that the existing carbon material for catalyst carrier cannot effectively balance high specific surface area and high degree of order.

[0005] To achieve the above purpose, the embodiment of the present application provides a carbon material for catalyst carrier, which has a graphite microcrystalline structure, the interplanar spacing d 002 of the graphite microcrystalline structure measured by X-ray diffraction method is <0.355 nm, the lateral size La of the graphite microcrystalline structure is 2 nm~14 nm, and the longitudinal stacking height Lc of the graphite microcrystalline structure is 1.5 nm~13 nm; the specific surface area S BET of the carbon material is 100 m 2 / g~1200 m 2 / g, and the carbon material satisfies: 30%≤Φ≤95%; Φ is the grain gap degree of the carbon material;

[0006] .

[0007] In some embodiments, the specific surface area S BET of the carbon material is 400 m 2 / g~1200 m 2 / g, La is 2 nm~6 nm, Lc is 1.5 nm~5 nm, and the grain gap degree Φ is 50%-95%.

[0008] In some embodiments, the specific surface area S BET of the carbon material is 100 m 2 / g~400 m 2 / g, La is 3.5 nm~13 nm, Lc is 2 nm~13 nm, and the grain gap degree Φ is 30%~55%.

[0009] In some embodiments, the total content of metals in the carbon material is <100 ppm, the metals including any one or more of Fe, Co, Ni, Cr, Mn, Cu, Al, Zn, Na, K, Ca, Mg.

[0010] In some embodiments, the G peak position in the Raman spectrum of the carbon material is 1580 cm -1 ~1590 cm -1 , and the half-peak width of the G peak is 25 cm -1 ~50 cm -1 .

[0011] And / or, the intensity ratio I 2G / I G of the 2G peak and the G peak in the Raman spectrum of the carbon material is 0.2~0.8.

[0012] And / or, the Dv50 particle size of the carbon material is 20 nm~1000 nm.

[0013] The embodiment of the present application also proposes a preparation method of the carbon material for catalyst carrier, comprising the following steps: carbonizing an organic carbon source in an inert atmosphere at 800 ℃~1500 ℃ for 0.5 h~8 h to obtain an intermediate A; treating the intermediate A in a mixed atmosphere of activating gas and inert gas at 400 ℃~600 ℃ for 0.5 h~5 h to form a porous product; crushing the porous product to nanoscale particles;

[0014] Graphitizing the nanoscale particles to obtain the carbon material.

[0015] In some embodiments, the organic carbon source includes at least one of phenol-formaldehyde resin, polyimide, polystyrene, lignin, coal tar, pitch, benzopyrene, polyacrylonitrile, polyvinyl alcohol, polyethylene, polyvinylidene chloride, cellulose, carboxymethyl cellulose, citric acid, melamine, nitrogen ethyl carbazole, thiophene;

[0016] And / or, the volume ratio of the activating gas to the inert gas is 5:95 to 10:90; the activating gas includes at least one of H2O, O2, O3, CO2, air;

[0017] And / or, the particle size of the nanoscale particles is 20nm-1000nm.

[0018] And / or, the temperature of the graphitization treatment is 1800℃-2800℃, and the treatment time is 0.5h-3h.

[0019] The embodiment of the present application also provides a catalyst, which includes a carbon carrier and platinum particles loaded on the carbon carrier, and the carbon carrier includes the carbon material for the catalyst carrier or the carbon material prepared by the preparation method of the carbon material for the catalyst carrier.

[0020] In some embodiments, the mass percentage of the platinum particles in the catalyst is 20%-60% based on 100% of the mass of the catalyst; and / or, the average particle size of the platinum particles is 1nm-5nm.

[0021] The embodiment of the present application also provides a fuel cell, which includes a catalyst layer, and the catalyst layer includes the catalyst.

[0022] Compared with the prior art, the present application has the beneficial effects in the following aspects:

[0023] According to the experimental results, the carbon material has a specific surface area of 100-1200 m 2 / g, a crystal face spacing d 002 <0.355 nm, La is 2nm-14nm, and Lc is 1.5nm-13nm, and the grain gap degree Φ is limited in the range of 30%-95%, so that the carbon material has high specific surface and high order degree, effectively balances the high specific surface area and high order, and further improves the cycle retention rate and corrosion resistance of the carbon material.

[0024] The preparation method of the present application controls the structure of the carbon material through a staged process, solving the technical bottlenecks of the difficulty in coordinating high specific surface area and high order degree, metal catalyst pollution and pore closure in the preparation of traditional carbon carriers. The carbonization treatment stage promotes the aromatization and polycondensation of the organic carbon source in a high-temperature inert environment, forming an initial graphite microcrystalline framework, and the temperature-time window controls the carbon layer defect density and the growth degree of the microcrystalline; the pore-forming treatment introduces an open pore network by selectively etching the amorphous regions of the carbon framework in an oxidizing mixed atmosphere while retaining the microcrystalline structure, avoiding the pore collapse caused by complete graphitization; the nanoscale crushing process forms uniform nanoparticles by inputting mechanical energy to depolymerize carbon particle aggregates, providing a uniform grain growth substrate for subsequent graphitization and preventing pore closure caused by particle fusion during high-temperature treatment; and the final graphitization stage reconstructs the carbon layer arrangement under metal-free catalytic conditions, eliminates grain boundary stress through high-temperature annealing, and improves the stacking order and conductivity of the carbon layer. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0026] Figure 1 A schematic diagram of the grain structure of the carbon material of the embodiment of the present application;

[0027] Figure 2 A schematic diagram of the platinum loading of the carbon grain and pore structure of the carbon material of the embodiment of the present application;

[0028] Figure 3 A Raman spectrum of the carbon material of Example 1 of the present application;

[0029] Figure 4 A TEM image of the carbon material of Example 1 of the present application.

[0030] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0032] The ranges disclosed herein are intended to be "open" ranges, i.e., the upper and lower limits of the range are not included. The ranges are also intended to include any and all sub-ranges of the same, wherein each sub-range includes each integer between (and herein called "a range"). For example, a range of 0-10 is intended to include any and all sub-ranges between (and the end points of) the minimum value of zero and the maximum value of ten, that is, any one or a combination of the following ranges: 1-10, 3-7, 0-3, and 3- 0 are included in the range of 0-10. In other words, the range of 0-10 includes any range beginning with any integer between zero and 10 and ending with any integer between 10 and zero. The same applies to ranges having a lower limit of zero, such as 0-5, 0- 3, and 0- 1, and to ranges having an upper limit of 10, such as 5-10, 7-10, and 1-10. Also, the range of 0-10 includes any range beginning with any integer between 0 and 10 and ending with any integer between 0 and 10, such as 2-8, 4-6, and 6-8. It will be further understood that the endpoints of the ranges are included in the range (but not included in the range if either the upper or lower limit is not included). It will be further understood that the ranges include the endpoints and all the values between the endpoints, including integers within the range and fractions of the values in the range, as well as including the range itself. For example, the range "a-b" is intended to include "a-b," the value "a," the value "b," the value "a.1," "a.2," "a.3," and so on, up to the value "b." Similarly, if a minimum range value of 1 and a maximum range value of 3 are listed, then the following ranges are all contemplated: 1-3, 1-2, 2-3, 1.1-3, 1.2-3, 1.3-3, 1.4-3, 1.5-3, 1.6-3, 1.7-3, 1.8-3, 1.9-3, 2-3, 2.1-3, 2.2-3, 2.3-3, 2.4-3, 2.5-3, 2.6-3, 2.7-3, 2.8-3, 2.9-3, and 3-3. In this application, the use of "about" or "approximately" in connection with a value means that the exact value is not critical and any value that functions within typical

[0033] If not specified, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0034] If not specified, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0035] If not specified, all steps of the present application can be performed in sequence or randomly, and preferably in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) performed in sequence, or steps (b) and (a) performed in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0036] Fuel cells operate at high potentials and in oxygen-rich environments, which are prone to electrochemical oxidation corrosion of carbon materials. Carbon corrosion not only causes the collapse of electrode layer structure and the deterioration of pore structure, but also may cause the shedding of active materials, ultimately affecting the performance of fuel cells. Traditional graphite materials have excellent corrosion resistance, but their specific surface area is usually less than 50 m 2 / g, which cannot provide enough active sites.

[0037] On the other hand, carbon black and amorphous carbon materials such as activated carbon exhibit high specific surface area (over 1000 m 2 / g) and have abundant active material loading sites. However, due to the low degree of order and the presence of a large number of defect sites, they have poor resistance to electrochemical corrosion.

[0038] In addition, graphene obtained by metal intercalation or carbon nanotubes prepared by high-temperature metal catalysis, although relatively ordered and having a high specific surface area, have a high metal content and are prone to damage to the proton membrane.

[0039] Therefore, there is still a need for a carbon material with high specific surface area and high degree of order as a catalyst carrier to support fuel cells to achieve high performance and long operating life.

[0040] Based on this, the embodiment of the present application proposes a carbon material for a catalyst carrier, which has a graphite crystallite structure, the interplanar spacing d 002 of the graphite crystallite measured by X-ray diffraction is less than 0.355 nm, the lateral size La of the graphite crystallite is 2 nm to 14 nm, and the longitudinal stacking height Lc of the graphite crystallite is 1.5 nm to 13 nm; the specific surface area S BET of the carbon material is 100 m 2 / g to 1200 m 2 / g, and the carbon material satisfies: 30%≤Φ≤95%; Φ is the grain gap degree of the carbon material.

[0041] The carbon material for a catalyst carrier of the technical solution improves the performance and durability of the fuel cell catalyst by achieving the synergistic optimization of high specific surface area and order degree through specific structural parameters. The graphite crystallite structure refers to the micro-morphology of the material composed of short-range ordered graphite lamellar units inside, and the sp 2 hybrid carbon layer is arranged in a graphite-like manner, but the grain size is small and the long-range order is limited.

[0042] The catalyst carrier needs to use a material with high specific surface area to load the catalyst, and especially the carbon-based catalyst for fuel cells needs to load an active material amount of even more than 50%wt. However, the specific surface area is the total surface area per unit mass of the material, and the higher the specific surface area, the more surface is exposed, which requires reducing the particle size of the material to increase the surface area per unit mass. The smaller the particle size of the material, the higher the surface energy, and for carbon carriers, carbon corrosion is more likely to occur. Increasing the order degree of the carbon material to reduce the contact surface between the material and the environment contradicts the characteristic of "the carbon carrier needs to have high specific surface area to achieve high loading".

[0043] To obtain carbon materials with high specific surface area and high order degree, highly ordered materials are broken to increase the specific surface area, or small-grained high specific surface materials are obtained and then treated at high temperature to make the crystal grains grow in order. The latter scheme is usually adopted to obtain high specific surface materials, but in the process of grain growth, in addition to the reduction of surface area caused by grain growth, the surface area is also lost due to the closure of crystal faces caused by the excessive growth of part of the grains and the mutual extrusion of adjacent grains, and the mass transfer in the catalytic reaction process is reduced due to the decrease of the pore volume of the closed crystal faces. This part of the surface area loss needs to be avoided.

[0044] The applicant finds that by calculating the theoretical specific surface area of the material through the grain size and controlling the reasonable range of the ratio of the measured specific surface area of the material to the theoretical specific surface area, a material with high specific surface area and high order degree of grains can be obtained, balancing the platinum carrying performance and durability of the material.

[0045] Specifically, in the present application, the inter-grain gap degree is calculated by formula (a):

[0046] (a).

[0047] The technical solution quantitatively defines the inter-grain gap degree Φ, and refines the correlation between the specific surface area and the grain size of the carbon material. The inter-grain gap degree Φ represents the ratio of the actual specific surface area to the theoretical grain specific surface area per unit mass of the carbon material, which is calculated based on the percentage relationship between the measured specific surface area (S BET ) of the material and the theoretical specific surface area (S Grain ). Here, S Grain is a term or parameter defined as the specific surface area of the material when all the grains are separated from each other. Assuming that these grains are perfect crystals without defects and it is difficult to create holes inside the grains due to their extremely small size (a few nanometers), all the pores in the material are derived from the gaps between the grains. This parameter reflects the richness of the pore structure formed by the stacking of grains. When the Φ value tends to 100%, it can be considered that the grains in the material are nearly completely separated and not connected. When the gap between the grains is smaller than the nitrogen molecule (0.26 nm in size), it can be considered that the grain boundary is closed, the area of the closed grain boundary cannot be measured, resulting in a measured value lower than the theoretical value. The following is a detailed derivation of the formula for the inter-grain gap degree Φ.

[0048] Generally, carbon material particles are assembled by a large number of grains. When a particle has only one grain, the grain is in a completely separated and non-connected state. During the nitrogen adsorption and desorption test, nitrogen molecules can contact every crystal face, so the specific surface area (S BET ) measured by the nitrogen adsorption and desorption test should be equal to the specific surface area (S GrainIn heat-treated carbon materials, van der Waals forces, interlocking forces between defects, and partial chemical bonding cause the grains to adhere together, resulting in partial grain boundary closure. This prevents nitrogen molecules from permeating, and the measured specific surface area is smaller than the grain specific surface area. It can also be inferred that for particles composed of grains of equal size, the more permeable intergranular spaces between the grains, the higher the S... BET The larger the value, the better. Therefore, this patent defines grain spacing as: grain spacing = specific surface area (S) measured by nitrogen adsorption-desorption. BET ) divided by the average specific surface area per unit mass of grains (S Grain ×100%, as shown in formula (1). The porosity of the material is characterized by the grain spacing.

[0049] (1)

[0050] Specific surface area per unit mass of grain (S) Grain The following formula (2) can be used to calculate the result:

[0051] (2)

[0052] like Figure 1 As shown, the carbon material is a cuboid structure with a grain size of La nm and a vertical stacking height of Lc nm.

[0053] La can be calculated by the intensity ratio of the D peak and the G peak in the Raman spectrum of carbon (Raman laser wavelength λ = 514 nm), as shown in Equation 3:

[0054] (3)

[0055] Lc can be calculated using the Scherrer formula based on the XRD (002) diffraction peak characteristics of carbon (X-ray wavelength λ = 0.15406 nm, β is the full width at half maximum (FWHM) of the (002) diffraction peak, and ϴ is the (002) diffraction angle), as shown in Formula 4:

[0056] (4)

[0057] The average surface area of ​​a monomer grain is:

[0058] (5)

[0059] The average monomer grain volume is:

[0060] (6)

[0061] Through the interplanar spacing d 002The average carbon grain density that has not reached the full graphite state is calculated by the size change of the d- spacing (nm). (The graphite crystal density of graphite crystal spacing of 0.335 nm is 2.26 g / cm 3 .)

[0062] , (7)

[0063] The grain gap degree Φ,

[0064] (a)

[0065] The present technical solution is in the d 002 <0.355 nm, La is 2 nm-14 nm, Lc is 1.5 nm-13 nm, the specific surface area S BET is 100 m 2 / g-1200 m 2 / g, on the basis of limiting the value of Φ in the range of 30%-95%, the balance of multi-scale pore distribution and ordered structure is constructed. The traditional high specific surface area carbon material produces too many micropores due to disordered grain accumulation, which causes the catalyst metal particles to be embedded; and the graphite material causes insufficient porosity due to too large grain, and thus the specific surface area is low. The introduction of the value of Φ establishes a mathematical model correlation between the grain size, the interlayer spacing and the specific surface area, so that the material maintains a high specific surface area while forming an open pore structure by adjusting the grain stacking mode. This structural feature is mainly dominated by the inter-granular gap rather than the intra-granular micropore, which reduces the inactivation of active sites caused by the embedding of platinum catalyst in micropores, and the ordered arrangement of inter-granular mesoporous network promotes the proton transport of reaction substances.

[0066] In addition, by calculating the limited grain gap degree Φ, the problem of balancing the high specific surface and high order of traditional carbon materials is solved. This numerical range makes the carbon material have both open pores to provide high specific surface area and maintain structural stability through the close connection between the grains. The introduction of formula (a) makes the grain gap degree a quantifiable control parameter, which relates the specific surface area measured by nitrogen adsorption and desorption to the theoretical specific surface area per unit mass of grain, accurately reflecting the accessibility of inter-granular pores. This technical means is applied in the high-temperature graphitization process, which avoids the situation of pore closure leading to a decrease in specific surface area. The coupling effect of grain gap degree and grain size provides sufficient dispersion sites and catalytic reaction transmission channels for catalysts under fuel cell working conditions, and inhibits the electrochemical oxidation corrosion of carbon matrix through the ordered arrangement of grains.

[0067] See Figure 2 , Figure 2This paper visually demonstrates the microstructure of the material in this application and its optimizing effect on platinum particle loading. The figure shows that graphite microcrystals (lateral dimension La, vertical stacking height Lc) form a three-dimensional network through ordered arrangement, with open mesoporous / macroporous channels formed between the grains (Φ value). The pores are mainly distributed in the grain gaps (amorphous intracellular micropores), avoiding the problem of platinum particles being embedded in the micropores of traditional carbon black. Platinum particles can be uniformly dispersed on the grain surface and pore edges, rather than embedded deep within the micropores, allowing the active sites to be fully exposed at the reaction interface. The short-range ordered carbon layer (d) on the grain surface... 002 <0.355 nm) through strong sp 2 Bonding enhances the anchoring stability of platinum particles and inhibits aggregation or detachment.

[0068] In some implementations, the specific surface area S of the carbon material BET 100m 2 / g~400m 2 / g, La is 3.5nm~13nm, Lc is 2nm~13nm, and the grain spacing Φ is 30%~55%.

[0069] In some implementations, the specific surface area S of the carbon material BET 400m 2 / g~1200m 2 / g, La is 2nm~6nm, Lc is 1.5nm~5nm, and the grain spacing Φ is 50%~95%.

[0070] This technical solution divides the specific surface area into intervals and determines the grain size La and longitudinal stacking height Lc that are suitable for each specific surface area interval based on the grain gap Φ, so as to balance the high specific surface area and high order of the carbon material used as catalyst support.

[0071] Specifically, when the specific surface area is 100m² 2 / g~400m 2 At / g, the grain size La and Lc can be adjusted to be within the range of 30%~55% to make the grain size La and Lc similar to 100m. 2 / g~400m 2 By matching the specific surface area per g, the catalyst's cycle performance is achieved to be above 90%, thus making carbon materials suitable for applications with high requirements for catalyst cycle life.

[0072] When the specific surface area is 400 m² 2 / g~1200m 2 At / g, the grain size La and Lc can be adjusted to be within the range of 50% to 95% to make the grain size La and Lc similar to 400 μm. 2 / g~1200m 2 / g to achieve a better matching relationship, and to achieve an Electrochemical Active Surface Area (ECSA) of 90 m 2 / g-Pt, and thus to make the carbon material suitable for application scenarios requiring high catalytic activity.

[0073] The technical solution allows flexible adjustment of material properties according to the requirements of specific application scenarios. For example, in working conditions requiring higher catalyst cycle life, 100 m 2 / g~400 m 2 / g, and then controlling the grain size La and Lc according to the grain gap degree to achieve a balance between high specific surface and high order. In application scenarios pursuing high catalytic activity, 400 m 2 / g~1200 m 2 / g, at which time the grain size La and Lc can also be controlled according to the grain gap degree to achieve a balance between high specific surface and high order. In this way, the technology not only improves the applicability of the material, but also meets the specific requirements of different applications.

[0074] In some embodiments, the total metal content of the carbon material is <100 ppm, and the metal includes any one or more of Fe, Co, Ni, Cr, Mn, Cu, Al, Zn, Na, K, Ca, Mg. Specifically, compared with the scheme of "obtaining a relatively ordered and high specific surface carbon carrier material by metal intercalation or by metal catalysis", the carbon material of the present application does not additionally add metal materials in the preparation process, and thus the total metal content of the carbon material is <100 ppm, which can reduce the damage to the proton membrane. It should be noted that the metal in the carbon material of the present application mainly comes from the metal impurities carried by the production equipment (such as carbonization furnace, ball mill, etc.) and the production raw materials, and therefore, when implementing the scheme of the present application, the production equipment or the production process can be optimized as needed to make the total metal content of the carbon material less than 90 ppm, 80 ppm, 70 ppm, 60 ppm, 50 ppm, etc. For example, when the metal in the carbon material mainly comes from the wear of the inner wall of the carbonization furnace, an inert ceramic coating can be sprayed on the inner wall of the carbonization furnace; or when the metal in the carbon material mainly comes from the metal impurities in the organic carbon source, the organic carbon source can be purified before the preparation of the carbon material of the present application.

[0075] In some embodiments, the G peak position in the Raman spectrum of the carbon material is 1580 cm -1 ~1590 cm -1 , and the half-peak width of the G peak is 25 cm -1 ~50 cm -1 .

[0076] G peak in Raman spectrum corresponds to sp 2 In-plane vibration mode of hybrid carbon atom, peak position at 1580~1590 cm -1 Interval, indicating the existence of moderate electronic coupling between carbon layers, different from the higher wave number characteristics (>1590 cm -1 ) of completely disordered carbon black and the lower wave number characteristics (<1580 cm -1 ) of completely graphitized, reflecting the material's combination of defect site activity and structural stability. The d 002 interplanar spacing measured by X-ray diffraction is the interlayer distance of the graphite (002) crystal plane, and its value less than 0.355 nm shows the close degree of carbon layer stacking close to ideal graphite (0.335 nm), indicating that the material has a high degree of graphitization order. The lateral size La refers to the average size of the graphite crystallite along the carbon layer plane direction, and the vertical stacking height Lc refers to the thickness of the carbon layer along the vertical direction. The limitation of the two (La: 2-15 nm, Lc: 1.5-15 nm) makes the crystallite form a controllable grain boundary distribution in nanometer scale, which not only maintains the high specific surface area characteristics, but also avoids the pore closure caused by excessive grain growth.

[0077] The technical solution combines high specific surface area (100~1200 m 2 / g) with ordered graphite crystalline structure, aiming at the performance contradiction of traditional carbon carriers in fuel cell environment: carbon black type materials with high specific surface area have poor corrosion resistance due to disordered structure, while high-order graphite materials have low specific surface area, which limits the dispersion of catalyst. The Raman G peak characteristics and d 002 value show that the material forms a stable short-range ordered structure at the atomic scale. This structure enhances the conjugation effect between carbon layers and reduces the electrochemical corrosion rate. The specific range of La and Lc forms a balanced distribution of grain boundaries and pores at the nanometer scale, which on the one hand provides high dispersion sites and catalytic reaction transmission channels for platinum catalyst, and on the other hand reduces the defect density of carbon layers by controlling the grain size. As a result, the carbon material exhibits optimized comprehensive performance in fuel cell applications: high specific surface area supports high loading of catalyst particles and full exposure of active sites, ordered crystalline structure inhibits the oxidative degradation of carbon matrix, and the synergistic distribution of grain boundaries and pores promotes the transmission efficiency of reactants, protons and electrons.

[0078] In some embodiments, the intensity ratio of the 2G peak to the G peak in the Raman spectrum of the carbon material I 2G / I G is 0.2~0.8.

[0079] The technical solution further refines the evaluation dimension of the order of the material by characterizing the electronic structure characteristics of the conjugated system in the carbon material. The 2G peak is located at about 1620 cm-1 Wave number region, derived from sp 2 High order mode of in-plane vibration of hybrid carbon atom or out-of-plane vibration mode, the intensity of which is related to the degree of electron delocalization of carbon layer conjugated system. 2G / I G The ratio reflects the conjugate integrity of C=C bond in carbon layer and the strength of interlayer electron interaction, when the ratio tends to 0.2, it indicates that the material has significant conjugate defects or interlayer stacking disorder, and when it approaches 0.8, it shows a highly delocalized π electron system and interlayer coupling.

[0080] The technical scheme limits I 2G / I G The ratio range solves the problem that the integrity of the conjugated system in the traditional carbon material is difficult to quantitatively control. A too low ratio (<0.2) corresponds to the rupture of the carbon layer conjugation or the stacking dislocation between the layers, resulting in an increase in the resistance of electron transmission; a too high ratio (>0.8) may be caused by the strong coupling between the layers due to excessive graphitization, which inhibits the exposure of the catalytic active sites. The ratio range of 0.2-0.8 indicates that the material has a moderate conjugate defect density and interlayer interaction, and such a structural characteristic forms a balance at the atomic scale: the moderate conjugate defects provide catalyst anchoring sites and enhance the dispersion stability of platinum particles; and the limited interlayer coupling maintains the electron transmission efficiency between the carbon layers and avoids the closure of the pores caused by excessive graphitization. The parameter forms a multidimensional synergistic control with the G peak position (1580-1590 cm -1 ) and the d 002 Spacing (<0.355 nm) to jointly construct a carbon carrier with defect activity and structural stability, thereby delaying the oxidation corrosion process of the carbon matrix under the high potential cycle working condition of the fuel cell and maintaining the high efficient charge transfer capability of the catalytic reaction interface.

[0081] In some embodiments, the Dv50 particle size of the carbon material is 20 nm-1000 nm. As an example, the Dv50 particle size of the carbon material can be 20 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, etc., which are typical but non-limiting values.

[0082] The embodiment of the present application also proposes a preparation method of the carbon material for the catalyst carrier, comprising the following steps: carbonizing an organic carbon source at 800-1500 DEG C for 0.5-8 h in an inert atmosphere to obtain an intermediate A; treating the intermediate A in a mixed atmosphere of an activating gas and an inert gas at 400-600 DEG C for 0.5-5 h to form a porous product; crushing the porous product into nanoscale particles; and graphitizing the nanoscale particles to obtain the carbon material.

[0083] The preparation method cooperatively controls the structural characteristics of the carbon material through a "carbonization-pore forming-crushing-graphitization" process. First, high-temperature carbonization treatment is used to form an initial graphite microcrystalline structure for the organic carbon source, laying a foundation for subsequent graphitization; then, pore forming treatment is used on the intermediate in a specific temperature range using an activating gas to form a porous structure to improve the specific surface area. The "activating gas" refers to a gaseous medium that participates in the chemical etching of the carbon skeleton during the pore forming treatment, which selectively removes disordered structure components in the carbon material through oxidation or gasification reactions to form a pore network in the intercrystalline gap. Then, the product is controlled to a nanoscale size through crushing treatment, which not only avoids the closure of pores caused by excessive grain growth during subsequent high-temperature graphitization, but also improves material dispersibility. Finally, graphitization treatment is used to improve the order of carbon layers while maintaining the pore structure, achieving a balance between high specific surface area and high graphitization degree. The temperature range, treatment time, and gas environment selection of each step collectively ensure the cooperative optimization of material grain size, pore structure, and order.

[0084] In some embodiments, the organic carbon source includes at least one of phenol formaldehyde resin, polyimide, polystyrene, lignin, coal tar, pitch, benzopyrene, polyacrylonitrile, polyvinyl alcohol, polyethylene, polyvinylidene chloride, cellulose, carboxymethyl cellulose, citric acid, melamine, nitrogen ethyl carbazole, and thiophene.

[0085] By limiting the type of organic carbon source, the aromaticity of the precursor is improved. The selected materials all contain benzene rings, conjugated structures, or cyclizable functional groups, which promote the formation of graphite microcrystalline structures during subsequent high-temperature treatment. Or they contain O, N, S heteroatoms, which can promote the dehydrogenation and cyclization reaction during carbonization, thereby facilitating the formation of aromatic structures (aromatization). The listed phenol formaldehyde resin, polyimide, polystyrene, etc. aromatic polymers form condensed aromatic fragments through the benzene ring structure and conjugated system at the initial stage of carbonization, promoting the directional growth of graphite microcrystals. Nitrogen / oxygen-containing linear polymers such as polyacrylonitrile and cellulose generate graphene-like fragments through dehydrogenation and cyclization during pyrolysis, and the released heteroatoms (N / O) act as pore-forming agents to promote micropore formation. Coal tar, pitch, and other polycyclic aromatic hydrocarbon mixtures form ordered carbon layer precursors by stacking molecular planes, reducing the graphitization activation energy.

[0086] In some embodiments, the volume ratio of the activating gas to the inert gas is 5:95 to 10:90; the activating gas includes at least one of H2O, O2, O3, CO2, and air.

[0087] As an example, the volume ratio of the activating gas to the inert gas can be 5:95, 6:94, 7:93, 8:92, 9:91, 10:90, etc. typical but non-limiting values. The volume ratio of the activating gas to the inert gas is controlled to be 5:95 to 10:90, which can form pores by oxidation in the pore-forming stage at 400℃ to 600℃, and avoid excessive oxidation to destroy the carbon skeleton structure. The heat treatment in the mixed gas atmosphere composed of the activating gas and the inert gas of the above-mentioned kind can remove the un-polymerized aromatic hydrocarbon fragments, oxidize and form pores in the material structure, obtain a high-porosity carbon material, and does not produce metal contamination in the pore-forming process.

[0088] In some embodiments, the particle size of the nanoscale particles is 20nm to 1000nm. Breaking the porous product into 20-1000nm nanoscale particles can not only maintain the pore structure during graphitization, but also achieve precise control of the grain size La and Lc by limiting the grain growth space. This particle size range also makes the material have good dispersibility, which is beneficial to the uniform distribution of platinum particles in the subsequent catalyst loading process, and provides abundant reaction transmission channels during the catalytic reaction process.

[0089] In some embodiments, the temperature of the graphitization treatment is 1800℃ to 2800℃, and the treatment time is 0.5h to 3h.

[0090] By controlling the graphitization treatment temperature to be 1800℃ to 2800℃, the carbon material can be prompted to form a short-range highly ordered graphite crystallite structure at high temperature, but excessive increase of the carbon grain size (La, Lc) caused by too high temperature is avoided, which in turn causes pore collapse or specific surface area reduction. The treatment time is limited to 0.5h to 3h, which can not only make the carbon layer structure fully ordered, but also prevent the closure of the grain gap caused by long-time high-temperature treatment, and maintain a high level of grain gap degree Φ. The synergistic control of temperature and time not only realizes the high degree of order characterized by the low wave number shift (1580-1590cm⁻¹) of the G peak in the Raman spectrum of the carbon material, but also retains a high specific surface area (100-1200m 2 / g) and pore structure by inhibiting excessive grain growth, thereby forming a balance between grain size and pore distribution at the micro level.

[0091] The embodiment of the present application also proposes a catalyst comprising a carbon carrier and platinum particles loaded on the carbon carrier, wherein the carbon carrier comprises the carbon material for the catalyst carrier described above, or the carbon material prepared by the preparation method of the carbon material for the catalyst carrier described above.

[0092] The carbon carrier (carbon material) has high specific surface area, suitable intercrystalline porosity and graphitization order, so that when platinum particles are loaded on the carbon carrier, nanoscale pores and high surface active sites can disperse the platinum particle size and provide abundant catalytic reaction transmission channels, and the ordered carbon layer structure enhances the electrical conductivity and durability of the carrier, forming a stable catalyst system.

[0093] In some embodiments, the mass percentage of platinum particles in the catalyst is 20% to 60% based on 100% of the mass of the catalyst.

[0094] The "mass percentage of platinum particles in the catalyst" herein refers to the platinum loading amount.

[0095] In some embodiments, the average particle size of the platinum particles is 1 nm to 5 nm.

[0096] The carbon carrier (the carbon material used for the catalyst carrier described above) of the embodiments has abundant micro-mesoporous structures, and as a catalytic carrier, can control the particle size distribution of the catalytically active metal to be 1-5 nm, can achieve a platinum loading amount of 20-60%, and has an electrochemical active surface area (ECSA) of >80 m 2 / g-Pt, and can prepare a high-activity catalyst. The electrochemical active surface area (ECSA) is a parameter used to describe the active surface area of a catalyst, especially a noble metal catalyst (such as platinum Pt). In a catalytic reaction, the effective active area of the catalyst has a direct impact on its performance: generally, the larger the active area, the higher the efficiency of the catalyst. ECSA>80 m 2 / g-Pt indicates that the electrochemical active surface area corresponding to each gram of platinum (Pt) is greater than 80 square meters. Here, "m 2 / g-Pt" is a unit, which refers to square meters per gram of platinum, and is used to standardize the specific surface area of different samples or materials, so that the activity of different catalysts can be compared. This value reflects the effective active surface size that can be provided by the catalyst using its mass, and is one of the important indicators for evaluating the performance of a catalyst.

[0097] The embodiments also provide a fuel cell comprising a catalyst layer, wherein the catalyst layer comprises the catalyst described above.

[0098] The catalyst layer of the fuel cell uses the catalyst described above, which loads platinum particles on a short-range high-order and high-specific-surface-area carbon material. The carbon material can provide sufficient platinum particle dispersion sites and catalytic reaction transmission channels through the high specific surface area (100-1200 m 2 / g), and can also provide a transmission channel for the catalytic reaction through the high graphitization order (d 002The carbon layer corrosion is inhibited by the platinum particles with a size of less than 0.355 nm. The platinum particles with a size of 1-5 nm can be loaded on the surface pores of the carrier, avoiding the embedding of the platinum particles in the deep pores of the traditional microporous structure. The closed pore structure makes the catalyst unable to contact the reactants, resulting in the problem of inactivation of active sites, and finally realizing the stable operation of the fuel cell.

[0099] The following will be described in conjunction with specific examples.

[0100] Example 1

[0101] The present example provides a carbon material, and a preparation method of the carbon material includes the following steps:

[0102] S1: polystyrene is placed in a roller continuous carbonization furnace, carbonized at 800°C for 8h under a nitrogen atmosphere, to obtain an intermediate A;

[0103] S2: the intermediate A is treated in a mixed gas atmosphere of H2O / N2 with a volume ratio of 5:95 at 500°C for 0.5h to form a porous product;

[0104] S3: the porous product is ground into nanoparticles with an average particle size of 500 nm by using a planetary ball mill;

[0105] S4: the nanoparticles are placed in a graphitization furnace and treated at 2200°C for 0.5h.

[0106] The carbon material has a grain gap degree Φ of 54%, a specific surface area of 800 m 2 / g, a G peak position of 1584.3 cm -1 , I 2G / I G =0.69, La=2.1 nm, d 002 =0.344 nm, and Lc=1.5 nm.

[0107] Example 2

[0108] The present example provides a carbon material, and a preparation method of the carbon material includes the following steps:

[0109] S1: polyvinylidene chloride resin is placed in a carbonization furnace, carbonized at 1200°C for 2h under a nitrogen atmosphere, to obtain an intermediate A;

[0110] S2: the intermediate A is treated in a mixed gas atmosphere of O2 / N2 with a volume ratio of 10:90 at 500°C for 5h to form a porous product;

[0111] S3: the porous product is crushed into nanoparticles with an average particle size of 40 nm by using a super micro powder crusher;

[0112] S4: the nanoparticles are placed in a graphitization furnace and treated at 1800°C for 2h.

[0113] The carbon material has a grain gap degree Φ of 93%, a specific surface area of 1200 m 2 / g, and a G peak position of 1589.2 cm -1 , I 2G / I G =0.78, La=2.4 nm, and d 002 =0.352 nm, Lc=1.8 nm.

[0114] Example 3

[0115] The present example provides a carbon material, and a preparation method of the carbon material includes the following steps:

[0116] S1: carboxymethyl cellulose is placed in a kiln, carbonized at 1000°C for 2h under a nitrogen atmosphere to obtain an intermediate A;

[0117] S2: the intermediate A is treated at 600°C for 3h under a mixed gas atmosphere of O2 / N2 with a volume ratio of 5:95 to form a porous product;

[0118] S3: the porous product is placed into a sand mill to be ground into nanoparticles with an average particle size of 200 nm;

[0119] S4: the nanoparticles are placed into a graphitization furnace for treatment at 2400°C for 2h.

[0120] The carbon material has a grain gap degree Φ of 80%, a specific surface area of 420 m 2 / g, a G peak position of 1583.6 cm -1 , I 2G / I G =0.47, La=5.5 nm, and d 002 =0.343 nm, Lc=4.6 nm.

[0121] Example 4

[0122] The present example provides a carbon material, and a preparation method of the carbon material includes the following steps:

[0123] S1: carboxymethyl cellulose is placed in a carbonization furnace, carbonized at 800°C for 2h under a nitrogen atmosphere to obtain an intermediate A;

[0124] S2: the intermediate A is treated at 400°C for 0.5h under a mixed gas atmosphere of O2 / N2 with a volume ratio of 5:95 to form a porous product;

[0125] S3: the porous product is placed into a sand mill to be ground into nanoparticles with an average particle size of 200 nm;

[0126] S4: the nanoparticles are placed into a graphitization furnace for treatment at 2000°C for 2h.

[0127] The carbon material has a grain gap degree Φ of 44%, a specific surface area of 410 m 2 / g, and a G peak position of 1584.0 cm -1 , I 2G / I G =0.42, La=3.9 nm, d 002 =0.345 nm, and Lc=2.0 nm.

[0128] Example 5

[0129] The present example provides a carbon material, and a preparation method of the carbon material includes the following steps:

[0130] S1: coal tar is subjected to atomization treatment, and is carbonized at 1500 DEG C. for 1 h under a nitrogen atmosphere in a fluidized bed to obtain an intermediate A;

[0131] S2: the intermediate A is treated at 600 DEG C. for 2 h under a mixed atmosphere of O3 / N2 at a volume ratio of 10:90 to form a porous product;

[0132] S3: the porous product is scattered into nanoparticles with an average particle size of 500 nm by a cyclone separator;

[0133] S4: the nanoparticles are treated at 2800 DEG C. for 3 h in a graphitization furnace.

[0134] The carbon material has a grain gap degree Φ of 37%, a specific surface area of 100 m 2 / g, a G peak position of 1581.0 cm -1 , I 2G / I G =0.22, La=13.0 nm, d 002 =0.343 nm, and Lc=7.1 nm.

[0135] Example 6

[0136] The present example provides a carbon material, and a preparation method of the carbon material includes the following steps:

[0137] S1: polyvinylidene chloride resin is placed in a kiln, and is carbonized at 1100 DEG C. for 2 h under a nitrogen atmosphere to obtain an intermediate A;

[0138] S2: the intermediate A is treated at 600 DEG C. for 3 h under a mixed atmosphere of O2 / N2 at a volume ratio of 5:95 to form a porous product;

[0139] S3: the porous product is put into a super micro-powder pulverizer to be pulverized into nanoparticles with an average particle size of 100 nm;

[0140] S4: the nanoparticles are treated at 2200 DEG C. for 3 h in a graphitization furnace.

[0141] The grain size Φ of this carbon material is 49%, and its specific surface area is 380m². 2 / g, G peak position 1582.5cm -1 I 2G / I G =0.44, La=4.5nm, d 002 =0.345nm, Lc=2.5nm.

[0142] Example 7

[0143] This embodiment provides a carbon material, the preparation method of which includes the following steps:

[0144] S1: Polystyrene is placed in a carbonization furnace and carbonized at 1300℃ for 2 hours under a nitrogen atmosphere to obtain intermediate A;

[0145] S2: Intermediate A is treated at 500°C for 1 hour in an O2 / N2 mixed atmosphere with a volume ratio of 10:90 to form a porous product;

[0146] S3: Grind the porous product in a sand mill until it becomes nanoparticles with an average particle size of 500 nm.

[0147] S4: Place the nanoparticles in a graphitization furnace and treat them at 2500℃ for 0.5h.

[0148] The grain size Φ of this carbon material is 53%, and its specific surface area is 139m². 2 / g, G peak position 1581.7cm -1 I 2G / I G =0.30, La=9.5nm, d 002 =0.344nm, Lc=12.8nm.

[0149] Comparative Example 1

[0150] Comparative Example 1 provides a carbon material, the preparation method of which includes the following steps:

[0151] S1: Natural graphite is pulverized into nanoparticles with an average particle size of 1200nm;

[0152] S2: Place the nanoparticles in a graphitization furnace and treat them at 2200℃ for 3 hours.

[0153] The grain size Φ of this carbon material is 27%, and its specific surface area is 76m². 2 / g, G peak position 1578.6cm -1 I 2G / I G =0.14, La=15.6nm, d 002=0.339nm, Lc=5.3nm.

[0154] Comparative Example 2

[0155] This embodiment provides a carbon material, the preparation method of which includes the following steps:

[0156] S1: Coal tar is placed in a kiln and carbonized at 1500℃ for 2 hours under a nitrogen atmosphere to obtain intermediate A;

[0157] S2: Intermediate A is treated in an O2 / N2 mixed atmosphere with a volume ratio of 5:95 at 400°C for 0.5 h to form a porous product;

[0158] S3: Grind the porous product in a ball mill until it becomes nanoparticles with an average particle size of 500 nm;

[0159] S4: Place the nanoparticles in a graphitization furnace and treat them at 2900℃ for 3 hours.

[0160] The grain size Φ of this carbon material is 28%, and its specific surface area is 41 m². 2 / g, G peak position 1579.8cm -1 I 2G / I G =0.19, La=21.2nm, d 002 =0.342nm, Lc=15.4nm.

[0161] Comparative Example 3

[0162] This embodiment provides a carbon material, the preparation method of which includes the following steps:

[0163] S1: Carboxymethyl cellulose was placed in a kiln and carbonized at 800°C for 2 hours under a nitrogen atmosphere to obtain intermediate A;

[0164] S2: Intermediate A is treated at 400°C for 2 hours in an O2 / N2 mixed atmosphere with a volume ratio of 5:95 to form a porous product;

[0165] S3: Place the porous product into an ultrafine pulverizer and grind it into nanoparticles with an average particle size of 500nm;

[0166] S4: Place the nanoparticles in a graphitization furnace and treat them at 1700℃ for 1 hour.

[0167] The carbon material has a grain size Φ of 29% and a specific surface area of ​​700 m². 2 / g, G peak position 1590.4cm -1 I 2G / I G =0.82, La=1.3nm, d 002= 0.363 nm, Lc = 1.0 nm.

[0168] Material performance test

[0169] In order to verify the progressiveness of the embodiments of the present application, the samples of the embodiments and the comparative examples were respectively tested as follows:

[0170] 1. Specific surface area S BET Test

[0171] According to GB / T 19587-2017, the nitrogen adsorption specific surface area analysis test method was used for testing, and the BET (Brunauer Emmett Teller) method was used for calculation. Specifically, after determining the adsorption amount of gas on the solid surface at different relative pressures, the monolayer adsorption amount of the sample was obtained based on the Brunauer-Emmett-Teller adsorption theory and its formula (BET formula), so as to calculate the specific surface area of the material.

[0172] 2. Raman spectrum

[0173] According to GB / T 30544.6-2016, the G peak, D peak, 2G peak, I 2G / I G and other parameters of the carbon material were tested and analyzed.

[0174] 3. Interplanar spacing

[0175] The interplanar spacing d 002 of the carbon material was tested by an X-ray powder diffractometer (XRD, instrument model: Bruker D8 ADVANCE), wherein the target material was Cu Kα, the test voltage was 40KV, the test current was 35mA, the scanning angle range was 10° to 90°, the scanning rate was 0.02° / s, and the strongest diffraction peak intensity was required to be greater than 10000, units: counts. The Fullprof software was used to refine the collected XRD spectrum to determine the phase structure. The C{002} interplanar spacing diffraction angle position was measured by XRD powder diffraction, and the interplanar spacing d 002 of the carbon material was obtained from the Bragg equation (Bragg diffraction formula) 2d 002 sinθ = λK.

[0176] 4. Grain size La and longitudinal stacking height Lc of graphite crystallites

[0177] Twenty carbon particles were randomly obtained, and the ratio ID / IG of the peak area ID of the carbon characteristic peak to the peak area IG of the graphite characteristic peak of the carbon particles was measured by Raman spectrum test (Raman laser wavelength λ = 514nm) to obtain the value Rn, n = 1, 2, 3…20; the I D / IG The average value of R is R;

[0178] ;

[0179] ;

[0180] In the formula, the X-ray wavelength λ = 0.15406 nm, β is the half-peak width of the (002) crystal face diffraction peak, and θ is the (002) crystal face diffraction angle.

[0181] 5. Dv50 particle size

[0182] The Dv50 particle size of the carbon material is a meaning known in the art, which represents the particle size corresponding to the cumulative volume distribution percentage of 50% of the material, and can be measured by instruments and methods known in the art. For example, it can be conveniently measured by referring to GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method, using a laser particle size analyzer. The testing instrument can be a Mastersizer 3000 laser particle size analyzer of Malvern Instruments Ltd., UK.

[0183] 6. Morphology characterization of carbon material

[0184] The carbon particles are dispersed in ethanol, dropped on a copper mesh, dried, and then observed. The FEI Tecnai G2F30 transmission electron microscope is used for testing, with an acceleration voltage of 120 kV, to observe the morphology and size of the sample.

[0185] 7. Total metal content

[0186] Referring to the national standard GB / T 24533-2019 Lithium Ion Battery Graphite Anode Material, the elements content is tested by ICP-OES through digestion in a high temperature and high pressure closed environment of a microwave digestion instrument.

[0187] Battery performance test

[0188] 1. Chloroplatinic acid is dissolved in ethylene glycol and added dropwise to the carbon material prepared in the above examples and comparative examples under vigorous stirring, dried, and then heated and reduced under a mixed gas of hydrogen and argon with a volume ratio of 1:9, the treatment conditions are 300°C, 90 min, then the carbon material is dispersed in water, H2PtCl6 and formic acid are added, stirred for 5 hours, filtered, washed, dried, and then a platinum carbon catalyst is obtained. By adding 10g of catalyst sample into aqua regia for digestion, filtering (if there is residue), constant volume, the platinum content of the platinum carbon catalyst is tested by ICP-OES (inductively coupled plasma atomic emission spectrometry).

[0189] 2. Test method of half-cell ECSA: 200 mg catalyst was weighed and 5% Nafion solution, deionized water and isopropyl alcohol were added in sequence, and the slurry was dispersed by ultrasonic to obtain a uniformly mixed slurry. The electrode surface catalyst loading was 50 μg / cm 2 ~ 200 μg / cm 2 , and an appropriate amount of the dispersed slurry was added to the smooth and clean disc electrode surface in two equal portions, and dried to serve as the working electrode. The electrode was placed in an electrolytic cell to form a three-electrode system. The reference electrode was a reversible hydrogen electrode (RHE), the counter electrode was a large-area Pt sheet, and the electrolyte was a saturated 0.1 mol / L HCIO4 solution.

[0190] Cyclic voltammetry was performed using a constant potential instrument. The cyclic voltammogram was tested: first, the catalyst was activated at a scan rate of 20 mV / s until the hydrogen desorption peak area no longer increased, and then scanned at a speed of 20 mV / s for 5 cycles, with a potential scan range of 0.05 V to 1.1 V vs RHE. The stable cyclic voltammogram was selected, and the hydrogen desorption peak (0.05 V to 0.4 V vs RHE) was integrated to obtain the area S, and the electrochemical active area ECSA was calculated according to the formula.

[0191] ECSA was calculated according to the formula:

[0192]

[0193] wherein S is the integral area of the hydrogen desorption / adsorption peak (A*V), C is the charge constant of hydrogen adsorbed on the smooth Pt surface (0.21 mC / cm 2 ), v is the scan rate (mV / s), and M is the mass of Pt on the working electrode (g).

[0194] 3. Test method of half-cell durability: 65°C air condition, 0.9 V for 3 s, 0.65 V for 2 s as a square wave cycle, and the ECSA retention rate after 50,000 cycles was tested.

[0195] Performance results

[0196] Table 1

[0197]

[0198] Table 2

[0199]

[0200] The physicochemical characteristics of Table 1 and the performance data of Table 2 show that the carbon materials of Examples 1-3 meet the specific surface area (400-1200 m 2 / g, La (2-6 nm), Lc (1.5-6 nm) and interlamellar porosity (50-95%) core parameter requirements, the catalyst ECSA≥90 m 2 / g-Pt effect, durability 50000 cycles after ECA retention rate of 80%. Far better than Comparative Example 3 (700 m 2 / g specific surface area, La=1.3nm, Lc=1.0nm) 59% ECSA retention rate, indicating that by controlling the degree of grain order structure (d 002 <0.344 nm, La>5nm, Lc>4nm) inhibits carbon matrix oxidation, breaks through the traditional carbon black high activity but low durability (commercial carbon black retention rate of only 55%) bottleneck, indicating that the material has moderate conjugated defects and interlayer coupling, while maintaining the high activity site of the catalyst, while improving the corrosion resistance, suitable for high activity scenarios.

[0201] The specific surface area of the carbon material of Example 4 meets (400-1200 m 2 / g), La (2-13 nm), Lc (1.5-6 nm) core parameter requirements, but the interlamellar porosity is less than 50%, although the ECSA retention rate is more than 80% after 50000 cycles of durability, but the ECSA is less than 90 m 2 / g-Pt, that is, the low interlamellar porosity limits the activity.

[0202] The carbon material of Examples 5-7 meets the specific surface area (100-400 m 2 / g), La (3.5-13 nm), Lc (2-13 nm) and interlamellar porosity (30%-55%) core parameter requirements, which realizes the catalyst ECSA≥80 m 2 / g-Pt effect, durability 50000 cycles after ECA retention rate of 90%. The material has low conjugated defects and moderate interlayer coupling, which has high durability and high activity site characteristics, suitable for corrosion-prone scenarios.

[0203] Comparative Example 1 because the grain is not fully oxidized, the broken particle size is insufficient (G peak 1574 cm -1 , La=15.6nm, I 2G / I G =0.14) resulting in insufficient specific surface area (91 m 2 / g) and Φ value (34%). Comparative Example 2 because of excessive graphitization (G peak 1579.8 cm -1 , I 2G / I G =0.19, ) resulting in excessive grain growth (La=21.2nm, Lc=15.4nm), specific surface area (41 m2 G) and insufficient Φ value (28%). Comparative Example 3 has insufficient graphitization degree (G peak 1590.4 cm -1 2G G =0.82, d 002 =0.363 nm), resulting in insufficient grain size (La=1.8 nm, Lc=1.4 nm) and Φ value (29%). The low platinum loading of Comparative Example 1 and Comparative Example 2 exposes the restriction of low inter-grain gap structure on catalytic performance, which inversely proves the effectiveness of the present application in solving technical contradictions through synergistic optimization of structure parameters.

[0204] Figure 3 The Raman spectrum of the carbon material of Example 1 is shown in the figure, which directly supports the core design of the carbon material "synergistic optimization of high specific surface area and graphitization order" through spectral data, and is mutually confirmed with the structure parameters (such as d 002 =0.344 nm) of Example 1 in Table 1.

[0205] Figure 4 The transmission electron microscope image reveals the micro-morphology of the carbon material, which directly proves from the nanometer scale that the carbon material of the present application has the structural advantage of "graphite microporous network".

[0206] The above only describes exemplary embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made under the technical concept of the present application, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.​​

Claims

1. A carbon material for use as a catalyst support, characterized in that: The carbon material has a graphite microcrystalline structure, and the interplanar spacing d of the graphite microcrystalline structure was measured by X-ray diffraction. 002 <0.355nm: The grain size La of the graphite microcrystals is 2 nm to 14 nm, which is calculated by the intensity ratio of the D peak and the G peak in the Raman spectrum of carbon. ; The longitudinal stacking height Lc of the graphite microcrystals is 1.5 nm to 13 nm, which is calculated by combining the XRD (002) diffraction peak characteristics of carbon with the Scherrer equation. , In the formula: λ is the X-ray wavelength, β is the half-width of the (002) crystal plane diffraction peak, and θ is the (002) crystal plane diffraction angle; The specific surface area S of the carbon material BET 100m 2 / g~1200m 2 / g; And the carbon material satisfies: 30%≤Φ≤95%; Φ represents the grain spacing of the carbon material. .

2. The carbon material for catalyst support as described in claim 1, characterized in that, The specific surface area S of the carbon material BET 400m 2 / g~1200m 2 / g, La is 2nm~6nm, Lc is 1.5nm~5nm, and the grain spacing Φ is 50%-95%.

3. The carbon material for catalyst support as described in claim 1, characterized in that, The specific surface area S of the carbon material BET 100m 2 / g~400m 2 / g, La is 3.5nm~13nm, Lc is 2nm~13nm, and the grain spacing Φ is 30%~55%.

4. The carbon material for catalyst support as described in claim 1, characterized in that, The total metal content of the carbon material is <100ppm, and the metals include any one or more of Fe, Co, Ni, Cr, Mn, Cu, Al, Zn, Na, K, Ca, and Mg.

5. The carbon material for catalyst support as described in any one of claims 1 to 4, characterized in that, The carbon material has a G peak at 1580 cm⁻¹ in the Raman spectrum. -1 ~1590cm -1 The half-width at half maximum (FWHM) of the G peak is 25 cm. -1 ~50cm -1 ; And / or, the intensity ratio of the 2G peak to the G peak in the Raman spectrum of the carbon material is I. 2G / I G The value is 0.2~0.8; And / or, the Dv50 particle size of the carbon material is 20nm~1000nm.

6. A method for preparing a carbon material for a catalyst support as described in any one of claims 1 to 5, characterized in that, Includes the following steps: An organic carbon source is carbonized at 800℃~1500℃ for 0.5h~8h in an inert atmosphere to obtain intermediate A; the organic carbon source includes at least one of phenolic resin, polyimide, polystyrene, lignin, coal tar, asphalt, benzo[a]pyrene, polyacrylonitrile, polyvinyl alcohol, polyethylene, polyvinylidene chloride, cellulose, carboxymethyl cellulose, citric acid, melamine, aziridine carbazole, and thiophene. The intermediate A is subjected to pore-forming treatment at 400℃~600℃ for 0.5h~5h in a mixed atmosphere of activating gas and inert gas to form a porous product; the volume ratio of the activating gas to the inert gas is 5:95 to 10:90; the activating gas includes at least one of H2O, O2, O3, CO2, and air; The porous product is broken down into nanoscale particles; The carbon material is obtained by graphitizing the nanoparticles; the graphitization temperature is 1800℃~2800℃ and the treatment time is 0.5h~3h.

7. The method for preparing carbon material for catalyst support as described in claim 6, characterized in that, The particle size of the nanoscale particles ranges from 20 nm to 1000 nm.

8. A catalyst, characterized in that, It includes a carbon support and platinum particles supported on the carbon support, wherein the carbon support includes the carbon material for catalyst support according to any one of claims 1 to 5, or the carbon material obtained by the preparation method of the carbon material for catalyst support according to any one of claims 6 to 7.

9. The catalyst as claimed in claim 8, characterized in that, Based on the mass of the catalyst being 100%, the mass percentage of the platinum particles in the catalyst is 20% to 60%. And / or, the average particle size of the platinum particles is 1 nm to 5 nm.

10. A fuel cell, characterized in that, It includes a catalyst layer, said catalyst layer comprising the catalyst of claim 8 or 9.

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