Carbon materials, carbon-supported platinum group metal catalysts, hydrogen fuel cells, and methods for preparing and applying the carbon-supported platinum group metal catalysts.

Abstract

This invention relates to platinum-carbon catalysts, their preparation methods, and applications. In the XPS analysis of the N1s spectrum of this platinum-carbon catalyst, besides a characteristic peak between 399 eV and 400.5 eV, there are no other characteristic peaks between 395 eV and 405 eV. The support for the platinum-carbon catalyst is nitrogen-doped conductive carbon black. This invention modifies the conductive carbon black support for the platinum-carbon catalyst, significantly improving the specific activity and electrochemical area of ​​the catalyst by controlling the doping form of the doping elements. Furthermore, it also improves the stability and carbon corrosion resistance of the platinum-carbon catalyst. In addition, this invention provides a simple method for preparing the above-mentioned platinum-carbon catalyst.

Description

[Technical Field]

[0001] This invention relates to carbon-supported platinum group metal catalysts, their preparation methods and applications, and particularly to carbon-supported platinum group metal catalysts for proton exchange membrane hydrogen fuel cells, their preparation methods and applications. [Previous Technology]

[0002] The oxygen reduction reaction (ORR) is a key reaction in the field of electrochemistry. For example, in fuel cells and metal-air batteries, the ORR is a major factor affecting battery performance. Doped carbon materials can be directly used as catalysts for the ORR. When used as ORR catalysts, literature reports the incorporation of elements such as nitrogen, phosphorus, boron, sulfur, fluorine, chlorine, bromine, and iodine into carbon materials. Among these, nitrogen, with an atomic radius close to that of carbon, easily enters the carbon lattice and is therefore the most commonly used doping element. Although there are many literature reports on the direct use of doped carbon materials as fuel cell catalysts, there is still a significant gap compared to platinum-carbon catalysts.

[0003] To date, the most effective oxygen reduction catalyst is the platinum-carbon catalyst, but it still has shortcomings. On the one hand, platinum resources are scarce and expensive. On the other hand, the dispersion of platinum metal in currently used commercial platinum-carbon catalysts is not ideal and it is prone to agglomeration and deactivation. The dissolution and agglomeration of platinum at the cathode of hydrogen fuel cells lead to a significant decrease in platinum surface area over time, affecting the lifespan of the fuel cell. Existing technologies mainly improve the performance of platinum-carbon catalysts by controlling the particle size, morphology, and structure of platinum, as well as the specific surface area and pore structure of the support; some literature also reports that the performance of platinum-carbon catalysts can be improved by modifying the carbon support.

[0004] Carbon supports can increase the specific surface area of ​​catalysts, reduce metal particle agglomeration, and improve metal utilization. Increasing the platinum loading on carbon supports is beneficial for manufacturing thinner, higher-performance membrane electrodes, but significantly increasing the platinum loading is more likely to cause accumulation between platinum metal particles, leading to a sharp decline in the utilization rate of active sites. In addition, the platinum loading of platinum-carbon catalysts for hydrogen fuel cells in practical applications is at least 20 wt%, which is much more difficult to manufacture than chemical platinum-carbon catalysts (platinum loading less than 5 wt%).

[0005] The deactivation of platinum-carbon catalysts caused by carbon corrosion in proton exchange membrane fuel cells has attracted considerable attention in this field. Furthermore, platinum accelerates the carbon corrosion rate; the higher the platinum loading, the faster the carbon corrosion. On the one hand, a higher number of defect sites on the carbon support is beneficial for increasing the platinum loading, but it also exacerbates carbon corrosion. On the other hand, increasing the degree of graphitization can alleviate carbon corrosion, but it also makes the carbon support surface chemically inert, making it difficult to uniformly disperse platinum on the carbon support.

[0006] The information disclosed in the foregoing background section is only used to enhance the understanding of the background of the present invention, and may include information that is not known to those skilled in the art. [Summary of the Invention]

[0007] The first objective of this invention is to provide a carbon-supported platinum group metal catalyst that significantly improves specific activity and electrochemical surface area, particularly under high platinum loading conditions. The second objective of this invention, based on the foregoing objectives, is to improve the overall performance of the catalyst, particularly enhancing the stability of specific activity and electrochemical surface area. The third objective of this invention, based on the foregoing objectives, is to improve the carbon corrosion resistance of the carbon-supported platinum group metal catalyst. The fourth objective of this invention, based on the foregoing objectives, is to provide a simple method for preparing the carbon-supported platinum group metal catalyst. Other objectives of this invention are embodied through the detailed discussion and examples provided herein.

[0008] In order to achieve one or more of the aforementioned objectives, the present invention provides the following technical solutions.

[0009] 1. A carbon-supported platinum group metal catalyst, characterized in that, in the N1s spectrum of the XPS analysis of the carbon-supported platinum group metal catalyst, there is a characteristic peak between 399 eV and 400.5 eV, and there are no or substantially no other characteristic peaks between 395 eV and 405 eV; the support of the carbon-supported platinum group metal catalyst is nitrogen-doped conductive carbon black; the platinum mass fraction of the carbon-supported platinum group metal catalyst is 20% to 70%, preferably 40% to 70%, for example, it can be 45% to 65%.

[0010] 2. The carbon-supported platinum group metal catalyst according to aspect 1, characterized in that the support for the carbon-supported platinum group metal catalyst is sulfur and nitrogen-doped conductive carbon black.

[0011] 3. The carbon-supported platinum group metal catalyst according to aspect 1, characterized in that, in the S2P spectrum of its XPS analysis, the area of ​​the characteristic peaks between 163 eV and 166 eV is greater than 92%, or greater than 95%, or greater than 98%, or only the characteristic peaks between 163 eV and 166 eV are located between 160 eV and 170 eV.

[0012] 4. The carbon-supported platinum group metal catalyst according to aspect 1, characterized in that the conductive carbon black is ordinary conductive carbon black, superconducting carbon black or extra-conducting carbon black.

[0013] 5. The carbon-supported platinum group metal catalyst according to aspect 1, characterized in that the platinum group metal is selected from platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), osmium (Os), and ruthenium (Ru), preferably selected from platinum, palladium, rhodium, and iridium, and even more preferably selected from platinum and palladium, for example, platinum.

[0014] 6. The carbon-supported platinum group metal catalyst according to aspect 1, characterized in that the resistivity of the carbon-supported platinum group metal catalyst is <10 Ω·m, preferably <2 Ω·m.

[0015] 7. A hydrogen fuel cell, characterized in that the anode and / or cathode of the hydrogen fuel cell use a carbon-supported platinum group metal catalyst as described in any one of aspects 1 to 6.

[0016] 8. A carbon material, characterized in that the carbon material is nitrogen-doped conductive carbon black, and in its XPS analysis N1s spectrum peaks, apart from the characteristic peaks between 399 eV and 400.5 eV, there are no other characteristic peaks between 395 eV and 405 eV.

[0017] 9. A method for preparing a carbon-supported platinum group metal catalyst as described in any one of aspects 1-6, comprising the following steps: (1) a step of impregnating a nitrogen source: mixing a carbon material with an aqueous solution of a nitrogen source (wherein, optionally, a small amount of ethanol is added as needed, such as dispersing the carbon material in a 20% aqueous ethanol solution), impregnating, to obtain a carbon material impregnated with a nitrogen source; (2) a step of manufacturing a nitrogen-doped carbon material: heating the carbon material impregnated with a nitrogen source obtained in step (1) to 1000°C to 1500°C in an inert gas at a rate of 8°C / min to 15°C / min, and then isothermal treatment for 0.5 h to 10 h to obtain a nitrogen-doped carbon material; and (3) a step of loading platinum group metals: using the nitrogen-doped carbon material obtained in step (2) as a support, loading platinum group metals;

[0018] The carbon material is preferably conductive carbon black.

[0019] 10. The preparation method according to aspect 9, characterized in that, in (2), the temperature of the isothermal treatment is 1150℃~1450℃.

[0020] 11. The preparation method according to aspect 9, characterized in that the nitrogen source is ammonia / or urea.

[0021] 12. The preparation method according to aspect 9, characterized in that the mass of the nitrogen source is based on the mass of nitrogen element contained therein, and the mass ratio of the carbon material to the nitrogen source is 30:1 to 1:2.

[0022] 13. The preparation method according to aspect 6, characterized in that the oxygen mass fraction in the XPS analysis of the carbon material is greater than 4%.

[0023] 14. The preparation method according to aspect 9, characterized in that the step of loading platinum group metals includes: (a) dispersing the nitrogen-doped carbon material obtained in step (2) with the platinum group metal precursor in an aqueous phase and adjusting the pH to 8-12; (b) adding a reducing agent for reduction; and (c) separating the solid and obtaining the platinum carbon catalyst by post-processing.

[0024] 15. The preparation method according to aspect 14, characterized in that the platinum group metal precursor is chloroplatinic acid, potassium chloroplatinate or sodium chloroplatinate; the concentration of the platinum group metal precursor is 0.5 mol / L to 5 mol / L.

[0025] 16. The preparation method according to aspect 14, characterized in that, in step (b), the reducing agent is selected from citric acid, ascorbic acid, formaldehyde, formic acid, ethylene glycol, sodium citrate, hydrazine hydrate, sodium borohydride and glycerol; the molar ratio of the reducing agent to platinum is 2 to 100; the reduction temperature is 50°C to 150°C; and the reduction time is 2 h to 15 h.

[0026] Not limited to any known theory, preferably, based on the analysis of experimental data on characteristic peaks located between 163 eV and 166 eV, for example as illustrated and discussed in this invention, it is believed that the characteristic peaks between 163 eV and 166 eV are characteristic peaks of thiophene-type sulfur. In one embodiment, preferably, it is believed that the characteristic peaks of thiophene-type sulfur are bimodal.

[0027] Heteroatoms can bond with carbon materials in various ways, and there are various interactions between heteroatoms. Different preparation methods, raw materials, and different operation steps and conditions in the doping process will affect the bonding mode between heteroatoms and carbon materials and the interactions between heteroatoms, resulting in significant differences in the properties of heteroatoms and carbon materials, and causing significant changes in their functions. In this field, how to control the bonding mode between heteroatoms and carbon materials and the interactions between heteroatoms is a challenge when doping atoms. The research of this invention has found that when doping conductive carbon black, by controlling the bonding mode between heteroatoms and conductive carbon black and the interactions between heteroatoms, carbon materials with unique properties can be produced, thereby significantly improving the specific activity and electrochemical area, improving the overall performance of catalysts, improving the stability of specific activity and electrochemical area, and improving the carbon corrosion resistance of carbon-supported platinum group metal catalysts, etc.

[0028] Compared with the prior art, the present invention can achieve the following beneficial technical effects. First, the present invention uses a simple method to manufacture a type of conductive carbon black with unique surface-doped atoms. Compared with existing doped carbon materials, the sulfur doped on the surface of this conductive carbon black exists only in the form of thiophene-type sulfur, and the nitrogen doped on the surface can exist only in the form of pyrrole-type nitrogen. These characteristics can significantly improve the specific activity and electrochemical area of ​​carbon-supported platinum group metal catalysts. Furthermore, the surface of this conductive carbon black can be doped with phosphorus and / or boron. The surface-doped phosphorus can have characteristic peaks only between 132.5 eV and 134.5 eV, and the surface-doped boron can have characteristic peaks only between 189 eV and 191 eV. These characteristics can improve the overall performance of carbon-supported platinum group metal catalysts, especially improving the specific activity and the stability of the electrochemical area. Furthermore, the surface of this conductive carbon black can be multi-doped with multiple (e.g., three or four) heteroelements. This feature is beneficial for improving the carbon corrosion resistance of carbon-supported platinum group metal catalysts. II. The doped conductive carbon black of this invention is suitable for manufacturing carbon-supported platinum group metal catalysts with high platinum loading, exhibiting excellent comprehensive catalytic performance and resistance to carbon corrosion even at platinum group metal loading levels as high as 70 wt%. III. The platinum loading of carbon-supported platinum group metal catalysts in practical hydrogen fuel cells is generally above 20 wt%, making it very difficult to manufacture high-performance catalysts with high platinum group metal loading. Chemical reduction methods are simple, but the utilization rate of platinum group metals is low, resulting in relatively low catalytic activity. However, using the doped conductive carbon black manufactured in this invention as a support, a high platinum loading catalyst with excellent specific activity and stability can be easily manufactured using an aqueous phase chemical reduction method.

[0029] As examples, the present invention provides the following exemplary embodiments, or combinations thereof:

[0030] The first series of exemplary embodiments of the present invention include:

[0031] 1. A platinum-carbon catalyst, characterized in that, in its XPS analysis of the N1s spectrum, apart from the characteristic peak between 399 eV and 400.5 eV, there are no other characteristic peaks between 395 eV and 405 eV.

[0032] 2. The platinum-carbon catalyst according to Embodiment 1, characterized in that, based on the mass of the catalyst, the mass fraction of platinum is 20% to 70%, preferably 40% to 70%.

[0033] 3. The platinum-carbon catalyst according to Example 1, characterized in that the resistivity of the platinum-carbon catalyst is <10 Ω·m.

[0034] 4. The platinum-carbon catalyst according to Example 1, characterized in that the support for the platinum-carbon catalyst is nitrogen-doped conductive carbon black, nitrogen-doped graphene, or nitrogen-doped carbon nanotubes.

[0035] 5. The platinum-carbon catalyst according to Example 4, characterized in that the conductive carbon black is EC-300J, EC-600JD, ECP600JD, VXC72, Black Pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXK 40B2.

[0036] 6. A method for preparing a platinum-carbon catalyst, comprising: (1) a step of impregnating a nitrogen source: mixing a carbon material with an aqueous solution of a nitrogen source and impregnating it to obtain a carbon material impregnated with a nitrogen source; (2) a step of manufacturing a nitrogen-doped carbon material: heating the carbon material impregnated with a nitrogen source obtained in (1) to 1000℃~1500℃ in an inert gas at a rate of 8℃ / min~15℃ / min, and then isothermal treatment for 0.5 h~10 h to obtain a nitrogen-doped carbon material; (3) a step of loading platinum: using the nitrogen-doped carbon material obtained in (2) as a support to load platinum.

[0037] 7. The preparation method according to Example 6, characterized in that, in (2), the temperature of the isothermal treatment is 1150℃~1450℃.

[0038] 8. The preparation method according to Example 6, wherein the nitrogen source is ammonia / or urea.

[0039] 9. The preparation method according to Example 6, characterized in that the mass of the nitrogen source is based on the mass of nitrogen element contained therein, and the mass ratio of the carbon material to the nitrogen source is 30:1 to 1:2.

[0040] 10. The preparation method according to Example 6, wherein the carbon material is conductive carbon black, graphene or carbon nanotubes.

[0041] 11. The preparation method according to Example 10, wherein the conductive carbon black is EC-300J, EC-600JD, ECP-600JD, VXC72, Black Pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXK 40B2.

[0042] 12. The preparation method according to Example 6, characterized in that the oxygen mass fraction in the XPS analysis of the carbon material is greater than 4%.

[0043] 13. The preparation method according to Example 6, characterized in that the resistivity of the carbon material is <10 Ω·m.

[0044] 14. The preparation method according to Example 6, characterized in that the specific surface area of ​​the carbon material is 10 m2 / g to 2000 m2 / g.

[0045] 15. The preparation method according to Example 6, characterized in that the step of loading platinum includes: (a) dispersing the nitrogen-doped carbon material obtained in (2) and the platinum precursor in an aqueous phase and adjusting the pH to 8-12; (b) adding a reducing agent for reduction; (c) separating the solid and obtaining the platinum carbon catalyst by post-processing.

[0046] 16. The preparation method according to Example 15, characterized in that the platinum precursor is chloroplatinic acid, potassium chloroplatinate or sodium chloroplatinate; and the concentration of the platinum precursor is 0.5 mol / L to 5 mol / L.

[0047] 17. The preparation method according to Example 15, characterized in that, in (b), the reducing agent is one or more of citric acid, ascorbic acid, formaldehyde, formic acid, ethylene glycol, sodium citrate, hydrazine hydrate, sodium borohydride or glycerol; the molar ratio of the reducing agent to platinum is 2 to 100; the reduction temperature is 50°C to 150°C; and the reduction time is 2 h to 15 h.

[0048] 18. A platinum-carbon catalyst, characterized in that the catalyst is prepared by any of the methods in Examples 6 to 17.

[0049] 19. A hydrogen fuel cell, characterized in that any of the platinum-carbon catalysts of Examples 1 to 5 and 18 are used in the anode and / or cathode of the hydrogen fuel cell.

[0050] The second series of exemplary embodiments of the present invention includes:

[0051] 1. A platinum-carbon catalyst, characterized in that it comprises a carbon support and platinum metal supported thereon, wherein the carbon support is a sulfur-nitrogen-doped carbon material; and the XPS analysis of the catalyst shows that in the S2P spectrum, between 160 eV and 170 eV, there is only a characteristic peak between 163 eV and 166 eV.

[0052] 2. The platinum-carbon catalyst according to Example 1 is characterized in that, in the N1s spectrum of the catalyst analyzed by XPS, there are no other characteristic peaks between 390 eV and 410 eV except for the characteristic peak between 399 eV and 400.5 eV.

[0053] 3. The platinum-carbon catalyst according to Example 1 is characterized in that, based on the mass of the catalyst, the mass fraction of platinum is 20% to 70%, preferably 40% to 70%.

[0054] 4. The platinum-carbon catalyst according to Example 1, characterized in that the characteristic peak located between 163 eV and 166 eV is located at 163.4 ± 0.5 eV and 164.7 ± 0.5 eV.

[0055] 5. The platinum-carbon catalyst according to Example 1, characterized in that the sulfur-nitrogen-doped carbon material is sulfur-nitrogen-doped conductive carbon black, sulfur-nitrogen-doped graphene, or sulfur-nitrogen-doped carbon nanotubes.

[0056] 6. A method for preparing a platinum-carbon catalyst, comprising: (1) a step of manufacturing a sulfur-nitrogen-doped carbon material; and (2) a step of loading platinum onto the sulfur-nitrogen-doped carbon material obtained in step (1) as a support;

[0057] Step (1) includes the operation of doping sulfur and the operation of doping nitrogen;

[0058] The sulfur doping operation includes: placing the carbon material in an inert gas containing thiophene and treating it at 1000℃~1500℃ for 0.5 h~10 h;

[0059] The nitrogen doping operation is performed before, after, or simultaneously with the sulfur doping operation.

[0060] 7. The preparation method according to Example 6, characterized in that the mass of thiophene is based on the mass of sulfur it contains, and the mass ratio of the carbon material to thiophene is 20:1 to 2:1.

[0061] 8. The preparation method according to Example 6, characterized in that, in the sulfur doping operation, the temperature is 1150°C to 1450°C.

[0062] 9. The preparation method according to Example 6, characterized in that the mass of the nitrogen source is based on the mass of the nitrogen element it contains, and the mass ratio of the carbon material to the nitrogen source is 30:1 to 1:2.

[0063] 10. The preparation method according to Example 6, wherein the carbon material is conductive carbon black, graphene or carbon nanotubes.

[0064] 11. The preparation method according to Example 6, characterized in that the resistivity of the carbon material is <10 Ω•m and the specific surface area is 10 m2 / g to 2000 m2 / g.

[0065] 12. The preparation method according to Example 6, characterized in that the step of loading platinum includes: (a) dispersing the sulfur-nitrogen-doped carbon material obtained in (1) and the platinum precursor in an aqueous phase and adjusting the pH to 8-12; (b) adding a reducing agent for reduction; (c) separating the solid and obtaining the platinum-carbon catalyst by post-processing.

[0066] 13. The preparation method according to Example 12, characterized in that, in (a), the platinum precursor is chloroplatinic acid, potassium chloroplatinate or sodium chloroplatinate; the concentration of the platinum precursor is 0.5 mol / L to 5 mol / L.

[0067] 14. The preparation method according to Example 12, characterized in that, in (b), the reducing agent is one or more of citric acid, ascorbic acid, formaldehyde, formic acid, ethylene glycol, sodium citrate, hydrazine hydrate, sodium borohydride or glycerol; the molar ratio of the reducing agent to platinum is 2 to 100; the reduction temperature is 60°C to 90°C; and the reduction time is 4 h to 15 h.

[0068] 15. A method for preparing a platinum-carbon catalyst, comprising: (1) a step of impregnating a nitrogen source: mixing a carbon material with an aqueous solution of a nitrogen source and impregnating it to obtain a carbon material impregnated with a nitrogen source; (2) a step of manufacturing a sulfur-nitrogen-doped carbon material: placing the carbon material impregnated with a nitrogen source obtained in (1) in an inert gas containing thiophene and treating it at 1000℃~1500℃ for 0.5 h~10 h to obtain a sulfur-nitrogen-doped carbon material; (3) a step of loading platinum onto the sulfur-nitrogen-doped carbon material obtained in step (2) as a support.

[0069] 16. A platinum-carbon catalyst, characterized in that it is prepared by any one of the methods in Examples 6 to 15.

[0070] 17. A hydrogen fuel cell, characterized in that the anode and / or cathode of the hydrogen fuel cell uses any of the platinum-carbon catalysts of Examples 1 to 5 and 16.

[0071] The exemplary embodiments of the third series of the present invention include:

[0072] 1. A nitrogen-doped carbon material, in which the N1s spectrum peaks of its XPS analysis show no other characteristic peaks between 395 eV and 405 eV except for the characteristic peaks between 399 eV and 400.5 eV.

[0073] 2. The nitrogen-doped carbon material according to Example 1, characterized in that the nitrogen mass fraction in the XPS analysis of the nitrogen-doped carbon material is 0.1% to 10%.

[0074] 3. The nitrogen-doped carbon material according to Example 1, characterized in that the oxygen mass fraction in the XPS analysis of the nitrogen-doped carbon material is >4%.

[0075] 4. The nitrogen-doped carbon material according to Example 1, characterized in that the resistivity of the nitrogen-doped carbon material is <10 Ω·m.

[0076] 5. The nitrogen-doped carbon material according to Example 1, characterized in that the specific surface area of ​​the nitrogen-doped carbon material is 10 m2 / g to 2000 m2 / g.

[0077] 6. The nitrogen-doped carbon material according to Example 1, characterized in that the nitrogen-doped carbon material is nitrogen-doped conductive carbon black, nitrogen-doped graphene, or nitrogen-doped carbon nanotube.

[0078] 7. The nitrogen-doped carbon material according to Example 6, characterized in that the conductive carbon black is EC-300J, EC-600JD, ECP600JD, VXC72, Black Pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXK 40B2.

[0079] 8. A carbon support for a platinum-carbon catalyst, characterized in that the carbon support is nitrogen-doped conductive carbon black, and in its XPS analysis of the N1s spectrum, apart from a characteristic peak between 399 eV and 400.5 eV, there are no other characteristic peaks between 395 eV and 405 eV; in its XPS analysis, the oxygen mass fraction is 4% to 15%, the nitrogen mass fraction is 0.2% to 5%; and its specific surface area is 200 m2 / g to 2000 m2 / g.

[0080] 9. The carbon carrier according to Example 8, wherein the conductive carbon black is EC-300J, EC-600JD, ECP-600JD, VXC72, Black Pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXK 40B2.

[0081] 10. A method for preparing a nitrogen-doped carbon material, comprising: (1) a step of impregnating a nitrogen source: mixing a carbon material with an aqueous solution of a nitrogen source and impregnating it to obtain a carbon material impregnated with a nitrogen source; (2) a step of manufacturing a nitrogen-doped carbon material: heating the carbon material impregnated with a nitrogen source obtained in (1) to 1000℃~1500℃ in an inert gas at a rate of 8℃ / min~15℃ / min, and then isothermal treatment for 0.5 h~10 h.

[0082] 11. The preparation method according to Example 10, characterized in that, in (2), the temperature of the isothermal treatment is 1150℃~1450℃.

[0083] 12. The preparation method according to Example 10, wherein the nitrogen source is ammonia / or urea.

[0084] 13. The preparation method according to Example 10 is characterized in that the mass of the nitrogen source is based on the mass of nitrogen it contains, and the mass ratio of the carbon material to the nitrogen source is 30:1 to 1:2; preferably 25:1 to 1:1.5.

[0085] 14. Examples of the application of nitrogen-doped carbon materials or carbon supports as electrode materials in electrochemistry according to any one of embodiments 1 to 9.

[0086] 15. A fuel cell, characterized in that the fuel cell uses a nitrogen-doped carbon material or carbon support as described in any of the exemplary embodiments 1 to 9.

[0087] 16. The fuel cell according to Example Embodiment 15, wherein the fuel cell is a hydrogen fuel cell.

[0088] 17. A metal-air battery, characterized in that the metal-air battery uses nitrogen-doped carbon material or carbon carrier as described in any of the exemplary embodiments 1 to 9.

[0089] 18. The metal-air battery according to Example Embodiment 17, wherein the metal-air battery is a lithium-air battery.

[0090] Other features and advantages of the present invention will be described in detail in the Detailed Description section.

Implementation Method

[0092] The present invention will be described in detail below with reference to specific embodiments. However, it should be noted that the scope of protection of the present invention is not limited by these specific embodiments and principle explanations, but is determined by the scope of the patent application.

[0093] In this invention, except for the contents explicitly stated, any matters or issues not mentioned are directly applicable to those known in the art without any changes. Moreover, any implementation described herein can be freely combined with one or more other implementations described herein, and the resulting technical solutions or technical ideas are considered as part of the original disclosure or record of this invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination to be obviously unreasonable.

[0094] All features disclosed in this invention can be combined arbitrarily, and such combinations should be understood as the content disclosed or recorded in this invention. Unless those skilled in the art consider such combinations to be obviously unreasonable, they should all be regarded as specifically disclosed and recorded in this invention. The numerical points disclosed in this specification include not only the numerical points specifically disclosed in the embodiments, but also the endpoints of each numerical range in the specification. Any combination of these numerical points should be regarded as the range disclosed or recorded in this invention.

[0095] The technical and scientific terms in this invention, where defined, shall be used as defined, and where not defined, shall be understood according to their common meaning in the art.

[0096] The “doping element” in this invention includes nitrogen, phosphorus, boron, sulfur, fluorine, chlorine, bromine and iodine, or is selected from these elements.

[0097] In this invention, the term "doped with" a certain element means that the one or more elements specifically mentioned are doped into the material. However, the material may also be doped with other elements besides the one or more elements specifically mentioned, especially those commonly used in the art.

[0098] In this invention, a material "doped" with a certain element means that one or more of the specifically mentioned elements are doped into the material; wherein, in one embodiment, the material may also be doped with other elements besides the one or more specifically mentioned elements; and preferably, the material does not contain any doping elements other than the one or more specifically mentioned elements.

[0099] In this invention, except for "carbon materials containing doped elements" which can be uniquely identified based on context or its own limitations, all other references to "carbon materials" refer to carbon materials without doped elements. The same applies to subordinate concepts of carbon materials.

[0100] In this invention, "carbon black" and "carbon black" are interchangeable technical terms. In this invention, the graphene, carbon nanotubes, and conductive carbon black used in the carbon materials described herein have concepts well-known in the art and belong to different concepts. However, according to this invention, a carbon material may contain a low content of one or more other carbon materials, as long as it still belongs to the kind of carbon material recognized by those skilled in the art. For example, "graphene" may contain trace amounts (e.g., less than 1%, or less than 0.1% by weight) of conductive carbon black and / or carbon nanotubes for various reasons. Preferably, for example, for the purposes of this invention, the conductive carbon black contains less than 5% by weight, preferably less than 2% by weight of graphene and / or carbon nanotubes.

[0101] In this invention, "inert gas" refers to a gas that, in the preparation method of this invention, does not cause any perceptible effect on the performance of the carbon-doped material. The same applies to the sub-concept of carbon material.

[0102] The numerical range defined in this invention includes the endpoints of the numerical range. The "range" disclosed herein is given in the form of a lower limit and an upper limit, for example, one or more lower limits and one or more upper limits. A given range can be defined by selecting a lower limit and an upper limit, the selected lower and upper limits defining the boundaries of the given range. All ranges defined in this way are inclusive and composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-110 and 80-120 are listed for a specific parameter, it is understood that ranges of 60-120 and 80-110 are also predictable. Furthermore, if the listed lower limits are 1 and 2 and the listed upper limits are 3, 4 and 5, then the following ranges are all predictable: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0103] In this invention, unless otherwise stated, the terms "comprising," "including," "containing," "having," and similar wording indicate an open-ended meaning, but should also be understood to explicitly disclose a closed-ended meaning. For example, "comprising" means that other elements not listed may also be included, but also explicitly discloses the inclusion of only the listed elements. Furthermore, as used herein, "comprising / including" is interpreted as explicitly stating the presence of the mentioned feature, integer, step, or component, but does not exclude the presence or addition of one or more other features, integers, steps, components, or groups thereof. Additionally, the term "comprising" is intended to include embodiments covered by the terms "substantially consisting of" and "consisting of." Similarly, the term "substantially consisting of" is intended to include embodiments covered by the term "consisting of."

[0104] In this invention, unless otherwise stated, all embodiments and preferred embodiments mentioned herein can be combined with each other to form new technical solutions. In particular, for example, with embodiments I and II covered by this invention, the technical features and solutions mentioned therein can be combined internally and with each other, unless such combination is contrary to the purpose of this invention.

[0105] In this invention, unless otherwise stated, all technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0106] In this invention, unless otherwise specified by context or self-definition, the term “pore volume” refers to the total pore volume of single-point adsorption when P / P0 is at its maximum.

[0107] In this invention, “there are basically no other characteristic peaks between 395 eV and 405 eV” means that, apart from the characteristic peaks between 399 eV and 400.5 eV (for example, the characteristic peaks of pyrrole nitrogen), the peak area of ​​any other characteristic peak is less than 10%, preferably less than 5%.

[0108] Implementation Method I

[0109] Embodiment I of the present invention provides a carbon-supported platinum group metal catalyst, in which the N1s spectrum peaks of its XPS analysis show no other characteristic peaks between 395 eV and 405 eV except for the characteristic peaks between 399 eV and 400.5 eV.

[0110] In one embodiment of Embodiment I, the carbon-supported platinum group metal catalyst according to the present invention does not contain any doping elements other than nitrogen.

[0111] In one embodiment of Embodiment I, the platinum group metal is platinum.

[0112] In one embodiment of Embodiment I, the carbon-supported platinum group metal catalyst according to the present invention does not contain any metal elements other than platinum.

[0113] In one embodiment of Embodiment I, the carbon-supported platinum group metal catalyst according to the present invention has a platinum mass fraction of 0.1% to 80%, preferably 20% to 70%, and more preferably 40% to 70%, based on the mass of the catalyst.

[0114] In one embodiment of Embodiment I, the resistivity of the carbon-supported platinum group metal catalyst according to the present invention is <10.0 Ω·m, preferably <2 Ω·m.

[0115] In one embodiment of Embodiment I, the specific surface area of ​​the carbon-supported platinum group metal catalyst according to the present invention is 80 m2 / g to 1500 m2 / g, preferably 100 m2 / g to 200 m2 / g.

[0116] In one embodiment of Embodiment I, the support for the carbon-supported platinum group metal catalyst according to the present invention is nitrogen-doped conductive carbon black, nitrogen-doped graphene, or nitrogen-doped carbon nanotubes.

[0117] In one embodiment of Embodiment I, for the carbon-supported platinum group metal catalyst according to the present invention, the conductive carbon black may be one or more of the following: Ketjen black series superconducting carbon black, Cabot series conductive carbon black, and a series of conductive carbon blacks produced by Evonik Degussa; preferably Ketjen black EC-300J, Ketjen black EC-600JD, Ketjen black ECP-600JD, VXC72, Black Pearls 2000, PRINTEX XE2-B, PRINTEX L6, or HIBLAXK 40B2.

[0118] Embodiment I of the present invention also provides a method for preparing a carbon-supported platinum group metal catalyst, comprising:

[0119] (1)Step of impregnating with nitrogen source: Mix carbon material with nitrogen source aqueous solution and impregnate to obtain carbon material impregnated with nitrogen source;

[0120] (2)Steps for manufacturing nitrogen-doped carbon materials: The carbon material impregnated with nitrogen source obtained in step (1) is heated to 1000℃~1500℃ in an inert gas at a rate of 8℃ / min~15℃ / min, and then kept at a constant temperature for 0.5 h~10 h to obtain nitrogen-doped carbon materials.

[0121] (3) Step of loading platinum group metals (e.g., platinum): using the nitrogen-doped carbon material obtained in step (2) as a carrier, the step of loading platinum group metals (e.g., platinum).

[0122] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the temperature of the isothermal treatment can be 1000℃~1500℃, preferably 1150℃~1450℃; the treatment time can be 0.5 h~10 h, preferably 1 h~5 h, more preferably 2 h~4 h.

[0123] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the nitrogen source can be ammonia water / or urea.

[0124] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the mass of nitrogen source is based on the mass of nitrogen element contained therein, and the mass ratio of carbon material to nitrogen source is 30:1 to 1:2; preferably 25:1 to 1:1.5.

[0125] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the carbon material can be conductive carbon black, graphene or carbon nanotubes.

[0126] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the conductive carbon black can be ordinary conductive black, super conductive black or extra conductive black. For example, the conductive carbon black can be one or more of the Ketjen black series superconducting carbon black, Cabot series conductive carbon black and the series of conductive carbon black produced by Evonik Degussa; preferably Ketjen black EC-300J, Ketjen black EC-600JD, Ketjen black ECP-600JD, VXC72, Black pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXK 40B2.

[0127] The preparation method of the carbon-supported platinum group metal catalyst according to Embodiment I of the present invention does not limit the method or source of the conductive carbon black. The conductive carbon black may be acetylene black, furnace black, etc.

[0128] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the ID / IG value of the conductive carbon black is generally 0.8 to 5, preferably 1 to 4. In the Raman spectrum, the peak located near 1320 cm⁻¹ is the D peak, and the peak located near 1580 cm⁻¹ is the G peak. ID represents the intensity of the D peak, and IG represents the intensity of the G peak.

[0129] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the graphene or carbon nanotube can be either unoxidized graphene or carbon nanotube, or it can be oxidized graphene or carbon nanotube.

[0130] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment I of the present invention, in the XPS analysis of the carbon material, the oxygen mass fraction is greater than 4%, preferably 4% to 15%.

[0131] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the resistivity of the carbon material is <10 Ω·m, preferably <5 Ω·m, more preferably <2 Ω·m.

[0132] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the carbon material in step (1) has a specific surface area of ​​10 m2 / g to 2000 m2 / g and a pore volume of 0.2 mL / g to 6.0 mL / g.

[0133] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment I of the present invention, in an embodiment of manufacturing nitrogen-doped carbon material, the carbon material is mixed with an aqueous nitrogen source, impregnated (generally 12 h to 72 h), dried (generally 70°C to 120°C), and then placed in a tube furnace. The tube furnace is heated (the heating rate can be 8°C / min to 15°C / min), and then treated at a high temperature (1000°C to 1500°C, preferably 1150°C to 1450°C) for a period of time (0.5 h to 10 h, generally 1 h to 5 h) to obtain the nitrogen-doped carbon material.

[0134] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the nitrogen-doped carbon material obtained in step (2) can be easily dispersed in the aqueous phase. However, for some carbon materials, such as Ketjen Black, it is difficult to directly disperse in the aqueous phase.

[0135] According to the method for preparing a carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the step of supporting the platinum group metal (e.g., platinum) includes:

[0136] (a) Disperse the nitrogen-doped carbon material obtained in step (2) with a platinum group metal precursor (e.g., a platinum precursor) in an aqueous phase and adjust the pH to 8 to 12 (preferably adjust the pH to 10 ± 0.5).

[0137] (b) Reduce by adding a reducing agent;

[0138] (c) The solid is separated and post-processed to obtain the carbon-supported platinum group metal (e.g., carbon-supported platinum) catalyst.

[0139] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the platinum group metal precursor (e.g., platinum precursor) is chloroplatinic acid, potassium chloroplatinate or sodium chloroplatinate; the concentration of the platinum group metal precursor (e.g., platinum precursor) is 0.5 mol / L to 5 mol / L.

[0140] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment I of the present invention, in step (a), the pH value of the aqueous phase is adjusted by sodium carbonate aqueous solution, potassium carbonate aqueous solution, potassium hydroxide aqueous solution, sodium hydroxide aqueous solution or ammonia.

[0141] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment I of the present invention, in step (b), the reducing agent is one or more of citric acid, ascorbic acid, formaldehyde, formic acid, ethylene glycol, sodium citrate, hydrazine hydrate, sodium borohydride or glycerol.

[0142] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment I of the present invention, in step (b), the molar ratio of the reducing agent to platinum is 2 to 100.

[0143] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment I of the present invention, in step (b), the reduction temperature is 50℃~150℃, preferably 60℃~90℃; the reduction time is 4 h~15 h, preferably 8 h~12 h.

[0144] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment I of the present invention, the post-treatment includes: washing, filtering and drying.

[0145] Embodiment I of the present invention also provides a carbon-supported platinum group metal catalyst, which is prepared by any of the methods described in Embodiment I of the present invention above.

[0146] Embodiment I of the present invention also provides a hydrogen fuel cell, wherein the anode and / or cathode of the hydrogen fuel cell use any of the carbon-supported platinum group metal catalysts described in Embodiment I of the present invention.

[0147] The present invention employs a simple method to dope nitrogen onto the surface of carbon materials in the form of pyrrole nitrogen, thereby producing a platinum-carbon electrode catalyst for the anode hydrogenation reaction or the cathode oxygen reduction reaction of hydrogen fuel cells. Compared with catalysts of the same carbon material and platinum loading, it has a higher half-wave potential, and in particular significantly improves the catalyst's ECSA, specific activity and stability.

[0148] In one embodiment of Embodiment I, when the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention is used for oxygen reduction reaction, in some embodiments, ECSA > 55 m2g-1-Pt, for example, between 55 m2g-1-Pt and 140 m2g-1-Pt.

[0149] In one embodiment of Embodiment I, when the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the invention is used for oxygen reduction reaction, in some embodiments, the rate of decrease in mass specific activity after 5000 cycles is <10%.

[0150] In one embodiment of Embodiment I, when the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention is used for oxygen reduction reaction, in some embodiments, the half-wave potential is >0.88V, for example 0.88V to 0.92V.

[0151] In one embodiment of Embodiment I, when the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention is used for oxygen reduction reaction, in some embodiments, the mass specific activity is >0.11A mg-1-Pt, for example 0.11A mg-1-Pt to 0.44A mg-1-Pt.

[0152] In one embodiment of Embodiment I, the carbon-supported platinum group metal catalyst of the present invention is a platinum-carbon catalyst.

[0153] Implementation Method II

[0154] Embodiment II of the present invention provides a carbon-supported platinum group metal catalyst, which includes a carbon support and platinum metal supported thereon, wherein the carbon support is a sulfur and nitrogen-doped carbon material; in the S2P spectrum of the catalyst analyzed by XPS, there are only characteristic peaks between 163 eV and 166 eV in the range of 160 eV to 170 eV.

[0155] In one embodiment of Embodiment II, the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention does not contain any doping elements other than sulfur and nitrogen.

[0156] In one embodiment of Embodiment I, the platinum group metal is platinum.

[0157] In one embodiment of Embodiment II, the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention does not contain any metal elements other than platinum.

[0158] In one embodiment of Embodiment II, the S2P spectrum of the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention has only characteristic peaks located between 163 eV and 166 eV in the XPS analysis.

[0159] In one embodiment of Embodiment II, the XPS analysis of the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention showed no characteristic peaks between 166 eV and 170 eV.

[0160] In one embodiment of Embodiment II, the N1s spectrum of the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention has no other characteristic peaks between 390 eV and 410 eV, except for the characteristic peak between 399 eV and 400.5 eV.

[0161] In one embodiment of Embodiment II, the N1s spectrum of the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention has one or two characteristic peaks between 399 eV and 400.5 eV in the XPS analysis.

[0162] In one embodiment of Embodiment II, for the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention, the mass fraction of platinum is 0.1% to 80%, preferably 20% to 70%, and more preferably 40% to 70%, based on the mass of the catalyst.

[0163] In one embodiment of Embodiment II, the resistivity of the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the invention is <10.0 Ω·m, preferably <2.0 Ω·m.

[0164] In one embodiment of Embodiment II, the specific surface area of ​​the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention is 80 m2 / g to 1500 m2 / g, preferably 100 m2 / g to 200 m2 / g.

[0165] In one embodiment of Embodiment II, for the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention, the sulfur-nitrogen-doped carbon material is sulfur-nitrogen-doped conductive carbon black, sulfur-nitrogen-doped graphene, or sulfur-nitrogen-doped carbon nanotubes. The conductive carbon black may be one or more of the Ketjen black series of superconducting carbon black, the Cabot series of conductive carbon black, and the series of conductive carbon blacks produced by Evonik Degussa; preferably EC-300J, EC-600JD, ECP-600JD, VXC72, Black Pearls 2000, PRINTEX XE2-B, PRINTEX L6, or HIBLAXK 40B2. The graphene or carbon nanotubes may be oxidized or unoxidized graphene or carbon nanotubes.

[0166] In one embodiment of Embodiment II, for the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention, the characteristic peak between 163 eV and 166 eV is a double peak, and in some Embodiment II, the double peak is located at 163.4 ± 0.5 eV and 164.7 ± 0.5 eV, respectively.

[0167] In one embodiment of Embodiment II, for the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention, based on the support mass of the carbon-supported platinum group metal catalyst, the mass fraction of sulfur is 0.2% to 3% and the mass fraction of nitrogen is 0.1% to 5% during XPS testing.

[0168] Embodiment II of the present invention also provides a method for preparing a carbon-supported platinum group metal catalyst (e.g., a platinum-carbon catalyst), comprising:

[0169] (1) Steps for manufacturing sulfur-nitrogen-doped carbon materials; and

[0170] (2)The step of loading platinum group metals (e.g., platinum) onto the sulfur-nitrogen-doped carbon material obtained in step (1);

[0171] Step (1) includes sulfur doping and nitrogen doping operations;

[0172] The sulfur doping operation includes: placing the carbon material in an inert gas containing thiophene and treating it at 1000℃~1500℃ (preferably isothermal treatment) for 0.5 h~10 h;

[0173] The nitrogen doping operation is performed before, after, or simultaneously with the sulfur doping operation.

[0174] In the preparation method of the carbon-supported platinum group metal catalyst according to Embodiment II of the present invention, if heating is required during the sulfur doping operation, the heating rate shall not be less than 8°C / min, and may be 8°C / min to 15°C / min.

[0175] According to the method for preparing the carbon-supported platinum group metal catalyst of Embodiment II of the present invention, when the nitrogen doping operation is performed before or after the sulfur doping operation, any existing known nitrogen doping method can be used. One embodiment is that, when the nitrogen doping operation is performed before the sulfur doping operation, a carbon material is mixed with a nitrogen source and treated in an inert gas at 300°C to 1500°C (preferably isothermal treatment) for 0.5 h to 10 h. Another embodiment is that, when the nitrogen doping operation is performed after the sulfur doping operation, a sulfur-doped carbon material is mixed with a nitrogen source and treated in an inert gas at 300°C to 1500°C (preferably isothermal treatment) for 0.5 h to 10 h.

[0176] According to the method for preparing a carbon-supported platinum group metal catalyst of Embodiment II of the present invention, when the nitrogen doping operation is performed simultaneously with the sulfur doping operation, the sulfur doping operation conditions are used. One embodiment involves first mixing the carbon material with a nitrogen source, and then simultaneously performing nitrogen and sulfur doping operations on the carbon material under the sulfur doping operation conditions.

[0177] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment II of the present invention, the mass of thiophene is based on the mass of sulfur, and the mass ratio of carbon material to thiophene is 20:1 to 2:1; preferably 10:1 to 4:1, more preferably 8:1 to 4:1.

[0178] In the preparation method of the carbon-supported platinum group metal catalyst according to Embodiment II of the present invention, the temperature in the sulfur doping operation is preferably 1100℃~1400℃, more preferably 1200℃~1400℃.

[0179] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment II of the present invention, the processing time for the sulfur doping operation and the nitrogen doping operation is 1 h to 5 h, preferably 2 h to 4 h.

[0180] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment II of the present invention, the mass of nitrogen source is based on the mass of nitrogen it contains, and the mass ratio of carbon material to nitrogen source is 30:1 to 1:2; preferably 25:1 to 1:1.5.

[0181] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment II of the present invention, the sulfur and nitrogen doped carbon material described in step (1) has only a characteristic peak between 163 eV and 166 eV in the S2P spectrum of its XPS analysis between 160 eV and 170 eV.

[0182] According to the preparation method of carbon-supported platinum group metal catalyst of embodiment II of the present invention, the sulfur and nitrogen doped carbon material in step (1) has a characteristic peak between 163 eV and 166 eV, which is a double peak. In some embodiments II, the double peaks are at 163.7 ± 0.5 eV and 165.0 ± 0.5 eV, respectively.

[0183] According to the method for preparing the carbon-supported platinum group metal catalyst of Embodiment II of the present invention, the carbon material is conductive carbon black, graphene, or carbon nanotubes. The conductive carbon black can be ordinary conductive blacks, superconducting blacks, or extraconducting blacks. For example, the conductive carbon black can be one or more of the Ketjen black series of superconducting carbon blacks, the Cabot series of conductive carbon blacks, and the series of conductive carbon blacks produced by Evonik Degussa; preferably, Ketjen black EC-300J, Ketjen black EC-600JD, Ketjen black ECP-600JD, VXC72, Black Pearls 2000, PRINTEX XE2-B, PRINTEX L6, or HIBLAXK 40B2. The graphene or carbon nanotubes can be unoxidized graphene or carbon nanotubes, or graphene or carbon nanotubes that have undergone oxidation treatment.

[0184] The preparation method of the carbon-supported platinum group metal catalyst according to Embodiment II of the present invention does not limit the method or source of the conductive carbon black. The conductive carbon black may be acetylene black, furnace black, etc.

[0185] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment II of the present invention, the ID / IG value of the carbon material is generally 0.8 to 5, preferably 1 to 4. In the Raman spectrum, the peak located near 1320 cm⁻¹ is the D peak, and the peak located near 1580 cm⁻¹ is the G peak. ID represents the intensity of the D peak, and IG represents the intensity of the G peak.

[0186] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment II of the present invention, the resistivity of the carbon material can be <10.0 Ω•m, preferably <5.0 Ω•m, and more preferably <2.0 Ω•m.

[0187] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment II of the present invention, in the XPS analysis of the carbon material, the oxygen mass fraction is greater than 2%, which can be 2% to 15%, preferably 2.5% to 12%.

[0188] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment II of the present invention, the specific surface area and pore volume of the carbon material can vary within a large range. Generally, the specific surface area is 10 m2 / g to 2000 m2 / g, and the pore volume is 0.02 mL / g to 6 mL / g.

[0189] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment II of the present invention, in one embodiment, the carbon material in step (1) is conductive carbon black with a specific surface area of ​​200 m2 / g to 2000 m2 / g.

[0190] In the preparation method of the carbon-supported platinum group metal catalyst according to Embodiment II of the present invention, the inert gas may be nitrogen or argon.

[0191] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment II of the present invention, in the sulfur doping operation of one embodiment, carbon material is placed in a tube furnace, a carrier gas containing thiophene is introduced, the tube furnace is heated to 1000°C to 1500°C at a rate of 8°C / min to 15°C / min, and then is kept at a constant temperature for 0.5 h to 10 h.

[0192] The carrier gas can be nitrogen or argon.

[0193] The volume fraction of thiophene in the carrier gas can be 0.1% to 5.0%.

[0194] According to the method for preparing a carbon-supported platinum group metal catalyst of Embodiment II of the present invention, the step of supporting the platinum group metal (e.g., platinum) includes:

[0195] (a) Disperse the sulfur-nitrogen-doped carbon material obtained in step (1) with a platinum group metal precursor (e.g., a platinum precursor) in an aqueous phase and adjust the pH to 8 to 12 (preferably adjust the pH to 10 ± 0.5).

[0196] (b) Reduce by adding a reducing agent;

[0197] (c) The solid is separated and post-processed to obtain the carbon-supported platinum group metal (e.g., carbon-supported platinum) catalyst.

[0198] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment II of the present invention, in step (a), the platinum group metal precursor (e.g., platinum precursor) is chloroplatinic acid, potassium chloroplatinate or sodium chloroplatinate; the concentration of the platinum group metal precursor (e.g., platinum precursor) is 0.5 mol / L to 5 mol / L.

[0199] According to the method for preparing carbon-supported platinum group metal catalyst of Embodiment II of the present invention, in step (a), the pH value of the aqueous phase is adjusted by sodium carbonate aqueous solution, potassium carbonate aqueous solution, potassium hydroxide aqueous solution, sodium hydroxide aqueous solution or ammonia.

[0200] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment II of the present invention, in step (b), the reducing agent is one or more of citric acid, ascorbic acid, formaldehyde, formic acid, ethylene glycol, sodium citrate, hydrazine hydrate, sodium borohydride or glycerol.

[0201] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment II of the present invention, in step (b), the molar ratio of the reducing agent to platinum is 2 to 100.

[0202] According to the preparation method of carbon-supported platinum group metal catalyst of Embodiment II of the present invention, in step (b), the reduction temperature is 50℃~150℃, preferably 60℃~90℃; the reduction time is 4 h~15 h, preferably 8 h~12 h.

[0203] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment II of the present invention, the sulfur and nitrogen-doped carbon material obtained in step (1) can be easily dispersed in the aqueous phase. However, for some carbon materials, such as Ketjen Black, it is difficult to directly disperse them in the aqueous phase.

[0204] According to the preparation method of the carbon-supported platinum group metal catalyst of Embodiment II of the present invention, the post-treatment includes: washing, filtering and drying.

[0205] Embodiment II of the present invention also provides a method for preparing a carbon-supported platinum group metal catalyst (e.g., a platinum-carbon catalyst), comprising:

[0206] (1)Step of impregnating with nitrogen source: Mix carbon material with nitrogen source aqueous solution and impregnate to obtain carbon material impregnated with nitrogen source;

[0207] (2)Steps for manufacturing sulfur-nitrogen-doped carbon materials: The carbon material impregnated with nitrogen source obtained in step (1) is placed in an inert gas containing thiophene and treated at 1000℃~1500℃ (preferably constant temperature treatment) for 0.5 h~10 h to obtain sulfur-nitrogen-doped carbon materials.

[0208] (3) The step of loading platinum group metals (e.g., platinum) onto the sulfur-nitrogen-doped carbon material obtained in step (2).

[0209] According to the aforementioned method for preparing carbon-supported platinum group metal catalysts, the carbon material impregnated with nitrogen source in step (1) is first dried, and then step (2) is performed.

[0210] In one embodiment of Embodiment II, the carbon-supported platinum group metal catalyst (e.g., platinum carbon catalyst) described in this embodiment is prepared by the preparation method of the carbon-supported platinum group metal catalyst (e.g., platinum carbon catalyst).

[0211] Embodiment II of the present invention also provides a hydrogen fuel cell, wherein the anode and / or cathode of the hydrogen fuel cell use any of the carbon-supported platinum group metal catalysts described in Embodiment II of the present invention.

[0212] In one embodiment of Embodiment II, the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) according to the present invention exhibits a mass-specific activity decrease rate of <10% after 5000 cycles when used for oxygen reduction reaction.

[0213] In one embodiment of Embodiment II, when the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) of the present invention is used for oxygen reduction reaction, in some Embodiment II, ECSA > 68.93 m2g-1-Pt, for example, in the range of 60.0 m2g-1-Pt to 100.0 m2g-1-Pt.

[0214] In one embodiment of Embodiment II, when the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) of the present invention is used for oxygen reduction reaction, in some Embodiment II-, the half-wave potential is >0.890 V, for example 0.89 V to 0.91 V.

[0215] In one embodiment of Embodiment II, the carbon-supported platinum group metal catalyst (e.g., platinum-carbon catalyst) of the present invention, when used for oxygen reduction reaction, has a mass-to-activity ratio > 0.15 A mg-1-Pt, such as 0.15 A mg-1-Pt to 0.35 A mg-1-Pt.

[0216] Existing carbon-supported platinum group metal catalysts for hydrogen fuel cells have the disadvantages of low specific activity and poor stability. This invention significantly improves the specific activity and stability of carbon-supported platinum group metal catalysts by doping sulfur and nitrogen in a specific form on the surface of the carbon support, especially improving the specific activity and stability of carbon-supported platinum group metal catalysts with high platinum loading.

[0217] In one embodiment of Embodiment II, the carbon-supported platinum group metal catalyst of the present invention is a platinum-carbon catalyst.

[0218] Example Section

[0219] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way.

[0220] Unless otherwise specified, all reagents used in this invention are of analytical purity and are commercially available.

[0221] Implementation Method I

[0222] Reagents, Instruments and Tests

[0223] This invention uses X-ray photoelectron spectroscopy (XPS) to detect elements on the surface of materials. The X-ray photoelectron spectroscopy instrument used is the VG Scientific ESCALab220i-XL model equipped with Avantage V5.926 software. The X-ray photoelectron spectroscopy analysis test conditions are: the excitation source is monochromatic AlKα X-rays, the power is 330 W, and the basic vacuum during analysis is 3 × 10⁻⁹ mbar. In addition, the electron binding energy is corrected using the C1s peak (284.3 eV) of elemental carbon, and the post-peaking processing software is XPSPEAK.

[0224] Elemental analysis instruments, methods and conditions: Elemental analyzer (Vario EL Cube), reaction temperature 1150℃, 5 mg sample weighed, reduction temperature 850℃, carrier gas helium flow rate 200 mL / min, oxygen flow rate 30 mL / min, oxygen passage time 70s.

[0225] The instrument, method and conditions for testing the platinum mass fraction in the platinum-carbon catalyst: Take 30 mg of the prepared Pt / C catalyst, add 30 mL of aqua regia, reflux at 120℃ for 12 h, cool to room temperature, take the supernatant, dilute it and test the Pt content by ICP-AES.

[0226] The high-resolution transmission electron microscope (HRTEM) used in this invention is model JEM-2100 (HRTEM) (Nippon Electron Ltd.). The high-resolution transmission electron microscope test conditions are: accelerating voltage of 200 kV. The particle size of the nanoparticles in the sample was obtained by measuring the electron microscope images.

[0227] BET test method: In this invention, the pore structure properties of the sample are determined by a Quantacam AS-6B analyzer, the specific surface area and pore volume of the catalyst are obtained by the Brunauer-Emmett-Taller (BET) method, and the pore distribution curve is calculated by the Barrett-Joyner-Halenda (BJH) method based on the desorption curve.

[0228] The Raman detection of the present invention uses a LabRAM HR UV-NIR laser confocal Raman spectrometer manufactured by HORIBA Corporation of Japan, with a laser wavelength of 532 nm.

[0229] Electrochemical performance testing was conducted using Solartron Analytical EnergyLab and Princeton Applied Research (Model 636A). The methods and testing conditions were as follows: The catalyst polarization curve (LSV) was measured at 1600 rpm in O2-saturated 0.1 M HClO4, and the CV curve was measured in Ar atmosphere in 0.1 M HClO4. The electrochemical active area (ECSA) was calculated based on these results. For stability testing, 5000 cycles were performed in O2-saturated 0.1 M HClO4 within the range of 0.6 V to 0.95 V, followed by testing LSV and ECSA using the same method. During these tests, the catalyst was prepared as a uniformly dispersed slurry and coated onto a 5 mm diameter glassy carbon electrode. The platinum content of the catalyst on the electrode was 3 μg to 4 μg.

[0230] Resistivity tester with four probes, instrument model KDY-1, method and test conditions: applied pressure 3.9±0.03 MPa, current 500±0.1mA.

[0231] VXC72 (Vulcan XC72, manufactured by Cabot Corporation, USA, production batch number) was purchased from Suzhou Yilongsheng Energy Technology Co., Ltd. Tested using the aforementioned instrumental methods, the results showed: specific surface area 258 m² / g, pore volume 0.388 mL / g, oxygen mass fraction 8.72%, ID / IG ratio 1.02, and resistivity 1.22 Ω•m.

[0232] Ketjenblack ECP600JD (manufactured by Lion Corporation, Japan, production batch number) was purchased from Suzhou Yilongsheng Energy Technology Co., Ltd. Tested using the aforementioned instrumental methods, the results showed: specific surface area 1362 m² / g, pore volume 2.29 mL / g, oxygen mass fraction 6.9%, ID / IG ratio 1.25, and resistivity 1.31 Ω•m.

[0233] The commercial platinum-carbon catalyst (code name HISPEC4000, manufactured by Johnson & Johnson) was purchased from Alfa Aesar. Test results showed that the mass fraction of platinum was 40.2%.

[0234] Example 1

[0235] This embodiment is used to illustrate the preparation of the nitrogen-doped carbon support of the present invention.

[0236] 1g of Vulcan XC72 was immersed in 20 mL of 2.5 wt% ammonia solution for 24 h; dried in an oven at 100℃; then placed in a tube furnace and heated to 1100℃ at a rate of 8℃ / min, and kept at that temperature for 3 h; after natural cooling, nitrogen-doped carbon support was obtained, which was designated as carbon support A.

[0237] Sample Characterization and Testing

[0238] The nitrogen mass fraction analyzed by XPS was 1.43%; the oxygen mass fraction analyzed by XPS was 9.31%; the specific surface area was 239 m2 / g; and the resistivity was 1.28 Ω•m.

[0239] Figure 1 is the XPS spectrum of carbon support A in Example 1.

[0240] Example 2

[0241] This embodiment is used to illustrate the preparation of the nitrogen-doped carbon support of the present invention.

[0242] 1g of Vulcan XC72 was soaked in 15 mL of 0.7 wt% urea aqueous solution for 24 h; dried in an oven at 100℃; then placed in a tube furnace and heated to 1200℃ at a rate of 10℃ / min, and kept at that temperature for 3 h; after natural cooling, nitrogen-doped carbon support was obtained, designated as carbon support B.

[0243] Sample Characterization and Testing

[0244] The nitrogen mass fraction determined by XPS analysis was 0.68%; the oxygen mass fraction determined by XPS analysis was 8.92%; and the resistivity was 1.25 Ω•m.

[0245] Example 3

[0246] This embodiment is used to illustrate the preparation of the nitrogen-doped carbon support of the present invention.

[0247] 10 mL of anhydrous ethanol was added to 1 g of Ketjenblack ECP600JD, followed by 25 mL of 10 wt% ammonia solution for 24 h of soaking; the mixture was dried in an oven at 100 °C; then placed in a tube furnace and heated to 1100 °C at a rate of 8 °C / min, and kept at that temperature for 3 h; after natural cooling, nitrogen-doped carbon support was obtained, designated as carbon support C.

[0248] Sample Characterization and Testing

[0249] The nitrogen mass fraction analyzed by XPS was 1.48%; the oxygen mass fraction analyzed by XPS was 11.22%; the specific surface area was 1369 m2 / g; and the resistivity was 1.36 Ω•m.

[0250] Figure 2 is the XPS spectrum of carbon support C in Example 3.

[0251] Example 4

[0252] This embodiment is used to illustrate the preparation of the nitrogen-doped carbon support of the present invention.

[0253] Add 10 mL of anhydrous ethanol to 1 g of Ketjenblack ECP600JD, then add 20 mL of 1 wt% urea aqueous solution and soak for 24 h; dry in an oven at 100 °C; then place in a tube furnace and heat the tube furnace to 1300 °C at a rate of 10 °C / min, and keep at that temperature for 3 h; after natural cooling, obtain nitrogen-doped carbon support, designated as carbon support D.

[0254] Sample Characterization and Testing

[0255] The nitrogen mass fraction determined by XPS analysis was 1.31%; the oxygen mass fraction determined by XPS analysis was 9.54%; and the resistivity was 1.34 Ω•m.

[0256] Example 5

[0257] This embodiment is used to illustrate the preparation of the platinum-carbon catalyst of the present invention.

[0258] Carbon support A was dispersed in deionized water at a ratio of 250 mL of water per gram of carbon support. 3.4 mmol of chloroplatinic acid was added per gram of carbon support, and the mixture was ultrasonically dispersed to form a suspension. 1 mol / L sodium carbonate aqueous solution was added to adjust the pH of the system to 10. The suspension was heated to 80°C, and formic acid was added with stirring to carry out a reduction reaction. The molar ratio of formic acid to chloroplatinic acid was 50:1. The reaction was continued for 10 h. The mixture after the reaction was filtered, washed with deionized water until the pH of the filtrate was neutral, filtered again, and then dried at 100°C to obtain the platinum-carbon catalyst.

[0259] Sample Characterization and Testing

[0260] The platinum mass fraction of the platinum-carbon catalyst is 39.7%.

[0261] Figure 3 is the XPS spectrum of the platinum-carbon catalyst of Example 5.

[0262] Figure 4 shows the polarization curves of the platinum-carbon catalyst in Example 5 before and after 5000 cycles.

[0263] The performance test results of the platinum-carbon catalyst are shown in Table 1.

[0264] Example 6

[0265] This example illustrates the preparation of a platinum-carbon catalyst.

[0266] The platinum-carbon catalyst was prepared according to the method of Example 5, except that the carbon support B prepared in Example 2 was used, and 1.3 mmol of chloroplatinic acid was added per gram of carbon support.

[0267] Sample Characterization and Testing

[0268] The platinum mass fraction of the platinum-carbon catalyst is 20.1%.

[0269] Figure 5 is the XPS spectrum of the platinum-carbon catalyst of Example 6.

[0270] The performance test results of the platinum-carbon catalyst are shown in Table 1.

[0271] Example 7

[0272] This embodiment is used to illustrate the preparation of the platinum-carbon catalyst of the present invention.

[0273] Carbon support C was dispersed in deionized water at a ratio of 250 mL of water per gram of carbon support. 12 mmol of chloroplatinic acid was added per gram of carbon support, and the suspension was formed by ultrasonic dispersion. The pH of the system was adjusted to 10 by adding 1 mol / L potassium hydroxide aqueous solution. The suspension was heated to 80°C, and sodium borohydride was added under stirring to carry out a reduction reaction. The molar ratio of reducing agent to platinum precursor was 5:1, and the reaction was maintained for 12 h. The mixture after the reaction was filtered, washed until the pH of the solution was neutral, and dried at 100°C to obtain the carbon-supported platinum catalyst.

[0274] Sample Characterization and Testing

[0275] The platinum mass fraction of the platinum-carbon catalyst is 70.0%.

[0276] Figure 6 is the XPS spectrum of the platinum-carbon catalyst of Example 7.

[0277] The performance test results of the platinum-carbon catalyst are shown in Table 1.

[0278] Example 8

[0279] This example illustrates the preparation of a platinum-carbon catalyst.

[0280] The platinum-carbon catalyst was prepared according to the method of Example 7, except that the carbon support D prepared in Example 4 was used, and 1.3 mmol of chloroplatinic acid was added per gram of carbon support.

[0281] Sample Characterization and Testing

[0282] The platinum mass fraction of the platinum-carbon catalyst is 20.1%.

[0283] Figure 7 is the XPS spectrum of the platinum-carbon catalyst of Example 8.

[0284] The performance test results of the platinum-carbon catalyst are shown in Table 1.

[0285] Compare with Example 1

[0286] The platinum-carbon catalyst was prepared according to the method of Example 5, except that the support was Vulcan XC72.

[0287] Sample Characterization and Testing

[0288] The platinum mass fraction of the platinum-carbon catalyst is 40.1%.

[0289] The performance test results of the platinum-carbon catalyst are shown in Table 1.

[0290] Compare with Example 2

[0291] The platinum-carbon catalyst was prepared and tested in the same manner as in Example 7, except that the carbon support was Ketjenblack ECP600JD and each gram of carbon support was dispersed with 200 mL of water and 50 mL of ethanol when loaded with Pt.

[0292] Sample Characterization and Testing

[0293] The platinum mass fraction of the platinum-carbon catalyst is 69.7%.

[0294] The performance test results of the platinum-carbon catalyst are shown in Table 1.

[0295] Comparison with Example 3

[0296] The platinum-carbon catalyst is a commercially available catalyst, code HISPEC4000.

[0297] Sample Characterization and Testing

[0298] The platinum mass fraction of the platinum-carbon catalyst is 40.2%.

[0299] Figure 8 shows the polarization curves of the platinum-carbon catalyst of Comparative Example 3 before and after 5000 cycles.

[0300] The performance test results of the platinum-carbon catalyst are shown in Table 1.

[0301] Table 1 sample Half-wave potential / V ECSA / m 2 g -1 -Pt Mass-to-activity ratio / A mg -1 -Pt Intrinsic activity / mA cm -2 The percentage decrease in activity after 5000 cycles / Example 5 0.92 74.10 0.255 0.345 1 Example 6 0.91 87.30 0.440 0.504 5 Example 7 0.88 55.04 0.114 0.207 8 Example 8 0.91 135.6 0.311 0.230 5 Compare with Example 1 0.89 33.63 0.135 0.401 28 Compare with Example 2 0.83 62.26 0.086 0.138 34 Compare with Example 3 0.88 57.32 0.124 0.216 twenty three

[0302] Implementation Method II

[0303] Reagents, Instruments and Tests

[0304] This invention uses X-ray photoelectron spectroscopy (XPS) to detect elements on the surface of materials. The X-ray photoelectron spectroscopy instrument used is an ESCALab220i-XL model manufactured by VG Scientific and equipped with Avantage V5.926 software. The X-ray photoelectron spectroscopy analysis test conditions are: the excitation source is monochromatic AlKα X-rays, the power is 330 W, and the basic vacuum during analysis is 3 × 10⁻⁹ mbar. In addition, the electron binding energy is corrected using the C1s peak (284.3 eV) of elemental carbon, and the post-peak-splitting software is XPSPEAK. The characteristic peaks of thiophene sulfur and nitrogen in the spectrum are the characteristic peaks after peak splitting.

[0305] Elemental analysis instruments, methods and conditions: Elemental analyzer (Vario EL Cube), reaction temperature 1150℃, 5 mg sample weighed, reduction temperature 850℃, carrier gas helium flow rate 200 mL / min, oxygen flow rate 30 mL / min, oxygen passage time 70s.

[0306] The instrument, method and conditions for testing the platinum mass fraction in the platinum-carbon catalyst: Take 30 mg of the prepared Pt / C catalyst, add 30 mL of aqua regia, reflux at 120℃ for 12 h, cool to room temperature, take the supernatant, dilute it and test the Pt content by ICP-AES.

[0307] The high-resolution transmission electron microscope (HRTEM) used in this invention is model JEM-2100 (HRTEM) (Nippon Electron Ltd.). The high-resolution transmission electron microscope test conditions are: accelerating voltage of 200 kV. The particle size of the nanoparticles in the sample was obtained by measuring the electron microscope images.

[0308] BET test method: In this invention, the pore structure properties of the sample are determined by a Quantacam AS-6B analyzer, the specific surface area and pore volume of the catalyst are obtained by the Brunauer-Emmett-Taller (BET) method, and the pore distribution curve is calculated from the desorption curve according to the Barrett-Joyner-Halenda (BJH) method.

[0309] The Raman detection of the present invention uses a LabRAM HR UV-NIR laser confocal Raman spectrometer manufactured by HORIBA Corporation of Japan, with a laser wavelength of 532 nm.

[0310] Electrochemical performance testing: Instruments used were Solartron Analytical EnergyLab and Princeton Applied Research (Model 636A). Methods and testing conditions: The catalyst polarization curve (LSV) was measured at 1600 rpm in O2-saturated 0.1M HClO4, and the CV curve was measured in Ar atmosphere in 0.1M HClO4. The electrochemical active area (ECSA) was calculated based on these results. For stability testing, 5000 cycles were performed in O2-saturated 0.1M HClO4 within the range of 0.6V to 0.95V, followed by testing LSV and ECSA using the same method. During the above tests, the catalyst was prepared as a uniformly dispersed slurry and coated onto a 5 mm diameter glassy carbon electrode. The platinum content of the catalyst on the electrode was 3 μg to 4 μg.

[0311] Resistivity tester with four probes, instrument model KDY-1, method and test conditions: applied pressure 3.9±0.03 MPa, current 500±0.1mA.

[0312] VXC72 (Vulcan XC72, manufactured by Cabot Corporation, USA, production batch number) was purchased from Suzhou Yilongsheng Energy Technology Co., Ltd. Tested using the aforementioned instrumental methods, the results showed: specific surface area 258 m² / g, pore volume 0.388 mL / g, oxygen mass fraction 8.72%, ID / IG ratio 1.02, and resistivity 1.22 Ω•m.

[0313] Ketjenblack ECP600JD (manufactured by Lion Corporation, Japan, production batch number) was purchased from Suzhou Yilongsheng Energy Technology Co., Ltd. Tested using the aforementioned instrumental methods, the results showed: specific surface area 1362 m² / g, pore volume 2.29 mL / g, oxygen mass fraction 6.9%, ID / IG ratio 1.25, and resistivity 1.31 Ω•m.

[0314] The commercial platinum-carbon catalyst (code name HISPEC4000, manufactured by Johnson & Johnson) was purchased from Alfa Aesar. Test results showed that the mass fraction of platinum was 40.2%.

[0315] Example II-1

[0316] This embodiment is used to illustrate the preparation of sulfur and nitrogen doped carbon materials.

[0317] 1 g of Vulcan XC72 was immersed in 20 mL of 2 wt% ammonia solution for 24 h, dried in an oven at 100 °C, and then placed in a tube furnace. Nitrogen carrier gas was introduced into the tube furnace through a bubbling flask containing thiophene. The furnace was heated to 1200 °C at a rate of 10 °C / min, then kept at that temperature for 3 h. After natural cooling, sulfur-nitrogen-doped carbon material was obtained, designated as carrier A. The mass of thiophene was based on the mass of sulfur it contained, and the mass ratio of Vulcan XC72 to thiophene was 3:1. The amount of thiophene used was controlled by the carrier gas flow rate. The carrier gas flow rate corresponding to different amounts of thiophene was pre-calibrated based on the flow time.

[0318] Sample Characterization and Testing

[0319] I. Sulfur- and Nitrogen-Doped Carbon Materials

[0320] The sulfur mass fraction determined by XPS analysis was 1.25%; the nitrogen mass fraction determined by XPS analysis was 0.54%; the specific surface area was 211 m2 / g, the pore volume was 0.421 mL / g; and the resistivity was 1.31 Ω•m.

[0321] Figure II-1 is the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material of Example II-1.

[0322] Figure II-2 is the XPS spectrum of nitrogen in the sulfur-nitrogen-doped carbon material of Example II-1.

[0323] Example II-2

[0324] 1 g of Vulcan XC72 was immersed in 20 mL of 20 wt% ammonia solution for 24 h, dried in an oven at 100 °C, and then placed in a tube furnace. Carrier gas (nitrogen) was introduced into the tube furnace through a bubbling flask containing thiophene. The furnace was heated to 1300 °C at a rate of 10 °C / min, then kept at this temperature for 3 h. After natural cooling, sulfur-nitrogen-doped carbon material was obtained, designated as carrier B. The mass of thiophene was based on the mass of sulfur it contained, and the mass ratio of Vulcan XC72 to thiophene was 9:1. The amount of thiophene used was controlled by the carrier gas permeation rate. The carrier gas permeation rate corresponding to different amounts of thiophene was pre-calibrated based on the permeation time.

[0325] Sample Characterization and Testing

[0326] The sulfur mass fraction was 0.91% according to XPS analysis; the nitrogen mass fraction was 0.62% according to XPS analysis; and the resistivity was 1.29 Ω•m.

[0327] Figure II-3 is the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material of Example II-2.

[0328] Example II-3

[0329] 10 mL of anhydrous ethanol was added to 1 g of Ketjenblack ECP600JD, followed by 20 mL of 20 wt% ammonia solution for 24 h of impregnation. After drying in an oven at 100℃, the mixture was placed in a tube furnace. Carrier gas (nitrogen) was introduced into the tube furnace through a bubbling flask containing thiophene. The furnace was heated to 1200℃ at a rate of 10℃ / min, and then kept at that temperature for 3 h. After natural cooling, sulfur-nitrogen-doped carbon material was obtained, designated as carrier C. The mass of thiophene was based on the mass of sulfur contained in the material, and the mass ratio of Ketjenblack ECP600JD to thiophene was 8:1. The amount of thiophene used was controlled by the carrier gas permeation rate. The carrier gas permeation rate corresponding to different amounts of thiophene was pre-calibrated based on the permeation time.

[0330] Sample Characterization and Testing

[0331] I. Sulfur- and Nitrogen-Doped Carbon Materials

[0332] The mass fraction of sulfur analyzed by XPS was 0.72%; the mass fraction of nitrogen analyzed by XPS was 1.84%; the specific surface area was 1317 m2 / g; and the resistivity was 1.38 Ω•m.

[0333] Figure II-4 is the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material of Example II-3.

[0334] Example II-4

[0335] This embodiment is used to illustrate the preparation of sulfur and nitrogen doped carbon materials.

[0336] 1 g of Vulcan XC72 was immersed in 20 mL of 2 wt% ammonia solution for 24 h, dried in an oven at 100 °C, and then placed in a tube furnace. Under nitrogen protection, the tube furnace was heated to 1200 °C at a rate of 10 °C / min and kept at that temperature for 3 h. Then, a carrier gas (nitrogen) was passed through a bubbling flask containing thiophene and then into the tube furnace. The furnace was kept at 1200 °C for another 3 h. After natural cooling, sulfur-nitrogen-doped carbon material was obtained, designated as carrier D. The mass of thiophene was based on the mass of sulfur it contained, and the mass ratio of Vulcan XC72 to thiophene was 3:1. The amount of thiophene used was controlled by the carrier gas flow rate. The carrier gas flow rate corresponding to different amounts of thiophene was pre-calibrated based on the flow time.

[0337] Sample Characterization and Testing

[0338] I. Sulfur- and Nitrogen-Doped Carbon Materials

[0339] The sulfur mass fraction determined by XPS analysis was 1.14%; the nitrogen mass fraction determined by XPS analysis was 0.14%.

[0340] Figure II-5 is the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material of Example II-4.

[0341] Example II-5

[0342] This embodiment is used to illustrate the preparation of the platinum-carbon catalyst of the present invention.

[0343] Carbon support A was dispersed in deionized water at a ratio of 250 mL of water per gram of carbon support. 3.4 mmol of chloroplatinic acid was added per gram of carbon support, and the mixture was ultrasonically dispersed to form a suspension. 1 mol / L sodium carbonate aqueous solution was added to adjust the pH of the system to 10. The suspension was heated to 80°C, and formic acid was added with stirring to carry out a reduction reaction. The molar ratio of formic acid to chloroplatinic acid was 50:1. The reaction was maintained for 10 h. The mixture after the reaction was filtered, washed with deionized water until the pH of the filtrate was neutral, filtered again, and then dried at 100°C to obtain the platinum-carbon catalyst.

[0344] Sample Characterization and Testing

[0345] The platinum mass fraction of the platinum-carbon catalyst is 39.9%.

[0346] Figure II-6 is a TEM image of the platinum-carbon catalyst of Example II-5.

[0347] Figure II-7 shows the polarization curve of the platinum-carbon catalyst in Example II-5.

[0348] Figure II-8 is the XPS spectrum of sulfur in the platinum-carbon catalyst of Example II-5.

[0349] Figure II-9 is the XPS spectrum of nitrogen in the platinum-carbon catalyst of Example II-5.

[0350] The performance test results of the platinum-carbon catalyst are shown in Table II-1.

[0351] Example II-6

[0352] This embodiment is used to illustrate the preparation of the platinum-carbon catalyst of the present invention.

[0353] The platinum-carbon catalyst was prepared according to the method of Example II-5, except that the carbon support B prepared in Example II-2 was used, and 1.3 mmol of chloroplatinic acid was added per gram of carbon support.

[0354] Sample Characterization and Testing

[0355] The platinum mass fraction of the platinum-carbon catalyst is 20.3%.

[0356] The performance test results of the platinum-carbon catalyst are shown in Table II-1.

[0357] Example II-7

[0358] This embodiment is used to illustrate the preparation of the platinum-carbon catalyst of the present invention.

[0359] Carbon support C was dispersed in deionized water at a ratio of 250 mL of water per gram of carbon support. 12 mmol of chloroplatinic acid was added per gram of carbon support, and the suspension was formed by ultrasonic dispersion. The pH of the system was adjusted to 10 by adding 1 mol / L potassium hydroxide aqueous solution. The suspension was heated to 80°C, and sodium borohydride was added under stirring to carry out a reduction reaction. The molar ratio of reducing agent to platinum precursor was 5:1, and the reaction was maintained for 12 h. The mixture after the reaction was filtered, washed until the pH of the solution was neutral, and dried at 100°C to obtain the carbon-supported platinum catalyst.

[0360] Sample Characterization and Testing

[0361] The platinum mass fraction of the platinum-carbon catalyst is 69.8%.

[0362] Figure II-10 is the XPS spectrum of sulfur in the platinum-carbon catalyst of Example II-7.

[0363] Figure II-11 is the XPS spectrum of nitrogen in the platinum-carbon catalyst of Example II-7.

[0364] The performance test results of the platinum-carbon catalyst are shown in Table II-1.

[0365] Example II-8

[0366] This embodiment is used to illustrate the preparation of the platinum-carbon catalyst of the present invention.

[0367] The platinum-carbon catalyst was prepared according to the method of Example II-5, except that the carbon support D prepared in Example II-4 was used.

[0368] Sample Characterization and Testing

[0369] The platinum mass fraction of the platinum-carbon catalyst is 39.9%.

[0370] The performance test results of the platinum-carbon catalyst are shown in Table II-1.

[0371] Comparative Example II-1

[0372] Sulfur-nitrogen-doped carbon materials were prepared using the same method as in Example II-1, except that the tube furnace was heated to 1200°C at a rate of 3°C / min.

[0373] Platinum-carbon catalysts were prepared using the same method as in Example II-5, except that the carbon support was the sulfur-nitrogen-doped carbon material prepared in Comparative Example II-1.

[0374] Sample Characterization and Testing

[0375] I. Sulfur- and Nitrogen-Doped Carbon Materials

[0376] The sulfur mass fraction determined by XPS analysis was 1.29%; the nitrogen mass fraction determined by XPS analysis was 0.58%; and the resistivity was 1.32 Ω•m.

[0377] Figure II-12 is the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material of Comparative Example II-1.

[0378] II. Platinum-carbon catalysts

[0379] The platinum mass fraction of the platinum-carbon catalyst is 40.1%.

[0380] Figure II-13 is a TEM image of the platinum-carbon catalyst of Comparative Example II-1.

[0381] Figure II-14 shows the polarization curve of the platinum-carbon catalyst of Comparative Example II-1.

[0382] Comparative Example II-2

[0383] Sulfur-nitrogen-doped carbon materials were prepared using the same method as in Example II-1, except that the isothermal treatment temperature was 700°C during the manufacturing of the sulfur-nitrogen-doped carbon materials.

[0384] Sample Characterization and Testing

[0385] The sulfur-nitrogen-doped carbon material of this Comparative Example II-2 had a sulfur mass fraction of 0.967% and a nitrogen mass fraction of 0.92% as determined by XPS analysis.

[0386] Figure II-15 is the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material of Comparative Example II-2.

[0387] Comparative Example II-3

[0388] The platinum-carbon catalyst is a commercially available catalyst, code HISPEC4000.

[0389] Sample Characterization and Testing

[0390] The platinum mass fraction of the platinum-carbon catalyst is 40.2%.

[0391] Figure II-16 shows the polarization curve of the platinum-carbon catalyst of Comparative Example II-3.

[0392] Comparative Example II-4

[0393] 10 mL of anhydrous ethanol was added to 1 g of Ketjenblack ECP600JD, followed by 25 mL of 10 wt% ammonia solution for 24 h of soaking; the mixture was dried in an oven at 100 °C; then placed in a tube furnace and heated to 1100 °C at a rate of 8 °C / min, and kept at that temperature for 3 h; after natural cooling, nitrogen-doped carbon support was obtained.

[0394] The aforementioned nitrogen-doped carbon support was dispersed in deionized water at a ratio of 250 mL of water per gram of carbon support. 12 mmol of chloroplatinic acid was added per gram of carbon support, and the suspension was formed by ultrasonic dispersion. 1 mol / L potassium hydroxide aqueous solution was added to adjust the pH of the system to 10. The suspension was heated to 80°C, and sodium borohydride was added under stirring to carry out a reduction reaction. The molar ratio of the reducing agent to the platinum precursor was 5:1, and the reaction was maintained for 12 h. The mixture after the reaction was filtered, washed until the pH of the solution was neutral, and dried at 100°C to obtain the carbon-supported platinum catalyst.

[0395] Sample Characterization and Testing

[0396] The nitrogen mass fraction of the nitrogen-doped carbon support was 1.48% according to XPS analysis.

[0397] The platinum mass fraction of the platinum-carbon catalyst is 70.0%.

[0398] The performance test results of the platinum-carbon catalyst are shown in Table II-1.

[0399] Comparative Example II-5

[0400] Ketjenblack ECP600JD was placed in a tube furnace. Carrier gas (nitrogen) was introduced into the tube furnace after passing through a bubbling flask containing thiophene. The furnace was heated to 1200℃ at a rate of 10℃ / min, then held at that temperature for 3 hours. After natural cooling, a sulfur-doped carbon support was obtained. The mass ratio of Ketjenblack ECP600JD to thiophene, based on the mass of sulfur, was 20:1. The amount of thiophene used was controlled by the carrier gas flow rate. The carrier gas flow rate corresponding to different amounts of thiophene was pre-calibrated based on the flow time.

[0401] The sulfur-doped carbon support was dispersed in deionized water at a ratio of 250 mL of water per gram of carbon support. 12 mmol of chloroplatinic acid was added per gram of carbon support, and the suspension was formed by ultrasonic dispersion. 1 mol / L potassium hydroxide aqueous solution was added to make the pH of the system 10. The suspension was heated to 80 °C, and sodium borohydride was added under stirring to carry out a reduction reaction. The molar ratio of the reducing agent to the platinum precursor was 5:1, and the reaction was maintained for 12 h. The mixture after the reaction was filtered, washed until the pH of the solution was neutral, and dried at 100 °C to obtain the carbon-supported platinum catalyst.

[0402] Sample Characterization and Testing

[0403] The sulfur mass fraction of the sulfur-doped carbon support was 0.76% according to XPS analysis.

[0404] The platinum mass fraction of the platinum-carbon catalyst is 70.2%.

[0405] The performance test results of the platinum-carbon catalyst are shown in Table II-1.

[0406] Table II-1 sample Half-wave potential / V ECSA / m 2 g -1 -Pt Mass-to-activity ratio / A mg -1 -Pt Intrinsic activity / mA cm -2 The percentage decrease in activity after 5000 cycles / Example II-5 0.91 68.93 0.203 0.294 3 Example II-6 0.91 87.30 0.330 0.378 5 Example II-7 0.89 92.66 0.184 0.199 1 Example II-8 0.90 37.98 0.158 0.417 3 Comparative Example II-3 0.88 57.32 0.124 0.216 twenty three Comparative Example II-4 0.88 55.04 0.114 0.207 8 Comparative Example II-5 0.89 95.59 0.181 0.189 3

[0407] As shown in Figures II-12 and II-15, in the sulfur-doped carbon material not manufactured according to the present invention, the characteristic peak between 163 eV and 166 eV (which, according to analysis, is presumed to be the characteristic peak of thiophene sulfur) is not only present, but also oxidized sulfur.

[0408] As shown in Table II-1, compared with "Comparative Example II-3", the sulfur and nitrogen doped conductive carbon black significantly improved the ECSA and mass ratio activity and stability of the platinum-carbon catalyst.

[0409] As shown in Table II-1, compared with Comparative Examples II-4 and II-5, it can be seen that conductive carbon black with characteristic peaks or single pyrrole nitrogen doping only between 163 eV and 166 eV improves the overall performance of platinum-carbon catalysts, such as further improving the specific activity and stability. [Simplified Explanation of the Diagram]

[0091] Effective Method I Figure I-1 is the XPS spectrum of the nitrogen-doped carbon support in Example 1. Figure I-2 is the XPS spectrum of the nitrogen-doped carbon support in Example 3. Figure I-3 is the XPS spectrum of the platinum-carbon catalyst in Example 5. Figure I-4 is the polarization curve of the platinum-carbon catalyst in Example 5 before and after 5000 cycles. Figure I-5 is the XPS spectrum of the platinum-carbon catalyst in Example 6. Figure I-6 is the XPS spectrum of the platinum-carbon catalyst in Example 7. Figure I-7 is the XPS spectrum of the platinum-carbon catalyst in Example 8. Figure I-8 is the polarization curve of the platinum-carbon catalyst in Comparative Example 3 before and after 5000 cycles. Effective Method II Figure II-1 is the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material in Example II-1. Figure II-2 is the XPS spectrum of nitrogen in the sulfur-nitrogen-doped carbon material in Example II-1. Figure II-3 is the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material in Example II-2. Figure II-4 shows the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material of Example II-3. Figure II-5 shows the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material of Example II-4. Figure II-6 shows the TEM image of the platinum-carbon catalyst of Example II-5. Figure II-7 shows the polarization curve of the platinum-carbon catalyst of Example II-5. Figure II-8 shows the XPS spectrum of sulfur in the platinum-carbon catalyst of Example II-5. Figure II-9 shows the XPS spectrum of nitrogen in the platinum-carbon catalyst of Example II-5. Figure II-10 shows the XPS spectrum of sulfur in the platinum-carbon catalyst of Example II-7. Figure II-11 shows the XPS spectrum of nitrogen in the platinum-carbon catalyst of Example II-7. Figure II-12 shows the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material of Comparative Example II-1. Figure II-13 shows the TEM image of the platinum-carbon catalyst of Comparative Example II-1. Figure II-14 shows the polarization curve of the platinum-carbon catalyst of Comparative Example II-1. Figure II-15 shows the XPS spectrum of sulfur in the sulfur-nitrogen-doped carbon material of Comparative Example II-2. Figure II-16 shows the polarization curve of the platinum-carbon catalyst of Comparative Example II-3.

Claims

1. A carbon-supported platinum group metal catalyst, characterized in that, in the N1s spectrum of the XPS analysis of the carbon-supported platinum group metal catalyst, there is a characteristic peak of pyrrole-type nitrogen between 399 eV and 400.5 eV, and there are no or essentially no other characteristic peaks between 395 eV and 405 eV, wherein the electron binding energy is corrected using the C1s peak of elemental carbon at 284.3 eV; the phrase "essentially no other characteristic peaks between 395 eV and 405 eV" means that, apart from the characteristic peak between 399 eV and 400.5 eV, the peak area of ​​any other characteristic peak is less than 10%; the support of the carbon-supported platinum group metal catalyst is nitrogen-doped conductive carbon black; the platinum mass fraction of the carbon-supported platinum group metal catalyst is 20% to 70%.

2. The carbon-supported platinum group metal catalyst as claimed in claim 1, wherein the support for the carbon-supported platinum group metal catalyst is sulfur-nitrogen-doped conductive carbon black.

3. The carbon-supported platinum group metal catalyst as claimed in claim 1, wherein in its XPS analysis of the S2P spectrum, the area of ​​the characteristic peaks between 160 eV and 170 eV and between 163 eV and 166 eV is greater than 92%, or only the characteristic peaks between 163 eV and 166 eV are present.

4. The carbon-supported platinum group metal catalyst as claimed in claim 1, wherein the conductive carbon black is ordinary conductive carbon black, superconducting carbon black, or extra-conducting carbon black.

5. The carbon-supported platinum group metal catalyst as claimed in claim 1, wherein the platinum group metal of the carbon-supported platinum group metal catalyst is selected from platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), osmium (Os), or ruthenium (Ru).

6. The carbon-supported platinum group metal catalyst as claimed in claim 1, wherein the resistivity of the carbon-supported platinum group metal catalyst is <10 Ω·m.

7. A hydrogen fuel cell, characterized in that the anode and / or cathode of the hydrogen fuel cell use a carbon-supported platinum group metal catalyst as described in any one of claims 1 to 6.

8. A carbon material, characterized in that the carbon material is nitrogen-doped conductive carbon black, and in the N1s spectrum of pyrrole-type nitrogen analyzed by XPS, there is a characteristic peak between 399 eV and 400.5 eV; apart from the characteristic peak between 399 eV and 400.5 eV, there are no other characteristic peaks between 395 eV and 405 eV, wherein the electron binding energy is corrected by the C1s peak of elemental carbon at 284.3 eV.

9. A method for preparing a carbon-supported platinum group metal catalyst as claimed in any one of claims 1-6, comprising the following steps: (1) impregnation with a nitrogen source: mixing carbon material with an aqueous solution of a nitrogen source and impregnating to obtain a carbon material impregnated with a nitrogen source, wherein the nitrogen source is ammonia or urea; (2) manufacturing a nitrogen-doped carbon material: heating the nitrogen-doped carbon material obtained in step (1) to 1000°C to 1500°C in an inert gas at a rate of 8°C / min to 15°C / min, and then isothermal treatment for 0.5 h to 10 h to obtain a nitrogen-doped carbon material; and (3) loading platinum group metals: loading platinum group metals onto the nitrogen-doped carbon material obtained in step (2) as a support.

10. The preparation method as claimed in claim 9, wherein in (2), the temperature of the isothermal treatment is 1150°C to 1450°C.

11. The preparation method as described in claim 9, wherein the nitrogen source is ammonia / or urea.

12. The preparation method as described in claim 9, wherein the mass of the nitrogen source is based on the mass of nitrogen element it contains, and the mass ratio of the carbon material to the nitrogen source is 30:1 to 1:

2.

13. The preparation method as described in claim 9, wherein the oxygen mass fraction in the XPS analysis of the carbon material is greater than 4%.

14. The preparation method as described in claim 9, wherein the step of loading the platinum group metal comprises: (a) Disperse the nitrogen-doped carbon material obtained in step (2) with the platinum group metal precursor in an aqueous phase and adjust the pH to 8-12; (b) Add a reducing agent for reduction; and (c) Separate the solid and obtain the carbon-supported platinum group metal catalyst by post-processing.

15. The preparation method as described in claim 14, wherein the platinum group metal precursor is chloroplatinic acid, potassium chloroplatinate, or sodium chloroplatinate; and the concentration of the platinum group metal precursor is 0.5 mol / L to 5 mol / L.

16. The preparation method as claimed in claim 14, wherein in step (b), the reducing agent is selected from citric acid, ascorbic acid, formaldehyde, formic acid, ethylene glycol, sodium citrate, hydrazine hydrate, sodium borohydride, or glycerol; the molar ratio of the reducing agent to platinum is 2 to 100; the reduction temperature is 50°C to 150°C; and the reduction time is 2 h to 15 h.

17. The preparation method as described in claim 9, wherein the carbon material is conductive carbon black.

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