CN114497600A

CN114497600A - Nitrogen-phosphorus doped carbon material, platinum-carbon catalyst, and preparation methods and applications thereof

Info

Publication number: CN114497600A
Application number: CN202110274853.4A
Authority: CN
Inventors: 荣峻峰; 赵红; 彭茜; 顾贤睿; 王厚朋; 张家康; 谢南宏
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2020-10-23
Filing date: 2021-03-15
Publication date: 2022-05-13

Abstract

The invention relates to a nitrogen-phosphorus doped carbon material, a platinum-carbon catalyst, and a preparation method and application thereof. On the surface of the nitrogen-phosphorus doped carbon material, nitrogen exists mainly in the form of pyrrole nitrogen. The platinum-carbon catalyst taking the nitrogen-phosphorus doped carbon material as the carrier has excellent specific quality activity, ECSA and stability.

Description

Nitrogen-phosphorus doped carbon material, platinum-carbon catalyst, and preparation methods and applications thereof

Technical Field

The invention relates to a nitrogen-phosphorus doped carbon material, a platinum-carbon catalyst, and a preparation method and application thereof.

Background

In the field of chemistry, carbon materials are both important supports and commonly used catalysts. The carbon element has rich bonding modes, and the carbon material can be modified in various modes so as to obtain more suitable performance.

The Oxygen Reduction Reaction (ORR) is a key reaction in the electrochemical field, for example in fuel cells and metal air cells, and is a major factor affecting cell performance. The carbon material doped with atoms can be directly used as a catalyst for oxygen reduction reaction. When used as an oxygen reduction catalyst, it has been reported in the literature that a carbon material is doped with elements such as nitrogen, phosphorus, boron, sulfur, fluorine, chlorine, bromine, iodine, etc., wherein nitrogen has a radius close to that of carbon atoms and easily enters into a carbon lattice, and thus is the most commonly used doping element. Phosphorus and nitrogen belong to the same main group, but in the case of a doped carbon material, phosphorus has characteristics that are substantially different from those of nitrogen due to differences in atomic radius and electronegativity. Although there are many reports of the direct use of doped carbon materials as fuel cell catalysts and some research results show better activity, there is a wide gap and distance from commercial use compared to platinum carbon catalysts. On one hand, the combination mode of the heteroatom and the carbon material and the catalytic mechanism thereof are not fully known in the field; on the other hand, each heteroatom has multiple bonding modes with the carbon material, and when multiple heteroatoms are doped, the situation is more complicated, so that how to control the bonding mode of the heteroatoms and the carbon material is the difficulty of doping atoms. In addition, such catalysts are generally not suitable for acidic environments, especially for important Proton Exchange Membrane Fuel Cells (PEMFCs).

The most effective oxygen reduction catalyst to date is the platinum carbon catalyst, and the currently used commercial platinum carbon catalyst has an undesirable dispersion of platinum metal and is prone to agglomeration deactivation, and on the other hand, platinum dissolution and agglomeration at the cathode of a hydrogen fuel cell causes a significant decrease in platinum surface area over time, affecting fuel cell life. It is highly desirable in the art to substantially increase its catalytic activity and stability in an attempt to facilitate its large-scale commercial use. Factors influencing the activity and stability of the platinum-carbon catalyst are many and complex, and some literatures believe that the activity and stability of the platinum-carbon catalyst are related to the particle size, morphology and structure of platinum, and the type, property and platinum loading of a carrier. In the prior art, the performance of the platinum-carbon catalyst is improved mainly by controlling the particle size, morphology and structure of platinum, the specific surface area and pore structure of a carrier; there is also a literature report that modifying groups are attached to the carbon surface to improve the performance of platinum-carbon catalysts by modifying the carbon support. Jinliang Zhu et al disclose a platinum-carbon catalyst using nitrogen and phosphorus doped carbon nanotubes as a carrier, which is obtained by calcining phosphoramidic acid resin (amide acid resin) and nickel foam at 850 ℃, wherein a metal catalyst is used and the temperature is high when the carrier of the catalyst is manufactured, the platinum-carbon catalyst has low platinum-carrying amount and unsatisfactory stability, and the specific activity of the platinum-carbon catalyst mass is reduced by 19.3% after 5000 cycles, for example (Direct and orientation of platinum nanoparticles on nitrogen and phosphorus-reduced carbon nanoparticles for oxidative reaction, electrochemical acta 158(2015) 374-382).

The platinum loading of the platinum-carbon catalyst of the hydrogen fuel cell in practical application is at least more than 20 wt%, which is much more difficult than the manufacturing difficulty of the chemical platinum-carbon catalyst (the platinum loading is less than 5 wt%). The platinum-carrying quantity is improved, so that a thinner membrane electrode with better performance can be manufactured, but the platinum-carrying quantity is greatly improved, so that the accumulation among platinum metal particles is easily caused, and the utilization rate of an active site is sharply reduced. How to more effectively utilize the catalytic active sites of the platinum metal particles and increase the contactable three-phase catalytic reaction interface, thereby improving the platinum utilization rate and the comprehensive performance of the fuel cell and the metal-air battery, is a key problem to be solved in the field.

The defect sites of the carbon carrier are more beneficial to improving the platinum carrying amount, but the carbon corrosion is aggravated at the same time, and the stability of the platinum-carbon catalyst is reduced. The carbon corrosion can be effectively relieved by improving the graphitization degree, but the surface of the carbon carrier is chemically inert due to high graphitization degree, so that platinum is difficult to be uniformly dispersed on the carbon carrier, and the problem is particularly difficult when the platinum carrying amount is high.

The chemical reduction method is a commonly used method for preparing the platinum-carbon catalyst, and has the advantages of simple process and low utilization rate and catalytic activity of platinum. The reason for this may be that the platinum nanoparticles are not uniformly dispersed due to irregularities in the pore structure of the carbon support.

The information disclosed in the foregoing background section is only for enhancement of background understanding of the invention and may include information that is not already known to those of ordinary skill in the art.

Disclosure of Invention

It is a first object of the present invention to provide a carbon material with unique properties. It is a second object of the present invention to provide a platinum-carbon catalyst having excellent properties on the basis of the carbon material. It is a third object of the invention to provide a platinum-carbon catalyst with a higher platinum loading in addition to the aforementioned objects. A fourth object of the invention is to improve the aqueous reduction process for making platinum carbon catalysts.

In order to achieve the above object, the present invention provides the following technical solutions.

1. A nitrogen-phosphorus doped carbon material, characterized in that N is analyzed by XPS_1sAmong the peaks, the peak area between 399eV and 400.5eV is 80% or more, preferably 90% or more of the peak area between 390eV and 410 eV.

2. The nitrogen-phosphorus-doped carbon material according to 1, wherein N is analyzed by XPS_1sIn the spectrum peaks, characteristic peaks exist between 399ev and 400.5ev and between 401ev and 402ev, and no other characteristic peaks exist between 390ev and 410 ev; wherein the ratio of the characteristic peak area between 399ev and 400.5ev to the characteristic peak area between 401ev and 402ev is more than 5 (preferably greater than 10).

3. The nitrogen-phosphorus-doped carbon material according to 1, wherein P is analyzed by XPS_2PAmong the peaks, there were one characteristic peak at 133.3. + -. 0.3eV and 134.1. + -. 0.3eV, respectively, and there were no other characteristic peaks at 125eV to 145 eV.

4. The nitrogen-phosphorus-doped carbon material according to any one of the above aspects, wherein the resistivity of the nitrogen-phosphorus-doped carbon material is less than 10 Ω · m, preferably less than 5 Ω · m, and more preferably less than 3 Ω · m.

5. The nitrogen-phosphorus-doped carbon material is characterized in that in XPS analysis of the nitrogen-phosphorus-doped carbon material, the mass fraction of nitrogen is 0.01-4%, and the mass fraction of phosphorus is 0.01-4%; the mass fraction of nitrogen is preferably 0.1-3%, and the mass fraction of phosphorus is preferably 0.02-2.5%.

6. The nitrogen-phosphorus-doped carbon material according to any one of the preceding claims, wherein the specific surface area of the nitrogen-phosphorus-doped carbon material is 10m²/g～2000m²A/g, preferably of 200m²/g～2000m²(ii)/g; the pore volume is 0.02mL/g to 6.0mL/g, preferably 0.2mL/g to 3.0 mL/g.

7. The nitrogen-phosphorus-doped carbon material is characterized by being nitrogen-phosphorus-doped graphene, nitrogen-phosphorus-doped carbon nanotubes or nitrogen-phosphorus-doped conductive carbon black.

8. The nitrogen-phosphorus doped carbon material according to 7, wherein the conductive carbon Black is EC-300J, EC-600JD, ECP-600JD, VXC72, Black pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXAXK 40B 2.

9. A preparation method of a nitrogen-phosphorus doped carbon material comprises the following steps: and (2) contacting the carbon material with a phosphorus source and a nitrogen source, and treating for 0.5-10 h at 300-800 ℃ in inert gas to obtain the nitrogen-phosphorus doped carbon material.

10. The preparation method of the nitrogen-phosphorus doped carbon material is characterized in that the mass ratio of the carbon material to the nitrogen source is 500: 1-5: 1; preferably 200: 1-10: 1.

11. the preparation method of the nitrogen-phosphorus doped carbon material is characterized in that the mass ratio of the carbon material to the phosphorus source is 10000: 1-10: 1; preferably 2000: 1-20: 1.

12. the preparation method of the nitrogen-phosphorus doped carbon material is characterized in that the nitrogen source is ammonia water or urea.

13. The preparation method of the nitrogen-phosphorus doped carbon material is characterized in that the phosphorus source is one or more of phosphoric acid, phosphate, pyrophosphate, polyphosphate, hydrogen phosphate, dihydrogen phosphate, phosphite and hypophosphite.

14. The preparation method of the nitrogen-phosphorus doped carbon material is characterized in that the treatment time is 1-5 h, preferably 2-4 h.

15. The preparation method of the nitrogen-phosphorus-doped carbon material is characterized in that the carbon material is graphene, a carbon nano tube or conductive carbon black.

16. The method for preparing the nitrogen-phosphorus doped carbon material is characterized in that the carbon material is EC-300J, EC-600JD, ECP-600JD, VXC72, Black pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXAXK 40B 2.

17. The preparation method of the nitrogen-phosphorus doped carbon material is characterized in that the mass fraction of oxygen in XPS analysis of the carbon material is more than 4%, preferably 4-15%.

18. The method for producing a nitrogen-phosphorus-doped carbon material according to any one of the above, wherein the carbon material has a resistivity of <10 Ω · m, preferably <5 Ω · m, and more preferably <2 Ω · m.

19. The method for producing the nitrogen-phosphorus-doped carbon material according to any one of the preceding claims, characterized in that the specific surface area of the carbon material is 10m²/g～2000m²A/g, preferably of 200m²/g～2000m²(ii)/g; the pore volume is 0.02mL/g to 6mL/g, preferably 0.2mL/g to 3 mL/g.

20. The nitrogen-phosphorus doped carbon material prepared by any one of the methods.

21. Any of the nitrogen-phosphorus doped carbon materials described above is used as an electrode material in electrochemistry.

22. A platinum-carbon catalyst comprising a carbon support and a platinum metal supported thereon, characterized in that N is analyzed by XPS thereof _1sAmong the peaks, the peak area between 399eV and 400.5eV is 80% or more, preferably 90% or more of the peak area between 390eV and 410 eV.

23. The platinum-carbon catalyst according to any one of the preceding claims, characterized in that the carbon support is a nitrogen-phosphorus doped carbon material.

24. The platinum-carbon catalyst is characterized in that the carbon carrier is a nitrogen-phosphorus doped carbon material of any one of 1-8 and 20.

25. A platinum-carbon catalyst according to any one of the preceding claims, characterised in that N is analysed in its XPS_1sAmong the spectral peaks, there is a characteristic peak between 399eV and 400.5eV, and there is no other characteristic peak between 390eV and 410 eV.

26. The platinum-carbon catalyst according to any one of the preceding claims, characterized in that, in XPS analysis thereof, there is no P between 125eV and 145eV_2PCharacteristic peak of (2).

27. The platinum-carbon catalyst according to any of the preceding claims, characterized in that the platinum-carbon catalyst has a resistivity of <10 Ω · m, preferably <2 Ω · m.

28. The platinum-carbon catalyst is characterized in that the nitrogen-phosphorus doped carbon material is nitrogen-phosphorus doped graphene, nitrogen-phosphorus doped carbon nanotube or nitrogen-phosphorus doped conductive carbon black.

29. The platinum-carbon catalyst according to 28, wherein the conductive carbon Black is EC-300J, EC-600JD, ECP-600JD, VXC72, Black pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXAXK 40B 2.

30. A method of preparing a platinum-carbon catalyst, comprising: (1) the method comprises the following steps of: contacting a carbon material with a phosphorus source and a nitrogen source, and treating for 0.5-10 h at 300-800 ℃ in an inert gas to obtain the nitrogen-phosphorus doped carbon material; (2) and (3) loading platinum by taking the nitrogen-phosphorus doped carbon material obtained in the step (1) as a carrier.

31. The method for preparing any one of the platinum-carbon catalysts described above, wherein in (1), the mass ratio of the carbon material to the nitrogen source, based on the mass of nitrogen contained in the nitrogen source, is 500: 1-10: 1; preferably 200: 1-10: 1.

32. the process for producing a platinum-carbon catalyst according to any one of the preceding claims, wherein in (1), the nitrogen source is ammonia water or urea.

33. The method for preparing a platinum-carbon catalyst according to any one of the preceding claims, wherein in (1), the mass ratio of the carbon material to the phosphorus source is 10000: 1-10: 1; preferably 2000: 1-20: 1.

34. the preparation method of any one of the platinum-carbon catalysts is characterized in that in the step (1), the phosphorus source is one or more of phosphoric acid, phosphate, pyrophosphate, polyphosphate, hydrogen phosphate, dihydrogen phosphate, phosphite and hypophosphite.

35. The method for preparing any of the foregoing platinum-carbon catalysts is characterized in that, in the step (1), the temperature is 400 to 700 ℃.

36. The method for preparing a platinum-carbon catalyst according to any one of the preceding claims, wherein the treatment time in (1) is 1 to 5 hours, preferably 2 to 4 hours.

37. The method for preparing a platinum-carbon catalyst according to any one of the preceding claims, wherein in (1), the carbon material is graphene, carbon nanotubes or conductive carbon black.

38. The method for preparing a platinum-carbon catalyst according to 37, wherein the conductive carbon Black is EC-300J, EC-600JD, ECP-600JD, VXC72, Black pears 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXAXK 40B 2.

39. The method for producing a platinum-carbon catalyst according to any one of the preceding claims, wherein in (1), the carbon material has an oxygen mass fraction of more than 4%, preferably 4% to 15%, in XPS analysis.

40. The method for producing a platinum-carbon catalyst according to any one of the above methods, wherein the carbon material in (1) has a resistivity of < 10. omega. m, preferably < 5. omega. m, more preferably < 2. omega. m.

41. A process for preparing a platinum-carbon catalyst as described in any of the preceding claimsCharacterized in that (1) the carbon material has a specific surface area of 10m ²/g～2000m²A ratio of/g, preferably 200m²/g～2000m²(iv) g; the pore volume is 0.02mL/g to 6mL/g, preferably 0.2mL/g to 3 mL/g.

42. The method for preparing a platinum-carbon catalyst according to any one of the preceding claims, wherein the step of supporting platinum comprises:

(a) dispersing the nitrogen-phosphorus doped carbon material obtained in the step (1) and a platinum precursor in a water phase, and adjusting the pH value to 8-12 (preferably, adjusting the pH value to 10 +/-0.5);

(b) adding a reducing agent for reduction;

(c) separating out solid, and post-treating to obtain the platinum-carbon catalyst.

43. The preparation method of any one of the platinum-carbon catalysts is characterized in that in (a), the platinum precursor is chloroplatinic acid, potassium chloroplatinate or sodium chloroplatinate; the concentration of the platinum precursor is 0.5-5 mol/L.

44. The preparation method of any one of the platinum-carbon catalysts is characterized in that in the 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; the molar ratio of the reducing agent to the platinum is 2-100; the reduction temperature is 60-90 ℃; the reduction time is 4-15 h.

45. A platinum-carbon catalyst is characterized by being prepared by any one of the preparation methods of the platinum-carbon catalyst.

46. A hydrogen fuel cell, characterized in that any one of the foregoing platinum-carbon catalysts is used in an anode and/or a cathode of the hydrogen fuel cell.

The heteroatom and the carbon material have various combination modes, and the combination mode of the heteroatom and the carbon material is influenced by different doping methods and raw materials and different operation steps and conditions in the doping process, so that the property difference of the heteroatom and the carbon material is caused, and the functions of the heteroatom and the carbon material are changed. In the art, how to control the bonding mode of the heteroatom to the carbon material is a difficulty in doping atoms. Controlling the bonding of heteroatoms to carbon materials makes it possible to produce carbon materials with unique propertiesThereby making it suitable for a particular application. The research of the invention finds that a unique carbon material can be obtained by roasting at a lower temperature after a carbon material is impregnated by a nitrogen source and a phosphorus source, and N analyzed by XPS (X-ray diffraction) of the carbon material_1sThe map shows that nitrogen doped on the surface of the carbon material exists mainly in the form of pyrrole nitrogen. Further research also finds that the nitrogen-phosphorus doped carbon material is suitable for serving as a carrier of a platinum-carbon catalyst of a hydrogen fuel cell.

Compared with the prior art, the invention can realize the following beneficial technical effects.

Firstly, the nitrogen-phosphorus doped carbon material is prepared by soaking a nitrogen source and a phosphorus source and then roasting at a lower temperature, and compared with the existing nitrogen-doped carbon material, nitrogen doped on the surface of the carbon material mainly exists in the form of pyrrole nitrogen.

Secondly, the carbon material prepared by the invention is suitable for being used as a carrier of a platinum-carbon catalyst, and is particularly suitable for preparing the platinum-carbon catalyst with high platinum loading.

And thirdly, the platinum carrying amount of the platinum-carbon catalyst of the hydrogen fuel cell in practical application is generally more than 20 wt%, and the difficulty in manufacturing the high platinum carrying amount catalyst with excellent performance is great. The chemical reduction method has simple process, but the utilization rate of platinum is low and the catalytic activity is lower. However, the nitrogen-phosphorus doped carbon material prepared by the invention is used as a carrier, and a high-platinum-loading-amount catalyst with good quality specific activity and stability can be easily prepared by adopting an aqueous phase chemical reduction method.

And fourthly, when the platinum-carbon catalyst manufactured by the invention is used as a hydrogen fuel cell catalyst, the platinum-carbon catalyst has excellent specific mass activity, ECSA and stability.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

Fig. 1 is an XPS spectrum of nitrogen for the nitrogen phosphorous doped carbon material of example 1.

FIG. 2 is an XPS spectrum of phosphorus for the nitrogen phosphorus doped carbon material of example 1.

FIG. 3 is an XPS spectrum of nitrogen for the nitrogen phosphorous doped carbon material of example 2.

FIG. 4 is an XPS spectrum of phosphorus for the nitrogen phosphorus doped carbon material of example 2.

Fig. 5 is an XPS spectrum of nitrogen for the nitrogen phosphorous doped carbon material of example 3.

FIG. 6 is an XPS spectrum of phosphorus for the nitrogen phosphorus doped carbon material of example 3.

FIG. 7 is a XPS spectrum of nitrogen for the nitrogen phosphorous doped carbon material of example 4.

FIG. 8 is an XPS spectrum of phosphorus for the nitrogen phosphorus doped carbon material of example 4.

Fig. 9 is a plot of polarization (LSV) before and after 5000 cycles of the platinum-carbon catalyst of example 5.

Fig. 10 is a CV curve of the platinum-carbon catalyst of example 5 before and after 5000 rounds.

Fig. 11 is an XPS spectrum of nitrogen for the platinum-carbon catalyst of example 5.

Figure 12 is an XPS spectrum of nitrogen for the platinum carbon catalyst of example 7.

Detailed Description

The present invention will be described in detail with reference to the following embodiments, but it should be understood that the scope of the present invention is not limited by these embodiments and the principle of the present invention, but is defined by the claims.

In the present invention, anything or matters not mentioned is directly applicable to those known in the art without any change except those explicitly described. Moreover, any embodiment described herein may be freely combined with one or more other embodiments described herein, and the technical solutions or ideas formed thereby are considered part of the original disclosure or description of the present invention and should not be considered as new matters not disclosed or contemplated herein, unless a person skilled in the art would consider such combination to be clearly unreasonable.

All of the features disclosed in this application can be combined in any combination which is understood to be disclosed or described in this application and which, unless clearly considered to be too irrational by a person skilled in the art, is to be considered as being specifically disclosed and described in this application. The numerical points disclosed in the present specification include not only the numerical points specifically disclosed in the examples but also the endpoints of each numerical range in the specification, and ranges in which any combination of the numerical points is disclosed or recited should be considered as ranges of the present invention.

Technical and scientific terms used herein are to be defined only in accordance with their definitions, and are to be understood as having ordinary meanings in the art without any definitions.

The "doping element" in the present invention means nitrogen, phosphorus, boron, sulfur, fluorine, chlorine, bromine and iodine.

In the present invention, unless the term "carbon material containing a doping element" is uniquely defined depending on the context or the self-definition, the term "carbon material" refers to a carbon material containing no doping element. So does the underlying concept of carbon material.

In the present invention, "carbon black" and "carbon black" are terms of art that can be substituted for each other.

The "inert gas" in the present invention means a gas that does not have any appreciable influence on the performance of the nitrogen-phosphorus doped carbon material in the production method of the present invention. So does the underlying concept of carbon material.

In the present invention, other references to "pore volume" are intended to refer to P/P, except where the context or limitations may be clear₀The maximum single point adsorption total pore volume.

The invention provides a nitrogen-phosphorus doped carbon material, N analyzed by XPS_1sAmong the spectrum peaks, the characteristic peak area between 399eV and 400.5eV accounts for more than 80%, preferably more than 90% of the characteristic peak area between 390eV and 410 eV.

The nitrogen-phosphorus doped carbon material according to the present invention, N analyzed by XPS thereof_1sIn the spectrum peaks, characteristic peaks exist between 399ev and 400.5ev and between 401ev and 402ev, and no other characteristic peaks exist between 390ev and 410 ev; wherein the ratio of the characteristic peak area between 399eV and 400.5eV to the characteristic peak area between 401eV and 402eV is greater than 5 (preferably greater than 10).

The nitrogen-phosphorus doped carbon material according to the present invention contains no other doping elements than nitrogen and phosphorus.

The nitrogen-phosphorus doped carbon material does not contain metal elements.

Nitrogen according to the inventionPhosphorus-doped carbon material, N in XPS analysis thereof_1sIn the spectrum peaks, except one characteristic peak between 399eV and 400.5eV and one characteristic peak between 401eV and 402eV, no other characteristic peak is present between 390eV and 410 eV.

Nitrogen-phosphorus doped carbon materials according to the invention, in some embodiments, P as analyzed by XPS thereof_2PIn the spectrum peaks, one characteristic peak is respectively at 133.3 +/-0.3 eV and 134.1 +/-0.3 eV, and no other characteristic peak is arranged at 125 to 145 eV.

The nitrogen-phosphorus doped carbon material according to the invention has a resistivity of <10.0 Ω · m, preferably <5.0 Ω · m, more preferably <3.0 Ω · m.

According to the nitrogen-phosphorus doped carbon material, in XPS analysis, the mass fraction of nitrogen is 0.01-4%, and the mass fraction of phosphorus is 0.01-4%; the nitrogen mass fraction is preferably 0.1-3%, and the phosphorus mass fraction is preferably 0.02-2.5%.

The nitrogen-phosphorus doped carbon material according to the present invention is not particularly limited in its oxygen content. Generally, the XPS analysis of the oxygen content of the compound is 2 to 15 percent.

The nitrogen-phosphorus doped carbon material according to the invention can have a specific surface area and a pore volume which vary within a relatively large range, for example, the specific surface area can be 10m²/g～2000m²The pore volume may be from 0.02mL/g to 6.0 mL/g. In one embodiment, the specific surface area is 200m²/g～2000m²The pore volume is 0.2mL/g to 3.0 mL/g.

According to the nitrogen-phosphorus-doped carbon material, the nitrogen-phosphorus-doped carbon material is nitrogen-phosphorus-doped graphene, a nitrogen-phosphorus-doped carbon nanotube or nitrogen-phosphorus-doped conductive carbon black. The Conductive carbon black can be common Conductive carbon black (Conductive Blacks), Super Conductive carbon black (Super Conductive Blacks) or special Conductive carbon black (Extra Conductive Blacks), for example, the Conductive carbon black can be one or more of Ketjen black series superconducting carbon black, Cabot series Conductive carbon black and series Conductive carbon black produced by Wingda Texas company; preferably Ketjen Black EC-300J, Ketjen Black EC-600JD, Ketjen Black ECP-600JD, VXC72, Black pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXK 40B 2.

The nitrogen-phosphorus doped carbon material provided by the invention has no limitation on the preparation method and source of the conductive carbon black. The conductive carbon black may be acetylene black, furnace black, or the like.

According to the nitrogen-phosphorus doped carbon material, the carbon nanotube or the graphene can be a carbon nanotube or graphene subjected to oxidation treatment, or can be a carbon nanotube or graphene not subjected to oxidation treatment.

According to the nitrogen-phosphorus doped carbon material, nitrogen and phosphorus are combined with the carbon material in a chemical bond mode.

The invention also provides a preparation method of the nitrogen-phosphorus doped carbon material, which comprises the following steps: and (3) contacting the carbon material with a phosphorus source and a nitrogen source, and treating (preferably, treating at constant temperature) for 0.5-10 h at 300-800 ℃ in inert gas to obtain the nitrogen-phosphorus doped carbon material.

According to the preparation method of the nitrogen-phosphorus doped carbon material, the carbon material is contacted with the phosphorus source and the nitrogen source in a mixing manner. The present invention is not limited to the order and manner of mixing the carbon material with the phosphorus and nitrogen sources, and those skilled in the art can select an appropriate order and manner based on the teaching and/or prior knowledge of the present invention. The present invention provides a preferred mixing mode: the carbon material is mixed with a solution of a phosphorus source and a nitrogen source (preferably an aqueous solution), impregnated and dried.

According to the preparation method of the nitrogen-phosphorus doped carbon material, the carbon material can be conductive carbon black, carbon nano tubes or graphene. The conductive carbon black can be one or more of Ketjen black series superconducting carbon black, Cabot series conductive carbon black and series conductive carbon black produced by Wingchudegusse company; preferably EC-300J, EC-600JD, ECP-600JD, VXC72, Black pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXK 40B 2.

According to the preparation method of the nitrogen-phosphorus doped carbon material, I_D/I_GThe value is generally 0.8 to 5, preferably 1 to 4. In the Raman spectrum, it is located at 1320cm^-1The nearby peak is D peak and is located at 1580cm^-1The nearby peak is G peak, I_DRepresents the intensity of the D peak, I_GRepresenting the intensity of the G peak.

According to the preparation method of the nitrogen-phosphorus doped carbon material, the nitrogen source is ammonia water or urea.

According to the preparation method of the nitrogen-phosphorus doped carbon material, the mass of the nitrogen source is calculated according to the mass of nitrogen contained in the nitrogen source, and the mass ratio of the carbon material to the nitrogen source is 500: 1-5: 1; preferably 200: 1-10: 1.

according to the preparation method of the nitrogen-phosphorus doped carbon material, the phosphorus source is one or more of phosphoric acid, phosphate, pyrophosphate, polyphosphate, hydrogen phosphate, dihydrogen phosphate, phosphite and hypophosphite.

According to the preparation method of the nitrogen-phosphorus doped carbon material, the mass of the phosphorus source is calculated by the mass of phosphorus contained in the carbon material, and the mass ratio of the carbon material to the phosphorus source is 10000: 1-10: 1; preferably, the ratio of 2000: 1-20: 1.

according to the preparation method of the nitrogen-phosphorus doped carbon material, the inert gas is nitrogen or argon.

According to the preparation method of the nitrogen-phosphorus doped carbon material, the temperature is raised if necessary, and the temperature raising rate can be 1-20 ℃/min, preferably 3-15 ℃/min, and more preferably 8-10 ℃/min.

According to the preparation method of the nitrogen-phosphorus doped carbon material, the temperature is preferably 400-700 ℃.

The time for the treatment is preferably 1 to 5 hours, more preferably 2 to 4 hours.

According to the method for producing a nitrogen-phosphorus doped carbon material of the present invention, the carbon material has a resistivity of <10 Ω · m, preferably <5 Ω · m, more preferably <2 Ω · m.

According to the preparation method of the nitrogen-phosphorus doped carbon material, the oxygen mass fraction is generally more than 4%, and preferably 4% -15% in XPS analysis of the carbon material.

According to the preparation method of the nitrogen-phosphorus doped carbon material, the specific surface area of the carbon material can be changed in a large range. Generally, the specific surface area is 10m ²/g～2000m²(iv) g; the pore volume is 0.02 mL/g-6 mL/g.

According to the preparation method of the nitrogen-phosphorus doped carbon material, in one embodiment, the carbon material impregnated with the phosphorus source and the nitrogen source is placed in a tube furnace, the tube furnace is heated to 300-800 ℃ (preferably 400-700 ℃) at the speed of 8-10 ℃/min in inert gas, and then the carbon material is treated at constant temperature for 0.5-10 h to obtain the nitrogen-phosphorus co-doped carbon material.

The inert gas is nitrogen or argon.

According to the preparation method of the nitrogen-phosphorus doped carbon material, a metal-containing catalyst is not used in the process of preparing the nitrogen-phosphorus doped carbon material.

The invention also provides the nitrogen-phosphorus doped carbon material prepared by any one of the methods.

Any of the nitrogen-phosphorus doped carbon materials described above is used as an electrode material in electrochemistry.

A platinum-carbon catalyst comprising a carbon support and a platinum metal supported thereon, characterized in that N is analyzed by XPS thereof_1sAmong the peaks, the peak area between 399eV and 400.5eV is 80% or more, preferably 90% or more of the peak area between 390eV and 410 eV.

According to the platinum-carbon catalyst, the carbon carrier is a nitrogen-phosphorus doped carbon material.

According to the platinum-carbon catalyst, the carbon carrier is any one of the nitrogen-phosphorus doped carbon materials.

The platinum-carbon catalyst according to the present invention, N analyzed in XPS thereof_1sAmong the spectrum peaks, there is a characteristic peak between 399 to 400.5eV, and there is no other characteristic peak between 390 to 410 eV.

The platinum-carbon catalyst according to the present invention does not contain other doping elements than nitrogen and phosphorus.

The platinum-carbon catalyst according to the present invention does not contain other metal elements than platinum.

According to the platinum-carbon catalyst of the present invention, the nitrogen and phosphorus are chemically bonded to the carbon material.

The platinum-carbon catalyst according to the present invention has no P between 125eV and 145eV in its XPS analysis_2PCharacteristic peak of (2).

According to the platinum-carbon catalyst of the present invention, a phosphorus signal (P, P) was detected in TG-MS (thermogravimetric-mass spectrometry) test₂O₃And P₂O₅)。

According to the platinum-carbon catalyst of 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.

The platinum-carbon catalyst according to the invention has a resistivity of <10.0 Ω · m, preferably <2.0 Ω · m.

According to the platinum-carbon catalyst of the present invention, the specific surface area of the platinum-carbon catalyst is 80m²/g～1500m²A/g, preferably of 100m²/g～200m²/g。

According to the platinum-carbon catalyst of the present invention, the carbon material may be conductive carbon black, graphene, or carbon nanotubes. The conductive carbon black can be one or more of Ketjen black series superconducting carbon black, Cabot series conductive carbon black and series conductive carbon black produced by Wingchuang Texaco company; preferably Ketjen Black EC-300J, Ketjen Black EC-600JD, Ketjen Black ECP-600JD, VXC72, Black pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXK 40B 2.

The invention provides a preparation method of a platinum-carbon catalyst, which comprises the following steps: the method comprises the following steps: (1) the method for preparing the nitrogen-phosphorus doped carbon material comprises the following steps: contacting a carbon material with a phosphorus source and a nitrogen source, and treating (preferably, treating at constant temperature) for 0.5-10 h at 300-800 ℃ in an inert gas to obtain the nitrogen-phosphorus doped carbon material; (2) and (3) loading platinum by taking the nitrogen-phosphorus doped carbon material obtained in the step (1) as a carrier.

According to the preparation method of the platinum-carbon catalyst of the present invention, the "contact manner of the carbon material with the phosphorus source and the nitrogen source" is the same as that of the corresponding parts in the foregoing, and the details of the present invention are omitted.

According to the preparation method of the platinum-carbon catalyst, in the step (1), the mass ratio of the carbon material to the nitrogen source is 500: 1-5: 1; preferably 200: 1-10: 1.

according to the preparation method of the platinum-carbon catalyst, in the step (1), the mass of the phosphorus source is calculated according to the mass of phosphorus contained in the carbon material, and the mass ratio of the carbon material to the phosphorus source is 10000: 1-10: 1; preferably 2000: 1-20: 1.

according to the preparation method of the platinum-carbon catalyst, the nitrogen source is ammonia water or urea.

According to the preparation method of the platinum-carbon catalyst, the phosphorus source is one or more of phosphoric acid, phosphate, pyrophosphate, polyphosphate, hydrogen phosphate, dihydrogen phosphate, phosphite and hypophosphite.

According to the preparation method of the platinum-carbon catalyst, the temperature is raised as required in the step (1), and the heating rate can be 1-20 ℃/min, preferably 3-15 ℃/min, and more preferably 8-10 ℃/min.

According to the preparation method of the platinum-carbon catalyst of the present invention, in (1), the temperature is preferably 400 to 700 ℃.

According to the preparation method of the platinum-carbon catalyst of the invention, in the step (1), the treatment time is 1 to 5 hours, preferably 2 to 4 hours.

According to the preparation method of the platinum-carbon catalyst of the invention, (1), the carbon material is graphene, conductive carbon black or carbon nanotubes. The conductive carbon Black is EC-300J, EC-600JD, ECP-600JD, VXC72, Black pearls 2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXK 40B 2.

According to the preparation method of the platinum-carbon catalyst, the nitrogen-phosphorus doped carbon material prepared in the step (1) can be easily dispersed in a water phase. However, it is difficult to disperse the carbon material such as ketjen black directly in the aqueous phase.

According to the preparation method of the platinum-carbon catalyst, in the step (1), in XPS analysis of the carbon material, the oxygen mass fraction is more than 4%, and preferably 4-15%.

According to the method for producing a platinum-carbon catalyst of the present invention, (1), the carbon material has a resistivity of <10 Ω · m, preferably <5 Ω · m, and more preferably <2 Ω · m.

According to the preparation method of the platinum-carbon catalyst of the present invention, in (1), the carbon material has a specific surface area of 10m²/g～2000m²A/g, preferably of 200m²/g～2000m²(ii)/g; hole(s)The volume is 0.02mL/g to 6mL/g, preferably 0.2mL/g to 3 mL/g.

A platinum-carbon catalyst is prepared by any one of the preparation methods of the platinum-carbon catalyst.

A hydrogen fuel cell comprising an anode and/or a cathode, wherein any one of the platinum-carbon catalysts described above is used.

When the platinum-carbon catalyst is used for oxygen reduction reaction, the reduction rate of ECSA after 5000 circles is less than 10%, and the reduction rate of specific mass activity after 5000 circles is less than 12%.

The platinum-carbon catalyst of the present invention is used in oxygen reduction reactions, in some cases ECSA>56m²g^-1Pt, e.g. at 56m²g^-1-Pt～88m²g^-1-Pt。

When the platinum-carbon catalyst of the present invention is used in an oxygen reduction reaction, the specific mass activity is shown in some cases>0.155A mg^-1Pt, e.g. 0.155A mg^-1-Pt～0.221A mg^-1-Pt。

The platinum-carbon catalyst of the present invention, when used in an oxygen reduction reaction, has a half-wave potential of >0.88V, such as 0.88V to 0.91V, in some cases.

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way.

Reagents, instruments and tests

Unless otherwise specified, all reagents used in the invention are analytically pure, and all reagents are commercially available.

The invention detects elements on the surface of the material by an X-ray photoelectron spectrum analyzer (XPS). The adopted X-ray photoelectron spectrum analyzer is an ESCALB 220i-XL type ray photoelectron spectrum analyzer which is manufactured by VG scientific company and is provided with Avantage V5.926 software, and the X-ray photoelectron spectrum analysis test conditions are as follows: the excitation source is monochromatized A1K alpha X-ray, the power is 330W, and the base vacuum is 3X 10 during analysis and test^-9mbar. In addition, the electron binding energy was corrected with the C1s peak (284.3eV) of elemental carbon, and the late peak processing software was XPSPEAK. Of nitrogen-phosphorus doped carbon materialsIn the spectrogram, the characteristic peaks of nitrogen and phosphorus are the characteristic peaks after peak separation.

Apparatus and method of elemental analysis, conditions: an element analyzer (Vario EL Cube), the reaction temperature is 1150 ℃, 5mg of the sample is weighed, the reduction temperature is 850 ℃, the flow rate of carrier gas helium is 200mL/min, the flow rate of oxygen is 30mL/min, and the oxygen introducing time is 70 s.

The instrument, the method and the conditions for testing the mass fraction of platinum in the platinum-carbon catalyst are as follows: and (3) adding 30mL of aqua regia into 30mg of the prepared Pt/C catalyst, condensing and refluxing for 12h at 120 ℃, cooling to room temperature, taking supernatant liquid for dilution, and testing the Pt content in the supernatant liquid by using ICP-AES (inductively coupled plasma-atomic emission Spectrometry).

The high-resolution transmission electron microscope (HRTEM) adopted by the invention is JEM-2100(HRTEM) (Nippon electronics Co., Ltd.), and the test conditions of the high-resolution transmission electron microscope are as follows: the acceleration voltage was 200 kV. The particle size of the nanoparticles in the sample is measured by an electron microscope picture.

BET test method: in the invention, the pore structure property of a sample is measured by a Quantachrome AS-6B type analyzer, the specific surface area and the pore volume of the catalyst are obtained by a Brunauer-Emmett-Taller (BET) method, and the pore distribution curve is obtained by calculating a desorption curve according to a Barrett-Joyner-Halenda (BJH) method.

The Raman detection adopts a LabRAM HR UV-NIR laser confocal Raman spectrometer produced by HORIBA company of Japan, and the laser wavelength is 532 nm.

Electrochemical performance test, instrument Model Solartron analytical energy lab and Princeton Applied Research (Model 636A), methods and test conditions: polarization curve LSV of catalyst at 1600rpm₂Saturated 0.1M HClO₄Test in (1), CV Curve under Ar atmosphere 0.1M HClO₄To calculate the electrochemically active area ECSA. At O in the stability test₂Saturated 0.1M HClO₄After 5000 cycles of scanning in the range of 0.6V to 0.95V, LSV and ECSA were tested as described above. During the test, the catalyst is prepared into evenly dispersed slurry and coated on a glassy carbon electrode with the diameter of 5mm, and the platinum content of the catalyst on the electrode is 3-4 mu g.

Resistivity test four-probe resistivity tester, instrument model KDY-1, method and test conditions: the applied pressure is 3.9 plus or minus 0.03MPa, and the current is 500 plus or minus 0.1 mA.

TG-MS test method: the test is carried out by adopting a German Chiz-resistant STA449F5-QMS403D type thermogravimetric-mass spectrometer, an ion source is an EI source, a quadrupole mass spectrometer adopts an MID mode, a transmission pipeline is a capillary tube with the length of 3 meters, and the temperature is 260 ℃; the temperature range is 55-1000 ℃, and the heating rate is 10 ℃/min.

VXC72(Vulcan XC72, produced by Kabot, USA) was purchased from Suzhou wingong sandisk energy science and technology, Inc. The results of the tests by the instrument method show that: specific surface area of 258m²(g), pore volume 0.388mL/g, oxygen mass fraction 8.72% by XPS analysis, I_D/I_G1.02, and a resistivity of 1.22. omega. m.

Ketjenblack ECP600JD (manufactured by Lion corporation, japan) was purchased from tsuzhou wingong sandisk energy science and technology limited. The results of the tests by the instrument method show that: specific surface area 1362m²Volume of pores/g, 2.29mL/g, XPS analysis oxygen mass fraction of 6.9%, I_D/I_G1.25, and resistivity of 1.31. omega. m.

Black Pearls 2000 (produced by Kabott, USA) is purchased from Suzhou wingong sandisk energy science and technology, Inc. The results of the tests by the instrument method show that: specific surface area 1479m ²G, XPS analysis oxygen mass fraction 9.13%, I_D/I_G1.14, and resistivity of 1.19. omega. m.

A commercial platinum-carbon catalyst (trade designation HISPEC4000, from Johnson Matthey corporation) was purchased from Alfa Aesar. The test result shows that: the mass fraction of platinum was 40.2%.

Example 1

This example illustrates the preparation of a nitrogen-phosphorous doped carbon material according to the present invention.

1g of Vulcan XC72 was immersed in 20mL of an aqueous solution having an ammonia concentration of 2.0 wt% and a sodium dihydrogen phosphate concentration of 2.0 wt% for 24 hours; drying in an oven at 100 ℃; then placing the tube furnace into a tube furnace, heating the tube furnace to 400 ℃ at the speed of 10 ℃/min, and carrying out constant temperature treatment for 2 h; and naturally cooling to obtain the nitrogen-phosphorus doped carbon material numbered as the carbon carrier A.

Sample characterization and testing

The nitrogen mass fraction by XPS analysis was 1.81%; the mass fraction of phosphorus analyzed by XPS was 2.13%; specific surface area of 249m²(ii)/g; resistivity 1.29. omega. m.

In FIG. 1, the ratio of the characteristic peak area between 399eV and 400.5eV to the characteristic peak area between 401eV and 402eV is 14.8.

Example 2

1g of Vulcan XC72 was immersed for 20h in 15mL of an aqueous solution with a urea concentration of 1.0 wt% and a phosphoric acid concentration of 1.6 wt%; drying in an oven at 100 ℃; then placing the tube furnace into a tube furnace, heating the tube furnace to 600 ℃ at the speed of 8 ℃/min, and carrying out constant temperature treatment for 2 h; and naturally cooling to obtain a nitrogen-phosphorus doped carbon material numbered as a carbon carrier B.

Sample characterization and testing

The nitrogen mass fraction by XPS analysis was 1.41%; the mass fraction of phosphorus analyzed by XPS was 1.98%; x specific surface area of 244m²(ii)/g; the resistivity was 1.31. omega. m.

In FIG. 3, the ratio of the characteristic peak area between 399eV and 400.5eV to the characteristic peak area between 401eV and 402eV is 11.9.

Example 3

Adding 10mL of absolute ethanol into 1g of Ketjenblack ECP600JD, and then adding 30mL of aqueous solution with 5 wt% of ammonia concentration and 0.15 wt% of sodium dihydrogen phosphate concentration for soaking for 24 h; drying in an oven at 100 ℃; then placing the tube furnace into a tube furnace, heating the tube furnace to 700 ℃ at the speed of 10 ℃/min, and carrying out constant temperature treatment for 3 h; and naturally cooling to obtain a nitrogen-phosphorus doped carbon material numbered as a carbon carrier C.

Sample characterization and testing

The nitrogen mass fraction by XPS analysis was 2.6%; the phosphorus mass fraction by XPS analysis was 0.13%; specific surface area of 1348m²(ii)/g; the resistivity was 1.34. omega. m.

In FIG. 5, the ratio of the characteristic peak area between 399eV and 400.5eV to the characteristic peak area between 401eV and 402eV is 6.3.

Example 4

1g of Black Pearls 2000 was immersed in 35mL of an aqueous solution having a urea concentration of 1.0 wt% and a phosphoric acid concentration of 0.25 wt% for 24 hours; drying in an oven at 100 ℃; then placing the tube furnace into a tube furnace, heating the tube furnace to 500 ℃ at the speed of 8 ℃/min, and carrying out constant temperature treatment for 3 h; and naturally cooling to obtain a nitrogen-phosphorus doped carbon material numbered as a carbon carrier D.

Sample characterization and testing

The nitrogen mass fraction by XPS analysis was 0.82%; the mass fraction of phosphorus analyzed by XPS was 0.31%; the specific surface area is 1466m²(ii)/g; the resistivity was 1.23. omega. m.

In FIG. 7, the ratio of the characteristic peak area between 399eV and 400.5eV to the characteristic peak area between 401eV and 402eV is 5.1.

Example 5

This example illustrates the preparation of a platinum carbon catalyst according to the invention.

Dispersing a carbon carrier A into deionized water according to the proportion that 250mL of water is used for each gram of carbon carrier, adding 3.4mmol of chloroplatinic acid into each gram of carbon carrier, performing ultrasonic dispersion to form a suspension, and adding 1mol/L of sodium carbonate aqueous solution to enable the pH value of the system to be 10; heating the suspension to 80 ℃, adding formic acid to carry out reduction reaction while stirring, wherein the molar ratio of the formic acid to the chloroplatinic acid is 50:1, and continuously maintaining the reaction for 10 hours; and filtering the reacted mixture, washing the mixture by deionized water until the pH value of the filtrate is neutral, filtering the mixture, and drying the filtrate at 100 ℃ to obtain the platinum-carbon catalyst.

Sample characterization and testing

The platinum mass fraction of the platinum-carbon catalyst was 40.3%.

No P exists between 125ev and 145ev in XPS analysis of platinum carbon catalyst_2pCharacteristic peak of (2).

Phosphorus signals (P, P) were detected in TG-MS (thermogravimetric-mass spectrometry) tests of platinum-carbon catalysts₂O₃And P₂O₅)。

The results of the platinum carbon catalyst performance test are shown in Table 1.

Example 6

This example illustrates the preparation of a platinum carbon catalyst.

A platinum carbon catalyst was prepared according to the method of example 5, except that: using the carbon support B prepared in example 2, 1.3mmol of chloroplatinic acid per gram of carbon support was added.

Sample characterization and testing

The platinum mass fraction of the platinum-carbon catalyst was 20.4%.

The results of the platinum carbon catalyst performance tests are shown in table 1.

Example 7

Dispersing a carbon carrier C in deionized water according to the proportion that 250mL of water is used for each gram of carbon carrier, adding 12mmol of chloroplatinic acid into each gram of carbon carrier, performing ultrasonic dispersion to form a suspension, and adding 1mol/L of potassium hydroxide aqueous solution to adjust the pH value of the system to 10; heating the suspension to 80 ℃, adding sodium borohydride while stirring for reduction reaction, wherein the molar ratio of the reducing agent to the platinum precursor is 5:1, and maintaining the reaction for 12 hours; and filtering the reacted mixture, washing until the pH value of the solution is neutral, and drying at 100 ℃ to obtain the carbon-supported platinum catalyst.

Sample characterization and testing

The platinum mass fraction of the platinum-carbon catalyst was 69.6%.

Example 8

This example illustrates the preparation of a platinum carbon catalyst.

A platinum carbon catalyst was prepared according to the method of example 7, except that: using the carbon support D prepared in example 4, 3.4mmol of chloroplatinic acid per gram of carbon support was added.

Sample characterization and testing

The platinum mass fraction of the platinum-carbon catalyst was 40.0%.

Comparative example 1

Dispersing Vulcan XC72 in deionized water according to the proportion that each gram of carbon carrier uses 250mL of water, adding 3.4mmol of chloroplatinic acid into each gram of carbon carrier, performing ultrasonic dispersion to form suspension, and adding 1mol/L of sodium carbonate aqueous solution to ensure that the pH value of the system is 10; heating the suspension to 80 ℃, adding formic acid to carry out reduction reaction while stirring, wherein the molar ratio of the formic acid to the chloroplatinic acid is 50:1, and continuously maintaining the reaction for 10 hours; and filtering the reacted mixture, washing the mixture by deionized water until the pH value of the filtrate is neutral, filtering the mixture, and drying the filtrate at 100 ℃ to obtain the platinum-carbon catalyst.

Sample characterization and testing

The platinum mass fraction of the platinum-carbon catalyst was 40.1%.

Comparative example 2

Dispersing Ketjenblack ECP600JD according to the proportion of using 200mL of water and 50mL of ethanol per gram of carbon carrier, adding 12mmol of chloroplatinic acid per gram of carbon carrier, performing ultrasonic dispersion to form a suspension, and adding 1mol/L of potassium hydroxide aqueous solution to adjust the pH value of the system to 10; heating the suspension to 80 ℃, adding sodium borohydride while stirring for reduction reaction, wherein the molar ratio of the reducing agent to the platinum precursor is 5:1, and maintaining the reaction for 12 hours; and filtering the reacted mixture, washing until the pH value of the solution is neutral, and drying at 100 ℃ to obtain the carbon-supported platinum catalyst.

Sample characterization and testing

The platinum mass fraction of the platinum-carbon catalyst was 69.7%.

Comparative example 3

The platinum carbon catalyst was a commercial catalyst purchased under the designation HISPEC 4000.

Sample characterization and testing

The platinum mass fraction of the platinum-carbon catalyst was 40.2%.

TABLE 1

Claims

2. The nitrogen-phosphorus doped carbon material according to claim 1, wherein P is analyzed by XPS_2PAmong the peaks, there were one characteristic peak at 133.3. + -. 0.3eV and 134.1. + -. 0.3eV, respectively, and there were no other characteristic peaks at 125eV to 145 eV.

3. The nitrogen-phosphorus doped carbon material according to claim 1, wherein the nitrogen mass fraction is 0.01 to 4% and the phosphorus mass fraction is 0.01 to 4% in XPS analysis.

4. The nitrogen-phosphorus-doped carbon material according to claim 1, wherein the nitrogen-phosphorus-doped carbon material is nitrogen-phosphorus-doped graphene, nitrogen-phosphorus-doped conductive carbon black, or nitrogen-phosphorus-doped carbon nanotubes.

5. The nitrogen-phosphorus doped carbon material of claim 4, wherein the conductive carbon Black is EC-300J, EC-600JD, ECP-600JD, VXC72, Black pearls 2000, PRINTEX XE2-B, PRINTEX L6, or HIBLAXAXK 40B 2.

6. A preparation method of a nitrogen-phosphorus doped carbon material comprises the following steps: and (2) contacting the carbon material with a phosphorus source and a nitrogen source, and treating for 0.5-10 h at 300-800 ℃ in inert gas to obtain the nitrogen-phosphorus doped carbon material.

7. The method for preparing a nitrogen-phosphorus doped carbon material as claimed in claim 6, wherein the mass ratio of the carbon material to the nitrogen source is 500: 1-5: 1.

8. The method for producing a nitrogen-phosphorus-doped carbon material according to claim 6, wherein the mass ratio of the carbon material to the phosphorus source is 10000: 1-10: 1.

9. the method for producing a nitrogen-phosphorus-doped carbon material according to claim 6, wherein the nitrogen source is ammonia water or urea.

10. The method for preparing nitrogen-phosphorus doped carbon material according to claim 6, wherein the phosphorus source is one or more of phosphoric acid, phosphate, pyrophosphate, polyphosphate, hydrogenphosphate, dihydrogenphosphate, phosphite and hypophosphite.

11. The method for producing a nitrogen-phosphorus-doped carbon material according to claim 6, wherein the carbon material has a specific resistance<10 omega. m, specific surface area of 10m²/g～2000m²In terms of/g, mass fraction of oxygen>4％。

12. A nitrogen-phosphorus doped carbon material, characterized in that it is produced by the method of any one of claims 6 to 11.

13. The nitrogen-phosphorus doped carbon material as claimed in any one of claims 1 to 5 and 12 for use as an electrode material in electrochemistry.

14. A platinum-carbon catalyst comprising a carbon support and a platinum metal supported thereon, characterized in that N is analyzed by XPS thereof _1sAmong the peaks, the peak area between 399eV and 400.5eV is 80% or more, preferably 90% or more of the peak area between 390eV and 410 eV.

15. A platinum carbon catalyst according to claim 14, wherein the carbon support is a nitrogen phosphorus doped carbon material.

16. Platinum-carbon catalyst according to claim 14, characterised in that the N analyzed in its XPS_1sAmong the spectral peaks, there were characteristic peaks between 399ev and 400.5ev, and there were no other characteristic peaks between 390ev and 410 ev.

17. The platinum-carbon catalyst according to claim 14, wherein in its XPS analysis there is no P between 125ev and 145ev_2PCharacteristic peak of (2).

18. A method of preparing a platinum carbon catalyst comprising: (1) the method for preparing the nitrogen-phosphorus doped carbon material comprises the following steps: contacting a carbon material with a phosphorus source and a nitrogen source, and treating for 0.5-10 h at 300-800 ℃ in an inert gas to obtain the nitrogen-phosphorus doped carbon material; (2) and (3) loading platinum by taking the nitrogen-phosphorus doped carbon material obtained in the step (1) as a carrier.

19. The method for preparing a platinum-carbon catalyst according to claim 18, wherein the step of supporting platinum comprises:

(a) dispersing the nitrogen-phosphorus doped carbon material obtained in the step (1) and a platinum precursor in a water phase, and adjusting the pH value to 8-12;

(b) Adding a reducing agent for reduction;

20. The method for preparing a platinum-carbon catalyst according to claim 18, wherein in (a), the platinum precursor is chloroplatinic acid, potassium chloroplatinate, or sodium chloroplatinate; the concentration of the platinum precursor is 0.5-5 mol/L.

21. The method for preparing a platinum-carbon catalyst according to claim 18, wherein 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 the platinum is 2-100; the reduction temperature is 60-90 ℃; the reduction time is 4-15 h.

22. A platinum carbon catalyst, characterized in that it is obtainable by a process according to any one of claims 18 to 21.

23. A hydrogen fuel cell, characterized in that a platinum-carbon catalyst according to any one of claims 14 to 17 and 22 is used in an anode and/or a cathode of the hydrogen fuel cell.