CN114122426A

CN114122426A - Platinum-carbon catalyst and preparation method and application thereof

Info

Publication number: CN114122426A
Application number: CN202010876774.6A
Authority: CN
Inventors: 赵红; 荣峻峰; 彭茜; 谢南宏; 张家康; 顾贤睿; 王厚朋
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: 2020-08-27
Filing date: 2020-08-27
Publication date: 2022-03-01
Anticipated expiration: 2040-08-27
Also published as: CN114122426B

Abstract

The invention relates to a platinum-carbon catalyst and a preparation method and application thereof. The platinum-carbon catalyst has higher electrochemical stability when being used for oxygen reduction reaction.

Description

Platinum-carbon catalyst and preparation method and application thereof

Technical Field

The invention relates to a platinum-carbon catalyst and a preparation method and application thereof, in particular to a boron-doped platinum-carbon catalyst and a preparation method and application thereof.

Background

The fuel cell serving as an energy conversion device for converting chemical energy into electric energy has the advantages of high energy conversion efficiency, low working temperature, environmental friendliness and the like, and is expected to be widely applied to various fields, particularly the field of transportation. Hydrogen fuel cells are currently the mainstream fuel cell technology, and catalysts and proton exchange membranes are the core of hydrogen fuel cell technology. In the development of hydrogen fuel cells, it has been a hot topic of scientific research to manufacture a high-efficiency and low-cost electrode catalyst, and since the exchange current density of the cathode Oxygen Reduction Reaction (ORR) is 4 to 5 orders of magnitude lower than that of the anode Hydrogen Oxidation Reaction (HOR) and the overpotential is large, the cathode oxygen reduction electrode catalyst has been the focus of research.

The carbon material doped with elements can be directly used as an alkaline fuel cell catalyst, although the literature of the catalytic material is more reported, the catalytic material is far from practical application, and in addition, the catalytic material is not suitable for a hydrogen fuel cell in an acidic environment.

The platinum-carbon catalyst is the most mature hydrogen fuel cell catalyst at present, but the price of platinum is high, and the catalytic activity and the stability are not ideal. Factors influencing the catalytic activity and stability of the platinum-carbon catalyst are many and complicated, and some literatures believe that the quality specific 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.

Increasing the amount of platinum loading is beneficial for making thinner, better performing membrane electrodes, but in the prior art, increasing the amount of platinum loading by a large margin results in a significant decrease in catalytic performance in terms of mass of platinum unit.

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 improve the catalyst activity and electrochemical stability of platinum-carbon catalysts. It is a second object of the present invention to provide a platinum-carbon catalyst with a higher platinum loading in addition to the aforementioned objects. A third object of the present invention is to improve the aqueous phase chemical reduction process for making platinum carbon catalysts.

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

1. A method of preparing a platinum carbon catalyst comprising: (1) mixing a boron source: mixing a carbon material with a boron source to obtain a carbon material mixed with the boron source; (2) a step of producing a boron-doped carbon material: carrying out high-temperature treatment on the carbon material mixed with the boron source obtained in the step (1) in inert gas to obtain a boron-doped carbon material; (3) loading platinum: and (3) loading platinum by using the boron-doped carbon material obtained in the step (2) as a carrier.

2. A method of preparing a platinum carbon catalyst comprising: (1) mixing a boron source: mixing and impregnating a carbon material with a boron source aqueous solution to obtain a boron source-impregnated carbon material; (2) a step of producing a boron-doped carbon material: carrying out high-temperature treatment on the carbon material impregnated with the boron source obtained in the step (1) in an inert atmosphere to obtain a boron-doped carbon material; (3) loading platinum: and (3) loading platinum by using the boron-doped carbon material obtained in the step (2) as a carrier.

3. The process according to any one of the preceding claims, wherein the temperature of the high-temperature treatment in (2) is 300 ℃ to 800 ℃ (preferably 400 ℃ to 600 ℃) and the treatment time is 0.5h to 10 h.

4. The preparation method according to any one of the preceding claims, characterized in that the duration of the isothermal treatment is between 1h and 5h, preferably between 1.5h and 4 h.

5. The preparation method according to any one of the preceding claims, characterized in that the boron source is one or more of boric acid and borate, preferably sodium borate.

6. The production method according to any one of the preceding claims, characterized in that the mass ratio of the carbon material to the boron source is 100: 1-5: 1; preferably 60: 1-15: 1.

7. a process according to any one of the preceding claims, characterized in that the carbon material is a conductive carbon Black, preferably EC-300J, EC-600JD, ECP-600JD, VXC72, Black pearls2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXAXK 40B 2.

8. The production method according to any one of the preceding claims, characterized in that the carbon material has an oxygen mass fraction of more than 4%, preferably 4% to 15%, in XPS analysis.

9. A production method according to any one of the preceding claims, characterized in that the carbon material has a resistivity of <10 Ω · m, preferably <5 Ω · m, more preferably <2 Ω · m.

10. A production method according to any one of the preceding claims, characterized in that the carbon material has a specific surface area of 10m²/g～2000m²/g。

11. The production method according to any one of the preceding claims, characterized in that the mass fraction of boron in the XPS analysis of the boron-doped carbon material is 0.1% to 10%, preferably 0.3% to 5%, more preferably 0.5% to 3%.

12. A production method according to any one of the preceding claims, characterized in that XPS analysis B of the boron-doped carbon material_1sAmong the spectral peaks, there is a characteristic peak between 190eV and 195eV, and there is no other characteristic peak between 185eV and 200 eV.

13. The production method according to any one of the preceding claims, characterized in that the step of supporting platinum comprises:

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

(b) adding a reducing agent for reduction;

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

14. The preparation method according to any one of the preceding claims, characterized in that the platinum precursor is chloroplatinic acid, potassium chloroplatinate or sodium chloroplatinate; the concentration of the platinum precursor is 0.5-5 mol/L.

15. The process according to any one of the preceding claims, wherein in (a), the pH of the aqueous phase is adjusted with an aqueous solution of sodium carbonate, an aqueous solution of potassium hydroxide, an aqueous solution of sodium hydroxide or aqueous ammonia.

16. The preparation method according to any one of the preceding claims, 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 the platinum is 2-100; the reduction temperature is 50-150 ℃, and preferably 60-90 ℃; the reduction time is 2 to 15 hours, preferably 8 to 12 hours.

17. The method of any one of the preceding claims, wherein said post-treatment comprises: washing, filtering and drying.

18. A platinum carbon catalyst, characterized in that the catalyst is prepared by any of the methods described above.

19. A platinum-carbon catalyst comprises a carbon support and platinum metal loaded thereon, wherein the carbon support is a boron-doped carbon material.

20. The platinum-carbon catalyst according to any one of the preceding claims, characterized in that it has B between 190eV and 195eV or not in XPS analysis_1sCharacteristic peak of (2).

21. The platinum-carbon catalyst according to any one of the preceding claims, characterized in that it has B between 185ev and 200ev or not in XPS analysis_1sCharacteristic peak of (2).

22. The platinum-carbon catalyst according to any one of the preceding claims, characterized in that XPS analysis B of the carbon support_1sAmong the spectral peaks, there is a characteristic peak between 190eV and 195eV, and there is no other characteristic peak between 185eV and 200 eV.

23. The platinum-carbon catalyst according to any one of the above, characterized in that the mass fraction of platinum is 0.1% to 80%, preferably 20% to 70%, more preferably 40% to 70%, based on the mass of the catalyst.

24. 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.

25. The platinum-carbon catalyst according to any of the preceding claims, characterized in that the ratio of the platinum-carbon catalyst is as defined in the tableNoodle 80m²/g～1500m²A/g, preferably of 100m²/g～200m²/g。

26. A platinum carbon catalyst according to any one of the preceding claims characterised in that the carbon material is a conductive carbon Black, preferably EC-300J, EC-600JD, ECP600JD, VXC72, Black pearls2000, PRINTEX XE2-B, PRINTEX L6 or hilblaxk 40B 2.

27. A hydrogen fuel cell characterized in that any one of 18 to 26 of platinum-carbon catalysts is used for an anode and/or a cathode of the hydrogen fuel cell.

28. A carbon material characterized in that it is analyzed by XPS B_1sAmong the spectral peaks, there is a characteristic peak between 190eV and 195eV, and there is no other characteristic peak between 185eV and 200 eV.

29. The carbon material according to claim 28, wherein the carbon material is conductive carbon black.

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

Firstly, the invention manufactures a novel carbon carrier by doping boron into a carbon material, and the platinum carbon catalyst manufactured by the carbon carrier can obviously improve the stability of the catalyst, for example, after 5000 circles of stability test, half-wave potential is basically not reduced, and ECSA is reduced by no more than 10%.

Secondly, the platinum-carrying amount of the industrial hydrogen fuel cell platinum-carbon catalyst is at least more than 20 wt%, and the technology in the field is expected to greatly improve the platinum-carrying amount and keep the platinum utilization rate still good, but the difficulty of manufacturing the high platinum-carrying catalyst with excellent performance is very great. The chemical reduction method has simple process, but the stability of the prepared catalyst is still to be improved. However, when the boron-doped carbon material produced by the present invention is used as a carrier, a high-platinum-loading catalyst having good specific activity and stability can be easily produced by an aqueous chemical reduction method. Some carbon materials are difficult to disperse in water, such as ketjen black, and must be pretreated or use an organic solvent, however, the boron-doped carbon material of the present invention can be easily dispersed in water.

When the platinum carrying amount is similar, the performance of the catalyst is obviously superior to that of a commercial catalyst, even if the platinum carrying amount is far higher than that of the commercial catalyst, the performances of the catalyst, such as half-wave potential, ECSA, specific quality activity and the like, are still equivalent to those of the commercial catalyst, the stability of the catalyst is still far higher than that of the commercial catalyst, and especially the ECSA is kept stable in long-period operation.

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 a boron doped carbon support of example 1.

Fig. 2 is an XPS spectrum of the boron doped carbon support of example 2.

Fig. 3 is an XPS spectrum of a boron doped carbon support of example 3.

Fig. 4 is an XPS spectrum of a boron doped carbon support of example 4.

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

Fig. 6 is a CV curve before and after 5000 cycles of the platinum-carbon catalyst of example 5.

Fig. 7 is an XPS spectrum of the platinum carbon catalyst of example 6.

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 thus formed are considered part of the original disclosure or original 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 otherwise specified as "carbon material containing a doping element" according to the context or self-restriction, the other references to "carbon material" refer 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 properties of the boron-doped carbon material in the production process of the present invention.

In the present invention, other references to "pore volume" are to P/P, except where the context or limitations may dictate₀The maximum single point adsorption total pore volume.

The invention provides a preparation method of a platinum-carbon catalyst, which comprises the following steps:

(1) mixing a boron source: mixing a carbon material with a boron source to obtain a carbon material mixed with the boron source;

(2) a step of producing a boron-doped carbon material: carrying out high-temperature treatment on the carbon material mixed with the boron source obtained in the step (1) in an inert atmosphere to obtain a boron-doped carbon material;

(3) loading platinum: and (3) loading platinum by using the boron-doped carbon material obtained in the step (2) as a carrier.

As a preferred embodiment of the present invention, the preparation method comprises:

(1) step of impregnating boron source: mixing and impregnating a carbon material with a boron source aqueous solution to obtain a boron source-impregnated carbon material;

(2) a step of producing a boron-doped carbon material: carrying out high-temperature treatment on the carbon material impregnated with the boron source obtained in the step (1) in inert gas to obtain a boron-doped carbon material;

(3) and (3) loading platinum by using the boron-doped carbon material obtained in the step (2) as a carrier.

According to the preparation method of the platinum-carbon catalyst of the present invention, for the high temperature treatment in (2), those skilled in the art can determine the appropriate temperature and time according to the teaching of the present invention or by simple experiment. The temperature of the high-temperature treatment can be 300-800 ℃, and is preferably 400-600 ℃; the treatment time may be 0.5 to 10 hours, preferably 1 to 5 hours.

According to the preparation method of the platinum-carbon catalyst, in the step (2), the temperature rise rate is 8-15 ℃.

According to the preparation method of the platinum-carbon catalyst, the boron source can be one or more of boric acid and borate, and is preferably sodium borate.

According to the preparation method of the platinum-carbon catalyst, the mass of the boron source is calculated according to the mass of the boron element contained in the boron source, and the mass ratio of the carbon material to the boron source is 100: 1-5: 1; preferably 60: 1-15: 1.

according to the preparation method of the platinum-carbon catalyst, the carbon material can be conductive carbon black, graphene or carbon nanotubes.

According to the preparation method of the platinum-carbon catalyst, the graphene or the carbon nanotube can be graphene or carbon nanotube which is not subjected to oxidation treatment, and can also be graphene or carbon nanotube which is subjected to oxidation treatment.

According to the preparation method of the platinum carbon catalyst, 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 Degussa; preferred are Ketjen Black EC-300J, Ketjen Black EC-600JD, Ketjen Black ECP-600JD, VXC72, Black pearls2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXK 40B 2.

According to the preparation method of the platinum-carbon catalyst, the preparation method and the source of the conductive carbon black are not limited. The conductive carbon black may be acetylene black, furnace black, or the like.

Preparation of platinum-carbon catalyst according to the invention, I of the carbon Material_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 the D peak and is located at 1580cm^-1The nearby peak is the 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 platinum-carbon catalyst, the carbon material has an oxygen mass fraction of more than 4%, preferably 4-15% in XPS analysis.

According to the method for producing a platinum-carbon catalyst of the present invention, 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, the carbon material in (1) has a specific surface area of 10m²/g～2000m²(ii)/g; the pore volume is 0.2mL/g to 6.0 mL/g.

According to the preparation method of the platinum-carbon catalyst, the impregnation operation further comprises a drying operation, preferably a drying operation, and the boron-doped carbon material is obtained after drying.

According to the preparation method of the platinum-carbon catalyst, in XPS analysis of the boron-doped carbon material, the mass fraction of boron is 0.1-10%, preferably 0.3-5%, and more preferably 0.5-3%.

XPS analysis B of the boron-doped carbon material according to the platinum-carbon catalyst of the invention_1sAmong the spectral peaks, there is a characteristic peak between 190eV and 195eV, and there is no other characteristic peak between 185eV and 200 eV.

According to the preparation method of the platinum-carbon catalyst, in an embodiment of manufacturing the boron-doped carbon material, the carbon material is mixed with a boron source aqueous solution, the mixture is immersed (generally for 12-72 hours), dried (generally for 70-120 ℃), then placed in a tube furnace, the tube furnace is heated (the heating rate is 8-15 ℃/min) under the protection of inert gas, and then the tube furnace is treated at a high temperature (300-800 ℃, preferably 400-600 ℃) for a period of time (0.5-10 hours, generally for 1-5 hours), so that the boron-doped carbon material is obtained.

According to the preparation method of the platinum-carbon catalyst, the boron-doped carbon material prepared in the step (2) can be easily dispersed in a water phase. However, it is difficult to directly disperse the carbon material in the aqueous phase, such as ketjen black.

According to the preparation method of the platinum-carbon catalyst, the inert gas is nitrogen or argon.

According to the preparation method of the platinum-carbon catalyst of the present invention, the step of supporting platinum comprises:

(b) adding a reducing agent for reduction;

According to the preparation method of the platinum-carbon catalyst, the platinum precursor is chloroplatinic acid, potassium chloroplatinate or sodium chloroplatinate; the concentration of the platinum precursor is 0.5-5 mol/L.

According to the preparation method of the platinum-carbon catalyst of the present invention, in (a), the pH of the aqueous phase is adjusted with an aqueous solution of sodium carbonate, an aqueous solution of potassium hydroxide, an aqueous solution of sodium hydroxide, or aqueous ammonia.

According to the preparation method of the platinum-carbon catalyst, 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.

According to the preparation method of the platinum-carbon catalyst, in the step (b), the molar ratio of the reducing agent to platinum is 2-100.

According to the preparation method of the platinum-carbon catalyst, in the step (b), the reduction temperature is 50-150 ℃, and preferably 60-90 ℃; the reduction time is 4 to 15 hours, preferably 8 to 12 hours.

According to the preparation method of the platinum-carbon catalyst, the post-treatment comprises the following steps: washing, filtering and drying.

According to the method for producing a platinum-carbon catalyst of the present invention, in the step of producing a boron-doped carbon material in (2), a metal-containing catalyst is not used.

A platinum carbon catalyst, the catalyst being made by any of the methods described above.

The invention provides a platinum-carbon catalyst, which comprises a carbon carrier and platinum metal loaded on the carbon carrier, wherein the carbon carrier is a boron-doped carbon material.

The platinum-carbon catalyst according to the present invention does not contain a doping element other than boron.

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

The platinum-carbon catalyst according to the present invention has a B content of 185 to 200eV or less in XPS analysis_1sCharacteristic peak of (2). In some embodiments, there is B between 190ev and 195ev_1sThe characteristic peak of (1) is not other between 185 to 200 eV.

The platinum-carbon catalyst according to the present invention, in XPS analysis thereof, has a bimodal peak between 190eV and 195eV, at 191.7 eV. + -. 0.5eV and 193.0 eV. + -. 0.5eV in some examples; no other characteristic peak exists between 185eV and 200 eV.

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.

According to the platinum-carbon catalyst of the present invention, the platinum-carbon catalyst has a resistivity of <10.0 Ω · m, preferably <2 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 invention, 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 Gusai company; preferred are Ketjen Black EC-300J, Ketjen Black EC-600JD, Ketjen Black ECP-600JD, VXC72, Black pearls2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXK 40B 2.

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

Carbon material, analysis B by XPS_1sAmong the spectral peaks, there is a characteristic peak between 190eV and 195eV, and there is no other characteristic peak between 185eV and 200 eV. In some embodiments, XPS analysis B of the carbon material_1sIn the spectrum peaks, the peak is double between 190eV and 195eV, which are respectively located at 191.7eV +/-0.3 eV and 192.6eV +/-0.3 eV, and no other characteristic peak is located between 185eV and 200 eV.

According to the carbon material of the present invention, the carbon material is conductive carbon black.

The carbon material according to the invention is free of doping elements other than boron.

The carbon material according to the present invention contains no metal element.

A method of producing a carbon material, comprising:

(2) a step of producing a carbon material: and (2) subjecting the carbon material mixed with the boron source obtained in (1) to high-temperature treatment in an inert gas to obtain the carbon material.

Other features of the preparation method of the carbon material are the same as the corresponding features of the preparation method of the platinum-carbon catalyst, and the invention is not repeated herein.

The invention adopts a simple method to firmly combine boron with the surface of the carbon material, thereby manufacturing the platinum-carbon electrode catalyst for hydrogen fuel cell anode hydrogen oxidation reaction or cathode oxygen reduction reaction, compared with the catalyst with the same carbon material and platinum carrying amount, the catalyst has higher quality specific activity and half-wave potential, and particularly, the ECSA of the catalyst and the stability thereof are obviously improved.

The platinum-carbon catalyst according to the invention is used in oxygenDuring the reduction reaction, ECSA>30m² g^-1Pt, e.g. at 30m²g^-1-Pt～100m² g^-1-Pt。

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

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

The platinum-carbon catalyst according to the present invention has a specific mass activity when used in an oxygen reduction reaction>0.12Amg^-1Pt, e.g. 0.12A mg^-1-Pt～0.20A mg^-1-Pt。

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 analytical tests in the invention are all carried out by the following instruments and methods.

The invention detects elements on the surface of the material by an X-ray photoelectron spectrum analyzer (XPS). The X-ray photoelectron spectrum analyzer is an ESCALB 220i-XL type ray electron 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 basic 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.

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.

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 258m²Per g, pore volume 0.388mL/g, oxygen mass fraction 8.72%, I_D/I_G1.02, and a resistivity of 1.22. omega. m.

Ketjenblack ECP600JD (manufactured by Lion corporation, ketchen), was purchased from tsuzhou winging sanden energy science and technology limited. The results of the tests by the instrument method show that: specific surface area 1362m²G, pore volume 2.29mL/g, oxygen mass fraction 6.9%, I_D/I_G1.25, and resistivity of 1.31. omega. m.

Commercial platinum carbon catalyst (trade name HISPEC4000, manufactured by Johnson Matthey corporation) was purchased from Alfa Aesar. And (3) testing results: the mass fraction of platinum was 40.2%.

Example 1

This example illustrates the preparation of a boron-doped carbon support according to the present invention.

1g of Vulcan XC72 was immersed for 16h in 15mL of 4.5 wt% aqueous sodium borate solution; 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 3 h; and naturally cooling to obtain the boron-doped carbon carrier, wherein the number of the boron-doped carbon carrier is carbon carrier A.

Sample characterization and testing

The boron mass fraction of XPS analysis is 1.6%; the oxygen mass fraction by XPS analysis was 10.3%; specific surface area of 238m²(ii)/g; resistivity 1.29. omega. m.

Fig. 1 is an XPS spectrum of a boron doped carbon support of example 1.

Example 2

1g of Vulcan XC72 was immersed in 15mL of 1.7 wt% aqueous sodium borate solution for 24 h; 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 2 h; and naturally cooling to obtain the boron-doped carbon carrier, which is numbered as carbon carrier B.

Sample characterization and testing

The boron mass fraction of XPS analysis is 0.72%; the oxygen mass fraction by XPS analysis was 10.2%; specific surface area of 245m²(ii)/g; resistivity was 1.26. omega. m.

Fig. 2 is an XPS spectrum of the boron doped carbon support of example 2.

Example 3

Adding 10mL of absolute ethanol into 1g of Ketjenblack ECP600JD, and then adding 25mL of 5 wt% sodium borate aqueous solution 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 600 ℃ at the speed of 5 ℃/min, and carrying out constant temperature treatment for 4 h; and naturally cooling to obtain the boron-doped carbon carrier, wherein the number of the boron-doped carbon carrier is carbon carrier C.

Sample characterization and testing

The boron mass fraction of XPS analysis is 2.5%; the oxygen mass fraction by XPS analysis was 9.6%; specific surface area of 1312m²(ii)/g; the resistivity was 1.40. omega. m.

Fig. 3 is an XPS spectrum of a boron doped carbon support of example 3.

Example 4

Adding 10mL of absolute ethanol into 1g of Ketjenblack ECP600JD, and then adding 25mL of 4 wt% sodium borate aqueous solution for soaking for 16 h; 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 3 h; and naturally cooling to obtain the boron-doped carbon carrier, wherein the number of the boron-doped carbon carrier is carbon carrier D.

Sample characterization and testing

The boron mass fraction by XPS analysis is 1.9%; the oxygen mass fraction by XPS analysis was 8.7%; the specific surface area is 1298m²(ii)/g; resistivity was 1.38. omega. m.

Fig. 4 is an XPS spectrum of a boron doped carbon support of example 4.

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 39.7%.

No B between 185ev and 200ev in XPS analysis of platinum carbon catalyst_1sCharacteristic peak of (2).

The results of the platinum carbon catalyst performance tests 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 20.2%.

Fig. 7 is an XPS spectrum of the platinum carbon catalyst of example 6.

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 69.8%.

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 40.1%.

Comparative example 1

A platinum carbon catalyst was prepared according to the method of example 5, except that: the carrier was Vulcan XC 72.

Sample characterization and testing

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

Comparative example 2

A platinum-carbon catalyst was produced and tested in the same manner as in example 7, except that: the carbon support was Ketjenblack ECP600JD, and was dispersed with 200mL water and 50mL ethanol per gram of carbon support when Pt was supported.

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 process according to claim 1, wherein in (2), the temperature of the high-temperature treatment is 300 ℃ to 800 ℃ and the treatment time is 0.5h to 10 h.

3. The method of claim 1, wherein the boron source is one or more of boric acid and a borate.

4. The production method according to claim 1, wherein the mass ratio of the carbon material to the boron source is 100:1 to 5:1, in terms of the mass of the boron element contained therein.

5. The process according to claim 1, wherein the carbon material is a conductive carbon Black, preferably EC-300J, EC-600JD, ECP-600JD, VXC72, Black pearls2000, PRINTEX XE2-B, PRINTEX L6 or HIBLAXAXK 40B 2.

6. The production method according to claim 1, wherein the carbon material has an oxygen mass fraction of more than 4% in XPS analysis.

7. The production method according to claim 1, wherein the carbon material has a resistivity of <10 Ω -m.

8. The production method according to claim 1, wherein the carbon material has a specific surface area of 10m²/g～2000m²/g。

9. The method according to claim 1, wherein the step of supporting platinum comprises: (a) dispersing the boron-doped carbon material obtained in the step (2) and a platinum precursor in a water phase, and adjusting the pH to 8-12; (b) adding a reducing agent for reduction; (c) separating out solid, and post-treating to obtain the platinum-carbon catalyst.

10. The method according to claim 9, wherein the platinum precursor is chloroplatinic acid, potassium chloroplatinate, or sodium chloroplatinate; the concentration of the platinum precursor is 0.5-5 mol/L.

11. The method according to claim 9, 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 50-150 ℃; the reduction time is 2-15 h.

12. A method of preparing a platinum carbon catalyst comprising: (1) mixing a boron source: mixing and impregnating a carbon material with a boron source aqueous solution to obtain a boron source-impregnated carbon material; (2) a step of producing a boron-doped carbon material: carrying out high-temperature treatment on the carbon material impregnated with the boron source obtained in the step (1) in an inert atmosphere to obtain a boron-doped carbon material; (3) loading platinum: and (3) loading platinum by using the boron-doped carbon material obtained in the step (2) as a carrier.

13. A platinum-carbon catalyst is characterized by being prepared by any one method of 1-12.

14. A platinum-carbon catalyst is characterized by comprising a carbon carrier and platinum metal loaded on the carbon carrier, wherein the carbon carrier is a boron-doped carbon material.

15. Platinum-carbon catalyst according to claim 14, characterized in that in its XPS analysis there is no B between 185 and 200eV_1SCharacteristic peak of (2).

16. Platinum-carbon catalyst according to claim 14, characterized in that the mass fraction of platinum is between 20% and 70%, preferably between 40% and 70%, based on the mass of the catalyst.

17. Platinum-carbon catalyst according to claim 14, characterized in that it has a resistivity <10 Ω -m.

18. A platinum carbon catalyst according to claim 14, characterised in that the carbon material is a conductive carbon Black, preferably EC-300J, EC-600JD, ECP600JD, VXC72, Black pearls2000, PRINTEX XE2-B, PRINTEX L6 or hilblaxk 40B 2.

19. A hydrogen fuel cell characterized in that the platinum-carbon catalyst of claim 13 or 14 is used in the anode and/or the cathode of the hydrogen fuel cell.

20. A carbon material characterized in that it is analyzed by XPS B_1sAmong the spectral peaks, there is a characteristic peak between 190eV and 195eV, and there is no other characteristic peak between 185eV and 200 eV.

21. The carbon material according to claim 20, wherein the carbon material is conductive carbon black.