CN116072899A

CN116072899A - Carbon-based catalyst, preparation method and application thereof, and hydrogen fuel cell

Info

Publication number: CN116072899A
Application number: CN202111280099.1A
Authority: CN
Inventors: 王厚朋; 顾贤睿; 谢南宏; 彭茜; 张家康; 张云阁
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: 2021-10-29
Filing date: 2021-10-29
Publication date: 2023-05-05

Abstract

The invention relates to a carbon-based catalyst, a preparation method and application thereof, and a hydrogen fuel cell. O of X-ray photoelectron spectrum of the carbon-based catalyst _1s Of the spectral peaks, a first characteristic peak exists at 536.2±0.2 eV. The carbon-based catalyst according to the present invention not only has improved activity but also exhibits improved long-period activity stability.

Description

Carbon-based catalyst, preparation method and application thereof, and hydrogen fuel cell

Technical Field

The invention relates to a carbon-based catalyst, a preparation method and application thereof, and also relates to a hydrogen fuel cell containing the carbon-based catalyst.

Background

It is known that the cathodic oxygen reduction reaction (Oxygen Reduction Reaction, ORR) in proton exchange membrane fuel cells is slow in kinetics and has an exchange current density of 10 ^-6 A/cm ² Much smaller than the hydrogen oxidation exchange current density of the anode, so that the kinetic activation of the fuel cell mainly exists in the cathodic oxygen reduction reaction, while the activation polarization is the largest of four polarization phenomena (ohmic polarization, concentration polarization, osmotic polarization and activation polarization), so that a catalyst with higher intrinsic activity is developed, and is increasingly important for improving the efficiency of the fuel cell. Also, since platinum noble metals have a cost of about 40% of the total fuel cell cost, it is also important how to improve the long-cycle stability of the catalyst.

The nature of the catalyst support is very important and it determines the catalyst utilization, the electron transfer rate and the performance of the final electrode catalyst. The catalyst carriers widely used at present are VXC-72 conductive carbon black and Ketjenback conductive carbon black, and although the catalyst carriers show better performance, corrosion still occurs at high potential (more than 1.1V), so that the supported catalyst particles agglomerate and grow up, the electrochemical specific surface area is reduced, and the main reason is lower graphitization degree. Thus, increasing the graphitization degree of the carbon support is an important way to increase the stability, and the large-diameter graphene tube with high graphitization degree, which is reported at present, has very stable performance under acidic conditions, but has relatively low specific surface area, and the performance in fuel cells is not ideal. On the other hand, the current preparation technology of platinum carbon catalyst (Pt/C catalyst) generally synthesizes Pt nano particles firstly, then deposits the Pt nano particles on a carbon carrier through an adsorption process, and the interaction between the nano particles and the carbon carrier is weaker, so that the catalyst particles are easy to fall off, and meanwhile, the electron transfer resistance is increased, so that the ORR overpotential is high.

The results of these studies indicate that the morphology, size and surface functional groups or defect sites of the carbon support play an important role in the electrochemical reaction of the catalyst nanoparticles, and finally determine the activity, stability and other properties of the battery.

In the prior art, the impregnation reduction method is the most common method for preparing the Pt/C catalyst, the method is to directly use strong reducibility reduction impregnation of sodium borohydride to obtain the Pt/C material, the particle size of the prepared Pt particles is about 8-10 nanometers, the method is favorable for mass preparation, but the particle size distribution of the catalyst is difficult to control, the reduction process is more severe, and the problem of environmental safety is easy to generate.

In view of the above, the preparation of a catalyst with high activity and long-period stability is still a technical problem to be solved in proton exchange membrane fuel cells.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a catalyst for a fuel cell, which has high activity and long-period stability.

According to a first aspect of the present invention, there is provided a carbon-based catalyst comprising a carbonaceous carrier and a platinum element supported on the carbonaceous carrier, wherein the carbon-based catalyst has an X-ray photoelectron spectrum of O _1s Of the spectral peaks, a first characteristic peak exists at 536.2±0.2 eV.

According to a second aspect of the present invention, there is provided a method for preparing a carbon-based catalyst, the method comprising the steps of:

Step S1, soaking the carbon-based raw material in an organic solvent to obtain a first carbon-based material, wherein the organic solvent is a ketone solvent;

s2, contacting the first carbon-based material with an oxidant to obtain a second carbon-based material, wherein the oxidant is one or more than two selected from peroxides;

step S3, contacting the second carbon-based material with nitric acid to obtain a third carbon-based material;

step S4, roasting the third carbon-based material in an inactive atmosphere to obtain a carbonaceous carrier, wherein the roasting temperature is 800-1800 ℃;

s5, dispersing the carbonaceous carrier and the platinum precursor in an aqueous phase, adding a pH value regulator into the aqueous phase, and regulating the pH value of the aqueous phase to be alkaline to obtain an aqueous dispersion;

and S6, contacting the aqueous dispersion with a reducing agent, and reducing at least part of the platinum precursor into metal platinum, wherein the reducing agent is an acidic organic reducing agent, the molar ratio of the reducing agent to the platinum precursor is 4-1000:1, and the platinum precursor is calculated by platinum element.

According to a third aspect of the present invention there is provided a carbon-based catalyst prepared by the method of the second aspect of the present invention.

According to a fourth aspect of the present invention there is provided the use of a carbon-based catalyst according to the first or third aspect of the present invention in a fuel cell.

According to a fifth aspect of the present invention there is provided a hydrogen fuel cell having an anode and/or cathode comprising the carbon-based catalyst of the first or third aspect.

The carbon-based catalyst according to the present invention not only has improved activity but also exhibits improved long-period activity stability.

Drawings

FIG. 1 is XPS spectra of carbon-based catalysts prepared in example 1, comparative example 1, and comparative example 2.

FIG. 2 is an ORR stability test curve for the carbon-based catalyst prepared in example 1.

Detailed Description

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

According to a first aspect of the present invention, there is provided a carbon-based catalyst comprising a carbonaceous carrier and elemental platinum supported on the carbonaceous carrier.

According to the carbon-based catalyst of the present invention, O of X-ray photoelectron spectrum of the carbon-based catalyst _1s Of the spectral peaks, a first characteristic peak exists at 536.2±0.2 eV. By O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (2), O in the carbon-based catalyst, which is determined by the first characteristic peak _1s The content of (2) is 3 to 5 mol%, preferably 3.5 to 5 mol%. The first characteristic peak is an isolated CO molecule and/or CO adsorbed on the carbon-based catalyst ₂ Of molecules

Spectral peaks of oxygen in the group.

According to the carbon-based catalyst of the present invention, O of X-ray photoelectron spectrum of the carbon-based catalyst _1s Of the spectral peaks, a second characteristic peak exists at 532±0.4eV and a third characteristic peak exists at 533.5 ±0.2 eV. The second characteristic peak is

The third characteristic peak is a characteristic peak of oxygen in C-OH. The carbon-based catalyst according to the invention is prepared by measuring O by X-ray photoelectron spectroscopy _1s Based on the total amount of (2), O in the carbon-based catalyst, which is determined by the third characteristic peak _1s The content of (2) is 55 to 70 mol%, preferably 60 to 65 mol%. Preferably as determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (2), O in the carbon-based catalyst determined by the second characteristic peak _1s And O determined by the third characteristic peak _1s The molar ratio of (2) is 1.4-2.2:1. More preferably, as determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (2), O in the carbon-based catalyst determined by the second characteristic peak _1s And O determined by the third characteristic peak _1s The molar ratio of (2) is 1.6-2.1:1. Further preferably, with O as determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (C), in the carbon-based catalyst, from the firstO determined by two characteristic peaks _1s And O determined by the third characteristic peak _1s The molar ratio of (2) is 1.7-2:1.

In the present invention, "first", "second" and "third" appearing before "characteristic peak" are used to distinguish characteristic peaks appearing at different positions, so that characteristic peaks appearing at different positions are more clearly described, and the "first", "second" and "third" have no particular limitation on "characteristic peak" itself.

The carbon-based catalyst according to the present invention has a surface oxygen content of 5 mol% or more based on the total amount of surface elements of the carbon-based catalyst measured by X-ray photoelectron spectroscopy, and the surface oxygen content is measured by X-ray photoelectron spectroscopy. Preferably, the carbon-based catalyst has a surface oxygen content of 5 to 7 mole% based on the total amount of surface elements of the carbon-based catalyst as determined by X-ray photoelectron spectroscopy. More preferably, the carbon-based catalyst has a surface oxygen content of from 5.2 to 6.2 mole percent, based on the total amount of surface elements of the carbon-based catalyst as determined by X-ray photoelectron spectroscopy.

In the invention, the content of oxygen elements on the surface of the carbon-based catalyst is determined by adopting X-ray photoelectron spectroscopy, and the specific method is as follows:

(1) Performing X-ray photoelectron spectroscopy analysis on the carbon-based catalyst to obtain an X-ray photoelectron spectroscopy spectrum, wherein the mole content of the oxygen element is obtained by taking the percentage value of the sum of the peak area of the 1s spectrum peak of the oxygen element and the peak area of the 1s spectrum peak of each element;

(2) Dividing the peak of O1s spectrum in the X-ray photoelectron spectrum, wherein the characteristic peak appearing in 536.2+/-0.2 eV is a first characteristic peak, which corresponds to isolated CO molecules and/or CO adsorbed on the carbon-based catalyst ₂ Of molecules

Oxygen in the group; characteristic peaks appearing at 532.+ -. 0.4eV are second characteristic peaks corresponding to +.>

Oxygen in the radical;the characteristic peak appearing at 533.5.+ -. 0.2eV is a third characteristic peak, and the percentage value of the sum of the peak area of one characteristic peak and the peak area of each characteristic peak is taken as the content of the oxygen species corresponding to the characteristic peak, corresponding to oxygen in the C-OH group.

According to the carbon-based catalyst of the present invention, the content of the platinum element is 0.1 to 80% by weight, the content of the carbonaceous carrier is 20 to 99.9% by weight, and the carbonaceous carrier is calculated as the carbon element, based on the total amount of the carbon-based catalyst. Preferably, the content of the platinum element is 10 to 60 wt% and the content of the carbonaceous carrier is 40 to 90 wt% based on the total amount of the carbon-based catalyst, and the carbonaceous carrier is calculated as the carbon element. More preferably, the content of the platinum element is 20 to 50 wt% and the content of the carbonaceous carrier is 50 to 80 wt% based on the total amount of the carbon-based catalyst, and the carbonaceous carrier is calculated as the carbon element. Further preferably, the content of the platinum element is 30 to 45 wt% and the content of the carbonaceous carrier is 55 to 70 wt% based on the total amount of the carbon-based catalyst, and the carbonaceous carrier is calculated as the carbon element.

In the invention, the content of platinum element and carbonaceous carrier in the carbon-based catalyst is measured by an Inductively Coupled Plasma (ICP) method.

According to the carbon-based catalyst of the present invention, the carbonaceous carrier is conductive carbon black. Preferred examples of the conductive carbon black may include, but are not limited to, one or more of Vulcan XC72, ketjen EC300J, ketjen EC600J, blackpearls 2000, and blackpears 3000. The specific surface area of the carbonaceous carrier is preferably 200 to 2000m according to the carbon-based catalyst of the invention ² Preferably 250-1500m ² And/g. The specific surface area of the carbonaceous carrier is preferably 200 to 2000m according to the carbon-based catalyst of the invention ² Preferably 250-1500m ² /g。

In the present invention, the specific surface area is measured by a specific surface area and pore size analyzer (BET) method.

step S1, soaking the carbon-based raw material in an organic solvent to obtain a first carbon-based material;

s2, contacting the first carbon-based material with an oxidant to obtain a second carbon-based material;

and step S6, contacting the aqueous dispersion with a reducing agent, and reducing at least part of the platinum precursor into metal platinum, wherein the reducing agent is an acidic organic reducing agent.

In step S1, the organic solvent is selected from ketone solvents (e.g., C ₃ -C ₅ Ketone) of (c) is preferably acetone. The soaking can be carried out at normal temperature or at elevated temperature. Preferably, the temperature of the organic solvent is 50-70 ℃. The duration of the soaking may be selected according to the soaking temperature, and in general, the duration of the soaking may be 5 to 12 hours, preferably 6 to 10 hours. The organic solvent is used in an amount to submerge the carbon-based raw material, and generally, the volume ratio of the organic solvent to the carbon-based raw material may be 1-3:1.

In step S1, after the soaking is completed, the solid phase and the liquid phase may be separated by a conventional method (e.g., filtration), and the obtained solid phase may be dried, thereby obtaining the first carbon-based material. The drying may be carried out at a temperature of 80-120 ℃ and the duration of the drying may be 5-15 hours, preferably 8-12 hours. The drying may be performed under normal pressure or under reduced pressure.

In step S2, the oxidizing agent is one or more selected from peroxides. Preferably, the oxidizing agent is one or more selected from hydrogen peroxide and an organic peroxide represented by formula (I):

in the formula I, R ₁ And R is ₂ Each selected from H, C ₄ -C ₁₂ Alkyl, C of (2) ₆ -C ₁₂ Aryl, C of (2) ₇ -C ₁₂ Aralkyl of (a)

And R is ₁ And R is ₂ Not simultaneously H, R ₃ Is C ₄ -C ₁₂ Straight or branched alkyl or C ₆ -C ₁₂ Aryl groups of (a).

In the invention, C ₄ -C ₁₂ Specific examples of alkyl groups of (a) may include, but are not limited to, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, tert-pentyl, hexyl (including various isomers of hexyl), cyclohexyl, octyl (including various isomers of octyl), nonyl (including various isomers of nonyl), decyl (including various isomers of decyl), undecyl (including various isomers of undecyl), and dodecyl (including various isomers of dodecyl).

In the invention, C ₆ -C ₁₂ Specific examples of the aryl group of (a) may include, but are not limited to, phenyl, naphthyl, methylphenyl and ethylphenyl.

In the invention, C ₇ -C ₁₂ Specific examples of the aralkyl group of (a) may include, but are not limited to, phenylmethyl, phenylethyl, phenyl-n-propyl, phenyl-n-butyl, phenyl-t-butyl, phenyl-isopropyl, phenyl-n-pentyl and phenyl-n-butyl.

Specific examples of the organic peroxide may include, but are not limited to: tert-butyl hydroperoxide, cumene hydroperoxide, ethylbenzene hydroperoxide, cyclohexylhydroperoxide, dicumyl peroxide, dibenzoyl peroxide, di-tert-butyl peroxide and lauroyl peroxide.

Preferably, in step S2, the oxidizing agent is hydrogen peroxide.

In step S2, the first carbon-based material is contacted with an oxidizing agent in a liquid phase in the presence of a liquid dispersion medium. The liquid dispersion medium may be water and/or C ₁ -C ₄ Preferably water. In a preferred embodiment, an oxidizing agent is dissolved in a liquid dispersion medium to form an oxidizing agent solution, and the oxidizing agent solution is contacted with a first carbon-based material. In this preferred embodiment, hydrogen peroxide is preferably used as the oxidizing agent solution. The concentration of hydrogen peroxide in the hydrogen peroxide may be 8-20 wt%.

In step S2, the contacting is preferably performed at a temperature of 50-70 ℃. The duration of the contact may be selected according to the temperature of the contact, preferably 5 to 12 hours. The amount of the oxidizing agent may be selected according to the amount of the first carbon-based material. Preferably, the mass ratio of the oxidizing agent to the first carbon-based material is 1-3:1.

In step S2, after the oxidizer treatment is completed, the solid phase and the liquid phase may be separated by a conventional method (e.g., filtration), and the obtained solid phase may be dried, thereby obtaining the second carbon-based material. The drying may be carried out at a temperature of 80-120 ℃ and the duration of the drying may be 5-15 hours, preferably 8-12 hours. The drying may be performed under normal pressure or under reduced pressure.

In step S3, the concentration of nitric acid may be 10 to 30 wt%. The mass ratio of the nitric acid to the second carbon-based material is 1-3:1, the nitric acid is treated with HNO ₃ And (5) counting. In step S3, the contacting is preferably carried out at a temperature of 50-70 ℃. In step S3, the duration of the contact may be selected according to the temperature of the contact, and preferably, the duration of the contact may be 5 to 12 hours.

In step S3, after the nitric acid treatment is completed, the solid phase and the liquid phase may be separated by a conventional method (e.g., filtration), and the obtained solid phase may be dried, thereby obtaining the third carbon-based material. The drying may be carried out at a temperature of 80-120 ℃ and the duration of the drying may be 5-15 hours, preferably 8-12 hours. The drying may be performed under normal pressure or under reduced pressure.

In step S4, roasting the third carbon-based material in an inert atmosphere at a temperature of 800-1800 ℃ to obtain the carbonaceous carrier. The method according to the present invention, when the calcination is performed at a higher temperature, the finally prepared carbon-based catalyst shows improved electrochemical catalytic activity and stability compared to when the calcination is performed at a temperature lower than 800 ℃. Preferably, the third carbon-based material is calcined in an inert atmosphere at a temperature of 900-1600 ℃ to obtain a carbonaceous carrier, for example: the firing temperature may be 900 ℃, 910 ℃, 920 ℃, 930 ℃, 940 ℃, 950 ℃, 960 ℃, 970 ℃, 980 ℃, 990 ℃, 1000 ℃, 1010 ℃, 1020 ℃, 1030 ℃, 1040 ℃, 1050 ℃, 1060 ℃, 1070 ℃, 1090 ℃, 1100 ℃, 1110 ℃, 1120 ℃, 1130 ℃, 1140 ℃, 1150 ℃, 1160 ℃, 1170 ℃, 1180 ℃, 1190 ℃, 1200 ℃, 1210 ℃, 1220 ℃, 1230 ℃, 1240 ℃, 1250 ℃, 1260 ℃, 1270 ℃, 1280 ℃, 1290 ℃, 1300 ℃, 1310 ℃, 1320 ℃, 1340 ℃, 1350 ℃, 1360 ℃, 1370 ℃, 1380 ℃, 1390 ℃, 1400 ℃, 1410 ℃, 1420 ℃, 1440 ℃, 1450, 1460 ℃, 1470 ℃, 1480 ℃, 1490 ℃, 1500 ℃, 1510 ℃, 1520 ℃, 1530, 1540 ℃, 1550, 1560 ℃, 1580 ℃, 1590 ℃, or 1600 ℃. In a particularly preferred embodiment, the third carbon-based material is calcined at a temperature of 1000-1500 ℃, preferably 1000-1200 ℃, in an inert atmosphere to obtain the carbonaceous carrier. The inert atmosphere may be an atmosphere formed of nitrogen and/or a group zero gas, for example: the atmosphere formed by one or two or more gases of nitrogen, argon and helium is preferably a nitrogen atmosphere. The duration of the calcination may be selected according to the calcination temperature, and preferably, the duration of the calcination is 5 to 20 hours. More preferably, the duration of the calcination is 8-15 hours. Further preferably, the duration of the calcination is 10-12 hours.

In step S5, the carbonaceous carrier and the platinum precursor are dispersed in an aqueous phase, and then the pH value of the aqueous dispersion is adjusted to be alkaline, to obtain an aqueous dispersion. In step S5, the dispersion medium of the aqueous dispersion contains water, and only water may be used as the dispersion medium, or water may be used in combination with another dispersion medium (for example, alcohol) as the dispersion medium. According to the method of the invention, the dispersion medium of the aqueous dispersion liquid is preferably water, so that the cost can be reduced, the amount of waste liquid can be reduced, and the method is more environment-friendly. In step S5, the aqueous dispersion is capable of sufficiently dispersing the carbonaceous carrier and the platinum precursor in the aqueous phase even without the use of a complexing agent, and in accordance with the method of the present invention, it is preferable that no complexing agent is used in step S5, which simplifies the operation and reduces the cost.

In step S5, the concentration of the platinum precursor in the aqueous dispersion may be 0.01 to 0.1mol/L, preferably 0.01 to 0.05mol/L. The platinum precursor may be a conventional choice. Preferably, the platinum precursor is one or more selected from chloroplatinic acid, potassium chloroplatinate and sodium chloroplatinate. More preferably, the platinum precursor is chloroplatinic acid.

In step S5, the amount of the platinum precursor may be selected according to the desired platinum content in the carbon-based catalyst. Generally, the platinum precursor is used in an amount such that the content of the platinum element is 0.1 to 80 wt% and the content of the carbonaceous carrier is 20 to 99.9 wt% based on the total amount of the carbon-based catalyst in the finally prepared carbon-based catalyst. Preferably, the platinum precursor is used in an amount such that the content of the platinum element is 10 to 60 wt% and the content of the carbonaceous carrier is 40 to 90 wt% based on the total amount of the carbon-based catalyst in the finally prepared carbon-based catalyst, and the carbonaceous carrier is calculated as the carbon element. More preferably, the platinum precursor is used in such an amount that the content of the platinum element is 20 to 50% by weight, the content of the carbonaceous carrier is 50 to 80% by weight, and the carbonaceous carrier is calculated as carbon element, based on the total amount of the carbon-based catalyst in the finally prepared carbon-based catalyst. Further preferably, the platinum precursor is used in such an amount that the content of the platinum element is 30 to 45% by weight, and the content of the carbonaceous carrier is 55 to 70% by weight, based on the total amount of the carbon-based catalyst, in the finally prepared carbon-based catalyst, and the carbonaceous carrier is calculated as the carbon element.

In step S5, the carbonaceous carrier, the platinum precursor, and water are dispersed by ultrasonic waves, and the carbonaceous carrier and the platinum precursor are sufficiently mixed. Preferably, the frequency of the ultrasonic wave is 100-1000W. More preferably, the frequency of the ultrasonic wave is 100-500W. The duration of the ultrasonic dispersion may be 0.2 to 0.5 hours. The carbonaceous support, platinum precursor, and water may be dispersed in a common ultrasonic dispersion device.

In step S5, the pH of the aqueous phase in which the carbonaceous carrier and the platinum precursor are dispersed is adjusted to be alkaline, preferably the pH of the aqueous phase is adjusted to 8 to 14, for example: the pH of the aqueous phase is adjusted to 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, 13.1, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8, 13.14 or 13.14. More preferably, the pH of the aqueous phase is adjusted to 10-13. A pH adjustor may be added to the aqueous phase to adjust the pH to alkaline. The pH regulator is preferably one or more of sodium carbonate, potassium hydroxide and sodium hydroxide. The pH adjustor is preferably provided in the form of an aqueous solution, and the concentration of the aqueous solution may be conventionally selected without particular limitation.

In step S6, the reducing agent is an acidic organic reducing agent. Preferably, the reducing agent is one or more of citric acid, ascorbic acid and formic acid. In a more preferred embodiment, the reducing agent is citric acid and/or formic acid. In a particularly preferred embodiment, the reducing agent is formic acid and/or citric acid. In this particularly preferred embodiment, the reducing agent is more preferably formic acid.

According to the method of the present invention, in step S6, the molar ratio of the reducing agent to the platinum precursor, calculated as elemental platinum, is 4-1000:1. In step S6, the reducing agent is used in excess of the stoichiometric ratio, and the pH of the reaction system is adjusted to be acidic while reducing the platinum precursor to metallic platinum, so that the platinum precursor reacts with the reducing agent under the acidic condition, and the finally prepared carbon-based catalyst shows improved electrochemical catalytic activity. Preferably, the molar ratio of the reducing agent to the platinum precursor is from 5 to 200:1, the platinum precursor being based on elemental platinum, for example: the molar ratio of the reducing agent to the platinum precursor may be 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1, 80:1, 85:1, 90:1, 95:1, 100:1, 105:1, 110:1, 115:1, 120:1, 125:1, 130: 1. 135:1, 140:1, 145:1, 150:1, 155:1, 160:1, 165:1, 170:1, 175:1, 180:1, 185:1, 190:1, 195:1, 200:1, 205:1, 210:1, 215:1, 220:1, 225:1, 230:1, 235:1, 240:1, 245:1, 250:1, 255:1, 260:1, 265:1, 270:1, 275:1, 280:1, 285:1, 290:1, 295:1, 300:1, 305:1, 310:1, 315:1, 320:1, 325:1, 330:1, 335:1, 340:1, 345:1, 350:1, 355:1, 360:1, 365:1, 300:1 370:1, 375:1, 380:1, 385:1, 390:1, 395:1, 400:1, 405:1, 410:1, 415:1, 420:1, 425:1, 430:1, 435:1, 440:1, 445:1, 450:1, 455:1, 460:1, 465:1, 470:1, 475:1, 480:1, 485:1, 490:1, 495:1, 500:1, 505:1, 510:1, 515:1, 520:1, 525:1, 530:1, 535:1, 540:1, 545:1, 550:1, 555:1, 560:1, 565:1, 570:1, 575:1, 580:1, 585:1, 590:1, 595:1 or 600:1, the platinum precursor is calculated by platinum element. More preferably, the molar ratio of the reducing agent to the platinum precursor is from 5 to 100:1, the platinum precursor being based on elemental platinum. Further preferably, the molar ratio of the reducing agent to the platinum precursor is 5-10:1, the platinum precursor being based on elemental platinum.

In step S6, the reducing agent is contacted with the aqueous dispersion at 50-150 ℃. Preferably, in step S6, the reducing agent is contacted with the aqueous dispersion at 80-130 ℃. More preferably, in step S6, the reducing agent is contacted with the aqueous dispersion at a temperature of 90-120 ℃. In step S6, the duration of the reduction reaction may be selected according to the temperature at which the reduction reaction is performed. Preferably, in step S6, the duration of the aqueous dispersion and the reducing agent may be between 4 and 12 hours, preferably between 6 and 10 hours. In step S6, the reduction is carried out in an inert atmosphere, for example, in an atmosphere of nitrogen and/or a zero-group gas (such as argon and/or helium),

according to the method of the present invention, a solid phase material may be separated from the reduction mixture obtained in step S6 by a conventional separation method, and the separated solid phase material may be washed with water and dried sequentially to obtain a carbon-based catalyst. In general, the reduced mixture obtained in step S6 may be subjected to solid-liquid separation by one or a combination of two or more of filtration, centrifugation and sedimentation to obtain a solid phase substance. The drying is preferably carried out at a temperature of 60-120 ℃, more preferably at a temperature of 80-110 ℃. The duration of the drying may be 8-24 hours, preferably 10-15 hours. The drying may be carried out at normal pressure or at a pressure lower than atmospheric pressure.

Carbon-based catalyst prepared by the method according to the second aspect of the invention, O of X-ray photoelectron spectrum of the carbon-based catalyst _1s Of the spectral peaks, a first characteristic peak exists at 536.2±0.2 eV. Determination of O by X-ray photoelectron spectroscopy _1s Based on the total amount of (2), O in the carbon-based catalyst, which is determined by the first characteristic peak _1s The content of (2) is generally 3 to 5 mol%, preferably 3.5 to 5 mol%. The first characteristic peak corresponds to isolation

Spectral peaks of oxygen in the group.

Carbon-based catalyst prepared by the method according to the second aspect of the invention, X-rays of the carbon-based catalystO of photoelectron spectroscopy _1s Of the spectral peaks, a second characteristic peak exists at 532±0.4eV and a third characteristic peak exists at 533.5 ±0.2 eV. The second characteristic peak is

The third characteristic peak is a characteristic peak of oxygen in C-OH. Preferably as determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (2), O in the carbon-based catalyst determined by the second characteristic peak _1s And O determined by the third characteristic peak _1s The molar ratio of (2) is 1.4-2.2:1. More preferably, as determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (2), O in the carbon-based catalyst determined by the second characteristic peak _1s And O determined by the third characteristic peak _1s The molar ratio of (2) is 1.6-2.1:1. Further preferably, with O as determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (2), O in the carbon-based catalyst determined by the second characteristic peak _1s And O determined by the third characteristic peak _1s The molar ratio of (2) is 1.7-2:1.

The carbon-based catalyst prepared by the method according to the second aspect of the present invention has a surface oxygen content of 5 mol% or more based on the total amount of surface elements of the carbon-based catalyst measured by X-ray photoelectron spectroscopy. Preferably, the carbon-based catalyst has a surface oxygen content of 5 to 7 mole% based on the total amount of surface elements of the carbon-based catalyst as determined by X-ray photoelectron spectroscopy. More preferably, the carbon-based catalyst has a surface oxygen content of from 5.2 to 6.2 mole percent, based on the total amount of surface elements of the carbon-based catalyst as determined by X-ray photoelectron spectroscopy.

According to a fourth aspect of the present invention there is provided the use of a carbon-based catalyst according to the present invention in a fuel cell.

According to a fifth aspect of the present invention there is provided a hydrogen fuel cell, the anode and/or cathode of which contains a carbon-based catalyst according to the present invention.

The present invention will be described in detail with reference to examples, but the scope of the present invention is not limited thereto.

In the following examples and comparative examples, X-ray photoelectron spectroscopy (XPS) analysis was performed on an ESCALab model 250X-ray photoelectron spectrometer equipped with Thermo Avantage V5.926 software, manufactured by Thermo Scientific, with an excitation source of monochromating A1 Ka X-rays, an energy of 1486.6eV, a power of 150W, a transmission energy of 30eV for narrow scanning, and a base vacuum of 6.5X10 at the time of analysis ^-10 mbar, electron binding energy was corrected with the C1s peak of elemental carbon (284.6 eV), data processing was performed on ThermoAvantage software, and quantitative analysis was performed in an analysis module using a sensitivity factor method. The samples were dried for 3 hours at a temperature of 150 ℃ and 1 atm under helium atmosphere prior to testing.

In the following examples and comparative examples, the content of metallic platinum and carbonaceous carrier in the carbon-based catalyst was measured by an inductively coupled plasma spectrometry (ICP) method.

In the following examples and comparative examples, the electrochemical activity test method of the carbon-based catalyst was a rotary disk test method, in which the catalyst was prepared into slurry and was applied dropwise to a glass carbon electrode having a diameter of 5mm, and the electrode was dried to be tested (ensuring that the Pt loading on the electrode was 18-22. Mu.g/cm) ² Within a range of (2); wherein the test conditions of the catalyst polarization curve are as follows: 0.1M HClO ₄ The solution is saturated by oxygen, the voltage scanning range is 0-1.0V vs RHE, the scanning speed is 10mV/s, and the rotating speed of the rotating disc electrode is 1600r/min; the test conditions for the electrochemically active area were: 0.1M HClO ₄ The solution is saturated by nitrogen, the voltage scanning range is 0-1.0V vs RHE, the scanning speed is 50mV/s, the area of the hydrogen desorption peak on the curve is integrated,

wherein, the calculation formula of the electrochemical active area (ECSA) of the carbon-based catalyst is as follows:

wherein S is _H In order to be the area of the peak,

v is the scanning speed, which is 0.05V/s,

M _pt for the mass of Pt dripped on the glassy carbon electrode；

Mass specific activity of the carbon-based catalyst (The mass specific activity, A/mg _Pt ) The calculation formula of (2) is as follows:

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wherein i is _k Is kinetic current, unit is mA/cm ² The calculation is calculated according to a K-L equation, and the equation is as follows:

i _L for limiting diffusion current, reading directly through ORR curve;

m _Pt the unit of Pt loaded on the glassy carbon electrode is mg _Pt /cm ² 。

The following conductive carbon blacks are referred to in the following examples and comparative examples:

(1) Conductive carbon black with Ketjen EC300J, available from Japanese lion king, particle diameter in 50-100nm, specific surface area of 1200m ² /g；

(2) Conductive carbon black with Ketjen EC600J, available from Japanese lion king, particle diameter in the range of 50-100nm, and specific surface area of 1500m ² /g；

(3) Conductive carbon black with the trade name Vulcan XC72, available from Carbter, having a particle diameter in the range of 50-100nm and a specific surface area of 260m ² /g。

Examples 1-10 illustrate the invention.

Example 1

(1) Preparation of the Carrier

Ketjen EC300J conductive carbon black was soaked with acetone (analytically pure) at 60℃for 8 hours, wherein the mass ratio of acetone to conductive carbon black was 2:1. After the soaking is finished, carrying out suction filtration to obtain a solid phase substance, and drying the solid phase substance at 100 ℃ for 8 hours to obtain the carbon black soaked by the acetone.

Mixing the carbon black soaked by the acetone with hydrogen peroxide with the mass concentration of 20% (the mass ratio of the hydrogen peroxide to the carbon black is 2:1), and reacting for 12 hours at 60 ℃. After the reaction is completed, the reaction mixture is subjected to suction filtration, and the obtained solid phase substance is dried for 12 hours at 100 ℃ to obtain the carbon black treated by hydrogen peroxide.

Mixing the carbon black treated by hydrogen peroxide with 30% nitric acid aqueous solution (HNO) ₃ The mass ratio of the catalyst to the carbon black is 2:1), and the reaction is carried out for 12 hours at 60 ℃. After the reaction is completed, the reaction mixture is subjected to suction filtration, and the obtained solid phase substance is dried for 12 hours at 100 ℃ to obtain the carbon black treated by nitric acid.

The carbon black treated with nitric acid was calcined at 1100℃for 10 hours in a nitrogen atmosphere to obtain a carbon black support.

(2) Preparation of aqueous dispersions

0.6g of carbon black support was added to 150mL of deionized water, and chloroplatinic acid (2 mmol) was then added thereto, and the resultant mixture was subjected to ultrasonic dispersion. Wherein the power of the ultrasonic wave is 100W, and the ultrasonic dispersion time is 0.5h.

Sodium carbonate was added as a pH adjuster to the aqueous dispersion obtained by ultrasonic treatment to adjust the pH of the aqueous dispersion to 13, thereby obtaining an aqueous dispersion.

(3) Reduction reaction

The aqueous dispersion was heated to 120℃and formic acid (10 mmol) was added as a reducing agent with stirring to effect a reduction reaction, wherein the molar ratio of reducing agent to chloroplatinic acid was 5:1. after the addition of the reducing agent is completed, the heating condition is kept unchanged, and the reaction is continued for 10 hours.

After the reaction was completed, the reduction reaction mixture was filtered, and the solid phase material was collected and washed with deionized water. The washed solid phase material was dried in vacuo at 100℃for 12h. The solid phase material obtained by the drying was ground to obtain 1g of a carbon-based catalyst (particle diameter in the range of 1 to 3 μm) whose mass content of platinum was determined to be 40%.

As shown in fig. 1, in the finally prepared carbon-based catalyst, the surface oxygen content was 6.0 mol% based on the total amount of the surface elements of the catalyst by XPS analysis; the content of O1s determined from the first characteristic peak was 4.9 mol%, the content of O1s determined from the second characteristic peak was 32.7 mol%, and the content of O1s determined from the third characteristic peak was 62.4 mol%, based on the total amount of O1s determined from the X-ray photoelectron spectroscopy. The electrochemical properties of the prepared carbon-based catalyst (circle 1) and after 5000 circles (as shown in fig. 2) were measured using a rotating disk test, and specific experimental results are shown in table 1.

Comparative example 1

A carbon-based catalyst was produced in the same manner as in example 1, except that step (1) was not conducted, but Ketjen EC300J carbon black as a raw material in step (1) of example 1 was directly used in step (2) and further in step (3) to produce a carbon-based catalyst (the mass content of platinum in the carbon-based catalyst was determined to be 40.1%). The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1. As shown in fig. 1, the surface oxygen content was 5.1 mole% based on the total amount of the catalyst surface elements by XPS analysis; as shown in fig. 1, the finally prepared carbon-based catalyst did not have the first characteristic peak, and the content of O1s determined from the second characteristic peak was 46.9 mol% and the content of O1s determined from the third characteristic peak was 53.1 mol% based on the total amount of O1s determined from the X-ray photoelectron spectroscopy.

Example 2

A carbon-based catalyst was prepared in the same manner as in example 1 except that in step (1), carbon black treated with nitric acid was calcined in a nitrogen atmosphere at a temperature of 1500℃for 10 hours to obtain a carbon black support. The mass content of platinum in the carbon-based catalyst was determined to be 39.8%. In the finally prepared carbon-based catalyst, the surface oxygen content is 6.0 mol percent based on the total amount of the surface elements of the catalyst through XPS analysis; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (a) and O determined by the first characteristic peak _1s Is 4.9 mol% as determined by the second characteristic peak _1s Is 32.7 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 62.4 mol%. The test was carried out using a rotating disc,the electrochemical properties of the prepared carbon-based catalyst (circle 1) and those after 5000 circles were measured, and the experimental results are shown in table 1.

Comparative example 2

A carbon-based catalyst was prepared in the same manner as in example 1 except that in step (1), carbon black treated with nitric acid was calcined in a nitrogen atmosphere at a temperature of 400℃for 10 hours to obtain a carbon black support. The mass content of platinum in the carbon-based catalyst was determined to be 39.7%. The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1. In the finally prepared carbon-based catalyst, the surface oxygen content is 5.2 mol percent based on the total amount of the surface elements of the catalyst through XPS analysis; as shown in fig. 1, the catalyst had no first characteristic peak, and the content of O1s determined from the second characteristic peak was 45.8 mol% and the content of O1s determined from the third characteristic peak was 54.2 mol% based on the total amount of O1s determined from the X-ray photoelectron spectroscopy.

Example 3

A carbon-based catalyst was prepared in the same manner as in example 1 except that in step (1), carbon black treated with nitric acid was calcined in a nitrogen atmosphere at a temperature of 900℃for 10 hours to obtain a carbon black support. The mass content of platinum in the carbon-based catalyst was determined to be 39.7%. In the finally prepared carbon-based catalyst, the surface oxygen content is 5.9 mol percent based on the total amount of the surface elements of the catalyst through XPS analysis; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (a) and O determined by the first characteristic peak _1s Is 3.9 mole percent, O as determined by the second characteristic peak _1s Is 33.6 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 62.5 mol%. The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1.

Example 4

A carbon-based catalyst was prepared in the same manner as in example 1, except that in step (1), a catalyst obtained by the process was subjected to the process of nitroThe acid-treated carbon black was calcined at 1600℃for 10 hours in a nitrogen atmosphere to obtain a carbon black support. The mass content of platinum in the carbon-based catalyst was determined to be 39.3%. In the finally prepared carbon-based catalyst, the surface oxygen content is 5.8 mol percent based on the total amount of the surface elements of the catalyst through XPS analysis; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (a) and O determined by the first characteristic peak _1s Is 4.3 mol% as determined by the second characteristic peak _1s Is 34.0 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 61.7 mol%. The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1.

Example 5

A carbon-based catalyst was prepared in the same manner as in example 1, except that in step (3), the reducing agent was replaced with an equimolar amount of citric acid. The mass content of platinum in the carbon-based catalyst was determined to be 38.9%. In the finally prepared carbon-based catalyst, the surface oxygen content is 5.9 mol percent based on the total amount of the surface elements of the catalyst through XPS analysis; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (a) and O determined by the first characteristic peak _1s Is 4.5 mol% as determined by the second characteristic peak _1s Is 31.9 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 63.6 mol%. The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1.

Example 6

A carbon-based catalyst was prepared in the same manner as in example 1, except that in step (3), the reducing agent was replaced with an equimolar amount of ascorbic acid. The mass content of platinum in the carbon-based catalyst was determined to be 39.5%. In the finally prepared carbon-based catalyst, the surface oxygen content is 5.7 mol percent based on the total amount of the surface elements of the catalyst through XPS analysis; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (1) by the first specialO for peak determination _1s Is 4.2 mol% as determined by the second characteristic peak _1s Is 32.3 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 63.5 mol%. The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1.

Comparative example 3

A carbon-based catalyst was prepared in the same manner as in example 1, except that in step (3), the reducing agent was replaced with an equimolar amount of propylene glycol. The mass content of platinum in the carbon-based catalyst was determined to be 40.0%. In the finally prepared carbon-based catalyst, the surface oxygen content is 4.1 mol percent based on the total amount of the surface elements of the catalyst through XPS analysis; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (a) and O determined by the first characteristic peak _1s Is 0 mole% as determined by the second characteristic peak _1s Is 45.9 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 54.1 mol%. The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1.

Comparative example 4

A carbon-based catalyst was prepared in the same manner as in example 1, except that in step (3), the reducing agent was replaced with an equimolar amount of ethylene glycol. The mass content of platinum in the carbon-based catalyst was determined to be 39.9%. In the finally prepared carbon-based catalyst, the surface oxygen content is 4.3 mol percent based on the total amount of the surface elements of the catalyst through XPS analysis; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (a) and O determined by the first characteristic peak _1s Is 0 mole% as determined by the second characteristic peak _1s Is 45.3 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 54.7 mol%. The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1.

Example 7

A carbon-based catalyst was prepared in the same manner as in example 1, except that in step (3), the molar ratio of formic acid to chloroplatinic acid as a reducing agent was 10:1. The mass content of platinum in the carbon-based catalyst was determined to be 40.0%. In the finally prepared carbon-based catalyst, the surface oxygen content is 5.2 mol percent based on the total amount of the surface elements of the catalyst through XPS analysis; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (a) and O determined by the first characteristic peak _1s Is 4.2 mol% as determined by the second characteristic peak _1s Is 34.5 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 61.3 mol%. The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1.

Example 8

A carbon-based catalyst was prepared in the same manner as in example 1, except that in step (3), the molar ratio of formic acid to chloroplatinic acid as a reducing agent was 100:1. The mass content of platinum in the carbon-based catalyst was determined to be 39.9%. In the finally prepared carbon-based catalyst, the surface oxygen content is 5.3 mol percent based on the total amount of the surface elements of the catalyst through XPS analysis; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (a) and O determined by the first characteristic peak _1s Is 4.5 mol% as determined by the second characteristic peak _1s Is 32.5 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 63.0 mol%. The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1.

Comparative example 5

A carbon-based catalyst was prepared in the same manner as in example 1, except that in step (3), the molar ratio of formic acid to chloroplatinic acid as a reducing agent was 1:1. The mass content of platinum in the carbon-based catalyst was determined to be 37.6%. XPS analysis shows that the total amount of the surface elements of the catalyst is taken asThe surface oxygen content was 4.1 mol% based on the reference; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (a) and O determined by the first characteristic peak _1s Is 0 mole% as determined by the second characteristic peak _1s Is 46.3 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 53.7 mol%. The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1.

Comparative example 6

A carbon-based catalyst was prepared in the same manner as in example 1, except that in step (3), the molar ratio of formic acid to chloroplatinic acid as a reducing agent was 2:1. The mass content of platinum in the carbon-based catalyst was determined to be 37.6%. In the finally prepared carbon-based catalyst, the surface oxygen content is 4.3 mol percent based on the total amount of the surface elements of the catalyst through XPS analysis; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (a) and O determined by the first characteristic peak _1s Is 0 mole% as determined by the second characteristic peak _1s Is 45.4 mol%, O as determined by the third characteristic peak _1s The content of (2) was 54.6 mol%. The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1.

Example 9

(1) Preparation of the Carrier

A carbon-based catalyst was produced in the same manner as in example 1, except that Ketjen EC 600J conductive carbon black was used as a raw material in step (1), thereby producing a carbon-based catalyst. The mass content of platinum in the carbon-based catalyst was determined to be 40.0%.

The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1. XPS analysis shows that the surface oxygen content of the carbon-based catalyst is 5.3 mol percent based on the total amount of the surface elements of the catalyst; by O determined by X-ray photoelectron spectroscopy _1s Is the total amount of (1)Reference, O determined by the first characteristic peak _1s Is 4.5 mol% as determined by the second characteristic peak _1s Is 32.4 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 63.1 mol%.

Example 10

(1) Preparation of the Carrier

Carbot XC72 conductive carbon black was soaked with acetone (analytically pure) at 60℃for 12h, wherein the mass ratio of acetone to conductive carbon black was 3:1. After the soaking is finished, carrying out suction filtration to obtain a solid phase substance, and drying the solid phase substance at 100 ℃ for 12 hours to obtain the carbon black soaked by the acetone.

Mixing the carbon black soaked by the acetone with hydrogen peroxide with the mass concentration of 8% (the mass ratio of the hydrogen peroxide to the carbon black is 3:1), and reacting for 12 hours at 60 ℃. After the reaction is completed, the reaction mixture is subjected to suction filtration, and the obtained solid phase substance is dried for 12 hours at 100 ℃ to obtain the carbon black treated by hydrogen peroxide.

Mixing the carbon black treated by hydrogen peroxide with 30% nitric acid aqueous solution (HNO) ₃ 3:1 mass ratio with carbon black), and reacting at 60 ℃ for 12h. After the reaction is completed, the reaction mixture is subjected to suction filtration, and the obtained solid phase substance is dried for 12 hours at 100 ℃ to obtain the carbon black treated by nitric acid.

The carbon black treated with nitric acid is roasted for 12 hours in nitrogen atmosphere at the temperature of 1000 ℃ to obtain the carbon black carrier.

(2) Preparation of aqueous dispersions

Sodium carbonate was added to the aqueous dispersion obtained by ultrasonic treatment as a pH adjuster, and the pH of the aqueous dispersion was adjusted to 12 to obtain an aqueous dispersion.

(3) Reduction reaction

The aqueous dispersion was heated to 120℃and formic acid (10 mmol) was added as a reducing agent with stirring to effect a reduction reaction, wherein the molar ratio of the reducing agent to chloroplatinic acid was 100:1. After the addition of the reducing agent is completed, the heating condition is kept unchanged, and the reaction is continued for 10 hours.

After the reaction was completed, the reduction reaction mixture was filtered, and the solid phase material was collected and washed with deionized water. The washed solid phase material was dried in vacuo at 100℃for 12h. The solid phase material obtained by the drying was pulverized to obtain 1g of a carbon-based catalyst (particle diameter in the range of 1 to 3 μm), and the mass content of platinum in the carbon-based catalyst was determined to be 40.4%.

XPS analysis shows that the surface oxygen content of the carbon-based catalyst is 5.4 mol percent based on the total amount of the surface elements of the catalyst; by O determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (a) and O determined by the first characteristic peak _1s Is 4.3 mol% as determined by the second characteristic peak _1s Is 32.5 mole percent, O as determined by the third characteristic peak _1s The content of (2) was 63.2 mol%.

The electrochemical properties (1 st turn) and the electrochemical properties after 5000 turns of the prepared carbon-based catalyst were measured using a rotating disk test, and the experimental results are shown in table 1.

FIG. 1 is XPS spectra of carbon-based catalysts prepared in example 1, comparative example 1, and comparative example 2. As can be seen from fig. 1, the carbon-based catalyst prepared by the method of the present invention had a first characteristic peak at 536.2±0.2eV, however, the carbon-based catalysts prepared in comparative examples 1 and 2 did not have the characteristic peak. The first characteristic peak corresponds to isolated CO molecules and/or CO adsorbed on the carbon-based catalyst ₂ Of molecules

Oxygen in the radical, isolated CO molecules and/or CO present in the carbon-based catalyst ₂ The molecule has a certain influence on the electronic structure of platinum in the carbon-based catalyst, and is helpful for improving the activity and stability of the carbon-based catalyst.

From the results of table 1, it can be seen that the carbon-based catalyst according to the present invention has not only higher activity but also higher stability. FIG. 2 is a graph showing the ORR stability test of the carbon-based catalyst prepared in example 1, and it can be seen from FIG. 2 that the carbon-based catalyst according to the present invention maintains high ORR performance after 5000 cycles.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

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Claims

1. A carbon-based catalyst comprising a carbonaceous carrier and a platinum element supported on the carbonaceous carrier, characterized in that the carbon-based catalyst has an X-ray photoelectron spectrum of O _1s Of the spectral peaks, a first characteristic peak exists at 536.2±0.2 eV.

2. The carbon-based catalyst of claim 1, wherein O is measured by X-ray photoelectron spectroscopy _1s Based on the total amount of (2), O in the carbon-based catalyst, which is determined by the first characteristic peak _1s The content of (2) is 3 to 5 mol%, preferably 3.5 to 5 mol%.

3. The carbon-based catalyst according to claim 1 or 2, wherein the carbon-based catalyst has an X-ray photoelectron spectrum O _1s Of the spectral peaks, a second characteristic peak exists at 532±0.4eV and a third characteristic peak exists at 533.5 ±0.2 eV;

preferably as determined by X-ray photoelectron spectroscopy _1s Based on the total amount of (2), O in the carbon-based catalyst determined by the second characteristic peak _1s And from the thirdCharacteristic peak-determined O _1s The molar ratio of (2) is 1.4-2.2:1, preferably 1.6-2.1:1, more preferably 1.7-2:1.

4. a carbon-based catalyst according to any one of claims 1 to 3, wherein the carbon-based catalyst has a surface oxygen content of 5 mole% or more, based on the total molar amount of C as determined by X-ray photoelectron spectroscopy, said surface oxygen content being determined by X-ray photoelectron spectroscopy;

preferably, the surface oxygen content of the carbon-based catalyst is 5 to 7 mole%, preferably 5.2 to 6.2 mole%.

5. The carbon-based catalyst according to any one of claims 1 to 4, wherein the content of the platinum element is 0.1 to 80% by weight and the content of the carbonaceous carrier is 20 to 99.9% by weight, based on the total amount of the carbon-based catalyst;

preferably, the content of the platinum element is 10 to 60 wt%, the content of the carbonaceous carrier is 40 to 90 wt%, and the carbonaceous carrier is calculated as carbon element;

more preferably, the content of the platinum element is 30 to 45 wt% and the content of the carbonaceous carrier is 55 to 70 wt% based on the total amount of the carbon-based catalyst, and the carbonaceous carrier is calculated as the carbon element.

6. The carbon-based catalyst of any one of claims 1-5, wherein the carbonaceous carrier is conductive carbon black;

preferably, the specific surface area of the carbonaceous carrier is 200-2000m ² Preferably 250-1500m ² /g。

7. A method of preparing a carbon-based catalyst, the method comprising the steps of:

step S6, contacting the aqueous dispersion with a reducing agent to reduce at least part of the platinum precursor into metal platinum, wherein the reducing agent is an acidic organic reducing agent, and the molar ratio of the reducing agent to the platinum precursor is 4-1000:1, the platinum precursor is calculated by platinum element.

8. The preparation method according to claim 7, wherein in step S1, the organic solvent is acetone;

preferably, in step S1, the temperature of the organic solvent is 50-70 ℃, and the duration of the soaking is 5-12 hours.

9. The production method according to claim 7, wherein in step S2, the oxidizing agent is hydrogen peroxide;

preferably, in step S2, the mass ratio of the oxidizing agent to the first carbon-based material is 1-3:1, a step of;

preferably, in step S2, the temperature of the contacting is 50-70 ℃ and the duration of the contacting is 5-12 hours.

10. The production method according to claim 7, wherein in step S3, a mass ratio of nitric acid to the second carbon-based material is 1 to 3:1, the nitric acid is treated with HNO ₃ Counting;

preferably, in step S3, the temperature of the contacting is 50-70 ℃ and the duration of the contacting is 5-12 hours.

11. The preparation method according to claim 7, wherein in step S4, the third carbon-based material is calcined at a temperature of 900-1600 ℃, preferably 1000-1500 ℃, more preferably 1000-1200 ℃ in an inert atmosphere;

preferably, in step S4, the duration of the calcination is 5-12 hours.

12. The production method according to claim 7, wherein in step S5, the concentration of the platinum precursor in the aqueous dispersion is 0.01 to 0.1mol/L, preferably 0.01 to 0.05mol/L;

preferably, the platinum precursor is one or more selected from chloroplatinic acid, potassium chloroplatinate and sodium chloroplatinate.

13. The production method according to claim 7 or 12, wherein in step S5, the platinum precursor is used in such an amount that the content of the platinum element is 0.1 to 80% by weight and the content of the carbonaceous carrier is 20 to 99.9% by weight, based on the total amount of the carbon-based catalyst, in the finally produced carbon-based catalyst;

14. The preparation method according to claim 7, wherein in step S5, the pH of the aqueous phase is adjusted to 8-14, preferably to 10-13;

Preferably, in step S5, the pH adjustor is one or more of sodium carbonate, potassium hydroxide and sodium hydroxide.

15. The preparation method according to claim 7, wherein in step S6, the reducing agent is one or more of citric acid, ascorbic acid and formic acid;

preferably, in step S6, the reducing agent is formic acid.

16. The production method according to claim 7 or 15, wherein in step S6, the molar ratio of the reducing agent to the platinum precursor is 5 to 200:1, the platinum precursor is calculated by platinum element;

preferably, the molar ratio of the reducing agent to the platinum precursor is between 5 and 100:1, the platinum precursor is calculated by platinum element;

more preferably, the molar ratio of the reducing agent to the platinum precursor is from 5 to 10:1, the platinum precursor is calculated by platinum element.

17. The preparation method according to any one of claims 7, 15 and 16, wherein in step S6, the contacting is performed at a temperature of 50-150 ℃, preferably at a temperature of 80-130 ℃, more preferably at a temperature of 90-120 ℃;

preferably, in step S6, the duration of the contact is 4-12 hours.

18. A carbon-based catalyst prepared by the method of any one of claims 7-17.

19. Use of a carbon-based catalyst as claimed in any one of claims 1 to 6 and 18 in a fuel cell.

20. A hydrogen fuel cell having an anode and/or a cathode comprising the carbon-based catalyst of any one of claims 1-6 and 18.