Catalyst, preparation method and application thereof

Abstract

A catalyst, a preparation method and an application thereof, belonging to the field of fuel cell technology; the method comprises: obtaining a catalyst body, the catalyst body comprising a carrier and catalyst particles, the catalyst particles being loaded on the carrier; heat-treating the catalyst body in a mixed gas atmosphere to obtain a catalyst, the mixed gas comprising hydrogen, carbon monoxide and carbon dioxide; heat-treating the catalyst body in a mixed gas containing hydrogen, carbon monoxide and carbon dioxide, utilizing the disproportionation reaction of carbon monoxide to generate carbon and carbon dioxide, thereby forming a carbon coating layer on the catalyst particles, while hydrogen can hinder the continuity of carbon generation points generated by carbon monoxide during the heat treatment process, thereby forming a carbon coating layer with pores, and carbon dioxide can dynamically adjust the balance of the carbon monoxide disproportionation reaction, ultimately making the carbon coating layer on the catalyst particles loose and porous, thereby improving the durability of the catalyst and having little effect on the catalytic activity.

Description

Technical Field

[0001] The present application relates to the field of fuel cell technology, and in particular to a catalyst and a preparation method and application thereof. Background Art

[0002] A proton exchange membrane fuel cell (PEMFC) is an electrochemical device that uses a proton exchange membrane as an electrolyte to generate electricity through the reaction of hydrogen and oxygen. It boasts high efficiency, low noise, and zero emissions, and is widely used in transportation, aerospace, backup power, and other fields. The performance of a PEMFC is highly dependent on the efficiency of its catalyst. Both the hydrogen oxidation reaction (HOR) at the anode and the oxygen reduction reaction (ORR) at the cathode require catalysts to accelerate the electrochemical reactions. The cathode ORR, due to its slow kinetics, is a key step limiting PEMFC efficiency. Therefore, cathode ORR catalysts require higher catalytic activity and durability. Metal catalysts such as platinum or platinum alloys are typically used for the cathode.

[0003] Traditional metal catalyst particles are typically supported on a carrier to improve their dispersibility and stability. However, these particles are prone to sintering, poisoning, or corrosion during the catalytic reaction, resulting in decreased catalyst activity and durability. To overcome these issues, existing technologies have employed coating the metal catalyst particles with a protective layer to improve their stability and durability. Common coating materials include carbon materials.

[0004] Existing carbon coating technologies are mainly achieved through chemical vapor deposition (CVD), sol-gel method and other methods. However, these methods have some disadvantages: ① The carbon coating layer has a dense structure: Traditional carbon coating methods often form a dense carbon coating layer. Although it can effectively protect the metal catalyst particles, it also significantly hinders the contact between the reactants and the catalyst, resulting in a significant reduction in catalytic activity. ② The thickness of the carbon coating layer is difficult to accurately control: During the preparation process, the thickness of the carbon coating layer is usually difficult to accurately control, resulting in unstable catalyst performance. ③ Harsh preparation conditions: Existing carbon coating methods usually require high temperature, high pressure or complex reaction conditions, which increases the preparation cost and operation difficulty. Summary of the Invention

[0005] The present application provides a catalyst and a preparation method and application thereof, which can improve the durability of the catalyst and have little effect on the catalytic activity.

[0006] In a first aspect, the present invention provides a method for preparing a catalyst, the method comprising:

[0007] obtaining a catalyst body, wherein the catalyst body comprises a carrier and catalyst particles, and the catalyst particles are supported on the carrier;

[0008] heat-treating the catalyst body in a mixed gas atmosphere to obtain a catalyst, wherein the mixed gas includes hydrogen, carbon monoxide and carbon dioxide;

[0009] The ratio of the volume V1 of the hydrogen to the volume V2 of the carbon monoxide satisfies: 10:300≤V1:V2≤40:300, and the ratio of the volume V3 of the carbon dioxide to the volume V2 of the carbon monoxide satisfies: 50:300≤V3:V2≤300:300.

[0010] In the technical solution of the embodiment of the present application, the catalyst body is heat-treated in a mixed gas containing hydrogen, carbon monoxide and carbon dioxide in a specific proportion, and carbon and carbon dioxide are generated by the disproportionation reaction of carbon monoxide, so as to form a carbon coating layer on the catalyst particles. At the same time, hydrogen can hinder the continuity of the carbon generation points generated by carbon monoxide during the heat treatment process, thereby forming a carbon coating layer with pores, and carbon dioxide can dynamically adjust the balance of the carbon monoxide disproportionation reaction to regulate the thickness of the carbon coating layer, so that the carbon coating layer on the catalyst particles is finally in the form of a loose thin layer, which can improve the durability of the catalyst and has little effect on the catalytic activity.

[0011] In some embodiments, the ratio of the volume V1 of the hydrogen to the volume V2 of the carbon monoxide satisfies: 30:300≤V1:V2≤40:300, and the ratio of the volume V3 of the carbon dioxide to the volume V2 of the carbon monoxide satisfies: 100:300≤V3:V2≤200:300.

[0012] In the above implementation process, by optimizing and controlling the volumes of hydrogen and carbon dioxide, the thickness and porosity of the carbon coating layer are adjusted, thereby enabling the catalyst to better balance catalytic activity and durability.

[0013] In some embodiments, the ratio of the flow rate of the mixed gas to the mass of the catalyst particles is 100 ml / min·g to 800 ml / min·g.

[0014] In the above implementation process, by regulating the ratio of the flow rate of the mixed gas to the mass of the catalyst particles, the thickness and porosity of the carbon coating layer are adjusted, thereby achieving a better balance between catalytic activity and durability of the catalyst.

[0015] In some embodiments, the loading amount of the catalyst particles in the catalyst body is 40 wt % to 70 wt %.

[0016] In some embodiments, the heat treatment temperature is 300° C. to 600° C.; and / or

[0017] The heat treatment time is 1h~3h; and / or

[0018] The heating rate of the heat treatment is 5°C / min to 15°C / min.

[0019] In the above implementation process, if the heat treatment temperature is too high or the time is too long, the catalyst particles will easily sinter and become larger, and the particle size distribution will deteriorate, resulting in reduced catalytic activity and durability of the catalyst. If the heat treatment temperature is too low or the time is too short, the carbon coating layer formed will be too thin or the crystallinity will be too low, which is not conducive to improving the durability of the catalyst. By setting the heat treatment temperature to 300°C to 600°C and the time to 1 hour to 3 hours, the prepared catalyst can have both good catalytic activity and durability.

[0020] In the above implementation process, the catalyst body is prepared by a polyol reduction method.

[0021] In the above implementation process, the polyol reduction method includes:

[0022] mixing the carrier and the catalyst particle precursor with a polyol to obtain a mixed solution;

[0023] Adjusting the mixed solution to an alkaline solution and performing a reflux reaction to obtain an intermediate solution;

[0024] The intermediate solution is adjusted to an acidic solution to obtain a catalyst body.

[0025] In the above implementation process, the polyol includes ethylene glycol; and / or

[0026] The pH value of the alkaline solution is 10-11; and / or

[0027] The reflux reaction temperature is 150° C. to 170° C.; and / or

[0028] The reflux reaction time is 5h~7h; and / or

[0029] The pH value of the acidic solution is 1-2.

[0030] In the above implementation process, the components of the catalyst particles include at least one of a noble metal or an alloy of a noble metal and a transition metal; and / or

[0031] The particle size of the catalyst particles is 2nm~3nm; and / or

[0032] The support includes at least one of a carbon support and an oxide support.

[0033] In second aspect, an embodiment of the present application provides a catalyst, which includes a carrier and catalyst particles, the catalyst particles are loaded on the carrier, the surface of the catalyst particles is coated with a carbon coating layer, the thickness of the carbon coating layer is 1nm~2nm, and the ratio of the measured electrochemically active surface area of ​​the catalyst to the theoretical electrochemically active surface area is above 0.75.

[0034] In some embodiments, the ratio of the measured electrochemically active surface area to the theoretical electrochemically active surface area of ​​the catalyst is 0.8 to 0.9; and / or

[0035] The catalyst particles include at least one of a noble metal or an alloy of a noble metal and a transition metal; and / or

[0036] The particle size of the catalyst particles is 2nm~3nm; and / or

[0037] The support includes at least one of a carbon support and an oxide support.

[0038] In a third aspect, an embodiment of the present application provides a membrane electrode, which includes a catalyst layer, and the catalyst layer includes the catalyst prepared by the method provided in the first aspect or the catalyst provided in the second aspect.

[0039] In a fourth aspect, an embodiment of the present application provides a fuel cell, which includes the membrane electrode provided in the third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0041] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0042] Figure 1 A schematic flow chart of the method provided in the embodiment of the present application;

[0043] Figure 2 This is a TEM image of the catalyst provided in Example 3 of the present application;

[0044] Figure 3 This is a TEM image of the catalyst provided in Comparative Example 5 of this application. DETAILED DESCRIPTION

[0045] The embodiments of the present application will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.

[0046] In the description of this application specification, the terms "including", "comprising", etc. mean "including but not limited to". In this document, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. In this document, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e. a and b), ac, bc, or abc, where a, b and c can be single or multiple.

[0047] In the prior art, there is a method of improving the stability and durability of metal catalyst particles by coating them with a protective layer. Common coating materials include metal oxides, carbon materials, etc. However, the existing methods of coating carbon coating layers are complex, costly, and cannot simultaneously meet the requirements of catalyst activity and durability. For example, an organic phase precursor (high cost) is used to generate a carbon coating layer using the carbon source in the precursor, but the thickness is uncontrollable and it is easy to block active sites; or oxides are used, which are not conductive in themselves and have a great impact on activity, and the thickness is uncontrollable; or a single atmosphere is used for carbon coating, but the effect is still poor, and the thickness and coverage density are uncontrollable.

[0048] The present application intends to provide a catalyst, a preparation method and an application thereof, which can improve the durability of the catalyst and have little effect on the catalytic activity by heat treating the catalyst body in a mixed gas containing hydrogen, carbon monoxide and carbon dioxide.

[0049] Figure 1 For a flowchart of the method provided in the embodiment of this application, please refer to Figure 1 , the present application embodiment provides a method for preparing a catalyst, the method comprising:

[0050] S1. Obtaining a catalyst body, the catalyst body comprising a carrier and catalyst particles, the catalyst particles being supported on the carrier;

[0051] S2. The catalyst body is heat-treated in a mixed gas atmosphere to obtain a catalyst, wherein the mixed gas includes hydrogen, carbon monoxide and carbon dioxide; the ratio of the volume V1 of the hydrogen to the volume V2 of the carbon monoxide satisfies: 10:300≤V1:V2≤40:300, and the ratio of the volume V3 of the carbon dioxide to the volume V2 of the carbon monoxide satisfies: 50:300≤V3:V2≤300:300.

[0052] The method forms a carbon coating on the catalyst particles by heat-treating the catalyst body in a mixed gas containing hydrogen, carbon monoxide and carbon dioxide in a specific ratio, utilizing the disproportionation reaction of carbon monoxide to generate carbon and carbon dioxide. At the same time, hydrogen can hinder the continuity of the carbon generation points generated by carbon monoxide during the heat treatment process, thereby forming a carbon coating with pores, and carbon dioxide can dynamically adjust the balance of the carbon monoxide disproportionation reaction to regulate the thickness of the carbon coating. Ultimately, the carbon coating on the catalyst particles is in the form of a loose thin layer, which can improve the durability of the catalyst and has little effect on the catalytic activity.

[0053] Specifically, the heat treatment process can be as follows: 2g of the catalyst body, platinum-carbon catalyst, is placed in a crucible, which is then placed in a horizontal tube furnace. The device is then checked for airtightness. A temperature program is set with a heating rate of 10°C / min and a holding time of 2h. Before starting the program, the tube is purged with inert gas for 30 minutes, and the corresponding atmosphere ratio is adjusted before starting the heating program. After the program is completed, the catalyst is removed to obtain a catalyst coated with a carbon layer.

[0054] As an optional embodiment, the ratio of the volume V1 of hydrogen to the volume V2 of carbon monoxide satisfies: 30:300≤V1:V2≤40:300, and the ratio of the volume V3 of carbon dioxide to the volume V2 of carbon monoxide satisfies: 100:300≤V3:V2≤200:300.

[0055] By optimizing and controlling the volume of hydrogen and carbon dioxide, the thickness and porosity of the carbon coating layer can be adjusted, thereby enabling the catalyst to better balance catalytic activity and durability.

[0056] For example, the ratio V1:V2 of the volume V1 of hydrogen to the volume V2 of carbon monoxide may be 10:300, 15:300, 20:300, 25:300, 30:300, 35:300 or 40:300, or any value within the range of 10:300≤V1:V2≤40:300. The ratio V3:V2 of the volume V3 of carbon dioxide to the volume V2 of carbon monoxide may be 50:300, 60:300, 70:300, 80:300, 90:300, 100:300, 110:300, 120:300, 130:300, 140:300, 150:300, 160:300, 170:300, 180:300. 300, 190:300, 200:300, 210:300, 220:300, 230:300, 240:300, 250:300, 260:300, 270:300, 280:300, 290:300, 300:300, etc. It can also be any value within the range of 50:300≤V3:V2≤300:300.

[0057] As an optional embodiment, the ratio of the flow rate of the mixed gas to the mass of the catalyst particles is 100 ml / min·g to 800 ml / min·g. The loading amount of the catalyst particles in the catalyst body is 40 wt% to 70 wt%.

[0058] By regulating the ratio of the flow rate of the mixed gas to the mass of the catalyst particles, the thickness and porosity of the carbon coating layer can be adjusted, thereby achieving a better balance between catalytic activity and durability of the catalyst.

[0059] For example, the ratio of the flow rate of the mixed gas to the mass of the catalyst particles can be 100 ml / min·g, 150 ml / min·g, 200 ml / min·g, 250 ml / min·g, 300 ml / min·g, 350 ml / min·g, 400 ml / min·g, 450 ml / min·g, 500 ml / min·g, 550 ml / min·g, 600 ml / min·g, 650 ml / min·g, 700 ml / min·g, 750 ml / min·g, 800 ml / min·g, etc., and can also be any value within the range of 100 ml / min·g to 800 ml / min·g. The loading amount of the catalyst particles in the catalyst body can be 40 wt%, 45 wt%, 50 wt%, 55 wt%, 60 wt%, 65 wt%, 70 wt%, etc., and can also be any value within the range of 40 wt% to 70 wt%.

[0060] As an optional embodiment, the heat treatment temperature is 300°C to 600°C; the heat treatment time is 1h to 3h; and the heating rate of the heat treatment is 5°C / min to 15°C / min. If the heat treatment temperature is too high or the time is too long, the catalyst particles will easily sinter and become larger, and the particle size distribution will deteriorate, resulting in reduced catalytic activity and durability of the catalyst. If the heat treatment temperature is too low or the time is too short, the carbon coating layer formed will be too thin or the crystallinity will be too low, which is not conducive to improving the durability of the catalyst. By setting the heat treatment temperature to 300°C to 600°C and the time to 1h to 3h, the prepared catalyst can have both good catalytic activity and durability.

[0061] Illustratively, the temperature of the heat treatment can be 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, etc., and it can also be any value within the range of 300°C to 600°C. The heat treatment time can be 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h, 3h, etc., and it can also be any value within the range of 1h to 3h. The heating rate of the heat treatment can be 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, 11°C / min, 12°C / min, 13°C / min, 14°C / min, 15°C / min, etc., and it can also be any value within the range of 5°C / min to 15°C / min.

[0062] The catalyst body can be prepared by a polyol reduction method or purchased from the market.

[0063] As an optional embodiment, the polyol reduction method includes:

[0064] S1.1. Mixing the support and the catalyst particle precursor with a polyol to obtain a mixed solution;

[0065] S1.2. adjusting the mixed solution to an alkaline solution and performing a reflux reaction to obtain an intermediate solution;

[0066] S1.3. Adjust the intermediate solution to an acidic solution to obtain the catalyst body.

[0067] Wherein, the polyol comprises ethylene glycol; and / or

[0068] The pH value of the alkaline solution is 10-11; and / or

[0069] The reflux reaction temperature is 150° C. to 170° C.; and / or

[0070] The reflux reaction time is 5h~7h; and / or

[0071] The pH value of the acidic solution is 1-2.

[0072] Specifically, the preparation process using a platinum-carbon catalyst as the catalyst body is described as follows: 1.2 g of the carrier and a precursor containing 1.8 g of a precious metal are added to 1500 ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution is adjusted to 10-11 with a 1M alkaline solution (NaOH, KOH). The solution is then refluxed in a 160°C oil bath for 6 hours. After the reaction is complete and cooled, the pH of the solution is adjusted to 1-2 with a 1M acid solution (HCl, HNO3). After stirring for 12 hours, the solution is filtered and washed with deionized water, and then dried in a 60°C vacuum drying oven for 12 hours to obtain the desired platinum-carbon catalyst.

[0073] As an optional embodiment, the catalyst particles are composed of at least one of a noble metal or an alloy of a noble metal and a transition metal. For example, the catalyst particles may be composed of platinum, a platinum-cobalt alloy, or the like.

[0074] As an optional embodiment, the particle size of the catalyst particles is 2 nm to 3 nm. For example, the particle size of the catalyst particles can be 2 nm, 2.1 nm, 2.2 nm, 2.3 nm, 2.4 nm, 2.5 nm, 2.6 nm, 2.7 nm, 2.8 nm, 2.9 nm, 3 nm, etc., and can also be any value within the range of 2 nm to 3 nm.

[0075] As an optional embodiment, the support includes at least one of a carbon support or an oxide support.

[0076] Based on the same inventive concept, an embodiment of the present application also provides a catalyst, which includes a carrier and catalyst particles, the catalyst particles are loaded on the carrier, the surface of the catalyst particles is coated with a carbon coating layer, the thickness of the carbon coating layer is 1nm~2nm, and the ratio of the measured electrochemically active surface area of ​​the catalyst to the theoretical electrochemically active surface area is above 0.75.

[0077] The catalyst has a carbon coating layer with a thickness of 1nm to 2nm, which can improve the durability of the catalyst. The ratio of the measured electrochemically active surface area to the theoretical electrochemically active surface area of ​​the catalyst is above 0.75, and it has high catalytic activity.

[0078] As an optional embodiment, the ratio of the measured electrochemically active surface area of ​​the catalyst to the theoretical electrochemically active surface area is 0.8 to 0.9. Exemplarily, the ratio of the measured electrochemically active surface area of ​​the catalyst to the theoretical electrochemically active surface area can be 0.75, 0.76, 0.77, 0.78, 0.79, 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89 or 0.9, etc., and can also be any value within the range of 0.75 or more, preferably, any value within the range of 0.8 to 0.9.

[0079] As an optional embodiment, the catalyst particles include at least one of a noble metal or an alloy of a noble metal and a transition metal. For example, the catalyst particles may include platinum, a platinum-cobalt alloy, or the like.

[0080] As an optional embodiment, the particle size of the catalyst particles is 2 nm to 3 nm. For example, the particle size of the catalyst particles can be 2 nm, 2.1 nm, 2.2 nm, 2.3 nm, 2.4 nm, 2.5 nm, 2.6 nm, 2.7 nm, 2.8 nm, 2.9 nm, 3 nm, etc., and can also be any value within the range of 2 nm to 3 nm.

[0081] As an optional embodiment, the support includes at least one of a carbon support or an oxide support.

[0082] Based on the same inventive concept, an embodiment of the present application further provides a membrane electrode, which includes a catalyst layer, and the catalyst layer includes the catalyst provided above.

[0083] The membrane electrode is realized based on the above-mentioned catalyst. The specific content of the catalyst can be referred to the above-mentioned embodiment. Since the membrane electrode adopts part or all of the technical solutions of the above-mentioned embodiment, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be repeated here.

[0084] As an optional embodiment, the membrane electrode further includes a gas diffusion layer and a proton exchange membrane, and the proton exchange membrane, the catalyst layer and the gas diffusion layer are arranged in sequence.

[0085] Based on the same inventive concept, an embodiment of the present application further provides a fuel cell, which includes the membrane electrode provided above.

[0086] The fuel cell is realized based on the above-mentioned membrane electrode. The specific content of the membrane electrode can be referred to the above-mentioned embodiment. Since the fuel cell adopts part or all of the technical solutions of the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0087] The present application will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present application only and are not intended to limit the scope of the present application. The experimental methods in the following examples where specific conditions are not specified are usually measured in accordance with national standards. If there are no corresponding national standards, then the methods are carried out in accordance with general international standards, conventional conditions, or according to the conditions recommended by the manufacturer.

[0088] Example 1

[0089] A catalyst, the preparation process is as follows:

[0090] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0091] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The apparatus was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min, and then the temperature was adjusted to a mixed gas (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 10:300:100, with a mixed gas flow rate of 410ml / min). The temperature program was then started. After the program ended, the catalyst was removed to obtain a catalyst coated with a carbon layer.

[0092] Example 2

[0093] A catalyst, the preparation process is as follows:

[0094] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0095] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The device was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min, and then the temperature was adjusted to a mixed gas (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 20:300:100, with a mixed gas flow rate of 420ml / min). The temperature program was then started. After the program ended, the catalyst was removed to obtain a catalyst coated with a carbon layer.

[0096] Example 3

[0097] A catalyst, the preparation process is as follows:

[0098] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0099] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The device was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min, and then the mixture (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 30:300:100, with a flow rate of 430ml / min) was introduced. The temperature program was then started. After the program was completed, the catalyst was removed to obtain a catalyst coated with a carbon layer.

[0100] Figure 2This is the TEM image of the catalyst provided in Example 3 of the present application. It can be seen from the image that the distance from the particle to the edge is the thickness of the carbon layer, which is about 1.5 nm, and the catalyst particle size distribution is uniform and the size is uniform.

[0101] Example 4

[0102] A catalyst, the preparation process is as follows:

[0103] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0104] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The device was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min, and then adjusted to introduce a mixed gas (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 40:300:100, with a mixed gas flow rate of 440ml / min). The temperature program was then started. After the program ended, the catalyst was removed to obtain a catalyst coated with a carbon layer.

[0105] Example 5

[0106] A catalyst, the preparation process is as follows:

[0107] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0108] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The apparatus was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min, and then the temperature was adjusted to a mixed gas (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 30:300:50, with a mixed gas flow rate of 380ml / min). The temperature program was then started. After the program ended, the catalyst was removed to obtain a catalyst coated with a carbon layer.

[0109] Example 6

[0110] A catalyst, the preparation process is as follows:

[0111] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0112] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The apparatus was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min. The temperature was then adjusted to introduce a mixed gas of hydrogen, carbon monoxide, and carbon dioxide (with a volume ratio of 30:300:200) at a flow rate of 530ml / min. The heating program was then initiated. After the program concluded, the catalyst was removed to obtain a carbon-coated catalyst.

[0113] Example 7

[0114] A catalyst, the preparation process is as follows:

[0115] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0116] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The device was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min, and then adjusted to introduce a mixed gas (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 30:300:300, with a mixed gas flow rate of 630ml / min). The temperature program was then started. After the program ended, the catalyst was removed to obtain a catalyst coated with a carbon layer.

[0117] Example 8

[0118] A catalyst, the preparation process is as follows:

[0119] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0120] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The apparatus was checked for airtightness and a temperature program was set: 300°C, a heating rate of 10°C / min, and a holding time of 1h. Before starting the program, the tube was purged with inert gas for 30min, and then the temperature was adjusted to a mixed gas (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 30:300:100, with a mixed gas flow rate of 430ml / min). The temperature program was then started. After the program ended, the catalyst was removed to obtain a catalyst coated with a carbon layer.

[0121] Comparative Example 1

[0122] A catalyst, the preparation process is as follows:

[0123] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0124] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The apparatus was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min, and then a mixed gas (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 0:300:100, with a flow rate of 400ml / min) was introduced. The temperature program was then started. After the program ended, the catalyst was removed to obtain a carbon-coated catalyst.

[0125] Comparative Example 2

[0126] A catalyst, the preparation process is as follows:

[0127] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0128] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The device was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min, and then adjusted to introduce a mixed gas (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 50:300:100, with a mixed gas flow rate of 450ml / min). The temperature program was then started. After the program ended, the catalyst was removed to obtain a catalyst coated with a carbon layer.

[0129] Comparative Example 3

[0130] A catalyst, the preparation process is as follows:

[0131] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0132] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The device was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min, and then a mixed gas (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 30:300:0, with a mixed gas flow rate of 330ml / min) was introduced. The temperature program was then started. After the program was completed, the catalyst was removed to obtain a catalyst coated with a carbon layer.

[0133] Comparative Example 4

[0134] A catalyst, the preparation process is as follows:

[0135] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0136] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The device was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min, and then adjusted to introduce a mixed gas (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 30:300:400, with a mixed gas flow rate of 730ml / min). The temperature program was then started. After the program ended, the catalyst was removed to obtain a catalyst coated with a carbon layer.

[0137] Comparative Example 5

[0138] A catalyst, the preparation process is as follows:

[0139] 1.2g of carbon support EC600 and a chloroplatinic acid precursor containing 1.8g of platinum were added to 1500ml of ethylene glycol, ultrasonicated for 30 minutes, and then the pH of the solution was adjusted to 11 with a 1M alkaline solution (NaOH), and then refluxed in a 160°C oil bath for 6 hours. After the reaction was completed and cooled, the pH of the solution was adjusted to 1 with a 1M acid solution (HNO3). After stirring for 12 hours, it was filtered and washed with deionized water, and then placed in a vacuum drying oven at 60°C and dried for 12 hours to obtain the catalyst body platinum carbon catalyst.

[0140] 2g of the prepared platinum-carbon catalyst was placed in a crucible, which was then placed in a horizontal tubular furnace (with an inner diameter of 10cm). The apparatus was checked for airtightness and a temperature program was set: 600°C, a heating rate of 10°C / min, and a holding time of 2h. Before starting the program, the tube was purged with inert gas for 30min, and then the mixture (hydrogen, carbon monoxide, and carbon dioxide in a volume ratio of 0:300:0, with a flow rate of 300ml / min) was introduced. The temperature program was then started. After the program ended, the catalyst was removed to obtain a catalyst coated with a carbon layer.

[0141] Figure 3 This is a TEM image of the catalyst provided in Comparative Example 5 of the present application. It can be seen from the image that the distance from the particle to the edge is the thickness of the carbon layer, which is about 5 nm.

[0142] The catalysts provided in each embodiment and comparative example were subjected to a carbon coating thickness test, an actual ECSA / theoretical ECSA test, and a durability test. The specific test process is as follows:

[0143] Carbon coating thickness test: The average thickness of the carbon coating was obtained by TEM characterization (60 measurement points).

[0144] Actual ECSA / theoretical ECSA test: The actual ECSA was obtained by CV test, specifically: a glassy carbon rotating disk electrode (RDE, Pine Research Instrumentation) was used as the working electrode, connected to a CHI 600E (CHInstruments) electrochemical workstation, a Hydroflex hydrogen reference electrode (Gaskatel) was used as the reference electrode, and a platinum wire coil was used as the counter electrode. The electrolyte was a 0.1 M HClO4 aqueous solution. Cyclic voltammetry (CV) tests were performed at room temperature using a nitrogen-saturated HClO4 solution with a scan rate of 50 mV / s and a potential range of 0.05-1.1 V (relative to the reversible hydrogen electrode, VRHE). The average charge during hydrogen adsorption and desorption was calculated to be 210 µC / cm 2 , and thus calculate the specific electrochemically active surface area (ECSA). The theoretical ECSA is calculated based on the geometric surface area of ​​the catalyst, usually assuming that the catalyst particles are of an ideal shape (such as a sphere) and calculated based on their size and density; the calculation formula for the theoretical ECSA is as follows: ECSA 理论 =4Πr 2 *N, where r is the radius of the catalyst particle, which is an average particle size obtained by collecting the particle sizes of multiple particles (300) in TEM. N is the number of particles in the catalyst. Assuming 1g of catalyst, N = 1 / m (the mass of one particle), m = 21.45*V, and V is the volume of a single particle.

[0145] Durability testing was conducted in a three-electrode system using a glassy carbon rotating disk electrode (RDE, PineResearch Instrumentation) as the working electrode, connected to a CHI 600E (CH Instruments) electrochemical workstation, a Hydroflex hydrogen reference electrode (Gaskatel) as the reference electrode, and a platinum wire coil as the counter electrode. The electrolyte was a 0.1 M aqueous HClO₄ solution. Cyclic voltammetry (CV) was performed at room temperature using a nitrogen-saturated HClO₄ solution at a scan rate of 50 mV / s over the potential range of 0.05–1.1 V (vs. reversible hydrogen electrode, VRHE). The specific electrochemically active surface area (ECSA) was calculated by calculating the average charge during hydrogen adsorption and desorption, taking a value of 210 µC / cm². Oxygen reduction reaction (ORR) activity testing was performed at room temperature using an oxygen-saturated HClO₄ solution using a rotating disk electrode (RDE) method with a scan rate of 10 mV / s, a rotation rate of 1600 rpm, and a potential range of 0.05-1.1 VRHE. Accelerated durability testing (ADT) was performed at room temperature using an oxygen-saturated HClO₄ solution at a rotation rate of 1600 rpm and a scan rate of 0.1 V / s. Cyclic voltammetry (CV) and oxygen reduction reaction (ORR) polarization curves were measured after 20,000 cycles in a potential range of 0.6-1.1 VRHE.

[0146] The results are shown in the following table:

[0147]

[0148] As can be seen from the above table, by adopting the method provided in the embodiments of the present application, by heat treating the catalyst body in a mixed gas containing hydrogen, carbon monoxide and carbon dioxide in a specific proportion, the obtained catalyst can have good durability and has little effect on its catalytic activity.

[0149] By comparing the data of Examples 1-4 and Comparative Example 1, it can be seen that when the mixed gas does not contain hydrogen, the formed carbon coating layer is relatively dense, which can improve the durability of the catalyst, but has low catalytic activity.

[0150] By comparing the data of Examples 1-4 and Comparative Example 2, it can be seen that when the hydrogen content in the mixed gas is too high, the carbon coating layer formed cannot effectively improve the durability of the catalyst, and the excessively high hydrogen content will cause the catalyst particles to be uneven in size, resulting in lower catalytic activity and durability of the catalyst.

[0151] By comparing the data of Examples 5-7 and Comparative Example 3, it can be seen that when the mixed gas does not contain carbon dioxide, the formed carbon coating layer is thicker, which can improve the durability of the catalyst, but has a lower catalytic activity.

[0152] By comparing the data of Examples 5-7 and Comparative Example 4, it can be seen that when the carbon dioxide content in the mixed gas is too high, basically no carbon coating layer is formed, resulting in lower durability of the catalyst.

[0153] By comparing the data of Example 3 and Example 8, it can be seen that when the heat treatment time is short and the temperature is low, the formed carbon coating layer has low crystallinity, which is not conducive to improving the durability of the catalyst.

[0154] The foregoing description is merely a specific embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for preparing a catalyst, characterized in that: The method comprises: Obtaining a catalyst body, wherein the catalyst body comprises a carrier and catalyst particles, the catalyst particles are supported on the carrier, the catalyst particles are platinum catalysts, and the carrier is a carbon carrier; heat-treating the catalyst body in a mixed gas atmosphere to obtain a catalyst, wherein the mixed gas includes hydrogen, carbon monoxide and carbon dioxide; The ratio of the volume V1 of the hydrogen to the volume V2 of the carbon monoxide satisfies: 10:300≤V1:V2≤40:300, and the ratio of the volume V3 of the carbon dioxide to the volume V2 of the carbon monoxide satisfies: 50:300≤V3:V2≤300:

300.

2. The method for preparing the catalyst according to claim 1, wherein The ratio of the volume V1 of the hydrogen to the volume V2 of the carbon monoxide satisfies: 30:300≤V1:V2≤40:300, and the ratio of the volume V3 of the carbon dioxide to the volume V2 of the carbon monoxide satisfies: 100:300≤V3:V2≤200:300; and / or The ratio of the flow rate of the mixed gas to the mass of the catalyst particles is 100 ml / min·g to 800 ml / min·g.

3. The method for preparing the catalyst according to any one of claims 1 to 2, characterized in that The heat treatment temperature is 300°C to 600°C; and / or The heat treatment time is 1h~3h; and / or The heating rate of the heat treatment is 5°C / min to 15°C / min.

4. The method for preparing the catalyst according to claim 1, wherein The catalyst body is prepared by a polyol reduction method.

5. The method for preparing the catalyst according to claim 4, wherein: The polyol reduction method comprises: mixing the carrier and the catalyst particle precursor with a polyol to obtain a mixed solution; Adjusting the mixed solution to an alkaline solution and performing a reflux reaction to obtain an intermediate solution; The intermediate solution is adjusted to an acidic solution to obtain a catalyst body.

6. The method for preparing the catalyst according to claim 5, wherein The polyol comprises ethylene glycol; and / or The pH value of the alkaline solution is 10-11; and / or The reflux reaction temperature is 150° C. to 170° C.; and / or The reflux reaction time is 5h~7h; and / or The pH value of the acidic solution is 1-2.

7. The method for preparing the catalyst according to claim 1, wherein The particle size of the catalyst particles is 2nm~3nm.

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