High performance pt / c catalyst and method for preparing the same

Abstract

The application discloses a high-performance Pt / C catalyst prepared by carrier modification and a preparation method thereof. The high-performance Pt / C catalyst comprises a carbon carrier and Pt nanoparticles loaded on the carbon carrier, and the carbon carrier is treated by urea through an equal-impregnation method before loading. The carrier after urea treatment has a significantly reduced number of micropores and a significantly increased N content on the surface. The high-performance Pt / C catalyst is prepared by using the carrier and through hydrothermal treatment. The Pt / C catalyst prepared by the method has good catalytic activity and stability, a half-wave potential of 0.87 V, an electrochemical active specific surface area only decreased by 2% after 50000 cycles, and an almost unchanged half-wave potential. The catalyst has good performance in membrane electrode measurement, and a peak power density of 1.3 W / cm 2 . The catalyst has simple preparation, excellent performance and good industrial application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of fuel cells, and particularly relates to a high-performance Pt / C catalyst and a preparation method thereof. BACKGROUND

[0002] Clean energy represented by lithium batteries has become a common goal pursued by the whole society. Fuel cell technology has advantages such as high energy density and large power density compared with lithium batteries, and plays an important role in energy transformation today. Among them, the application of proton exchange membrane fuel cells is the most extensive. In the proton exchange membrane fuel cell, the slow oxygen reduction process in the cathode limits its wide application. Pt / C catalyst is widely used in proton exchange membrane fuel cells due to its good catalytic activity and stability. The carrier has an important influence on its catalytic performance, and it is of great significance to the development of proton exchange membrane fuel cells to prepare high-activity Pt / C catalyst by simply and efficiently modifying the carrier.

[0003] CN 116779881A discloses a preparation method for preparing a fuel cell catalyst by carrier modification technology. The modified carbon carrier is obtained by mixing and treating the carbon carrier and the oxidizing agent solution, then the modified carbon carrier is mixed with a nitride to obtain a pretreated carbon carrier, and then the pretreated carbon carrier is mixed with ethylene glycol to obtain a carbon slurry. At the same time, a polyol solution of chloroplatinic acid and lye are mixed and subjected to microwave treatment to obtain Pt nanocolloid. The Pt nanocolloid is mixed with the carbon slurry, and the pH is adjusted to obtain the Pt / C catalyst. However, the preparation method has a long process, and the carbon carrier modification process needs to use an oxidizing agent, which is not environmentally friendly.

[0004] CN 114171749A discloses a preparation method for preparing a fuel cell catalyst by carrier modification technology. A high-compatibility C is obtained by hydrothermal treatment of the C carrier under high-temperature acidic conditions, and then a Pt / C catalyst is prepared by mixing and reducing the precursor solution. The method needs to use nitric acid which is seriously polluting to the environment during the treatment of the carrier, which is not environmentally friendly. At the same time, the high-temperature process also needs to consume a lot of energy.

[0005] In the above prior art, the treatment process of the carrier C of the Pt / C catalyst is complex and not environmentally friendly, the energy consumption is high, and the subsequent preparation process of the Pt / C catalyst is complicated and difficult to scale up. Therefore, it is necessary to find a simple modification technology for the C carrier to prepare a high-performance Pt / C catalyst. SUMMARY

[0006] The purpose of the present application is to provide a new simple carrier modification technology to prepare a high-performance Pt / C catalyst in view of the defects of the prior art.

[0007] In order to achieve the above object, the present application adopts the following technical scheme: A high-performance Pt / C catalyst, comprising: a carbon carrier and Pt nanoparticles loaded on the carbon carrier, wherein the carbon carrier is treated by urea through an equal-impregnation method before loading.

[0008] Further, the particle size of the Pt nanoparticles is 1-10 nm, and the Pt loading amount is 10%-60% in mass content.

[0009] Further, after the carbon carrier is treated by the equal-impregnation method, the surface micropore volume of the carbon carrier is 0.01-0.05 cm 3 / g, the micropore specific surface area is 10-65 m 2 / g, and the average pore size is 4-8 nm.

[0010] Further, after the carbon carrier is treated by the equal-impregnation method, the surface nitrogen content of the carbon carrier is 0.5%-25%, and the oxygen content is 5%-15%.

[0011] Further, the carbon carrier is XC-72C, Ketjen black, EC300J, Denka black carbon black, or Black Pears2000 carbon black.

[0012] A preparation method of the high-performance Pt / C catalyst, comprising the following steps:

[0013] (1) Pretreatment of the carbon carrier: urea is dispersed in water to form a urea solution, then the solution is mixed with the carbon carrier uniformly, and is placed at room temperature for 12-120 h, and then is placed in an oven at 60-120 ℃ for 24-48 h, and is ground after drying to obtain the pretreated carbon carrier;

[0014] (2) Reduction preparation of the loaded catalyst: the pretreated carbon carrier in step (1) is added to a glycol solution to form a carrier-glycol mixture, and a platinum salt precursor aqueous solution is added, and the Pt loading amount is set to 10 wt%-60 wt%, and the mixture is sealed, and is subjected to hydrothermal reaction, and after the reaction is completed, is subjected to suction filtration, washing, and drying to obtain the Pt / C catalyst.

[0015] Further, the mass concentration of the urea solution in step (1) is 1%-15%, and the mass ratio of the urea solution to the carbon carrier is 1-10:1.

[0016] Further, the mass concentration of the carrier-glycol mixture in step (2) is 3%-15%.

[0017] Further, the platinum salt precursor used in step (2) is chloroplatinic acid hexahydrate, platinum acetylacetone, or platinum acetate, and the mass concentration of the platinum salt precursor aqueous solution is 0.05%-30%.

[0018] Further, the temperature of the hydrothermal reaction in step (2) is 80-180℃, and the time is 2-72h.

[0019] The new carrier treatment technology and the high performance Pt / C catalyst obtained by using the above technology are adopted in the application, urea is impregnated on the carbon carrier by the equal impregnation method, and then the high performance Pt / C catalyst is prepared by mixing the dried and ground carbon carrier with the mixed solution of platinum salt precursor, water and ethylene glycol, and hydrothermal treatment.

[0020] The application uses urea to treat the carrier, and the number of micropores of the treated carrier is significantly reduced, and the N content on the surface is significantly increased. The high performance Pt / C catalyst is prepared by using the treated carrier and hydrothermal treatment. The Pt / C catalyst prepared by this method has a particle size distribution of Pt nanoparticles between 1-10nm, an electrochemical active specific surface area of 50 m 2 / g, and a half-wave potential of 0.87V. Meanwhile, the catalyst has good stability, and the electrochemical active specific surface area only decreases by 2% after 50000 cycles, and the half-wave potential is almost unchanged.

[0021] The catalyst prepared in the application also has good performance in membrane electrode measurement, and the peak power density can reach 1.3W / cm 2 The catalyst is simple to prepare, has excellent performance, and has good industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the Pt nanoparticle particle size distribution diagram of example 1.

[0023] Figure 2 is the CV diagram of the catalyst prepared in example 1 and the commercial Pt / C.

[0024] Figure 3 is the LSV diagram of the catalyst prepared in example 1 and the commercial Pt / C.

[0025] Figure 4 is the CV stability test diagram of the catalyst prepared in example 1.

[0026] Figure 5 is the LSV stability test diagram of the catalyst prepared in example 1.

[0027] Figure 6 is the membrane electrode performance test diagram of the catalyst prepared in example 1. DETAILED DESCRIPTION

[0028] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application, so that those skilled in the art can better understand the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0029] It should be noted that the terms "comprising" and "having" and any variations thereof in the specification and claims of the present application and the above-described drawings are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units that are not clearly listed or inherent to the process, method, product or device. Embodiments

[0030] Pre-treatment process of carbon carrier:

[0031] (1) Take 1g XC-72 C carrier and place it in a beaker;

[0032] (2) Take 0.8g urea and dissolve it in 4g deionized water;

[0033] (3) Use a dropper to add the above urea solution to the weighed XC-72 C in four times, and stir evenly after each time;

[0034] (4) Dry the above mixture in an 80-degree oven for 24h for standby;

[0035] (5) Grind the above dried sample.

[0036] Preparation of 20% Pt / C catalyst:

[0037] (1) Take 0.8g of the pre-treated carbon carrier and place it in a 100ml hydrothermal kettle;

[0038] (2) Add 70ml of ethylene glycol solution and ultrasonic for 30min;

[0039] (3) Add 0.53g of chloroplatinic acid hexahydrate and stir evenly;

[0040] (4) Hydrothermal treatment at 120℃ for 12h;

[0041] (5) After hydrothermal treatment, filter, wash and dry to obtain 20% Pt / C catalyst.

[0042] Table 1 is the specific surface area and pore size distribution comparison of the carrier before and after urea treatment. Table 2 is the element analysis data of the carrier before and after urea treatment.

[0043] From table 1 we can see that after the treatment of urea, the volume of micropore of XC-72C decreased from 0.05cm 3 / g to 0.03cm 3 / g, the specific surface area of micropore decreased from 91m 2 / g to 65m 2 / g, the average pore size increased from 4.7nm to 5.7nm, from table 2 we can see that the nitrogen content on the surface increased from 0.5% to 2.2%, the oxygen content increased from 2.0% to 8.7%. Further, we can use the catalyst prepared by the carrier treated by urea as the carrier to prepare high performance catalyst.

[0044] Figure 1 The TEM image of the catalyst we prepared, from the image we can see that the Pt nanoparticle size distribution of the Pt / C catalyst prepared by the carrier treated by urea is uniform, generally between 2-3nm.

[0045] Figure 2 The CV electrochemical test image of the catalyst we prepared, from the image we can see that the electrochemical active specific surface area of the Pt / C catalyst prepared by the carrier treated by urea is greater than that of the Pt / C catalyst without urea treatment and the commercial Johnson Matthey Pt / C catalyst

[0046] Figure 3 The LSV electrochemical test image of the catalyst we prepared, from the image we can see that the half-wave potential of the Pt / C catalyst prepared by the carrier treated by urea is 0.87V, which is significantly higher than that of the Pt / C catalyst without urea treatment and the commercial Johnson Matthey Pt / C catalyst

[0047] Figure 4 、 5 The stability test results of the catalyst we prepared, from the image we can see that after 50000 cycles, the electrochemical active specific surface area and the half-wave potential do not decrease significantly, indicating that the catalyst has good stability.

[0048] Figure 6 The membrane electrode test results of the catalyst we prepared, from the image we can see that the power density of the membrane electrode prepared by the Pt / C catalyst prepared by the carrier treated by urea can reach 1.3W / cm 2 , which is higher than that of the commercial Pt / C catalyst.

[0049] Table 1

[0050] Sample Specific surface area (m 2 / g)]]> Micropore area (m 2 / g) Micropore volume (cm 3 / g)]]> Before XC-72 treatment 200 91 0.05 After XC-72 treatment 170 65 0.03

[0051] Table 2

[0052] Sample C content N content O content Before XC-72 treatment 97.5% 0.5% 2.0% After XC-72 treatment 89.1% 2.2% 8.7% Example

[0053] Pre-treatment procedure of carbon support:

[0054] (1) Take 1 g XC-72 C support and place it in a beaker;

[0055] (2) Take 0.4 g urea and dissolve it in 4 g deionized water;

[0056] (3) Use a dropper to add the above urea solution to the weighed XC-72 C in four times, and stir evenly after each time;

[0057] (4) Dry the above mixture in an 80-degree oven for 24 h for standby;

[0058] (5) Grind the above dried sample.

[0059] Preparation of 20% Pt / C catalyst:

[0060] (1) Take 0.8 g of pre-treated carbon support and place it in a 100 ml hydrothermal kettle;

[0061] (2) Add 70 ml of ethylene glycol solution and ultrasonic for 30 min;

[0062] (3) Add 0.53 g of chloroplatinic acid hexahydrate and stir evenly;

[0063] (4) Hydrothermal at 120°C for 12 h;

[0064] (5) After hydrothermal, filter, wash and dry to obtain 20% Pt / C catalyst. Example

[0065] Pre-treatment procedure of carbon support:

[0066] (1) Take 1 g XC-72 C support and place it in a beaker;

[0067] (2) Take 1.2 g urea and dissolve it in 4 g deionized water;

[0068] (3) Use a dropper to add the above urea solution to the weighed XC-72 C in four times, and stir evenly after each time;

[0069] (4) Dry the above mixture in an 80-degree oven for 24 h for standby;

[0070] (5) Grind the above dried sample.

[0071] Preparation of 20% Pt / C catalyst:

[0072] (1) Take 0.8 g of pretreated carbon carrier and place it in a 100 ml hydrothermal kettle;

[0073] (2) Add 70 ml of ethylene glycol solution and ultrasonic for 30 min;

[0074] (3) Add 0.53 g of chloroplatinic acid hexahydrate and stir evenly;

[0075] (4) Hydrothermal treatment at 120°C for 12 h;

[0076] (5) After hydrothermal treatment, filter, wash and dry to obtain 20% Pt / C catalyst. Example

[0077] Pretreatment process of carbon carrier:

[0078] (1) Take 1 g of XC-72 C carrier and place it in a beaker;

[0079] (2) Take 0.8 g of urea and dissolve it in 4 g of deionized water;

[0080] (3) Use a dropper to add the above urea solution to the weighed XC-72 C in four times, and stir evenly after each time;

[0081] (4) Dry the mixture in an 80°C oven for 24 h for standby;

[0082] (5) Grind the dried sample.

[0083] Preparation of 20% Pt / C catalyst:

[0084] (1) Take 0.8 g of pretreated carbon carrier and place it in a 100 ml hydrothermal kettle;

[0085] (2) Add 70 ml of ethylene glycol solution and ultrasonic for 30 min;

[0086] (3) Add 0.53 g of chloroplatinic acid hexahydrate and stir evenly;

[0087] (4) Hydrothermal treatment at 150°C for 12 h;

[0088] (5) After hydrothermal treatment, filter, wash and dry to obtain 20% Pt / C catalyst. Example

[0089] Pretreatment process of carbon carrier:

[0090] (1) Take 1 g of XC-72 C carrier and place it in a beaker;

[0091] (2) Take 0.8 g of urea and dissolve it in 4 g of deionized water;

[0092] (3) The above urea solution was added to the XC-72 C by a dropper in four times, and stirred after each time;

[0093] (4) The mixture was dried in an oven at 80 degrees for 24 hours for standby;

[0094] (5) The dried sample was ground.

[0095] Preparation of 20% Pt / C catalyst:

[0096] (1) 0.8g of the pretreated carbon carrier was weighed and placed in a 100ml hydrothermal kettle;

[0097] (2) 70ml of ethylene glycol solution was added and ultrasonic treated for 30min;

[0098] (3) 0.53g of chloroplatinic acid hexahydrate was added and stirred evenly;

[0099] (4) Hydrothermal treatment was carried out at 180 degrees for 12 hours;

[0100] (5) After the hydrothermal treatment, the 20% Pt / C catalyst was obtained after filtration, washing and drying. Example

[0101] Preparation of 20% Pt / C catalyst:

[0102] (1) 1g of XC-72 C carrier was weighed and placed in a beaker;

[0103] (2) 0.8g of urea was weighed and dissolved in 4g of deionized water;

[0104] (3) The above urea solution was added to the XC-72 C by a dropper in four times, and stirred after each time;

[0105] (4) The mixture was dried in an oven at 80 degrees for 24 hours for standby;

[0106] (5) The dried sample was ground.

[0107] Preparation of 20% Pt / C catalyst:

[0108] (1) 0.8g of the pretreated carbon carrier was weighed and placed in a 100ml hydrothermal kettle;

[0109] (2) 60ml of ethylene glycol solution was added and ultrasonic treated for 30min;

[0110] (3) 0.53g of chloroplatinic acid hexahydrate was added and stirred evenly;

[0111] (4) Hydrothermal treatment was carried out at 150 degrees for 12 hours;

[0112] (5) After hydrothermal reaction, the 20% Pt / C catalyst was obtained by filtration, washing and drying.

[0113] The preferred embodiments of the present application have been described above with the preferred embodiments, but the present application is not limited to the above examples, and various modifications and changes can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high performance Pt / C catalyst characterized in that The application relates to a carbon carrier and Pt nanoparticles loaded on the carbon carrier, wherein the carbon carrier is treated by an equal-impregnation method with urea before loading, the equal-impregnation is that urea is dispersed in water to form a urea solution, and then the solution is uniformly mixed with the carbon carrier. The particle size of the Pt nanoparticles is 1-10 nm, and the Pt loading amount is 10-60% in mass content.

2. The high performance Pt / C catalyst of claim 1, wherein: After the equal-impregnation method is used to treat the carbon carrier, the surface nitrogen content is 0.5-5%, and the surface oxygen content is 5-15%.

3. The high performance Pt / C catalyst of claim 1, wherein: The carbon carrier has a surface micropore volume of 0.01-0.05 cm 3 / g, a micropore specific surface area of 10-65 m 2 / g, and an average pore diameter of 4-8 nm after being treated by the method of equal-amount impregnation.

4. The high performance Pt / C catalyst of claim 1, wherein: The carbon carrier is XC-72C, Ketjen black, EC300J, Denka black carbon black or Black Pears 2000 carbon black.

5. The high performance Pt / C catalyst of claim 1, wherein: The application is characterized in the following steps:

6. A method for preparing the high performance Pt / C catalyst according to any one of claims 1 to 5, (1) Pretreatment of the carbon carrier: urea is dispersed in water to form a urea solution, then the solution is uniformly mixed with the carbon carrier by an equal-impregnation method, and is placed at room temperature for 12-120 h, and then is placed in an oven at 60-120 DEG C for 24-48 h, and after drying, is ground to obtain the pretreated carbon carrier; (2) Reduction preparation of the loaded catalyst: the pretreated carbon carrier in step (1) is added into an ethylene glycol solution to form a carrier-ethylene glycol mixed solution, and a platinum salt precursor aqueous solution is added, the Pt loading amount is set to be 10-60 wt%, and then the mixture is sealed, is subjected to hydrothermal reaction, after the reaction is completed, is subjected to suction filtration, washing and drying to obtain a Pt / C catalyst. The mass concentration of the urea solution in step (1) is 1-15%, and the mass ratio of the urea solution to the carbon carrier is 1-10:

1.

7. The method of claim 6, wherein: The mass concentration of the carrier-ethylene glycol mixed solution in step (2) is 3-15%.

8. The method of claim 6, wherein: The platinum salt precursor used in step (2) is chloroplatinic acid hexahydrate, platinum acetylacetone or platinum acetate, and the mass concentration of the platinum salt precursor aqueous solution is 0.05-30%.

9. The method of claim 6, wherein: The temperature of the hydrothermal reaction in step (2) is 80-180 DEG C, and the time is 2-72 h.

10. The method of claim 6, wherein: ​

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