Microwave-assisted activated carbon carrier supported platinum catalyst as well as preparation method and application thereof
By using a microwave-assisted activated carbon support method to prepare platinum catalysts, the problems of easy agglomeration and weak binding force of platinum particles in Pt/C catalysts were solved, and uniform dispersion of Pt particles and high catalytic performance were achieved.
Patent Information
- Application Number
- CN202510930477.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-07
- Publication Date
- 2025-11-04
AI Technical Summary
In existing Pt/C catalysts, platinum particles tend to agglomerate and have weak bonding with the carbon support, leading to a decline in catalytic performance. Traditional modification methods also affect the specific surface area and conductivity of the support.
Microwave-assisted activation of carbon support was used to mix it with hydrogen peroxide and urea. Oxygen- and nitrogen-containing functional groups were introduced onto the surface of the carbon support by microwave irradiation, forming a bifunctional anchoring mechanism to improve the uniformity and dispersibility of Pt particles.
It significantly improves the electrochemical active area and catalytic performance of Pt/C catalysts, enhances the uniformity of Pt particles, and achieves a more uniform particle size distribution, thus avoiding agglomeration.
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Figure CN120895665A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of fuel cell catalysts, and particularly relates to a high-performance Pt / C catalyst material prepared by microwave pretreatment of a carbon carrier and a polyol reduction method. BACKGROUND
[0002] As a high-efficiency and clean power generation device, a fuel cell has a core material, namely a cathode catalyst, which has a decisive influence on the performance of the cell. At present, a platinum-carbon (Pt / C) catalyst has been widely applied in industry due to its excellent oxygen reduction reaction (ORR) activity, but still has some technical bottlenecks.
[0003] Firstly, platinum particles are prone to agglomeration. The Pt / C catalyst prepared by the traditional polyol impregnation reduction method generally has the problem that platinum nanoparticles are prone to migration and agglomeration, resulting in an increase in particle size, a decrease in active sites, and a decrease in catalytic performance, which is particularly obvious when the Pt loading is high. Secondly, the interaction between the carbon carrier and the metal nanoparticles is weak. The surface of the commercial carbon carrier (such as Vulcan XC-72R) is relatively inert, and the binding force between the Pt nanoparticles and the carrier is insufficient, which leads to the easy falling off of the Pt nanoparticles from the carrier during operation. Thirdly, the modification methods for the carbon carrier in the prior art have inherent defects. Although the treatment process of oxidizing the carbon carrier with a strong acid (such as nitric acid) can introduce oxygen-containing functional groups to anchor Pt, it can also lead to a decrease in the specific surface area of the carbon carrier and a decrease in the conductivity; although the introduction of an organic protective agent (such as PVP) can inhibit the agglomeration of Pt, it can block the pores of the carrier, and the subsequent high-temperature or chemical cleaning to remove the protective agent is easy to leave impurities, which affects the activity of the catalyst. SUMMARY
[0004] The purpose of the present application is to provide a microwave-assisted activated carbon carrier supported platinum catalyst to solve the above problems.
[0005] Another purpose of the present application is to provide a preparation method of a microwave-assisted activated carbon carrier supported platinum catalyst.
[0006] Still another purpose of the present application is to provide an application of a microwave-assisted activated carbon carrier supported platinum catalyst.
[0007] In order to achieve the above purposes, the present application provides the following technical solutions:
[0008] A preparation method of a microwave-assisted activated carbon carrier supported platinum catalyst, comprising the following steps:
[0009] (1) adding hydrogen peroxide and urea into the carbon carrier, mixing to form a slurry, and then performing microwave treatment, cleaning and drying to obtain a pretreated carbon carrier;
[0010] (2) chloroplatinic acid, sodium hydroxide and hydrogen peroxide are added into ethylene glycol to prepare a mixed solution;
[0011] (3) the pretreated carbon carrier obtained in step (1) is added into the solution of step (2), ultrasonic dispersion is carried out, and then reaction is carried out at 120-198 ℃ for 1-2 minutes, and then Pt / C catalyst is obtained through suction filtration, washing and drying.
[0012] In the above method for preparing a microwave-assisted activated carbon carrier loaded platinum catalyst, the concentration of hydrogen peroxide in step (1) is 2-5 wt%, the mass ratio of the carbon carrier to hydrogen peroxide is 1:5-1:10, the mass ratio of the carbon carrier to urea is 1:0.5-1:1, the frequency of the microwave is 2.45 GHz, and after the slurry is boiled, the microwave irradiation is continued for 20-60 seconds.
[0013] In the above method for preparing a microwave-assisted activated carbon carrier loaded platinum catalyst, the concentration of H2PtCl6 in the mixed solution in step (2) is 5-35 mmol / L, the concentration of NaOH is 0.1 mol / L, and the concentration of H2O2 is 0.1 mol / L.
[0014] In the above method for preparing a microwave-assisted activated carbon carrier loaded platinum catalyst, the loading amount of the carbon carrier in step (3) is 4-9 g / L.
[0015] A microwave-assisted activated carbon carrier loaded platinum catalyst prepared according to the above preparation method.
[0016] The application of a microwave-assisted activated carbon carrier loaded platinum catalyst prepared according to the above preparation method in a fuel cell.
[0017] Compared with the prior art, the application has the following advantages:
[0018] The application adopts microwave irradiation of a carbon carrier / hydrogen peroxide / urea mixed slurry, rapidly introduces oxygen-containing and nitrogen-containing functional groups on the surface of the carbon carrier at the same time, uses the bifunctional anchoring mechanism formed by the synergistic effect of the two functional groups to jointly anchor Pt particles, thereby improving the uniformity and dispersity of the Pt particles, reducing the difference in particle size distribution, and significantly improving the performance of the catalyst. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 The scanning electron microscope photos of the Pt / C catalyst in Example 1 (a) and Comparative Samples 1-3 (b-d).
[0020] Figure 2 The cyclic voltammetry curves of the Pt / C catalyst in Example 1 (a) and Comparative Samples 1-3 (b-d). DETAILED DESCRIPTION
[0021] The application will be further described in detail through specific examples.
[0022] Example 1
[0023] The present example provides a method for preparing a microwave-assisted activated carbon carrier loaded platinum catalyst, comprising the following steps:
[0024] (1) mixing carbon carrier (Vulcan XC-72R) with 4wt% hydrogen peroxide and urea at a mass ratio of 1:7:0.7, stirring to form a slurry, placing in a microwave oven, opening the microwave at a frequency of 2.45GHz, irradiating the slurry until it boils, then continuing to maintain for 30 seconds, then filtering, washing and drying the slurry to obtain a pretreated carbon carrier;
[0025] (2) adding chloroplatinic acid, sodium hydroxide and hydrogen peroxide into ethylene glycol to prepare a mixed solution, wherein the concentration of H2PtCl6 is 20.5mmol / L, the concentration of NaOH is 0.1mol / L, and the concentration of H2O2 is 0.1mol / L;
[0026] (3) adding the pretreated carbon carrier obtained in step (1) into the solution obtained in step (2) at a loading of 6g / L, ultrasonic dispersion, heating to 160℃ under stirring, maintaining for 1 minute, cooling, vacuum filtering the product, washing with deionized water for multiple times, and drying in a vacuum oven to obtain a Pt / C catalyst material. The Pt / C catalyst material can be used for fuel cells.
[0027] In order to verify the beneficial effects of hydrogen peroxide, urea and microwave irradiation in the present application, three other pretreatment methods were adopted for the carbon carrier to prepare three comparative samples, as follows:
[0028] Comparative sample 1: the carbon carrier was mixed with 4wt% hydrogen peroxide to form a slurry, and treated by microwave irradiation.
[0029] Comparative sample 2: the carbon carrier was mixed with a urea solution to form a slurry, the mass ratio of carbon carrier, water and urea was 1:5:0.5, and the slurry was treated by microwave irradiation.
[0030] Comparative sample 3: the carbon carrier was treated with 30wt% nitric acid without microwave irradiation.
[0031] Deionized water and isopropyl alcohol were mixed in equal volumes to form a uniform mixed solvent. Then, a 5wt% perfluorosulfonic acid resin (Nafion) solution was added dropwise into the mixed solvent, and the addition amount was 12.5μL / mL. Subsequently, the Pt / C catalyst was added into the above solution at a loading of 2mg / mL, and the catalyst slurry was treated with 200W ultrasonic wave for 30 minutes, and the water bath temperature was kept below 20℃ during the treatment process.
[0032] The electrochemical active area of the test catalyst material was determined by cyclic voltammetry (CV) in an argon-saturated 0.5 mol / L H2SO4 electrolyte. In a potential range of -0.25-1.0 V (vs. SCE), the electrode was first scanned at a scan rate of 100 mV / s until the curve was stable and the hydrogen desorption peak area no longer increased, and then the scan rate was changed to 50 mV / s and the scanning was continued for 5 cycles, and the stable CV curve was recorded.
[0033] The Pt / C catalyst material prepared according to the method of the present example has a Pt loading of about 40 wt%, and the average size of the Pt nanoparticles is 2.4 nm, which is significantly lower than that of the three comparative samples (5.4 nm, 3.9 nm and 4.0 nm, respectively). The Pt particles obtained in the present example are highly dispersed on the surface of the carbon support, while the three comparative samples all show different degrees of agglomeration, as shown in Figure 1 .
[0034] The Pt / C catalyst material prepared according to the method of the present example has an electrochemical active area (ECSA) of 114 m 2 / g, which is significantly higher than that of the three comparative samples (42 m 2 / g, 33 m 2 / g and 75 m 2 / g, respectively), as shown in Figure 2 .
[0035] Example 2:
[0036] The present example provides a method for preparing a microwave-assisted activated carbon support loaded platinum catalyst, comprising the following steps:
[0037] (1) Mix the carbon support (Vulcan XC-72R) with 2 wt% hydrogen peroxide and urea at a mass ratio of 1:5:0.5, stir to form a slurry, and place it in a microwave oven. Turn on the microwave at a frequency of 2.45 GHz, irradiate the slurry until it boils, and then continue to maintain for 20 seconds. Then, filter, wash and dry the slurry to obtain a pretreated carbon support;
[0038] (2) Add chloroplatinic acid, sodium hydroxide and hydrogen peroxide to ethylene glycol to prepare a mixed solution, wherein the concentration of H2PtCl6 is 5 mmol / L, the concentration of NaOH is 0.1 mol / L, and the concentration of H2O2 is 0.1 mol / L;
[0039] (3) The pretreated carbon carrier obtained in step (1) is added to the solution obtained in step (2) at a loading of 9 g / L, and after ultrasonic dispersion, it is heated to 120°C under stirring, kept for 1 minute, and then cooled. The product is vacuum filtered, washed with deionized water for several times, and dried in a vacuum oven to obtain a Pt / C catalyst material. The Pt / C catalyst material prepared in this example has a Pt loading of about 30 wt%, the average size of Pt nanoparticles is 2.1 nm, which are highly uniformly dispersed on the surface of the carbon carrier, and the electrochemical active surface area (ECSA) is 107 m 2 / g. The Pt / C catalyst material can be used in fuel cells.
[0040] Example 3:
[0041] This example provides a method for preparing a microwave-assisted activated carbon carrier loaded platinum catalyst, comprising the following steps:
[0042] (1) Carbon carrier (Vulcan XC-72R) is mixed with 5 wt% hydrogen peroxide and urea at a mass ratio of 1:9:0.9, stirred to form a slurry, and placed in a microwave oven. The microwave with a frequency of 2.45 GHz is turned on, and the slurry is irradiated until it boils. Then the slurry is filtered, washed, and dried to obtain a pretreated carbon carrier;
[0043] (2) Chloroplatinic acid, sodium hydroxide, and hydrogen peroxide are added to ethylene glycol to prepare a mixed solution, wherein the concentration of H2PtCl6 is 35 mmol / L, the concentration of NaOH is 0.1 mol / L, and the concentration of H2O2 is 0.1 mol / L;
[0044] (3) The pretreated carbon carrier obtained in step (1) is added to the solution obtained in step (2) at a loading of 4 g / L, and after ultrasonic dispersion, it is heated to 190°C under stirring, kept for 2 minutes, and then cooled. The product is vacuum filtered, washed with deionized water for several times, and dried in a vacuum oven to obtain a Pt / C catalyst material.
[0045] The Pt / C catalyst material prepared in this example has a Pt loading of about 50 wt%, the average size of Pt nanoparticles is 3.0 nm, which are highly uniformly dispersed on the surface of the carbon carrier, and the electrochemical active surface area (ECSA) is 96 m 2 / g. The Pt / C catalyst material can be used in fuel cells.
[0046] The specific embodiments described herein are merely illustrative of the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them with similar ways without departing from the spirit of the present application.
Claims
1. A method for preparing a platinum catalyst supported on a carbon support with microwave-assisted activation, characterized in that... Includes the following steps: (1) Add hydrogen peroxide and urea to the carbon carrier, mix them to form a slurry, then microwave treat it, clean and dry it to obtain a pretreated carbon carrier. (2) Add chloroplatinic acid, sodium hydroxide and hydrogen peroxide to ethylene glycol to prepare a mixed solution; (3) Add the pretreated carbon support obtained in step (1) to the solution in step (2), disperse it by ultrasonication, react it at 120-198℃ for 1-5 minutes, and obtain the Pt / C catalyst by filtration, washing and drying.
2. The method for preparing a microwave-assisted activated carbon-supported platinum catalyst as described in claim 1, characterized in that, In step (1), the concentration of hydrogen peroxide is 2-5 wt%, the mass ratio of carbon carrier to hydrogen peroxide is 1:5-1:10, the mass ratio of carbon carrier to urea is 1:0.5-1:1, the microwave frequency is 2.45 GHz, and after the slurry boils, the microwave irradiation continues for 20-60 seconds.
3. The method for preparing a microwave-assisted activated carbon-supported platinum catalyst as described in claim 1, characterized in that, In step (2), the concentration of H2PtCl6 in the mixed solution is 5-35 mmol / L, the concentration of NaOH is 0.1 mol / L, and the concentration of H2O2 is 0.1 mol / L.
4. The method for preparing a microwave-assisted activated carbon-supported platinum catalyst as described in claim 1, characterized in that, In step (3), the loading of the pretreated carbon carrier obtained in step (1) is 4 to 9 g / L.
5. A microwave-assisted activated carbon-supported platinum catalyst prepared by the method according to any one of claims 1 to 4.
6. The application of the microwave-assisted activated carbon-supported platinum catalyst prepared by the method according to any one of claims 1 to 4 in fuel cells.