Platinum-carbon catalyst as well as preparation method and application thereof

Abstract

The invention provides a platinum-carbon catalyst as well as a preparation method and application thereof, and relates to the technical field of catalysts. The platinum-carbon catalyst is prepared from the following raw materials: a carbon carrier, a platinum precursor and ethylene glycol, wherein the ethylene glycol is simultaneously used as a solvent and a reducing agent. The preparation method comprises the following steps: carrying out heat treatment on the carbon carrier; taking a platinum precursor, ethylene glycol and the carbon carrier subjected to heat treatment, mixing, stirring and performing ultrasonic treatment to obtain a mixed material; adjusting the pH value of the mixed material, and then raising the temperature for reaction; and filtering, washing and drying the reactant in sequence to obtain the product catalyst. A reducing agent and a protective agent do not need to be additionally added in the preparation process, so that the production cost is reduced; meanwhile, the technological process is optimized, operation is easy, waste and loss caused by slurry transfer are avoided, and the product catalyst is good in particle uniformity, uniform in dispersion, excellent in performance and capable of being applied to preparation and assembly of fuel cell products.

Description

Technical Field

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

[0002] A fuel cell is a device that continuously converts the chemical energy of fuel and oxidant into electrical energy. Fuel cells achieve energy conversion in a chemical way, are not limited by the Carnot cycle of heat engines, and have a high conversion efficiency. The catalyst determines the discharge performance and life of the fuel cell and is a key material for the fuel cell. At present, the most widely used catalyst is the platinum-carbon catalyst, which is composed of Pt nanoparticles dispersed on a carbon powder carrier.

[0003] In the current traditional platinum-carbon catalyst preparation process, due to process defects, the reaction slurry will cause material loss and waste during the transfer process, and the particle size of the product catalyst will become larger, affecting the quality of the product catalyst; in addition, most of the existing processes require the additional addition of reducing agents and protective agents, and the process cost is relatively high. Summary of the invention

[0004] The purpose of the present application is to provide a platinum-carbon catalyst and a preparation method thereof, wherein no additional reducing agent and protective agent need to be added during the preparation process, thereby helping to reduce production costs; at the same time, the process flow is optimized, the operation is simple, and the waste and loss caused by slurry transfer are avoided, and the product catalyst particles have good uniformity, are evenly dispersed, and have excellent performance.

[0005] Another object of the present application is to provide an application of the above-mentioned platinum-carbon catalyst in a fuel cell, which can be used to prepare and assemble fuel cell products.

[0006] The technical solution of this application is as follows:

[0007] On the one hand, an embodiment of the present application provides a platinum-carbon catalyst, which is prepared from raw materials including the following components: a carbon support, a platinum precursor, and ethylene glycol; wherein the ethylene glycol serves as both a solvent and a reducing agent.

[0008] Furthermore, in some embodiments of the present application, the carbon carrier is carbon black; and the platinum precursor is chloroplatinic acid hexahydrate solution or platinum nitrate solution.

[0009] Furthermore, in some embodiments of the present application, the carbon carrier is a commercially available conductive carbon black selected from Cabot or Ketjen black carbon black.

[0010] Furthermore, in some embodiments of the present application, in the raw material components, the mass ratio of the above-mentioned ethylene glycol to the above-mentioned carbon carrier used is 400-500.

[0011] Furthermore, in some embodiments of the present application, in the raw material components, the volume ratio of the above-mentioned platinum precursor to the above-mentioned ethylene glycol is 0.1-1.

[0012] Furthermore, in some embodiments of the present application, the concentration of the above-mentioned chloroplatinic acid hexahydrate solution or the above-mentioned platinum nitrate solution is 10 g / L.

[0013] Furthermore, in some embodiments of the present application, the platinum content in the above-mentioned platinum-carbon catalyst is 20-50%.

[0014] The present invention also provides a method for preparing the above-mentioned platinum-carbon catalyst, which comprises the following steps:

[0015] S1: heat treating the carbon support;

[0016] S2: taking a platinum precursor, ethylene glycol, and a heat-treated carbon support, mixing, stirring, and ultrasonicating to obtain a mixed material;

[0017] S3: adjusting the pH of the mixed material, and then raising the temperature to react;

[0018] S4: The reactants in the above step S3 are filtered, washed, and dried in sequence to obtain a product catalyst.

[0019] Furthermore, in some embodiments of the present application, in the above step S1, the carbon carrier is heat-treated in an air or protective gas atmosphere at a rate of 2 to 6°C / min to 400 to 600°C for a treatment time of 2 to 6 hours.

[0020] Furthermore, in some embodiments of the present application, the protective gas is nitrogen.

[0021] Furthermore, in some embodiments of the present application, in the above step S2, the stirring rate is 150r / min, the ultrasonic power is 0.8KW, and the ultrasonic amplitude is 20KHz; stirring and ultrasonic treatment are performed for 0.5h to disperse the material to obtain a mixed material.

[0022] Furthermore, in some embodiments of the present application, when performing ultrasound, the rated power of the ultrasonic generator used is 2KW, and the power range is 40-100%.

[0023] Furthermore, in some embodiments of the present application, in the above step S3, alkali is added to the mixture to adjust the pH to 8-12, and then the temperature is raised to react.

[0024] Furthermore, in some embodiments of the present application, the alkali is any one of a sodium hydroxide solution, a potassium hydroxide solution, and a sodium carbonate solution.

[0025] Furthermore, in some embodiments of the present application, in the above step S3, after adjusting the pH of the mixed material, the temperature is raised to 80-100° C. and reacted for 1-4 hours.

[0026] Furthermore, in some embodiments of the present application, in the above step S4, a drying process is performed in a vacuum environment at 80°C.

[0027] On the other hand, an embodiment of the present application also provides an application of the above-mentioned platinum-carbon catalyst in a fuel cell.

[0028] Compared with the prior art, the embodiments of the present application have at least the following advantages or beneficial effects:

[0029] In view of the above aspects, the present application embodiment provides a platinum-carbon catalyst and a preparation method thereof, wherein ethylene glycol is used as a material solvent and a reaction reducing agent at the same time as a raw material, and no additional reducing agent or protective agent is required in the subsequent reaction production process, which helps to simplify the operation process and reduce the cost of process raw materials; its scheme simplifies the process steps so that the mixing, dispersion and reaction of materials can be carried out in the same reaction equipment, thereby avoiding the loss and waste of materials caused by slurry transfer, and also helps to ensure the quality of the product catalyst, and the obtained product platinum-carbon catalyst has good particle size uniformity, uniform dispersion, high catalytic performance and excellent quality. Its process flow and required equipment are simple, easy to operate, and help to improve production efficiency, and are more conducive to large-scale production of the process; its product catalyst has excellent performance and can be applied to the assembly and preparation of fuel cells, with high application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 This is a transmission electron microscope comparison diagram in Experimental Example 2 of this application;

[0032] Figure 2 This is a transmission electron microscope comparison diagram in Experimental Example 3 of this application;

[0033] Figure 3 This is a test diagram of the electrochemical activity area of ​​the catalyst in Experimental Example 4 of this application;

[0034] Figure 4 This is a polarization curve diagram of a single cell in Experimental Example 4 of this application. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0036] It should be noted that the term "include" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "include..." do not exclude the existence of other identical elements in the process, method, article or device including its elements.

[0037] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0038] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0039] Example 1

[0040] This embodiment provides a platinum-carbon catalyst, which is prepared by the following method:

[0041] S1: Take Cabot Vulcan XC-72R carbon support, heat it to 400℃ at a rate of 5℃ / min in nitrogen atmosphere, and heat it for 4h;

[0042] S2: Weigh 5 g of the heat-treated carbon carrier powder, 331.9 ml of a 10 g / L hexachloroplatinic acid solution, and 2000 ml of ethylene glycol, add them into a double-layer glass reactor, stir and mix at a rate of 150 r / min, and perform ultrasound at a power of 0.8 KW and an amplitude of 20 KHz. Stir and ultrasonicate for 0.5 h to disperse the materials to obtain a mixed material;

[0043] S3: Add 1.0 mol / L sodium hydroxide solution to the mixture to adjust the pH to 8.0, and then heat to 90°C for 2h;

[0044] S4: The reactants in the above step S3 are filtered and washed in sequence, and then dried in a vacuum environment at 80° C. to obtain a platinum-carbon catalyst product with a platinum content of 20%.

[0045] Example 2

[0046] This embodiment provides a platinum-carbon catalyst, which is prepared by the following method:

[0047] S1: Take Cabot Vulcan XC-72R carbon support, heat it to 500°C at a rate of 5°C / min in a nitrogen atmosphere, and heat it for 4 hours;

[0048] S2: Weigh 5 g of the heat-treated carbon carrier powder, 569 ml of a 10 g / L hexachloroplatinic acid solution, and 2000 ml of ethylene glycol, add them into a double-layer glass reactor, stir and mix at a rate of 150 r / min, and perform ultrasound at a power of 0.8 KW and an amplitude of 20 KHz. Stir and ultrasonicate for 0.5 h to disperse the materials to obtain a mixed material;

[0049] S3: Add 1.0 mol / L potassium hydroxide solution to the mixture to adjust the pH to 9.0, and then heat to 90°C for 2h;

[0050] S4: The reactants in the above step S3 are filtered and washed in sequence, and then dried in a vacuum environment at 80° C. to obtain a platinum-carbon catalyst product with a platinum content of 30%.

[0051] Example 3

[0052] This embodiment provides a platinum-carbon catalyst, which is prepared by the following method:

[0053] S1: Take Ketjen Black ECP300 carbon support, heat it to 600℃ at a rate of 5℃ / min in nitrogen atmosphere, and heat treatment time is 4h;

[0054] S2: Weigh 5 g of the heat-treated carbon carrier powder, 545.3 ml of a 10 g / L platinum nitrate solution, and 2000 ml of ethylene glycol, add them into a double-layer glass reactor, stir and mix at a rate of 150 r / min, and perform ultrasound at a power of 0.8 KW and an amplitude of 20 KHz. Stir and ultrasonicate for 0.5 h to disperse the materials to obtain a mixed material;

[0055] S3: Add 1.0 mol / L sodium carbonate solution to the mixture to adjust the pH to 10.0, and then heat to 90°C for 2h;

[0056] S4: The reactants in the above step S3 are filtered and washed in sequence, and then dried in a vacuum environment at 80° C. to obtain a platinum-carbon catalyst product with a platinum content of 40%.

[0057] Example 4

[0058] This embodiment provides a platinum-carbon catalyst, which is prepared by the following method:

[0059] S1: Take Ketjen Black ECP600JD carbon support, heat it to 500℃ at a rate of 5℃ / min in nitrogen atmosphere, and heat treatment time is 4h;

[0060] S2: Weigh 5 g of the heat-treated carbon carrier powder, 1332.5 ml of a 10 g / L hexachloroplatinic acid solution, and 2000 ml of ethylene glycol, add them into a double-layer glass reactor, stir and mix at a rate of 150 r / min, and perform ultrasound at a power of 0.8 KW and an amplitude of 20 KHz. Stir and ultrasonicate for 0.5 h to disperse the materials to obtain a mixed material;

[0061] S3: Add 1.0 mol / L sodium hydroxide solution to the mixture to adjust the pH to 12.0, and then heat to 90°C for 2h;

[0062] S4: The reactants in the above step S3 are filtered and washed in sequence, and then dried in a vacuum environment at 80° C. to obtain a platinum-carbon catalyst product with a platinum content of 50%.

[0063] Comparative Example 1

[0064] This comparative example provides a platinum-carbon catalyst, which is prepared by the following method:

[0065] Take Vulcan XC-72R carbon support and heat treat it at 500 °C for 4 h under nitrogen atmosphere;

[0066] Weigh 1 g of the heat-treated carbon support, disperse it in 400 ml of isopropanol, and treat it with ultrasound at a frequency of 50 kHz for 0.5 h. Then transfer the material to a mixture of 250 ml of ethylene glycol, 1 g of tartaric acid, and 1 g of malic acid, and stir it at 150 r / min for 1 h to obtain a mixed material.

[0067] Add 66.38 ml of 10 g / L chloroplatinic acid solution to the mixture, continue stirring for 3 h, and adjust the pH value of the mixture to 8 with sodium hydroxide solution;

[0068] Then, sodium borohydride solution was added to the material, and reduction reaction was carried out at 90°C for 7 hours. After the reaction was completed, the material was filtered, washed, and dried under vacuum at 80°C to obtain a platinum-carbon catalyst with a platinum content of 20%.

[0069] Comparative Example 2

[0070] This comparative example provides a platinum-carbon catalyst, which is prepared by the following method:

[0071] The Cabot Vulcan XC-72R carbon support was heated to 400°C at a rate of 5°C / min for 4 hours under a nitrogen atmosphere;

[0072] Weigh 5 g of the heat-treated carbon carrier powder, measure 331.9 ml of a 10 g / L hexachloroplatinic acid solution and 2000 ml of ethylene glycol, place them in a double-layer glass reactor, stir and mix at a rate of 150 rpm / min, and perform ultrasound at a power of 0.8 KW and an amplitude of 20 KHz. Stir and ultrasonicate for 0.5 h to disperse the materials to obtain a mixed material;

[0073] Add 1.0 mol / L sodium hydroxide solution to the mixture to adjust the pH to 8.0, then add 50 ml of 29 g / L sodium borohydride solution as a reducing agent, and then heat to 90°C to react for 2 hours;

[0074] After the reaction is completed, the reactants are filtered and washed in sequence, and then dried at 80° C. in a vacuum environment to obtain a platinum-carbon catalyst with a platinum content of 20%.

[0075] Experimental Example 1

[0076] The average particle sizes of the platinum-carbon catalysts produced in Examples 1 to 4 and Comparative Examples 1 to 2 were detected and compared. The results are shown in Table 1.

[0077] Table 1

[0078] Serial number Average particle size (nm) Example 1 2.72 Example 2 2.75 Example 3 2.69 Example 4 3.08 Comparative Example 1 5.3 Comparative Example 2 7.02

[0079] As can be seen from Table 1, the particle size of the platinum-carbon catalyst particles provided by Examples 1 to 4 of the present application is smaller, and the particle size difference between the products of each group of examples is not large, indicating that the production process of the present application is stable and the product uniformity is good. A protective agent is used in the scheme of Comparative Example 1, and the particle size of the catalyst product thereof is larger than that of the product of this embodiment; a reducing agent is additionally added in the scheme of Comparative Example 2, and the particle size of the catalyst product thereof is larger than that of the product of this embodiment.

[0080] Experimental Example 2

[0081] The catalyst product provided in Example 1 of the present application was compared with the commercially available catalyst model TEC10E20E of TANAKA Company by transmission electron microscopy. The results are as follows: Figure 1 shown.

[0082] Figure 1In the figure, the left side is an electron microscope image of the platinum-carbon catalyst product provided in Example 1 of the present application, and the right side is an electron microscope image of the catalyst product of the commercially available TANAKA company TEC10E20E model; it can be seen from the figure that the catalyst particle size levels of the two products are comparable, and the distribution is relatively uniform, and it can even be seen from the figure that the distribution level of this embodiment is slightly better, indicating that the particle distribution level of the product of the present application scheme can reach the top level in the market.

[0083] Experimental Example 3

[0084] The catalyst product provided in Example 4 of the present application was compared with the commercially available catalyst model TEC10E50E of TANAKA Company by transmission electron microscopy. The results are as follows: Figure 2 shown.

[0085] Figure 2 In the figure, the left side is an electron microscope image of the platinum-carbon catalyst product provided in Example 4 of the present application, and the right side is an electron microscope image of the catalyst product of the commercially available TANAKA company TEC10E50E model; it can be seen from the figure that the catalyst particle size levels of the two products are comparable and the distribution is relatively uniform, indicating that the particle distribution level of the product of the present application scheme can reach the top level in the market.

[0086] Experimental Example 4

[0087] The electrochemical active area test was performed on the catalyst product provided in Example 4 of the present application, and a fuel cell was assembled and prepared using the catalyst product, and its single cell polarization curve was measured.

[0088] The results are as follows Figure 3 and Figure 4 As shown; among them, Figure 3 This is a test diagram of the electrochemical active area of ​​the catalyst product of Example 4. Figure 4 This is the polarization curve of a single cell.

[0089] As can be seen from the figure: the electrochemical area result of Example 4 is 81.90m 2 / g Pt The membrane electrode polarization performance result is 0.642V@2.0A·cm -2 , which is at the same level as the commercially available TANAKA company's TEC10E50E catalyst, indicating that the catalyst performance of the product of this application scheme can reach the top level in the market.

[0090] In summary, the present application embodiment provides a platinum-carbon catalyst and its preparation method and application, wherein ethylene glycol is used as a material solvent and a reaction reducing agent as a raw material, and no additional reducing agent or protective agent is required in the subsequent reaction production process, which helps to simplify the operation process and reduce the cost of process raw materials; its scheme simplifies the process steps, so that the mixing, dispersion and reaction of materials can be carried out in the same reaction equipment, thereby avoiding the loss and waste of materials due to slurry transfer, and also helps to ensure the quality of the product catalyst, and the obtained product platinum-carbon catalyst has good particle size uniformity, uniform dispersion, high catalytic performance and excellent quality. Its process flow and required equipment are simple, easy to operate, and help to improve production efficiency, and are more conducive to large-scale production of the process; its product catalyst has excellent performance, can be applied to the assembly and preparation of fuel cells, and has high application value.

[0091] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

Claims

1. A platinum-carbon catalyst, characterized in that The invention is prepared from raw materials including the following components: a carbon carrier, a platinum precursor, and ethylene glycol; wherein the ethylene glycol is used as a solvent and a reducing agent at the same time.

2. The platinum-carbon catalyst according to claim 1, characterized in that The carbon carrier is carbon black; the platinum precursor is hexahydrate chloroplatinic acid solution or platinum nitrate solution.

3. The platinum-carbon catalyst according to claim 2, characterized in that In the raw material components, the mass ratio of the ethylene glycol used to the carbon carrier is 400-500.

4. The platinum-carbon catalyst according to claim 1, characterized in that In the raw material components, the volume ratio of the platinum precursor to the ethylene glycol is 0.1-1.

5. The platinum-carbon catalyst according to claim 1, characterized in that The platinum content in the platinum-carbon catalyst is 20-50%.

6. A method for preparing a platinum-carbon catalyst as claimed in any one of claims 1 to 5, characterized in that: It includes the following steps: S1: heat treating the carbon support; S2: taking a platinum precursor, ethylene glycol, and a heat-treated carbon support, mixing, stirring, and ultrasonicating to obtain a mixed material; S3: adjusting the pH of the mixed material, and then raising the temperature to react; S4: filtering, washing, and drying the reactants in step S3 in sequence to obtain a product catalyst.

7. The method for preparing a platinum-carbon catalyst according to claim 6, characterized in that: In the step S1, the carbon carrier is heat-treated in an air or protective gas atmosphere by heating to 400-600° C. at a rate of 2-6° C. / min for 2-6 hours.

8. The method for preparing a platinum-carbon catalyst according to claim 6, characterized in that: In the step S3, alkali is added to the mixture to adjust the pH to 8-12, and then the temperature is raised to react.

9. The method for preparing a platinum-carbon catalyst according to claim 6, characterized in that: In the step S3, after adjusting the pH of the mixed material, the temperature is raised to 80-100° C. and reacted for 1-4 hours.

10. Use of the platinum-carbon catalyst according to any one of claims 1 to 5 in a fuel cell.

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