Boron-doped carbon carrier, boron-doped platinum-carbon catalyst, and preparation methods and applications of boron-doped carbon carrier and boron-doped platinum-carbon catalyst

Abstract

The invention relates to a boron-doped carbon carrier, a boron-doped platinum-carbon catalyst, and preparation methods and applications of the boron-doped carbon carrier and the boron-doped platinum-carbon catalyst. The preparation method of the boron-doped platinum-carbon catalyst comprises the following steps: mixing and grinding a porous carbon material and phenylboronic acid according to a mass ratio of 1: (1.5-6), and roasting in an inert atmosphere at 600-900 DEG C to obtain a boron-doped carbon carrier; and mixing the boron-doped carbon carrier with a platinum precursor solution, adding an alcoholic solution, adjusting the pH value to 7-8 by using alkali liquor, heating and reducing in an oil bath at 80 DEG C for 4 hours, and washing and drying to obtain a final product. According to the invention, the interaction between the platinum and the carbon carrier is enhanced through boron doping, the average particle size of platinum nanoparticles of the obtained platinum-carbon catalyst is 2-3 nm, and the platinum-carbon catalyst has the advantages of uniform dispersion, high hydrogen evolution activity, good stability and the like, and is especially suitable for proton exchange membrane water electrolysis cathode hydrogen evolution reaction.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of catalysts, and in particular, relates to a boron-doped carbon carrier, a boron-doped platinum-carbon catalyst, and a preparation method and application thereof. BACKGROUND

[0002] With the acceleration of global population growth and industrialization, energy demand continues to rise. Traditional fossil energy such as coal, oil and natural gas is non-renewable, and the consumption process is accompanied by a large amount of CO2 emission. In order to achieve the goal of carbon neutralization, the development of clean energy has become an urgent need. Water electrolysis hydrogen production technology is considered as the core component of future clean energy system due to its advantages of wide raw material sources, high hydrogen purity and environmental protection. At present, proton exchange membrane water electrolysis (PEMWE) technology has become the most promising hydrogen production route due to its high current density, fast response ability and excellent system integration. However, its large-scale application is still restricted by the performance bottleneck and cost problem of cathode hydrogen evolution reaction catalyst.

[0003] Commercial platinum-carbon catalysts, as a representative class of electrocatalysts, play a crucial role in contemporary energy conversion and storage due to their near-ideal hydrogen adsorption free energy. However, under actual water electrolysis conditions, platinum-carbon catalysts still face severe stability and cost challenges. First, in a strong acidic environment, platinum nanoparticles are prone to migration and aggregation, resulting in a decrease in active sites. Second, the carbon carrier will undergo electrochemical oxidation corrosion at high potentials, thereby destroying the structural stability of the catalyst and further accelerating the performance decay of the catalyst. In addition, the high price of platinum metal further restricts the economic feasibility of PEMWE technology.

[0004] To improve the performance of platinum-carbon catalysts and reduce costs, researchers have explored various modification strategies. In carbon-based catalysts, doping different non-metallic or metallic elements can effectively adjust the electronic structure and surface chemical properties of the carbon carrier, thereby optimizing its interaction with metal nanoparticles. This modification method not only enhances the stability of the catalyst, but also improves its intrinsic activity through electronic effects. Boron exhibits special modification potential due to its unique electronic properties and atomic size advantages. Boron atoms have a small atomic radius and high electronegativity, and the introduction of boron atoms can significantly change the electronic structure of carbon materials, enhancing their electronic interaction with platinum nanoparticles, thereby effectively inhibiting the migration and aggregation of platinum. In addition, boron doping can also improve the oxidation resistance of the carbon carrier.

[0005] Therefore, it is of great significance to develop an efficient, low-cost and environmentally friendly preparation method for boron-doped platinum-carbon catalysts to promote the development of water electrolysis hydrogen production technology. SUMMARY

[0006] The purpose of the embodiments of the present application is to solve the problems of the prior art, and provide a boron-doped carbon carrier, a boron-doped platinum-carbon catalyst, and a preparation method and application thereof. By using phenylboronic acid as an organic boron source, and through a simple grinding-pyrolysis process, uniform doping of boron atoms in various carbon carriers can be achieved. Then, platinum nanoparticles are loaded on the boron-doped carbon carrier, and a boron-doped platinum-carbon catalyst is obtained. By boron doping, the interaction between platinum and the carbon carrier is enhanced, the dispersion and stability of platinum particles are significantly improved, and high electrochemical activity is maintained.

[0007] To achieve the above-mentioned purposes, the embodiments of the present application first provide a preparation method of a boron-doped carbon carrier, which comprises the following steps: mixing and grinding a porous carbon material and phenylboronic acid at a mass ratio of 1:(1.5-6) until the particle size D50 of the mixture is ≤100 μm, and then calcining at 600-900℃ for 2-4 hours under the protection of an inert gas to obtain the boron-doped carbon carrier.

[0008] Further preferably, the porous carbon material is selected from one of Ketjen black ECP600JD, Ketjen black EC600JD, Ketjen black EC300J, and Cabot BP2000. Preferably, it is Ketjen black ECP600JD.

[0009] Further preferably, the heating rate of the calcination is 3-8℃ / min.

[0010] Further preferably, the grinding uses mechanical grinding, and a ball mill or an agate mortar is used in the mechanical grinding. When manual grinding is performed using an agate mortar, the grinding time is not less than 40 min. When grinding is performed using a ball mill, the volume ratio of balls to materials is 1:3, the rotation speed is 400 rpm, and the grinding time is not less than 30 min.

[0011] Another purpose of the present application is to provide a boron-doped carbon carrier prepared by the above method. In the boron-doped carbon carrier, boron elements are mainly doped in the carbon skeleton in the form of chemical bonding, the atomic percentage content of boron elements is 6-11at%, and the specific surface area of the boron-doped carbon carrier is 900-1500 m 2 / g.

[0012] A further object of the present application is to provide a method for preparing a high-performance platinum-carbon catalyst using the above-mentioned boron-doped carbon carrier, which is not dependent on a specific type of carbon carrier or platinum precursor and has wide process compatibility. The method comprises the following steps: preparing a boron-doped carbon carrier by the method described above; and loading platinum nanoparticles on the boron-doped carbon carrier, wherein the method for loading the platinum nanoparticles is a liquid-phase reduction method, which comprises: mixing and dispersing the boron-doped carbon carrier with a platinum precursor solution, adding an alcohol solution, adjusting the pH to 7-10 with a lye, heating to reduce the metal precursor, and performing filtration, washing, and drying treatment on the product after heating reaction to obtain the boron-doped platinum-carbon catalyst.

[0013] Further preferably, the heating and reduction of the metal precursor refers to heating and reduction at 70-90℃ for 3-5 hours.

[0014] Further preferably, the heating and reduction of the metal precursor refers to oil bath heating, and the oil bath heating temperature is 80℃, and the heating time is 4 h.

[0015] Further preferably, the platinum precursor is at least one of chloroplatinic acid, platinum tetrachloride, and potassium chloroplatinate, and is preferably chloroplatinic acid.

[0016] Further preferably, the alcohol solution is at least one of ethylene glycol, ethanol, and glycerol, and the volume ratio of alcohol to water is 1:1.

[0017] Further preferably, the platinum loading amount can be controlled by adjusting the amount of platinum precursor, and the platinum loading amount is 10%-40%, and a typical value is 20%.

[0018] Further preferably, the lye is a sodium hydroxide solution or a potassium hydroxide solution.

[0019] Further preferably, the mixing and dispersing of the boron-doped carbon carrier and the platinum precursor solution is performed by stirring and ultrasonic dispersion, wherein the stirring time is 10 min, and the ultrasonic time is 30 min.

[0020] Further preferably, the washing solution in the above-mentioned step is an aqueous solution, and the washing number is 6-8 times.

[0021] Further preferably, the drying temperature in the above-mentioned step is 50-80℃, and the drying time is 10-14 h.

[0022] A further object of the present application is to provide a boron-doped platinum-carbon catalyst prepared by the above-mentioned method, which comprises a boron-doped carbon carrier and platinum nanoparticles loaded thereon.

[0023] Further preferably, the boron-doped platinum-carbon catalyst has a specific surface area of 10 mA·cm -2The hydrogen evolution overpotential under a current density is less than or equal to 85.2 mV, and the electrochemical mass activity is greater than or equal to 0.135 A mg -1 Pt; the platinum loading in the boron-doped platinum carbon catalyst is 20 wt%, and the average particle size of the platinum particles is 2-3 nm.

[0024] In addition, the application also provides an application of the catalyst in a hydrogen evolution reaction of a proton exchange membrane electrolysis water cathode.

[0025] Compared with the prior art, the application has the following remarkable advantages: 1. The application uses phenylboronic acid as a green boron source, and realizes uniform carbon support boron doping through high-temperature chemical bonding, thereby significantly enhancing the interface interaction between the carbon support and the active component.

[0026] 2. The application uses a liquid-phase reduction method, and ethylene glycol is used as a solvent and a reducing agent at the same time, so that the preparation process is green and safe, the operation process is simple, large-scale continuous production is suitable, and the cost is effectively reduced, thereby providing new inspiration for the hydrogen production industry by electrolysis of water.

[0027] 3. The nanoparticle size of the platinum carbon catalyst prepared by the application is 2-3 nm, and the boron doping improves the catalytic activity of the catalyst, thereby realizing higher efficiency and better stability in the process of electrolysis of water. BRIEF DESCRIPTION OF DRAWINGS

[0028] The above features and advantages of the application will become more apparent and easily understood from the following description of exemplary embodiments thereof in conjunction with the accompanying drawings.

[0029] Figure 1 A schematic diagram of a boron-doped platinum carbon catalyst preparation method; Figure 2 A Fourier transform infrared spectroscopy (FTIR) diagram of the boron-doped carbon support prepared in Example 1 of the application; Figure 3 An X-ray diffraction (XRD) spectrum of the boron-doped carbon support prepared in Example 1 of the application; Figure 4 A nitrogen adsorption / desorption curve and pore size distribution diagram of the boron-doped carbon support prepared in Example 1 of the application; Figure 5 XRD diagrams of platinum carbon catalysts with different boron doping ratios prepared in Examples 1-3 of the application. DETAILED DESCRIPTION

[0030] The following will be described by specific embodiments of the present application, familiar with the skilled person can easily understand the advantages and effects of the present application from the disclosure of the present application, it is clear that the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of the present application.

[0031] Example 1: (1) 0.5 g of Ketjenblack ECP600JD carbon powder and 0.75 g of phenylboronic acid were weighed and mixed, and then ground in a marquetry mortar for 40 min. After grinding, the mixture was tested by a laser particle size analyzer, and the particle size distribution D50 was measured to be 52 μm. The obtained uniform mixture was transferred to a porcelain boat and placed in a tube furnace under an inert gas protection atmosphere, heated to 600℃ at a heating rate of 5℃ / min, and kept at constant temperature for 3 h. After cooling to room temperature, the boron-doped carbon carrier was obtained, denoted as 1.5B@ECP600.

[0032] (2) 0.5 g of the boron-doped carbon powder in step (1) was weighed in a 500 mL three-necked round-bottom flask, 80 mL of deionized water was added, and after stirring for 10 min, it was placed in an ultrasonic cleaner for 30 min to uniformly disperse the carbon powder in water.

[0033] (3) 334 mg of chloroplatinic acid was weighed in a beaker, 20 mL of deionized water was added, and after ultrasonic treatment for 3 min to make the solution uniform, it was poured into the carbon powder solution in step (2), and stirred for 4 h to make the mixture uniform.

[0034] (4) 100 mL of ethylene glycol was added to the mixed solution in step (3), and after stirring for 15 min, 160 μL of 5 mol / L NaOH solution was added.

[0035] (5) The reaction system in step (4) was placed in an oil bath, heated at 80℃ for 4 h, and then cooled to room temperature and washed with deionized water for 6 times.

[0036] (6) The product was placed in a drying oven, dried at 60℃ for 14 h, then taken out, ground into powder with a mortar, and collected for use.

[0037] Example 2: (1) Take 0.5 g of Ketjen black ECP600JD carbon powder and 1.5 g of phenylboronic acid, mix and grind using a ball mill, with a ball-to-material volume ratio of 1:3, a rotation speed of 400 rpm, and a grinding time of 0.5 hours. After grinding, the mixture is tested using a laser particle size analyzer, and the particle size distribution D50 is measured to be 49 μm. The obtained uniform mixture is transferred to a porcelain boat and placed in a tube furnace under an inert gas protection atmosphere, heated to 600°C at a heating rate of 5°C / min, and kept at a constant temperature for 3 hours. After cooling to room temperature, a boron-doped carbon carrier is obtained, which is recorded as 3B@ECP600.

[0038] In this step, the particle size of the mixture after mixing and grinding of the carbon powder and phenylboronic acid needs to meet certain requirements: first, smaller particle size leads to more uniform mixing, which increases the uniformity of boron doping of the subsequently generated carrier; second, it improves the specific surface area of the subsequently generated carrier. The grinding step is not limited to the technical means adopted in Examples 1 and 2, and various existing physical crushing techniques can also be used. According to practice, the particle size of the mixture after mixing and grinding of the carbon powder and phenylboronic acid should meet D50≤100 μm, and on this basis, those skilled in the art can choose the grinding means and the fineness of grinding according to their own conditions and needs.

[0039] (2) Take 0.5 g of the boron-doped carbon powder in step (1) into a 500 mL three-necked round-bottom flask, add 80 mL of deionized water, stir for 10 min, and then place it in an ultrasonic cleaner for 30 min to uniformly disperse the carbon powder in water.

[0040] (3) Take 334 mg of chloroplatinic acid into a beaker, add 20 mL of deionized water, and ultrasonic for 3 min until the solution is uniform. Then pour it into the carbon powder solution in step (2) and stir for 4 h to make the mixture uniform.

[0041] (4) Add 100 mL of ethylene glycol to the mixed solution in step (3), stir for 15 min, and then add 170 μL of NaOH solution with a molar concentration of 5 mol / L.

[0042] (5) Place the reaction system in step (4) in an oil bath, heat at 80°C for 4 h, and then cool to room temperature and wash with deionized water for 6 times.

[0043] (6) Place the product in a drying box, dry at 60°C for 14 h, then grind into powder using a mortar and collect for use.

[0044] Example 3: (1) 0.5 g of Ketjenblack ECP600JD carbon powder and 3 g of phenylboronic acid were mixed and ground in a marver for 40 min. After grinding, the mixture was tested by a laser particle size analyzer, and the particle size distribution D50 was measured to be 45 μm. The obtained uniform mixture was transferred into a porcelain boat and heated to 600°C in a tube furnace under an inert gas atmosphere, with a heating rate of 5°C / min and a constant temperature time of 3 h. After cooling to room temperature, a boron-doped carbon carrier was obtained, which was recorded as 6B@ECP600.

[0045] (2) 0.5 g of the boron-doped carbon powder in step (1) was weighed into a 500 mL three-necked round-bottom flask, 80 mL of deionized water was added, and after stirring for 10 min, it was placed in an ultrasonic cleaner for ultrasonic treatment for 30 min to uniformly disperse the carbon powder in water.

[0046] (3) 334 mg of chloroplatinic acid was weighed into a beaker, 20 mL of deionized water was added, and after ultrasonic treatment for 3 min to make the solution uniform, it was poured into the carbon powder solution in step (2) and stirred for 4 h to make the mixture uniform.

[0047] (4) 100 mL of ethylene glycol was added to the mixed solution in step (3), and after stirring for 15 min, 180 μL of a 5 mol / L NaOH solution was added.

[0048] (5) The reaction system in step (4) was placed in an oil bath, heated at 80°C for 4 h, and after cooling to room temperature, it was washed with deionized water for 6 times.

[0049] (6) The product was placed in a drying box and dried at 60°C for 14 h, then taken out, ground into powder with a mortar, and collected for use.

[0050] Comparative Example 1: (1) 0.5 g of Ketjenblack ECP600JD carbon powder was weighed into a 500 mL three-necked round-bottom flask, 80 mL of deionized water was added, and after stirring for 10 min, it was placed in an ultrasonic cleaner for ultrasonic treatment for 30 min to uniformly disperse the carbon powder in water.

[0051] (2) 334 mg of chloroplatinic acid was weighed into a beaker, 20 mL of deionized water was added, and after ultrasonic treatment for 3 min to make the solution uniform, it was poured into the carbon powder solution in step (1) and stirred for 4 h to make the mixture uniform.

[0052] (3) 100 mL of ethylene glycol was added to the mixed solution in step (2), and after stirring for 15 min, 150 μL of a 5 mol / L NaOH solution was added.

[0053] (4) The reaction system in step (3) was placed in an oil bath, heated at 80°C for 4 h, and after cooling to room temperature, it was washed with deionized water for 6 times.

[0054] (5) The product was placed in a drying oven, dried at 60°C for 14 h, then taken out, ground into powder with a mortar, and collected for use.

[0055] Comparative Example 2: (1) 0.5 g Cabot BP2000 carbon powder was weighed into a 500 mL three-necked round-bottom flask, 80 mL deionized water was added, stirred for 10 min, and then placed in an ultrasonic cleaner for ultrasonic treatment for 30 min to uniformly disperse the carbon powder in the water.

[0056] (2) 334 mg chloroplatinic acid was weighed into a beaker, 20 mL deionized water was added, and ultrasonic treatment was performed for 3 min until the solution was uniform, then poured into the carbon powder solution of step (1), and stirred for 4 h to make the mixture uniform.

[0057] (3) 100 mL ethylene glycol was added to the mixed solution in step (2), stirred for 15 min, and then 150 μL of a 5 mol / L NaOH solution was added.

[0058] (4) The reaction system in step (3) was placed on an oil bath, heated at 80°C for 4 h, and then cooled to room temperature and washed with deionized water 6 times.

[0059] (5) The product was placed in a drying oven, dried at 60°C for 14 h, then taken out, ground into powder with a mortar, and collected for use.

[0060] Figure 1 The figure is a schematic diagram of the preparation method of the boron-doped platinum-carbon catalyst. First, the boron-doped carbon carrier prepared is characterized. XPS quantitative analysis confirms that the boron element has been successfully doped into the carbon matrix, and as the ratio of phenylboronic acid in the precursor increases from 1:1.5 to 1:6, the proportion of boron atoms in the carrier also increases (Table 1). Figure 2 The FTIR spectrum of the relevant sample in Example 1 provides evidence for the chemical bonding of boron atoms observed in the doped carrier. Combined with the XRD spectrum of Figure 3 , the results show that the doped carbon carrier maintains similar structural characteristics to the original carrier, and the main diffraction peaks do not change significantly, proving that the doping process used in the present application effectively avoids the destruction of the carbon skeleton structure by high temperature while introducing boron elements, successfully maintaining the basic integrity of the carbon skeleton, providing stable support for subsequent loading of platinum metal.

[0061]

[0062] Further analysis of the pore structure of the prepared carbon carrier, Figure 4The nitrogen adsorption desorption curve and pore size distribution graph of the boron-doped carbon carrier prepared in Example 1 of the present application are shown in Table 1. The test results show that the specific surface area of the doped carbon carrier is slightly lower than that of the original carrier, but still remains at a high level. Based on the above analysis, the preparation method provided by the present application can effectively dope boron without significantly sacrificing the structural characteristics of the carbon carrier.

[0063] Based on the boron-doped carbon carrier, the structure of the boron-doped platinum carbon catalyst prepared in the examples was characterized and its performance was evaluated. Figure 5 The XRD diffraction pattern of the prepared catalyst sample is shown in Table 2. All samples show typical platinum crystal diffraction peaks, which are consistent with the structural characteristics of platinum carbon catalysts. The average particle size of the nanoparticles is in the range of 2-3 nm. The synthesized catalysts were also tested for electrochemical performance. The average particle size of the catalysts prepared in Examples 1-3 and the detailed results of the electrochemical tests are as follows:

[0064] The boron doping enhances the electronic interaction between platinum and the carbon carrier, effectively inhibits the migration and agglomeration of platinum precursors during the reduction process, and is conducive to the formation of smaller and more uniform active sites. As can be seen from Table 2, the platinum carbon catalysts synthesized after doping boron can maintain an average particle size of less than 3 nm, and their catalytic performance and stability after 2000 cycles of durability test are better than those of the undoped catalysts.

[0065] The above embodiments are used to illustrate the inventive intent and embodiments of the present application, but those skilled in the art can understand that the above embodiments of the present application are only one of the preferred embodiments of the present application. Due to the limited space, all embodiments cannot be listed one by one, and any embodiment that can embody the technical solution of the claims of the present application is within the protection scope of the present application.

[0066] It should be noted that the above content is a further detailed description of the present application in combination with specific embodiments, and cannot be limited to the specific embodiments of the present application. Based on the above examples, those skilled in the art can make various improvements and modifications on the basis of the above examples, and these improvements or modifications fall within the protection scope of the present application.

Claims

1. A method for preparing a boron-doped carbon support, characterized in that, Includes the following steps: Porous carbon material and phenylboronic acid are mixed and ground at a mass ratio of 1:(1.5~6) until the particle size D50 of the mixture is ≤100 μm. Then, under inert gas protection, the mixture is calcined at 600~900℃ for 2~4 hours to obtain the boron-doped carbon support.

2. The method for preparing a boron-doped carbon support as described in claim 1, characterized in that: The porous carbon material is selected from one of Ketjen Black ECP600JD, Ketjen Black EC600JD, Ketjen Black EC300J, and Cabot BP2000.

3. The method for preparing a boron-doped carbon support as described in claim 1, characterized in that: The heating rate for roasting is 3~8℃ / min.

4. A boron-doped carbon support, characterized in that: Prepared by the method according to any one of claims 1-3, wherein boron is mainly doped into the carbon framework in the form of chemical bonding, the atomic percentage content of boron is 6-11 at%, and the specific surface area of ​​the boron-doped carbon support is 900-1500 m². ² / g.

5. A method for preparing a boron-doped platinum-carbon catalyst, characterized in that, Includes the following steps: Boron-doped carbon supports are prepared using the method described in any one of claims 1-3; Platinum nanoparticles are loaded onto the boron-doped carbon support. The method for loading the platinum nanoparticles is a liquid-phase reduction method, which includes: mixing and dispersing the boron-doped carbon support with a platinum precursor solution, adding an alcohol solution, adjusting the pH to 7-10 with an alkaline solution, heating to reduce the metal precursor, and filtering, washing and drying the product after the heating reaction to obtain the boron-doped platinum carbon catalyst.

6. The method for preparing a boron-doped platinum-carbon catalyst as described in claim 5, characterized in that: The metal precursor for heating and reduction refers to a metal precursor that has been heated and reduced at 70-90°C for 3-5 hours; the platinum precursor is at least one of chloroplatinic acid, platinum tetrachloride, and potassium chloroplatinate; the alcohol solution is at least one of ethylene glycol, ethanol, and glycerol, and the volume ratio of alcohol to water is 1:1; the alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution.

7. A boron-doped platinum-carbon catalyst, characterized in that, The boron-doped platinum-carbon catalyst prepared by the method described in claim 5 or 6 includes a boron-doped carbon support and platinum nanoparticles supported thereon.

8. The boron-doped platinum-carbon catalyst according to claim 7, characterized in that: The boron-doped platinum-carbon catalyst was subjected to 10 mA·cm⁻¹ -2 The hydrogen evolution overpotential at current density is ≤85.2 mV, and its electrochemical activity is ≥0.135 A mg. -1 The boron-doped platinum-carbon catalyst has a platinum loading of 20 wt% and an average platinum particle size of 2-3 nm.

9. The application of the boron-doped platinum-carbon catalyst as described in claim 7 in the hydrogen evolution reaction at the cathode of proton exchange membrane water electrolysis.

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