Mesoporous carbon carrier and preparation method thereof
By preparing mesoporous carbon supports using template methods and processing techniques, the problems of catalyst agglomeration and support corrosion in fuel cells were solved, the catalyst loading and stability were improved, and the mass transfer process of electrochemical reactions was promoted.
Patent Information
- Application Number
- CN202511158687.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-19
- Publication Date
- 2025-11-18
AI Technical Summary
The low specific surface area and simple pore structure of carbon black supports in existing fuel cells lead to easy agglomeration of catalyst particles, low utilization of active sites, and severe corrosion of carbon supports during long-term operation, affecting the durability of the battery. The chemical inertness of traditional mesoporous carbon makes the interaction between the catalyst and the support weak, making it difficult to achieve efficient loading and firm anchoring.
Mesoporous carbon supports were prepared using a template method. By mixing sulfur-containing compounds, templates, and activators, and combining alkali and acid treatments, the pore structure and sulfur doping amount were controlled to prepare mesoporous carbon supports with excellent specific surface area, ensuring uniform distribution of sulfur atoms and enhancing the interaction between the support and the catalyst.
This improved the catalyst loading on the mesoporous carbon support, enhanced the catalyst's activity and stability, promoted mass transfer in the electrochemical reaction, and enabled the industrial production of the mesoporous carbon support.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of fuel cells, in particular to a mesoporous carbon carrier and a preparation method thereof. BACKGROUND
[0002] As a kind of high-efficiency, clean energy conversion device, fuel cell has broad application prospects in new energy vehicles, distributed power generation and other fields due to its zero emission, high energy density and other advantages. At present, carbon black is widely used as the carrier of platinum-based catalyst in commercial fuel cells, but it has problems such as low specific surface area and single pore structure, which leads to easy agglomeration of catalyst particles, low utilization rate of active sites, and serious corrosion of carbon carrier in long-term operation, which seriously restricts the durability of the cell.
[0003] In recent years, mesoporous carbon materials are considered as ideal catalyst carrier candidate materials due to their high specific surface area, adjustable pore size distribution and good electrical conductivity. However, the chemical inertness of traditional mesoporous carbon makes the interaction between the carrier and the catalyst particles weak, and it is difficult to achieve efficient loading and firm anchoring of the catalyst. Sulfur doping can change the electronic structure of carbon materials by introducing heteroatoms, enhance the electronic interaction between the carrier and the catalyst, and at the same time, sulfur atoms can act as anchoring sites to inhibit the migration and shedding of metal particles, thereby improving the catalytic activity and stability. However, existing sulfur doping technologies are mostly based on post-treatment modification of existing carriers, which have problems such as uneven doping, difficult control of sulfur content, difficult adjustment of pore size, and easy collapse of mesoporous structure.
[0004] In summary, it is of great significance to develop a mesoporous carbon carrier material with simple process, controllable cost and uniform sulfur doping for promoting the performance improvement and commercial application of fuel cell catalysts. SUMMARY
[0005] In view of the above problems of the prior art, the present application provides a mesoporous carbon carrier and a preparation method thereof. The specific technical solutions are as follows: On the one hand, the present application provides a preparation method of a mesoporous carbon carrier, which comprises: S1: providing a sulfur-containing compound, a template, an activating agent and a solvent; S2: adding the sulfur-containing compound, the template and the activating agent into the solvent according to a predetermined mass ratio, stirring to obtain a mixed solution; S3: evaporating the liquid in the mixed solution to obtain a mixed powder; S4: grinding the mixed powder and performing heat treatment under an inert atmosphere to obtain a pretreated powder; S5: alkali treatment, acid treatment and drying of the pretreated powder to obtain a mesoporous carbon carrier.
[0006] In a possible implementation, a preset mass ratio of the sulfur-containing compound, the template and the activating agent is 1-4: 1-4: 0.5-2.
[0007] In a possible implementation, a solid content in the mixed solution is 20-50 mg / mL.
[0008] In a possible implementation, the sulfur-containing compound includes at least one of thiophene, 2,2'-bithiophene, benzothiophene and thioamide.
[0009] In a possible implementation, the template is silicon dioxide, and the silicon dioxide satisfies at least one of the following characteristics: A particle size of the silicon dioxide is 5-50 nm; A silicon content of the silicon dioxide is 99.5%-100%.
[0010] In a possible implementation, the solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran and acetone.
[0011] In a possible implementation, the heat treatment satisfies at least one of the following characteristics: A temperature of the heat treatment is 650-850 ℃; A time of the heat treatment is 1.5-3 h.
[0012] In a possible implementation, the alkali solution used in the alkali treatment includes at least one of a sodium hydroxide solution and a potassium hydroxide solution.
[0013] In a possible implementation, a concentration of the alkali solution is 1-3 mol / L.
[0014] In a possible implementation, a temperature of the alkali treatment is 60-90 ℃.
[0015] In a possible implementation, a time of the alkali treatment is 48-96 h.
[0016] In a possible implementation, the acid solution used in the acid treatment includes at least one of a sulfuric acid solution, a hydrochloric acid solution and a nitric acid solution.
[0017] In a possible implementation, a concentration of the acid solution is 0.1-1 mol / L.
[0018] In a possible implementation, a temperature of the acid treatment is 60-90 ℃.
[0019] In a possible implementation, a time of the acid treatment is 6-24 h.
[0020] In another aspect, the present application further provides a mesoporous carbon carrier prepared by the preparation method according to any one of the above.
[0021] Based on the above technical solution, the present application has the following beneficial effects: The present application adopts a template method to prepare mesoporous carbon carriers. By adding sulfur-containing compounds, templates and activating agents into solvents in a predetermined mass ratio and mixing, the pore structure, specific surface area and sulfur content of the carbon carrier can be controlled and designed under the joint action of the templates and activating agents. Through alkaline treatment and acid treatment, the templates and activating agents can be removed, and mesoporous carbon carriers with excellent specific surface area can be prepared, which helps to increase the loading amount of metal particles on the mesoporous carbon carrier, and the good pore structure can also promote the mass transfer in the electrochemical reaction process. Through the preparation method provided by the present application, the sulfur atoms can be uniformly distributed in the mesoporous carbon carrier, and the uniformly doped sulfur atoms can help to strengthen the interaction between the mesoporous carbon carrier and the metal particles, enhance the anchoring capacity of the mesoporous carbon carrier to the metal particles, and thus improve the activity and stability of the catalyst. The preparation method provided by the present application has simple steps, and the finished product prepared has good consistency, which is conducive to the industrial production of mesoporous carbon carriers. BRIEF DESCRIPTION OF DRAWINGS
[0022] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0023] Figure 1 The flowchart of the preparation method of the mesoporous carbon carrier provided by the embodiments of the present application is shown in the figure. Figure 2 The pore size distribution curve of the mesoporous carbon carrier provided by Embodiment 1 of the present application is shown in the figure. Figure 3 The cyclic voltammograms of a platinum-carbon catalyst provided by Embodiment 1 of the present application before and after 30000 cycles are shown in the figure. Figure 4 The linear sweep voltammograms of a platinum-carbon catalyst provided by Embodiment 1 of the present application before and after 30000 cycles are shown in the figure. DETAILED DESCRIPTION
[0024] 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. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.
[0025] It should be noted that, in the description of this application, the following definitions shall apply unless a different definition is given elsewhere in the claims or this specification. All numerical values, whether or not explicitly indicated, are defined herein as being modified by the term "about". The term "about" generally refers to a range of numerical values that a person skilled in the art would consider equivalent to the stated values to produce substantially the same properties, functions, results, etc. A range of numerical values indicated by a low value and a high value is defined as including all numerical values within that range and all subranges included within that range.
[0026] It should be noted that in the description of this application, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.
[0027] The following combination Figure 1 This application describes a method for preparing a mesoporous carbon support. The specification provides the method steps as described in the embodiments, but based on conventional or non-inventive methods, more or fewer steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only possible order. In actual implementation, the preparation method can be performed in the order shown in the embodiments or accompanying drawings, or in parallel. The method for preparing the mesoporous carbon support may include S1-S5: S1: Provides sulfur-containing compounds, templates, activators, and solvents; In a possible implementation, the sulfur-containing compound can be an organic compound containing sulfur-carbon bonds. Using an organic compound containing sulfur-carbon bonds to prepare a mesoporous carbon support can allow sulfur atoms to be embedded in the carbon lattice during the preparation process, so that the sulfur doping sites are uniformly distributed in the pores of the mesoporous carbon support in the finished product; and stable sulfur bonds can be formed during subsequent heat treatment, which is beneficial to increasing the sulfur doping content.
[0028] Specifically, the sulfur-containing compound includes at least one of thiophene, 2,2'-bithiophene, benzothiophene and thioamide. The mesoporous carbon carrier is prepared by using thiophene, which is conducive to constructing a high-conductivity thiophene-sulfur doped skeleton. After heat treatment, the sulfur atoms can be embedded in the carbon lattice to provide high-stable lattice sulfur doping, which is conducive to improving the conductivity of the mesoporous carbon carrier; 2,2'-bithiophene has double sulfur doping sites, which can enhance the anchoring effect of sulfur atoms; the benzene ring in benzothiophene can promote the generation of micropores, and the thiophene sulfur can release gas to form mesopores, which is conducive to preparing a mesoporous carbon carrier with high specific surface area; thioamide can be activated at a lower temperature, which is conducive to improving the preparation efficiency.
[0029] In a possible implementation, the template can be silica. Silica has high chemical stability during high-temperature carbonization process and will not react with carbon or decompose at high temperature. Moreover, silica can be removed by simple chemical etching, which is conducive to ensuring high purity of the mesoporous carbon carrier product. Understandably, the template material can be other materials with chemical stability, thermal stability and easy removal.
[0030] In a possible implementation, granular silica is used as a template to form a mesoporous template through the stacking gap between silica particles, which is used to prepare a mesoporous carbon carrier with disordered channels. Moreover, the granular silica has a high specific surface area, and using granular silica as a template is conducive to improving the specific surface area of the mesoporous carbon carrier product.
[0031] Specifically, the particle size of the silica is 5-50 nm. Understandably, the particle size of the silica can be any point value in the range of 5-50 nm. For example, the particle size of the silica can be 5 nm, 10 nm, 20 nm, 40 nm, 50 nm, etc. Preferably, the particle size of the silica is 20-30 nm. The particle size of the granular template directly affects the pore wall thickness of the mesoporous carbon material. Controlling the particle size of the silica in the above range can ensure the mechanical strength of the pore wall of the mesoporous carbon carrier and avoid compression of the pore volume due to too thick pore wall. If the particle size of the silica is less than the above range, the silica particles are prone to agglomeration, which cannot form uniform pores. If the particle size of the silica is greater than the above range, the specific surface area of the template decreases, which further leads to a smaller specific surface area of the mesoporous carbon carrier.
[0032] Specifically, the silicon content of the silicon dioxide is 99.5%-100%; it can be understood that the silicon content of the silicon dioxide can be any point value in 99.5%-100%; for example, the silicon content of the silicon dioxide can be 99.5%, 99.6%, 99.7%, 99.8%, 100%, etc. In this way, the silicon content of the silicon dioxide is controlled within the above range, the silicon dioxide has high purity, and the silicon dioxide can be completely removed in the subsequent alkali treatment process, avoiding that a large amount of impurities contained in the template are difficult to remove in the subsequent preparation process and are left in the carbon material, affecting the stability of the mesoporous carbon carrier.
[0033] In a possible implementation, the activator is used to promote the polymerization of the sulfur-containing compound; specifically, the activator can be cobalt nitrate hexahydrate, which can catalyze the decomposition and sulfuration reaction of the sulfur-containing compound in the subsequent heat treatment process, and is conducive to the construction of the sulfur-doped system.
[0034] In a possible implementation, the solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran, and acetone. The use of the above solvent can effectively disperse the sulfur-containing compound, the template, and the activator, so that the components are fully mixed and uniformly dispersed in the solvent, and the above solvent has a relatively low boiling point, facilitating the solvent evaporation step in the subsequent preparation process at a relatively low temperature.
[0035] S2: The sulfur-containing compound, the template, and the activator are added to the solvent in a preset mass ratio, and are stirred to obtain a mixed solution; Specifically, the stirring is used to uniformly disperse the sulfur-containing compound, the template, and the activator in the mixed solution, which is conducive to forming the mesoporous carbon carrier with uniform pores.
[0036] In a possible implementation, the preset mass ratio of the sulfur-containing compound, the template, and the activator is 1-4:1-4:0.5-2; it can be understood that the preset mass ratio of the sulfur-containing compound, the template, and the activator can be any point value in 1-4:1-4:0.5-2; for example, the preset mass ratio of the sulfur-containing compound, the template, and the activator is 1:1:2, 1:1:1, 2:1:1, 1:2:1, 4:4:0.5, etc. In this way, the preset mass ratio is controlled within the above range, which can effectively control the structure of the mesoporous carbon carrier, avoid that the low content of the template leads to the reduction of the specific surface area of the mesoporous carbon carrier, and at the same time, avoid that the high content of the template leads to the low carbon content of the mesoporous carbon carrier, which is difficult to be formed; and avoid that the high content of the activator leads to the agglomeration of the sulfur-containing compound, and the low content of the activator leads to the failure of the polymerization of the sulfur-containing compound. It can be understood that within the above range, the preset mass ratio can be adjusted according to the specific surface area and the sulfur-doped content required by the actual application of the mesoporous carbon carrier.
[0037] In a possible implementation, the solid content in the mixed solution is 20-50 mg / mL; it can be understood that the solid content in the mixed solution can be any point value in the range of 20-50 mg / mL; for example, the solid content in the mixed solution can be 20 mg / mL, 25 mg / mL, 30 mg / mL, 40 mg / mL, 50 mg / mL, etc. In this way, controlling the solid content in the mixed solution in the above range is conducive to the dispersion of the solid raw material in the solvent, and facilitates the removal of the solvent in the subsequent preparation step.
[0038] S3: evaporating the liquid in the mixed solution to obtain a mixed powder; In a possible implementation, step S3 includes: evaporating the liquid in the mixed solution by rotary evaporation to obtain a mixed powder. In this way, the solvent can be removed gently by rotary evaporation to inhibit the oxidation and hydrolysis of the sulfur-containing compound; during the rotary evaporation, the components in the mixed solution can be uniformly dispersed to effectively prevent the separation of the template and the sulfur-containing compound to generate pore defects.
[0039] S4: grinding the mixed powder and performing heat treatment in an inert atmosphere to obtain a pretreated powder; Specifically, by grinding the mixed powder, nanoscale particles are obtained, which is conducive to improving the specific surface area of the mesoporous carbon carrier; and by grinding, the finely dispersed mixed powder can be dispersed again to avoid the local aggregation of the template material and the sulfur-containing compound, so that the sulfur atoms are uniformly embedded in the carbon skeleton, which is conducive to forming connected pores in the mesoporous carbon carrier.
[0040] In a possible implementation, the inert atmosphere includes one or more of a nitrogen atmosphere and an argon atmosphere, to avoid the reaction of the mixed powder with oxygen during the heat treatment, while avoiding the introduction of impurities into the pretreated powder.
[0041] In a possible implementation, the temperature of the heat treatment is 650-850°C; it can be understood that the temperature of the heat treatment can be any point value in the range of 650-850°C; for example, the temperature of the heat treatment can be 650°C, 700°C, 750°C, 800°C, 850°C, etc. The heat treatment can cause the pretreated powder to be carbonized, in which the sulfur-containing compound is crosslinked to form a rigid carbon skeleton structure, and the sulfur atoms are embedded in the carbon skeleton to form a stable sulfur-doped structure. Controlling the temperature of the heat treatment in the above range can avoid the collapse of the mesoporous structure and the breakage of the sulfur-carbon bond caused by excessively high temperature, which affects the specific surface area and sulfur-doped content of the mesoporous carbon carrier; at the same time, it can avoid the insufficient carbonization caused by excessively low temperature, which affects the conductivity of the carbon carrier.
[0042] In a possible implementation, the heat treatment time is 1.5-3 hours; it can be understood that the heat treatment time can be any point value in the range of 1.5-3 hours; for example, the heat treatment time can be 1.5 hours, 2 hours, 2.3 hours, 2.5 hours, 3 hours, etc. Controlling the heat treatment time in the above range can avoid incomplete carbonization of the pretreated powder due to insufficient heat treatment time, while avoiding collapse of the mesoporous structure due to excessive heat treatment time.
[0043] S5: performing alkali treatment, acid treatment, and drying on the pretreated powder to obtain a mesoporous carbon carrier.
[0044] In a possible implementation, step S5 includes: performing alkali washing on the pretreated powder, filtering, and cleaning the first solid obtained by filtering, repeating the cleaning step until the conductivity of the first filtrate is less than a preset conductivity, to obtain an alkali-treated powder; performing acid washing on the alkali-treated powder, filtering, and cleaning the second solid obtained by filtering, repeating the cleaning step until the conductivity of the second filtrate is less than the preset conductivity, to obtain an acid-treated powder; and drying the acid-treated powder to obtain the mesoporous carbon carrier.
[0045] Specifically, the preset conductivity is 10 us / cm, and the preset conductivity is used to indicate the cleaning degree of the pretreated powder and the acid-treated powder. When the conductivity of the first filtrate is less than 10 us / cm, it is proved that the alkali solution on the first solid has been completely removed. When the conductivity of the second filtrate is less than 10 us / cm, it is proved that the acid solution on the second solid has been completely removed.
[0046] In a possible implementation, the alkali solution used in the alkali treatment includes at least one of a sodium hydroxide solution and a potassium hydroxide solution. Silicon dioxide can react with strong alkali to generate soluble silicate and water, and therefore, using the above alkali solution can remove silicon dioxide in the pretreated powder to remove the template and retain the pore structure.
[0047] In a possible implementation, the concentration of the alkali solution is 1-3 mol / L; it can be understood that the concentration of the alkali solution can be any point value in the range of 1-3 mol / L; for example, the concentration of the alkali solution can be 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, etc. Controlling the concentration of the alkali solution in the above range can effectively remove the template, avoid corrosion of the mesoporous carbon carrier structure due to too high concentration of the alkali solution, and avoid residual template blocking the mesoporous structure due to too low concentration of the alkali solution.
[0048] In possible implementation, the temperature of the alkali treatment is 60-90℃; it can be understood that the temperature of the alkali treatment can be any point value in 60-90℃; for example, the temperature of the alkali treatment can be 60℃, 65℃, 70℃, 80℃, 90℃, etc. Controlling the temperature of the alkali treatment in the above range can promote the reaction of the alkali solution and the template and effectively improve the reaction rate.
[0049] In possible implementation, the time of the alkali treatment is 48-96h; it can be understood that the time of the alkali treatment can be any point value in 48-96h; for example, the time of the alkali treatment can be 48h, 50h, 60h, 70h, 85h, 96h, etc. Controlling the time of the alkali treatment in the above range can ensure that the template is completely reacted with the alkali solution and avoid the influence of the residual template on the mesoporous structure.
[0050] In possible implementation, the acid solution used in the acid treatment includes at least one of a sulfuric acid solution, a hydrochloric acid solution and a nitric acid solution. The activator can be dissolved in the acid solution and undergo a dissociation reaction, and using the above acid solution can remove the activator in the pretreated powder and avoid the residual activator in the mesoporous carbon carrier, which affects the application effect of the mesoporous carbon carrier in the catalyst.
[0051] In possible implementation, the concentration of the acid solution is 0.1-1mol / L; it can be understood that the concentration of the acid solution can be any point value in 0.1-1mol / L; for example, the concentration of the acid solution can be 0.1mol / L, 0.2mol / L, 0.5mol / L, 0.8mol / L, 1mol / L, etc. Controlling the concentration of the acid solution in the above range can effectively remove the activator and impurities in the pretreated powder, avoid the corrosion of the mesoporous carbon carrier structure due to the too high concentration of the acid solution, and avoid the residual activator due to the too low concentration of the acid solution.
[0052] In possible implementation, the temperature of the acid treatment is 60-90℃; it can be understood that the temperature of the acid treatment can be any point value in 60-90℃; for example, the temperature of the acid treatment can be 60℃, 65℃, 70℃, 80℃, 90℃, etc. Controlling the temperature of the acid treatment in the above range can promote the reaction of the acid solution and the activator and effectively improve the reaction rate.
[0053] In possible implementation, the time of the acid treatment is 6-24h; it can be understood that the time of the acid treatment can be any point value in 6-24h; for example, the time of the acid treatment can be 6h, 10h, 12h, 20h, 24h, etc. Controlling the time of the acid treatment in the above range can ensure that the activator is completely reacted with the acid solution and avoid the influence of the residual activator on the application effect of the mesoporous carbon carrier.
[0054] In possible implementation, the drying temperature is 60-100 DEG C, and the drying time is 6-12 hours; it can be understood that the drying temperature can be any point value in 60-100 DEG C, and the drying time can be any point value in 6-12 hours; for example, the drying temperature can be 60 DEG C, 70 DEG C, 75 DEG C, 80 DEG C, 90 DEG C, 100 DEG C, etc., and the drying time can be 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 12 hours, etc. In this way, the drying temperature and the drying time are controlled in the above range, which can completely remove the moisture in the mesoporous carbon carrier.
[0055] In possible implementation, the mesoporous pore size of the mesoporous carbon carrier is 6-10 nm, which is helpful for mass transfer; the specific surface area is 1000-1400 m 2 / g, and the sulfur doping content is 10-15%, which has a high specific surface area and sulfur doping content, and is beneficial to improve the loading of metal particles on the mesoporous carbon carrier.
[0056] Based on the above preparation method, by adding the sulfur-containing compound, the template and the activator into the solvent in a predetermined mass ratio and mixing, the pore structure, the specific surface area and the sulfur doping content of the carbon carrier can be controlled and designed under the joint action of the template and the activator; and by alkali treatment and acid treatment, the template and the activator can be removed, and the mesoporous carbon carrier with excellent specific surface area is prepared, which is helpful to improve the loading amount of metal particles on the mesoporous carbon carrier in the catalyst, and the good pore structure can also promote the mass transfer in the electrochemical reaction process; by the preparation method provided in the present application, the sulfur element can be uniformly distributed in the mesoporous carbon carrier, and the uniformly doped sulfur atoms are helpful to strengthen the interaction between the mesoporous carbon carrier and the metal particles, enhance the anchoring capacity of the mesoporous carbon carrier to the metal particles, and thus improve the activity and stability of the catalyst.
[0057] On the other hand, the present application also provides a mesoporous carbon carrier, which is prepared by the preparation method of the mesoporous carbon carrier as described above, and has a high specific surface area and a good pore structure, which is helpful to improve the loading amount of metal particles on the mesoporous carbon carrier and promote the mass transfer in the electrochemical reaction process.
[0058] Specifically, the mesoporous pore size of the prepared mesoporous carbon carrier is 6-10 nm, the specific surface area is 1000-1400 m 2 / g, and the sulfur doping content is 10-15%, which has a high specific surface area and sulfur doping content, and is beneficial to improve the loading of metal particles on the mesoporous carbon carrier.
[0059] On the other hand, the present application also provides a catalyst, which comprises the mesoporous carbon carrier prepared by the preparation method of the mesoporous carbon carrier as described above.
[0060] The following describes specific embodiments of the present application in conjunction with the above mesoporous carbon carrier and preparation method thereof. The technical solutions of the present application are described in more detail in the following examples, which are only used for illustrative purposes, and various modifications and changes within the scope of the disclosure of the present application are obvious to those skilled in the art. The reagents and materials used in the examples can be obtained by commercial purchase or synthesized according to conventional methods, and can be used directly without further treatment, and the instruments and devices used in the examples are all commercially available.
[0061] Example 1 The present embodiment provides a mesoporous carbon carrier and a preparation method thereof, and the preparation method specifically comprises the following steps: 1. 3g of 2,2-bithiophene, 3g of silica powder, 1.5g of cobalt nitrate hexahydrate, and 250mL of 2-methyltetrahydrofuran are provided, wherein the particle size of the silica is 20nm, and the silicon content of the silica is 99.9%; 2. 3g of 2,2-bithiophene, 3g of silica powder, and 1.5g of cobalt nitrate hexahydrate are added to 250mL of 2-methyltetrahydrofuran, and stirred uniformly at room temperature to obtain a mixed solution; 3. The liquid in the mixed solution is removed by rotary evaporation, and then the solid powder is taken out and ground to obtain a mixed powder; 4. The mixed powder is ground and then heat treated under an argon atmosphere, the heating rate of the heat treatment is 10℃ / min, the heat treatment temperature is 850℃, the holding time is 2h, and the heat treated powder is naturally cooled to room temperature after the heat treatment to obtain a pretreated powder; 5. The pretreated powder is subjected to alkali treatment using a 1.8mol / L sodium hydroxide solution, the alkali treatment temperature is 70℃, the alkali treatment time is 72h, and filtration is performed to obtain a first solid and a first filtrate, the first solid is washed, and the washing step is repeated until the conductivity of the first filtrate is less than 10us / cm to obtain an alkali treated powder; 6. The alkali treated powder is subjected to acid treatment using a 0.5mol / L sulfuric acid solution, the acid treatment temperature is 70℃, the alkali treatment time is 10h, and filtration is performed to obtain a second solid and a second filtrate, the second solid is washed, and the washing step is repeated until the conductivity of the second filtrate is less than 10us / cm to obtain an acid treated powder; 7. The acid treated powder is dried in a blast drying oven at 60℃ for 12h to obtain a mesoporous carbon carrier. The specific surface area of the mesoporous carbon carrier prepared in the present embodiment is 1286m 2 / g, the average pore size is 7.4nm, and the sulfur doping content is 12.6wt.%.
[0062] The embodiment also provides a platinum-carbon catalyst prepared by using the mesoporous carbon carrier provided by the embodiment, and a preparation method of the platinum-carbon catalyst comprises the following steps: 1. 53.1 mg of chloroplatinic acid hexahydrate and 80 mg of the mesoporous carbon carrier are added into 20 mL of ultrapure water, and ultrasonic dispersion is performed to obtain a dispersion liquid; 2. The dispersion liquid is heated at a temperature of 60 ℃, and after being heated into a gel, the gel is transferred into a freeze dryer for drying to obtain a dried solid; 3. The dried solid is heated to 150 ℃ at a temperature increasing rate of 10 ℃ / min under a hydrogen-argon mixed gas with a volume concentration of 5%, and after being kept for 2 h, the temperature is naturally decreased to room temperature to obtain the platinum-carbon catalyst.
[0063] Embodiment 2 The embodiment provides a mesoporous carbon carrier and a preparation method thereof, and the preparation method specifically comprises the following steps: 1. 3 g of 2,2-bithiophene, 3 g of silica powder, 6 g of cobalt nitrate hexahydrate and 400 mL of 2-methyltetrahydrofuran are provided, wherein the particle size of the silica is 20 nm, and the silicon content of the silica is 99.9%; 2. 3 g of 2,2-bithiophene, 3 g of silica powder and 6 g of cobalt nitrate hexahydrate are added into 400 mL of 2-methyltetrahydrofuran, and stirring is performed at room temperature to obtain a mixed solution; 3. The liquid in the mixed solution is removed by using a rotary evaporation method, and then the solid powder is taken out and ground to obtain a mixed powder; 4. The mixed powder is ground and then heat-treated under an argon atmosphere, the temperature increasing rate of the heat treatment is 5 ℃ / min, the heat treatment temperature is 650 ℃, the heat preservation time is 2 h, and after the heat treatment, the temperature is naturally decreased to room temperature to obtain a pretreated powder; 5. The pretreated powder is subjected to alkali treatment by using a 2 mol / L sodium hydroxide solution, the alkali treatment temperature is 70 ℃, the alkali treatment time is 48 h, and then filtration is performed to obtain a first solid and a first filtrate, the first solid is washed, and the washing step is repeated until the conductivity of the first filtrate is less than 10 us / cm to obtain an alkali-treated powder; 6. The alkali-treated powder is subjected to acid treatment by using a 1 mol / L sulfuric acid solution, the acid treatment temperature is 70 ℃, the acid treatment time is 6 h, and then filtration is performed to obtain a second solid and a second filtrate, the second solid is washed, and the washing step is repeated until the conductivity of the second filtrate is less than 10 us / cm to obtain an acid-treated powder; 7. The acid-treated powder is dried in a blast drying oven at 100 ℃ for 6 h to obtain the mesoporous carbon carrier. In the embodiment, the specific surface area of the mesoporous carbon carrier prepared is 1210 m 2 / g, the average pore size is 7.8 nm, and the sulfur doping content is 13.8 wt.%.
[0064] The embodiment also provides a platinum-carbon catalyst prepared by using the mesoporous carbon carrier provided in the embodiment, and the preparation method of the platinum-carbon catalyst is the same as that in Embodiment 1, which is not described herein.
[0065] Comparative Example 1 The comparative example provides a mesoporous carbon carrier and a preparation method thereof, and the same parts as Embodiment 1 are not described herein, and the different parts from Embodiment 1 are that 3 g of 2,2-bithiophene, 3 g of silica powder and 0.5 g of cobalt nitrate hexahydrate are added into 217 mL of 2-methyltetrahydrofuran, and the mixture is stirred uniformly at room temperature to obtain a mixed solution; the specific surface area of the mesoporous carbon carrier prepared in the comparative example is 830 m 2 / g, the average pore size is 4.2 nm, and the sulfur doping content is 11.8 wt.%.
[0066] The comparative example also provides a platinum-carbon catalyst prepared by using the mesoporous carbon carrier provided in the comparative example, and the preparation method of the platinum-carbon catalyst is the same as that in Embodiment 1, which is not described herein.
[0067] Comparative Example 2 The comparative example provides a mesoporous carbon carrier and a preparation method thereof, and the same parts as Embodiment 1 are not described herein, and the different parts from Embodiment 1 are that the heat treatment temperature is 900 ℃; the specific surface area of the mesoporous carbon carrier prepared in the comparative example is 1136 m 2 / g, the average pore size is 8.2 nm, and the sulfur doping content is 2.1 wt.%.
[0068] The comparative example also provides a platinum-carbon catalyst prepared by using the mesoporous carbon carrier provided in the comparative example, and the preparation method of the platinum-carbon catalyst is the same as that in Embodiment 1, which is not described herein.
[0069] Table 1 shows the specific surface area, average pore size and sulfur doping content of the mesoporous carbon carrier prepared in Embodiments 1-2 and Comparative Examples 1-2.
[0070] Table 1
[0071] In the preferred parameter range, in combination with Embodiment 1 and Embodiment 2, the average pore size of the mesoporous carbon carrier is 7.4-7.8 nm, which is helpful for mass transfer and thus improves the activity of the platinum-carbon catalyst; the specific surface area of the mesoporous carbon carrier is 1210-1286 m 2 / g, and the sulfur doping content is 12.6-13.8 wt.%, which has a high specific surface area and sulfur doping content, and is beneficial to improve the loading of metal particles on the mesoporous carbon carrier.
[0072] refer to Figure 1 , Figure 1 The pore size distribution curve of the mesoporous carbon support in Example 1 is shown. Figure 1 The horizontal axis represents the aperture, indicating the size of the hole; the vertical axis on the left represents the aperture volume, showing the cumulative effect of aperture volume as the aperture diameter increases; the vertical axis on the right represents the differential aperture volume, showing the rate of change of aperture volume with aperture diameter. Figure 1 It can be seen that as the pore size increases, the pore volume first rises rapidly and then gradually flattens out. The differential pore volume shows a significant peak at a pore size of about 8 nm, which proves that the mesoporous carbon support has the largest number of mesopores with a pore size of about 8 nm and contributes the most to the pore volume. The pore size of the mesoporous carbon support is within this range, which is conducive to providing diffusion channels and adsorption sites.
[0073] In Comparative Example 1, a mesoporous carbon support was prepared using 3g of 2,2-bisthiophene, 3g of silica powder, and 0.5g of cobalt nitrate hexahydrate. The mass ratio of the sulfur-containing compound, template, and activator was 6:6:1. In Example 1, the mass ratio was 2:2:1, and in Example 2, it was 1:1:2. This shows that the activator content in Comparative Example 1 was significantly lower than in Examples 1 and 2. The specific surface area of the mesoporous carbon support in Comparative Example 1 was 830 m². 2 / g, with an average pore size of 4.2nm and a sulfur doping content of 11.8wt.%, all parameters are significantly lower than those in Examples 1-2, proving that the low activator content makes it impossible to fully create pores during the preparation process, making it difficult for sulfur-containing compounds to polymerize, resulting in a decrease in the specific surface area, average pore size, and sulfur doping content of the mesoporous carbon support.
[0074] The heat treatment temperature used in Comparative Example 2 was 900℃, while the heat treatment temperature in Example 1 was 850℃, and the heat treatment temperature in Example 2 was 650℃. It is evident that the heat treatment temperature used in Comparative Example 1 was significantly higher than that in Examples 1-2. The specific surface area of the mesoporous carbon support in Comparative Example 2 was 1136 m². 2 / g, with an average pore size of 8.2nm and a sulfur doping content of 2.1wt.%, compared to Examples 1-2, the sulfur doping content of the mesoporous carbon support in Comparative Example 2 was significantly reduced, proving that excessively high heat treatment temperature would affect the activity of the activator, thereby affecting the anchoring of sulfur atoms on the carbon support.
[0075] Electrochemical tests were performed on the platinum-carbon catalysts provided in the above examples and comparative examples. The test method included: adding 0.5 mL of ultrapure water, 2.5 mL of isopropanol, and 10 μL of 5% Nafion solution sequentially to 3 mg of platinum-carbon catalyst; ultrasonically mixing the materials to ensure uniform mixing; the ultrasonic treatment temperature was less than or equal to 20°C to obtain a dispersion slurry; and adjusting the catalyst loading on the electrode surface to 50 μg / cm³. 2The dispersion slurry was evenly added to the surface of the smooth RDE electrode in three times, and was naturally dried as a working electrode; a three-electrode system was built, the reference electrode was a reversible hydrogen electrode (RHE), the counter electrode was a carbon rod, and the electrolyte was a 0.1M perchloric acid solution saturated with N2.
[0076] Test the cyclic voltammetry curve: first, activate the platinum carbon catalyst at a scanning speed of 200 mV / s, then record the cyclic voltammetry (CV) curve and linear sweep voltammetry (LSV) curve at a scanning speed of 20 mV / s and 10 mV / s respectively in the voltage range of 0V-1.2V for evaluating the catalyst activity; finally, record the CV curve and LSV curve again after scanning 30000 times at a scanning speed of 100 mV / s in the voltage range of 0.6V-0.95V for evaluating the stability of the catalyst. Table 2 shows the test results of the platinum carbon catalysts in the examples and the comparative examples.
[0077] Table 2
[0078] The electrochemical test results of the platinum carbon catalyst in Example 1 are referenced Figure 3 and Figure 4 , Figure 3 shows the comparison of the initial CV curve and the CV curve after 30000 cycles of the platinum carbon catalyst, it can be seen that the current of the platinum carbon catalyst in Example 1 slightly decreases after 30000 cycles, which proves that the catalyst still has more active sites after long-term cycling; Figure 4 shows the comparison of the initial LSV curve and the LSV curve after 30000 cycles of the platinum carbon catalyst, Figure 4 the two curves almost overlap, which proves that the catalytic activity of the platinum carbon catalyst in Example 1 changes little after long-term cycling. According to Figure 3 and Figure 4 the experimental results shown, the platinum carbon catalyst in Example 1 has good stability.
[0079] In combination with Examples 1-2 and Comparative Examples 1-2, it can be known from Table 2 that the electrochemical active areas of the platinum carbon catalysts in Example 1 and Example 2 are 108 m 2 / gPt and 103 m 2 / gPt respectively, and the mass activities are 0.38 A / mg Pt@0.9V and 0.35 A / mg Pt@0.9V respectively, which are obviously higher than the electrochemical active areas of the platinum carbon catalysts in Comparative Example 1 and Comparative Example 2, which are 76 m 2 / gPt and 96 m 2 / g Pt, mass activity of 0.251 A / mg Pt@0.9 V and 0.31 A / mg Pt@0.9 V; the electrochemical active area is used to indicate the total area of active sites on the catalyst surface in contact with the electrolyte, and the mass activity is used to indicate the current density generated by the unit mass of catalyst. The electrochemical active area and mass activity of the platinum carbon catalysts in Examples 1-2 are larger, which proves that there are more active sites on the surface of the platinum carbon catalysts in Examples 1-2 to participate in the reaction, and the unit mass of catalyst can drive a higher reaction rate, which is conducive to improving the mass transfer and increasing the total current density, compared with Comparative Examples 1-2.
[0080] As can be seen from Table 2, after 30000 cycles of test, the electrochemical active area of the platinum carbon catalysts in Examples 1 and 2 is attenuated by 18% and 17% respectively, and the mass activity is attenuated by 13% and 15% respectively, while the electrochemical active area in Comparative Examples 1 and 2 is attenuated by 28% and 33% respectively, and the mass activity is attenuated by 32% and 41% respectively. The performance attenuation of the platinum carbon catalysts in Examples 1-2 is significantly lower than that in Comparative Examples 1-2, which proves that the platinum carbon catalysts in Examples 1-2 have good stability, and the higher sulfur doping content and specific surface area help to enhance the interaction between the mesoporous carbon support and the metal particles, thereby enhancing the anchoring ability of the mesoporous carbon support to the metal particles and improving the activity and stability of the platinum carbon catalyst.
[0081] As can be seen from the experimental results of the average particle size of platinum particles in Table 2, the average particle size of platinum particles in the platinum carbon catalyst in Example 1 before and after 30000 cycles of test is 2.1 nm and 2.2 nm respectively, and the average particle size of platinum particles in the platinum carbon catalyst in Example 2 before and after 30000 cycles of test is 2.3 nm and 2.3 nm respectively. It can be seen that the average particle size of platinum particles in the platinum carbon catalysts in Examples 1 and 2 is small, and the average particle size of platinum particles changes little after long-term cycling, which proves that the interaction between platinum particles and mesoporous carbon support is strong, which can inhibit the migration and agglomeration of platinum particles, so that the platinum carbon catalyst has good stability; while the average particle size of platinum particles in the platinum carbon catalyst in Comparative Example 1 changes from 4.3 nm to 5.4 nm before and after 30000 cycles of test, and the average particle size of platinum particles in the platinum carbon catalyst in Comparative Example 1 changes from 2.7 nm to 3.9 nm before and after 30000 cycles of test. It can be seen that the catalyst undergoes serious particle agglomeration or sintering during the cycling process, which proves that the catalyst has poor stability.
[0082] In summary, in the preferred parameter range, the mesoporous carbon support prepared in Example 1 and Example 2 can anchor platinum particles, the strong interaction between the mesoporous carbon support and platinum particles can inhibit the migration and agglomeration of platinum particles, thereby improving the activity and stability of platinum-carbon catalyst. In Comparative Example 1, the low content of activator makes it difficult to fully pore during the preparation process, and the sulfur-containing compound is difficult to polymerize, resulting in a decrease in the specific surface area, average pore size and sulfur-doped content of the mesoporous carbon support, a decrease in the interaction between the mesoporous carbon support and platinum particles, and the agglomeration of platinum particles, which affects the electrochemical activity and stability of the platinum-carbon catalyst. In Comparative Example 2, a higher heat treatment temperature is used, which affects the activity of the activator, resulting in a significant decrease in the sulfur-doped content, affecting the anchoring of platinum particles, and thereby resulting in poor activity and stability of the platinum-carbon catalyst.
[0083] The above description has fully disclosed the specific embodiments of the present application. It should be noted that any modification made by those skilled in the art to the specific embodiments of the present application does not deviate from the scope of the claims of the present application. Accordingly, the scope of the claims of the present application is not limited to the foregoing specific embodiments.
Claims
1. A method for preparing a mesoporous carbon support, characterized in that, The preparation method includes: S1: Provides sulfur-containing compounds, templates, activators, and solvents; S2: Add the sulfur-containing compound, the template, and the activator to the solvent according to a preset mass ratio, and stir to obtain a mixed solution; S3: Evaporate the liquid in the mixed solution to obtain a mixed powder; S4: Grind the mixed powder and heat-treat it under an inert atmosphere to obtain pretreated powder; S5: The pretreated powder is subjected to alkali treatment, acid treatment, and drying to obtain a mesoporous carbon support.
2. The preparation method according to claim 1, characterized in that, The preset mass ratio of the sulfur-containing compound, the template, and the activator is 1-4:1-4:0.5-2.
3. The preparation method according to claim 1, characterized in that, The solid content in the mixed solution is 20-50 mg / mL.
4. The preparation method according to any one of claims 1-3, characterized in that, The sulfur-containing compound includes at least one of thiophene, 2,2'-bisthiophene, benzothiophene, and thioamide.
5. The preparation method according to any one of claims 1-3, characterized in that, The template is silicon dioxide, and the silicon dioxide satisfies at least one of the following characteristics: The particle size of the silica is 5-50 nm; The silicon content of the silicon dioxide is 99.5%-100%.
6. The preparation method according to any one of claims 1-3, characterized in that, The solvent includes at least one of tetrahydrofuran, 2-methyltetrahydrofuran, and acetone.
7. The preparation method according to any one of claims 1-3, characterized in that, The heat treatment satisfies at least one of the following characteristics: The heat treatment temperature is 650-850℃; The heat treatment time is 1.5-3 hours.
8. The preparation method according to any one of claims 1-3, characterized in that, The alkaline treatment satisfies at least one of the following characteristics: The alkaline solution used in the alkaline treatment includes at least one of sodium hydroxide solution and potassium hydroxide solution; The concentration of the alkaline solution is 1-3 mol / L; The temperature for the alkali treatment is 60-90℃; The alkali treatment time is 48-96 hours.
9. The preparation method according to any one of claims 1-3, characterized in that, The acid treatment satisfies at least one of the following characteristics: The acid solution used in the acid treatment includes at least one of sulfuric acid solution, hydrochloric acid solution and nitric acid solution; The concentration of the acid solution is 0.1-1 mol / L; The acid treatment temperature is 60-90℃; The acid treatment time is 6-24 hours.
10. A mesoporous carbon support, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.