Method for preparing platinum-iron-carbon catalyst by using waste rubber powder, and platinum-iron-carbon catalyst and use thereof

Abstract

The present application relates to the technical fields of fossil resource recycling and fuel cell catalysts, and particularly to a method for preparing a platinum-iron-carbon catalyst by using waste rubber powder, and a platinum-iron-carbon catalyst and a use thereof. The method in the present application comprises: performing pyrolysis treatment on first waste rubber powder to obtain pyrolytic carbon; mixing the pyrolytic carbon with metal salts, a complexing agent, and water to obtain a first mixture, wherein the metal salts include a platinum salt and an iron salt; heating the first mixture under stirring, so as to obtain a sol; drying the sol and then calcining same to obtain a catalyst precursor; mixing second waste rubber powder with the catalyst precursor to obtain a second mixture; and performing microwave radiation treatment on the second mixture to obtain a platinum-iron-carbon catalyst. The technical solution of the present application provides a simple and low-cost method for preparing a highly active platinum-iron-carbon catalyst, and also realizes high-value recycling of waste rubber.

Description

A method for preparing a platinum-iron-carbon catalyst from waste rubber powder, the platinum-iron-carbon catalyst and its application. Technical Field

[0001] This application relates to the fields of fossil resource recycling and fuel cell catalyst technology, specifically to a method for preparing a platinum-iron-carbon catalyst using waste rubber powder, the platinum-iron-carbon catalyst, and its application. Background Technology

[0002] A solid polymer membrane electrolyte fuel cell (SPMEFC) is a type of fuel cell that uses a solid polymer electrolyte as the ion conduction medium. These cells typically operate at relatively low temperatures and are therefore also known as low-temperature fuel cells.

[0003] Solid polymer membrane electrolyte fuel cells mainly consist of key components such as a proton exchange membrane, catalyst layer, gas diffusion layer, bipolar plates, and current collectors. Among these, the proton exchange membrane serves to isolate the fuel from the oxidant and conduct protons (hydrogen ions). + The catalyst layer, coated on both sides of the proton exchange membrane, serves to accelerate the oxidation of hydrogen (at the anode) and the reduction of oxygen (at the cathode). The gas diffusion layer ensures uniform gas transport and supports the catalyst. The bipolar plate is used to distribute the reaction gas, conduct electricity, and dissipate heat. The current collector is responsible for connecting multiple individual cells to form a battery stack to provide sufficient voltage and power.

[0004] Currently, SPEMFC commonly uses platinum-carbon catalysts to prepare the catalyst layer. Platinum-carbon catalysts are catalyst materials that support platinum nanoparticles on a carbon support. The commonly used carbon support is carbon black (such as Cabot XC-72). Since the bond between carbon black and platinum particles is not tight enough, it is difficult to load platinum catalyst particles. Usually, carbon black needs to be pretreated, which increases the preparation cost and makes the preparation process more complicated, which is not conducive to large-scale industrial production and application.

[0005] To improve the performance and reduce the cost of platinum-carbon catalysts, researchers have conducted extensive studies on their preparation methods and material composition. These studies include using precipitation conversion processes, chemical reduction methods, and microwave dielectric heating techniques to improve the dispersion of platinum in carbon supports; using inexpensive metals to replace platinum to reduce costs; and adjusting the size and morphology of platinum-carbon catalysts to improve their catalytic activity and stability. Despite these efforts, the commercial application of platinum-carbon catalysts still faces challenges. On the one hand, the preparation process of platinum-carbon catalysts needs further simplification to adapt to large-scale production and application. On the other hand, the consumption of carbon raw materials, platinum raw materials, and necessary reagents for platinum-carbon catalysts needs further control to meet people's pursuit of energy conservation and environmental protection.

[0006] Therefore, it is necessary to develop a simple, low-cost, and environmentally friendly method for preparing platinum-carbon catalysts. Summary of the Invention

[0007] Based on this, one or more embodiments of this application provide a method for preparing a platinum-iron-carbon catalyst using waste rubber powder, the platinum-iron-carbon catalyst, and its application. The method for preparing the platinum-iron-carbon catalyst in this application greatly simplifies the preparation process, reduces the preparation cost, has low raw material costs, consumes few reagents, and the obtained platinum-iron-carbon catalyst has high electrochemical activity and high bonding strength between the active particles and the carbon support.

[0008] The technical solution of this application includes the following steps:

[0009] A method for preparing a platinum-iron-carbon catalyst using waste rubber powder includes:

[0010] The first waste rubber powder was pyrolyzed to obtain pyrolytic carbon;

[0011] The pyrolytic carbon is mixed with a metal salt, a complexing agent, and water to obtain a first mixture; the metal salt includes platinum salt and iron salt; the molar ratio of the total metal cations in the metal salt to the total carbon atoms in the pyrolytic carbon is (0.1-0.5):1;

[0012] The first mixture was heated while stirring to obtain a sol;

[0013] The sol was dried to obtain a dry gel, and the dry gel was calcined to obtain a catalyst precursor.

[0014] The second waste rubber powder is mixed with the catalyst precursor to obtain a second mixture; the mass of the second waste rubber powder accounts for 5% to 20% of the total mass of the second mixture.

[0015] The second mixture was subjected to microwave irradiation to obtain the platinum-iron-carbon catalyst.

[0016] In one embodiment, the first waste rubber powder is subjected to pyrolysis treatment to obtain pyrolytic carbon, comprising:

[0017] A first inert gas is introduced into the first waste rubber powder, and the mixture is treated at a first temperature for a first time to obtain the pyrolytic carbon.

[0018] Wherein, the first temperature is 550℃~650℃, and the first time is 2h~6h;

[0019] Optionally, the flow rate of the inert gas is 150 mL / min to 250 mL / min.

[0020] In one embodiment, the molar ratio of the platinum salt to the iron salt is (1-9):1.

[0021] The molar ratio of the total cations in the metal salt to the complexing agent is 1:(0.8-1.25).

[0022] In one embodiment, the first mixture is heated under stirring to obtain a sol, comprising:

[0023] The first mixture was stirred at a first stirring speed and a second temperature for a second time to obtain the sol;

[0024] The first stirring speed is 600 rpm to 1000 rpm, the second temperature is 50℃ to 70℃, and the second time is 30 min to 90 min.

[0025] In one embodiment, the sol is dried to obtain a dry gel, comprising:

[0026] The sol was subjected to rotary evaporation at a third temperature and a third time under a first vacuum to obtain a wet gel.

[0027] The wet gel is dried at a fourth temperature for a fourth time to obtain a dry gel;

[0028] The first vacuum degree is 0.01 MPa to 0.05 MPa, the third temperature is 50°C to 70°C, and the third time is 0.3 h to 1 h.

[0029] The fourth temperature is 70℃~90℃, and the fourth time is 12h~24h.

[0030] In one embodiment, the dry gel is calcined to obtain the catalyst precursor, comprising:

[0031] The catalyst precursor was prepared by subjecting the dry gel to a fifth temperature for a fifth time.

[0032] The fifth temperature is 330℃~450℃, and the fifth time is 2h~4h.

[0033] In one embodiment, the second mixture is subjected to microwave irradiation to obtain a platinum-carbon catalyst, comprising the following steps:

[0034] The platinum-carbon catalyst is prepared by passing a second inert gas into the second mixture and heating it under a first microwave power for a sixth time.

[0035] The first microwave power is 400W to 1000W, and the sixth time is 10min to 20min.

[0036] In one embodiment, the method for preparing a platinum-iron-carbon catalyst using waste rubber powder satisfies at least one of the following conditions:

[0037] (1) The platinum salt includes at least one of chloroplatinic acid, platinum nitrate and platinum acetate;

[0038] (2) The iron salt includes at least one of ferric nitrate, ferrous sulfate and ferric chloride;

[0039] (3) The complexing agent includes at least one of citric acid, disodium ethylenediaminetetraacetate, acetylacetone, aminotriacetic acid, oxalic acid, glycine and polyvinylpyrrolidone;

[0040] (4) The water is deionized water.

[0041] A platinum-iron-carbon catalyst prepared by the method described above for preparing a platinum-iron-carbon catalyst using waste rubber powder, wherein the platinum-iron-carbon catalyst simultaneously possesses electrocatalytic and thermocatalytic properties.

[0042] An application of the platinum-iron-carbon catalyst described above in the preparation of solid polymer membrane electrolyte fuel cells; and / or,

[0043] As a dehydrogenation catalyst for the thermocatalytic hydrogen production from organic waste.

[0044] The technical solution of this application addresses the problems of complex preparation methods, environmentally unfriendly preparation methods, and high cost of carbon support raw materials in current solid polymer membrane electrolyte fuel cell catalyst layer materials. It provides a method for preparing platinum-iron-carbon catalysts using waste rubber powder. This method uses waste rubber as a carbon and hydrogen source and loads metal components using appropriate methods, thereby comprehensively reducing the preparation cost of platinum-carbon catalysts. At the same time, it also realizes the high-value conversion and recycling of fossil resources.

[0045] The method for preparing platinum-iron-carbon catalysts using waste rubber powder in this application simplifies the preparation process compared to existing technologies, eliminates the need for hazardous reagents such as strong acids and strong bases, saves costs, is environmentally friendly, and is easy to scale up, thus having great application potential.

[0046] The platinum-carbon catalyst prepared by the method of preparing platinum-iron-carbon catalyst using waste rubber powder has a high bonding strength between the metal element and the carbon support, and the metal element is uniformly distributed in the carbon support, which effectively improves the stability and electronic conductivity of the platinum-carbon catalyst. The high degree of graphitization of the carbon support effectively enhances the anti-reverse polarity performance of the platinum-carbon catalyst.

[0047] The platinum-iron-carbon catalyst of this application possesses both electrocatalytic and thermocatalytic properties. It can be used to prepare solid polymer membrane electrolyte fuel cells and can also be used as a high-efficiency, low-cost dehydrogenation catalyst for green hydrogen production from organic waste, including biomass, waste plastics, and waste rubber. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0049] Figure 1 is a transmission electron microscope image of the platinum-iron-carbon catalyst of Example 1 of this application. In Figure 1, A, B, and C correspond to different sampling sites, and the scale bar is 5 nm. Detailed Implementation

[0050] The present application is further described below with reference to embodiments and examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Furthermore, it should be understood that after reading the teachings of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the protection scope of the appended claims.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0052] the term

[0053] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0054] The term "and / or" as used herein includes any one of two or more related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations encompass any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected using at least two conjunctions selected from "and / or," "or / and," or "and / or," it should be understood that, in this application, the technical solution undoubtedly includes solutions connected by "logical AND," and also undoubtedly includes solutions connected by "logical OR." For example, "A and / or B" includes three parallel solutions: A, B, and A+B.

[0055] In this application, terms such as "furthermore" and "optionally" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0056] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0057] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, optional numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0058] In this application, weight can be a well-known unit of mass in the chemical industry, such as μg, mg, g, or kg.

[0059] Waste rubber refers to rubber products that have lost their usability. Common waste rubber in daily life includes waste rubber hoses, waste tires, and waste rubber shoes. These products are difficult to degrade naturally, and if not handled properly, they can have an impact on the environment. Therefore, they need to be recycled and reused through appropriate methods.

[0060] Platinum-carbon catalysts are supported catalysts on activated carbon, belonging to the category of precious metal catalysts. They are particularly important in the field of fuel cells, used in chemical reactions such as hydrogen oxidation, methanol oxidation, formic acid oxidation, and oxygen reduction, and are commonly used materials in hydrogen fuel cells and water electrolysis. Although platinum-carbon catalysts have high catalytic efficiency, their cost is relatively high, mainly due to the high price of platinum itself and the carbon black used as a support, as well as the complex preparation process.

[0061] One aspect of this application provides a method for preparing a platinum-iron-carbon catalyst using waste rubber powder. This method uses waste rubber as a carbon and hydrogen source, reducing the cost of the catalyst at the raw material level and simplifying the preparation process, effectively reducing the preparation cost. The method is simple and easy to mass-produce; moreover, it does not require the use of organic solvents and strong acids and bases, making it environmentally friendly. At the same time, the method can be compared with the field of high-value recycling of other types of organic solid waste raw materials, and has a wide range of application potential.

[0062] In one embodiment, the waste rubber powder is derived from waste tire rubber powder. The waste tire stock is large, making recycling easier. Furthermore, the waste tire rubber powder has a higher carbon-to-hydrogen ratio, which is more conducive to providing the hydrogen and carbon sources required for reduction and loading.

[0063] In one embodiment, a method for preparing a platinum-iron-carbon catalyst using waste rubber powder includes:

[0064] The first waste rubber powder was pyrolyzed to obtain pyrolytic carbon;

[0065] The pyrolytic carbon is mixed with a metal salt, a complexing agent, and water to obtain a first mixture; the metal salt includes platinum salt and iron salt; the molar ratio of the total cations in the metal salt to the total carbon atoms in the pyrolytic carbon is (0.1-0.5):1;

[0066] The first mixture was heated while stirring to obtain a sol;

[0067] The sol was dried and then calcined to obtain a catalyst precursor.

[0068] The second waste rubber powder is mixed with the catalyst precursor to obtain a second mixture; the mass of the second waste rubber powder accounts for 5% to 20% of the total mass of the second mixture.

[0069] The second mixture was subjected to microwave irradiation to obtain the platinum-iron-carbon catalyst.

[0070] In one embodiment, the first waste rubber powder is subjected to pyrolysis treatment to obtain pyrolytic carbon, comprising:

[0071] A first inert gas is introduced into the first waste rubber powder, and the pyrolytic carbon is obtained at a first temperature and for a first time.

[0072] Wherein, the first temperature is 550℃~650℃, and the first time is 2h~6h;

[0073] Optionally, the flow rate of the inert gas is 150 mL / min to 250 mL / min.

[0074] In one embodiment, the molar ratio of the platinum salt to the iron salt is (1-9):1;

[0075] The molar ratio of the total cations in the metal salt to the complexing agent is 1:(0.8-1.25).

[0076] In one embodiment, the first mixture is heated under stirring to obtain a sol, comprising:

[0077] The first mixture was stirred at a first stirring speed and at a second temperature for a second time to obtain the sol;

[0078] The first stirring speed is 600 rpm to 1000 rpm, the second temperature is 50℃ to 70℃, and the second time is 30 min to 90 min.

[0079] In one embodiment, the sol is dried to obtain a dry gel, and the dry gel is calcined to obtain the catalyst precursor.

[0080] The sol, after drying, yields a dry gel, comprising:

[0081] The sol was subjected to rotary evaporation at a third temperature and a third time under a first vacuum to obtain a wet gel.

[0082] The wet gel is dried at a fourth temperature for a fourth time to obtain a dry gel;

[0083] The first vacuum degree is 0.01 MPa to 0.05 MPa, the third temperature is 50°C to 70°C, and the third time is 0.3 h to 1 h.

[0084] The fourth temperature is 70℃~90℃, and the fourth time is 12h~24h.

[0085] In one embodiment, the dry gel is calcined to obtain the catalyst precursor, comprising:

[0086] The catalyst precursor was prepared by subjecting the dry gel to a fifth temperature for a fifth time.

[0087] The fifth temperature is 330℃~450℃, and the fifth time is 2h~4h.

[0088] In one embodiment, the second mixture is subjected to microwave irradiation to obtain a platinum-carbon catalyst, comprising the following steps:

[0089] The platinum-carbon catalyst is prepared by passing a second inert gas into the second mixture and heating it under a first microwave power for a sixth time.

[0090] The first microwave power is 400W to 1000W, and the sixth time is 10min to 20min.

[0091] In one embodiment, the method for preparing a platinum-iron-carbon catalyst using waste rubber powder satisfies at least one of the following conditions:

[0092] (1) The platinum salt includes at least one of chloroplatinic acid, platinum nitrate and platinum acetate;

[0093] (2) The iron salt includes at least one of ferric nitrate, ferrous sulfate and ferric chloride;

[0094] (3) The complexing agent includes at least one of citric acid, disodium ethylenediaminetetraacetate, acetylacetone, aminotriacetic acid, oxalic acid, glycine and polyvinylpyrrolidone;

[0095] (4) The water is deionized water.

[0096] In another aspect, this application provides a platinum-iron-carbon catalyst prepared by the method described above for preparing a platinum-iron-carbon catalyst using waste rubber powder. This method employs a sol-gel combustion method to precisely control the content and proportion of various metal components in the catalyst, and to ensure that each metal component is uniformly dispersed. The method also utilizes the high carbon-to-hydrogen ratio of the waste rubber heat, and uses microwave radiation heating to decompose the waste rubber into pyrolytic carbon and pyrolytic hydrogen in a short time, and can achieve the reduction of platinum and iron active particles and the generation of carbon in one step. At the same time, the catalyst active particles are embedded in the carbon support, which improves the bonding strength between the metal particles and the carbon support. The resulting platinum-iron-carbon catalyst has good uniformity, strong anti-reverse polarity performance, high activity, and good electronic conductivity.

[0097] In another aspect, this application provides the application of the platinum-iron-carbon catalyst described above in the preparation of fuel cell catalysts.

[0098] The technical solution of this application addresses the problems of complex preparation methods, environmentally unfriendly preparation methods, and high cost of carbon support raw materials in current solid polymer membrane electrolyte fuel cell catalyst layer materials. It provides a method for preparing platinum-iron-carbon catalysts using waste rubber powder. This method uses waste rubber as a carbon and hydrogen source, adopts inexpensive and readily available carbon sources, reduces the preparation cost of platinum-carbon catalysts, and also realizes the high-value conversion and recycling of fossil resources.

[0099] The method for preparing platinum-iron-carbon catalysts using waste rubber powder in this application simplifies the preparation process compared to existing technologies, eliminates the need for hazardous reagents such as strong acids and strong bases, saves costs, is environmentally friendly, and is easy to scale up.

[0100] The platinum-carbon catalyst prepared by the method of preparing platinum-iron-carbon catalyst using waste rubber powder has a high bonding strength between the metal element and the carbon support, and the metal element is uniformly distributed in the carbon support, which effectively improves the stability and electronic conductivity of the platinum-carbon catalyst. The high degree of graphitization of the carbon support effectively enhances the anti-reverse polarity performance of the platinum-carbon catalyst.

[0101] The following are some specific examples.

[0102] For experimental parameters not specified in the following specific embodiments, please refer to the guidelines given in this application document first, or refer to experimental manuals or other experimental methods known in the art, or refer to the experimental conditions recommended by the manufacturer.

[0103] The raw materials and reagents involved in the following specific embodiments can be obtained commercially or prepared by those skilled in the art using known methods.

[0104] The waste rubber powder used in this application embodiment is sourced from waste tire rubber powder, purchased from Shaanxi Hongrui Rubber Products Co., Ltd.

[0105] Example 1

[0106] (1) Take 50g of waste tire rubber powder and place it in a pyrolysis reactor. Pass N2 (200mL / min) through it and pyrolyze it at 550℃ for 6h to obtain pyrolytic carbon.

[0107] (2) Pyrolytic carbon (1.0 mol based on 12 g) was mixed with chloroplatinic acid (0.09 mol), ferric nitrate nonahydrate (0.01 mol), citric acid (0.1 mol) and deionized water to obtain the first mixture;

[0108] (3) The first mixture was heated and stirred at 600 rpm and 50°C for 90 min to obtain a sol;

[0109] (4) The water in the sol was evaporated by rotary vacuum evaporation (0.01 MPa, 70℃) to obtain a wet gel. The evaporation time was about 0.3 h.

[0110] (5) Place the wet gel in a vacuum drying oven and dry it at 80°C to obtain a dry gel. The drying time is about 18 hours.

[0111] (6) The dry gel was placed in a tube furnace and calcined at 330°C for 4 hours to obtain a fluffy catalyst precursor;

[0112] (7) Take another 0.5g of waste tire rubber powder and mix it with the catalyst precursor to obtain a second mixture, which contains 5w% waste tire rubber powder;

[0113] (8) Place the second mixture in a microwave radiation reactor, introduce N2, and stop introducing N2 after the air is exhausted. Then, microwave irradiate the mixture at 800W for 15 minutes. After the reactor cools to room temperature, remove it to obtain platinum-carbon-iron catalyst S1.

[0114] Example 2

[0115] (1) Place 10g of waste tire rubber powder in a pyrolysis reactor, introduce N2 (200ml / min), and pyrolyze at 650℃ for 3h to obtain waste tire pyrolysis carbon;

[0116] (2) Pyrolytic carbon (0.36 mol based on 4.4 g) was mixed with chloroplatinic acid (0.06 mol), ferric nitrate nonahydrate (0.05 mol), citric acid (0.9 mol) and deionized water to obtain the first mixture;

[0117] (3) The first mixture was heated and stirred at 700 rpm and 55°C for 60 min to obtain a sol;

[0118] (4) The water in the sol was evaporated by rotary vacuum evaporation (0.03 MPa, 65℃) to obtain a wet gel. The evaporation time was about 0.5 h.

[0119] (5) Place the wet gel in a vacuum drying oven and dry it at 80°C to obtain a dry gel. The drying time is about 18 hours.

[0120] (6) The dry gel was placed in a tube furnace and calcined at 450°C for 3.5 h to obtain a fluffy catalyst precursor;

[0121] (7) Take another 0.4g of waste tire rubber powder and mix it with the catalyst precursor to obtain a second mixture, which contains 10w% waste tire rubber powder.

[0122] (8) Place the second mixture in a microwave radiation reactor, introduce N2, and stop introducing N2 after the air is exhausted. Then, microwave irradiate the mixture at 700W for 20 minutes. After the reactor cools to room temperature, remove it to obtain platinum-carbon-iron catalyst S2.

[0123] Example 3

[0124] (1) Place 10g of waste tire rubber powder in a pyrolysis reactor, introduce N2 (200ml / min), and pyrolyze at 620℃ for 3.5h to obtain waste tire pyrolysis carbon;

[0125] (2) Pyrolytic carbon (0.25 mol based on 3 g) was mixed with chloroplatinic acid (0.07 mol), ferric nitrate nonahydrate (0.03 mol), citric acid (0.11 mol) and deionized water to obtain the first mixture;

[0126] (3) The first mixture was heated and stirred at 900 rpm and 60℃ for 45 min to obtain a sol;

[0127] (4) The water in the sol was evaporated by rotary vacuum evaporation (0.05MPa, 60℃) to obtain wet gel, and the evaporation time was about 1 hour;

[0128] (5) Place the wet gel in a vacuum drying oven and dry it at 80°C to obtain a dry gel. The drying time is about 18 hours.

[0129] (6) The dry gel was placed in a tube furnace and calcined at 420°C for 3 hours to obtain a fluffy catalyst precursor;

[0130] (7) Take another 0.5g of waste tire rubber powder and mix it with the catalyst precursor to obtain a second mixture, which contains 15w% waste tire rubber powder;

[0131] (8) Place the second mixture in a microwave radiation reactor, introduce N2, stop introducing N2 after the air is exhausted, microwave radiation treatment at 1000W for 10 min, and take it out after the reactor cools to room temperature to obtain platinum carbon iron catalyst S3.

[0132] Example 4

[0133] (1) Place 50g of waste tire rubber powder in a pyrolysis reactor, introduce N2 (200ml / min), and pyrolyze at 500℃ for 2h to obtain waste tire pyrolysis carbon;

[0134] (2) Pyrolytic carbon (1 mol based on 12 g) is mixed with chloroplatinic acid (0.5 mol), ferric nitrate nonahydrate (0.5 mol), citric acid (0.8 mol) and deionized water to obtain the first mixture;

[0135] (3) The first mixture was heated and stirred at 800 rpm and 70°C for 30 min to obtain a sol;

[0136] (4) The water in the sol was evaporated by rotary vacuum evaporation (0.05MPa, 60℃) to obtain wet gel, and the evaporation time was about 1 hour;

[0137] (5) Place the wet gel in a vacuum drying oven and dry it at 80°C to obtain a dry gel. The drying time is about 18 hours.

[0138] (6) The dry gel was placed in a tube furnace and calcined at 300°C for 2 hours to obtain a fluffy catalyst precursor;

[0139] (7) Take another 1g of waste tire rubber powder and mix it with the catalyst precursor to obtain a second mixture, which contains 18w% waste tire rubber powder.

[0140] (8) Place the second mixture in a microwave radiation reactor, introduce N2, and stop introducing N2 after the air is exhausted. Then microwave irradiate at 900W for 12 minutes. After the reactor cools to room temperature, take it out to obtain platinum-carbon-iron catalyst S4.

[0141] Comparative Example 1

[0142] (1) Place 10g of waste tire rubber powder in a pyrolysis reactor, introduce N2 (200ml / min), and pyrolyze at 600℃ for 3h to obtain waste tire pyrolysis carbon;

[0143] (2) Pyrolytic carbon (0.33 mol based on 4 g) was mixed with chloroplatinic acid (0.07 mol), ferric nitrate nonahydrate (0.03 mol), citric acid (0.11 mol) and deionized water to obtain the first mixture;

[0144] (3) The first mixture was heated and stirred at 900 rpm and 60℃ for 40 min to obtain a sol;

[0145] (4) The water in the sol was evaporated by rotary vacuum evaporation (0.05MPa, 60℃) to obtain wet gel, and the evaporation time was about 1 hour;

[0146] (5) Place the wet gel in a vacuum drying oven and dry it at 80°C to obtain a dry gel. The drying time is about 18 hours.

[0147] (6) The dry gel was placed in a tube furnace and calcined at 420°C for 3 hours to obtain a fluffy catalyst precursor;

[0148] (7) Take another 0.5g of waste tire rubber powder and mix it with the catalyst precursor to obtain a second mixture, which contains 12w% waste tire rubber powder;

[0149] (8) The second mixture was placed in an electrically heated fixed-bed reactor, N2 was introduced, and after the air was purged, the N2 was stopped. The mixture was heated at 800°C for 10 min. After the reactor cooled to room temperature, it was taken out to obtain platinum-carbon-iron catalyst D1.

[0150] Comparative Example 2

[0151] (1) Place 10g of waste tire rubber powder in a pyrolysis reactor, introduce N2 (200ml / min), and pyrolyze at 600℃ for 3h to obtain waste tire pyrolysis carbon;

[0152] (2) Pyrolytic carbon (0.33 mol based on 4 g) was mixed with chloroplatinic acid (0.01 mol), ferric nitrate nonahydrate (0.01 mol), citric acid (0.02 mol) and deionized water to obtain the first mixture;

[0153] (3) The first mixture was heated and stirred at 800 rpm and 60℃ for 40 min to obtain a sol;

[0154] (4) The water in the sol was evaporated by rotary vacuum evaporation (0.03MPa, 60℃) to obtain a wet gel. The evaporation time was about 1 hour.

[0155] (5) Place the wet gel in a vacuum drying oven and dry it at 90°C to obtain a dry gel. The drying time is about 18 hours.

[0156] (6) The dry gel was placed in a tube furnace and calcined at 400°C for 3 hours to obtain a fluffy catalyst precursor;

[0157] (7) Take another 0.5g of waste tire rubber powder and mix it with the catalyst precursor to obtain a second mixture, which contains 10w% waste tire rubber powder.

[0158] (8) The second mixture was placed in an electrically heated fixed-bed reactor, N2 was introduced, and after the air was purged, the N2 was stopped. The mixture was heated at 750°C for 10 min. After the reactor cooled to room temperature, it was taken out to obtain platinum-carbon-iron catalyst D2.

[0159] Comparative Example 3

[0160] (1) Place 10g of waste tire rubber powder in a pyrolysis reactor, introduce N2 (200ml / min), and pyrolyze at 600℃ for 3h to obtain waste tire pyrolysis carbon;

[0161] (2) Pyrolytic carbon (0.33 mol based on 4 g) was mixed with chloroplatinic acid (0.07 mol), ferric nitrate nonahydrate (0.03 mol), citric acid (0.10 mol) and deionized water to obtain the first mixture;

[0162] (3) The first mixture was heated and stirred at 900 rpm and 60℃ for 50 min to obtain a sol;

[0163] (4) The water in the sol was evaporated by rotary vacuum evaporation (0.05MPa, 55℃) to obtain wet gel, and the evaporation time was about 1 hour;

[0164] (5) Place the wet gel in a vacuum drying oven and dry it at 90°C to obtain a dry gel. The drying time is about 20 hours.

[0165] (6) The dry gel was placed in a tube furnace and calcined at 400°C for 3 hours to obtain a fluffy catalyst precursor;

[0166] (7) Take another 2g of waste tire rubber powder and mix it with the catalyst precursor to obtain a second mixture, which contains 50w% waste tire rubber powder.

[0167] (8) The second mixture was placed in an electrically heated fixed-bed reactor, N2 was introduced, and after the air was purged, the N2 was stopped. The mixture was heated at 800°C for 10 min. After the reactor cooled to room temperature, it was taken out to obtain platinum-carbon-iron catalyst D3.

[0168] II. Application of the platinum-carbon-iron catalyst in the above embodiments in battery preparation

[0169] (1) Appearance

[0170] The transmission electron microscope (TEM) image of Example 1 is shown in Figure 1. According to Figure 1, A, B, and C are TEM images of different sampling sites. It can be seen from these images that the active metal particles are embedded in the surface of the carbon support, forming a strong binding between the active particles and the carbon support.

[0171] (2) Test results of the catalyst

[0172] The platinum-carbon-iron catalysts (platinum-carbon-iron catalysts S1-S4, D1) prepared in the above embodiments and comparative examples were tested using a rotating disk electrode system, and the corresponding test data were obtained. The test results of each embodiment and comparative example are shown in Table 1.

[0173] Table 1

[0174]

[0175] According to Table 1, the half-wave potentials of the platinum-carbon-iron catalysts S1-S3 in Examples 1-3 reached 0.926V, 0.921V, and 0.917V, respectively, and the calculated catalyst mass activities reached 0.386A / mg to 0.541A / mg. The half-wave potential of catalyst S4 in Example 4 was 0.901V, and the mass activity was 0.241A / mg. The half-wave potentials of the platinum-carbon-iron catalysts D1-D3 in Comparative Examples 1-3 were only 0.706V to 0.89V, and the mass activities were 0.150A / mg to 0.175A / mg. By comparing the characterization results of the catalysts in Examples 1-4 and Comparative Examples 1-3, it can be seen that the platinum-carbon-iron catalysts obtained by the preparation method of this application have higher electrochemical catalytic activity.

[0176] All references to this application are incorporated herein by reference as if each document were individually incorporated herein by reference. Unless they conflict with the purpose and / or technical solution of this application, all cited references are incorporated herein by reference in their entirety and for all purposes. When references are cited in this application, the definitions of relevant technical features, terms, nouns, phrases, etc., are also incorporated herein by reference. Examples and preferred embodiments of the cited technical features may also be incorporated herein by reference, but only to the extent that they enable the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, this application shall prevail or modifications shall be made adaptably to the description in this application.

[0177] The technical features of the above-described embodiments and examples can be combined in any suitable manner. For the sake of brevity, not all possible combinations of the technical features in the above-described embodiments and examples are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0178] The embodiments described above merely illustrate several implementation methods of this application and should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Furthermore, it should be understood that after reading the above teachings, those skilled in the art can make various alterations or modifications to this application, and the equivalent forms obtained also fall within the protection scope of this application. It should also be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the protection scope of the appended claims. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing a platinum-iron-carbon catalyst using waste rubber powder, characterized in that, include: The first waste rubber powder was pyrolyzed to obtain pyrolytic carbon; The pyrolytic carbon is mixed with a metal salt, a complexing agent, and water to obtain a first mixture; the metal salt includes platinum salts and iron salts. The molar ratio of the total metal cations in the metal salt to the total carbon atoms in the pyrolytic carbon is (0.1–0.5):1; The first mixture was heated while stirring to obtain a sol; The sol was dried to obtain a dry gel, and the dry gel was calcined to obtain a catalyst precursor. The second waste rubber powder is mixed with the catalyst precursor to obtain a second mixture; the mass of the second waste rubber powder accounts for 5% to 20% of the total mass of the second mixture. The second mixture was subjected to microwave irradiation to obtain the platinum-iron-carbon catalyst.

2. The method for preparing platinum-iron-carbon catalyst from waste rubber powder according to claim 1, characterized in that, The first waste rubber powder is pyrolyzed to obtain pyrolytic carbon, including: A first inert gas is introduced into the first waste rubber powder, and the mixture is treated at a first temperature for a first time to obtain the pyrolytic carbon; wherein the first temperature is 550℃~650℃, and the first time is 2h~6h. Optionally, the flow rate of the inert gas is 150 mL / min to 250 mL / min.

3. The method for preparing platinum-iron-carbon catalyst from waste rubber powder according to claim 1 or 2, characterized in that, The molar ratio of the platinum salt to the iron salt is (1-9):

1. The molar ratio of the total cations in the metal salt to the complexing agent is 1:(0.8-1.25).

4. The method for preparing platinum-iron-carbon catalyst from waste rubber powder according to claim 1 or 2, characterized in that, The first mixture is heated under stirring to prepare a sol, comprising: The first mixture was stirred at a first stirring speed and a second temperature for a second time to obtain the sol; The first stirring speed is 600 rpm to 1000 rpm, the second temperature is 50℃ to 70℃, and the second time is 30 min to 90 min.

5. The method for preparing a platinum-iron-carbon catalyst from waste rubber powder according to claim 1 or 2, characterized in that, After drying, the sol is obtained as a dry gel, comprising: The sol was subjected to rotary evaporation at a third temperature and a third time under a first vacuum to obtain a wet gel. The wet gel is dried at a fourth temperature for a fourth time to obtain a dry gel; The first vacuum degree is 0.01 MPa to 0.05 MPa, the third temperature is 50°C to 70°C, and the third time is 0.3 h to 1 h. The fourth temperature is 70℃~90℃, and the fourth time is 12h~24h.

6. The method for preparing platinum-iron-carbon catalyst from waste rubber powder according to claim 5, characterized in that, The dry gel is calcined to obtain the catalyst precursor, comprising: The catalyst precursor was prepared by subjecting the dry gel to a fifth temperature for a fifth time. The fifth temperature is 330℃~450℃, and the fifth time is 2h~4h.

7. The method for preparing a platinum-iron-carbon catalyst from waste rubber powder according to claim 1 or 2, characterized in that, The second mixture was subjected to microwave irradiation to obtain a platinum-carbon-iron catalyst, comprising the following steps: The platinum-carbon-iron catalyst is prepared by passing a second inert gas into the second mixture and heating it under a first microwave power for a sixth time. The first microwave power is 400W to 1000W, and the sixth time is 10min to 20min.

8. The method for preparing a platinum-iron-carbon catalyst from waste rubber powder according to claim 1 or 2, characterized in that, At least one of the following conditions must be met: (1) The platinum salt includes at least one of chloroplatinic acid, platinum nitrate and platinum acetate; (2) The iron salt includes at least one of ferric nitrate, ferrous sulfate and ferric chloride; (3) The complexing agent includes at least one of citric acid, disodium ethylenediaminetetraacetate, acetylacetone, aminotriacetic acid, oxalic acid, glycine and polyvinylpyrrolidone; (4) The water is deionized water.

9. A platinum-iron-carbon catalyst prepared by the method for preparing a platinum-iron-carbon catalyst using waste rubber powder according to any one of claims 1 to 8, wherein the platinum-iron-carbon catalyst simultaneously possesses electrocatalytic and thermocatalytic properties.

10. The application of the platinum-iron-carbon catalyst according to claim 9, characterized in that, Used in the preparation of solid polymer membrane electrolyte fuel cells; and / or, As a dehydrogenation catalyst for the thermocatalytic hydrogen production from organic waste.

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