Method for preparing platinum-iron-carbon catalyst from waste rubber powder, platinum-iron-carbon catalyst and application

Abstract

The invention relates to the technical field of fossil resource recycling and fuel cell catalysts, in particular to a method for preparing a platinum-iron-carbon catalyst from waste rubber powder, the platinum-iron-carbon catalyst and application. The method comprises the following steps: performing pyrolysis treatment on first waste rubber powder to prepare pyrolytic carbon; mixing the pyrolytic carbon with a metal salt, a complexing agent and water to obtain a first mixture; the metal salt comprises platinum salt and ferric salt; heating the first mixture under stirring to prepare sol; drying the sol, and calcining to obtain a catalyst precursor; mixing the second waste rubber powder with the catalyst precursor to obtain a second mixture; and carrying out microwave radiation treatment on the second mixture to prepare the platinum-iron-carbon catalyst. According to the technical scheme, the preparation method of the high-activity platinum-carbon-iron catalyst is simple in process and low in cost, and high-value recycling of waste rubber is achieved.

Description

Technical Field

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

[0002] Solid Polymer Membrane Fuel Cell (SPMEFC) is a fuel cell that uses a solid polymer electrolyte as an ion-conducting medium. This type of fuel cell usually operates at a lower temperature, so it is also called a low-temperature fuel cell.

[0003] Solid polymer membrane electrolyte fuel cells are mainly composed of key components such as proton exchange membrane, catalyst layer, gas diffusion layer, bipolar plate and current collector. Among them, the proton exchange membrane plays a role in isolating fuel and oxidant, conducting protons (hydrogen ions H + ) and prevent electrons from passing through; the catalyst layer is coated on both sides of the proton exchange membrane to accelerate the oxidation reaction of hydrogen (at the anode) and the reduction reaction of oxygen (at the cathode); the gas diffusion layer ensures uniform gas transmission and supports the catalyst; the bipolar plate is used to distribute the reaction gas, conduct electricity and dissipate heat; the current collecting plate is responsible for connecting multiple single cells to form a battery stack to provide sufficient voltage and power.

[0004] At present, SPEMFC generally uses platinum-carbon catalyst to prepare the catalyst layer. Platinum-carbon catalyst is a catalyst material that loads platinum nanoparticles on a carbon carrier. The commonly used carbon carrier is carbon black (such as Cabot XC-72, etc.). Since the combination of 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. In addition, the preparation process is relatively complicated, which is not conducive to large-scale industrial production and application.

[0005] In order to improve the performance of platinum-carbon catalysts and reduce costs, researchers have conducted a lot of research on their preparation methods and material composition, including the use of precipitation conversion process, chemical reduction method and microwave dielectric heating technology to improve the dispersion of platinum in carbon carriers, the use of cheap metals to replace platinum to reduce costs, and the adjustment of the size and morphology of platinum-carbon catalysts to improve their catalytic activity and stability. Despite this, the commercial application of platinum-carbon catalysts still faces challenges. On the one hand, the preparation process of platinum-carbon catalysts needs to be further simplified to adapt to large-scale production and application. On the other hand, the consumption of carbon raw materials, platinum raw materials and necessary reagents of platinum-carbon catalysts needs to be further controlled to meet people's pursuit of energy conservation and environmental protection.

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

[0007] Based on this, one or more embodiments of the present application provide a method for preparing a platinum-iron-carbon catalyst using waste rubber powder, a platinum-iron-carbon catalyst and an application. The method for preparing a platinum-iron-carbon catalyst in the present application greatly simplifies the preparation process, reduces the preparation cost, has low raw material cost, and low reagent consumption. The prepared platinum-iron-carbon catalyst has high electrochemical activity and high bonding strength between the active particles and the carbon carrier.

[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 comprises:

[0010] The first waste rubber powder is subjected to pyrolysis treatment 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 comprises a platinum salt and an 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] heating the first mixture under stirring to obtain a sol;

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

[0014] Mixing a second waste rubber powder 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 is subjected to microwave radiation treatment 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] Passing a first inert gas into the first waste rubber powder, treating the first waste rubber powder at a first temperature for a first time, to obtain the pyrolytic carbon;

[0018] Wherein, the first temperature is 550°C to 650°C, and the first time is 2h to 6h;

[0019] Optionally, the flow rate of the inert gas is 150 mL / min~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] Stirring the first mixture at a first stirring speed and a second temperature for a second time to obtain the sol;

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

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

[0026] Rotating and evaporating the sol at a third temperature for a third time under a first vacuum degree to obtain a wet gel;

[0027] Drying the wet gel at a fourth temperature for a fourth time to obtain a dry gel;

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

[0029] The fourth temperature is 70° C. to 90° C., and the fourth time is 12 h to 24 h.

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

[0031] treating the xerogel at a fifth temperature for a fifth time to obtain the catalyst precursor;

[0032] The fifth temperature is 330° C. to 450° C., and the fifth time is 2 h to 4 h.

[0033] In one embodiment, subjecting the second mixture to microwave radiation treatment to obtain a platinum-carbon catalyst comprises the following steps:

[0034] Passing a second inert gas into the second mixture under the first microwave power for a sixth time to obtain the platinum-carbon catalyst;

[0035] The first microwave power is 400W~1000W, and the sixth time is 10min~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 comprises at least one of ferric nitrate, ferrous sulfate and ferric chloride;

[0039] (3) the complexing agent comprises at least one of citric acid, disodium ethylenediaminetetraacetic acid, acetylacetone, nitrilotriacetic acid, oxalic acid, glycine and polyvinylpyrrolidone;

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

[0041] A platinum-iron-carbon catalyst prepared by the method for preparing a platinum-iron-carbon catalyst using waste rubber powder as described above, wherein the platinum-iron-carbon catalyst has both electrocatalytic performance and thermal catalytic performance.

[0042] An application of the platinum iron carbon catalyst described above for preparing a solid polymer membrane electrolyte fuel cell; and / or,

[0043] As a dehydrogenation catalyst for thermal catalytic hydrogen production from organic waste.

[0044] The technical solution of the present application is aimed at the problems of the current catalyst layer materials of solid polymer membrane electrolyte fuel cells, such as complex preparation methods, environmental unfriendliness of the preparation methods, and high cost of carbon carrier raw materials. A method for preparing platinum iron carbon catalyst using waste rubber powder is provided. The method uses waste rubber as a carbon source and a hydrogen source, and loads the metal components by adopting a suitable method, thereby comprehensively reducing the preparation cost of the platinum carbon catalyst, while also realizing the high-value conversion and recycling of fossil resources.

[0045] The method of preparing platinum iron carbon catalyst using waste rubber powder in the present application simplifies the preparation process compared with the prior art, does not require the use of dangerous reagents such as strong acids and strong bases, saves costs and is environmentally friendly, is easy to scale up and produce, and has great application potential.

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

[0047] The platinum iron carbon catalyst of the present application has both electrocatalytic and thermal catalytic properties, and can be used to prepare solid polymer membrane electrolyte fuel cells. It can also be used as an efficient and low-cost dehydrogenation catalyst for green hydrogen production from organic waste, which includes biomass, waste plastics, waste rubber, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 This is a transmission electron microscope image of the platinum iron carbon catalyst of Example 1 of the present application, Figure 1 A, B, and C correspond to different sampling sites, and the scale bar is 5 nm. DETAILED DESCRIPTION

[0050] The present application will be further described below in conjunction with the embodiments and examples. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application. In addition, it should be understood that after reading the content taught in the present application, those skilled in the art may make various changes or modifications to the present application, and these equivalent forms also fall within the protection scope of the claims attached to the present application.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0052] the term

[0053] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

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

[0055] In the present application, "further", "optionally" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0056] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0057] In this application, when it comes to numerical intervals (i.e., numerical ranges), unless otherwise specified, the optional numerical distribution is considered continuous within the above numerical interval, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical range, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to integers within the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges included therein.

[0058] In the present application, weight may be μg, mg, g, kg or other mass units known in the chemical industry.

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

[0060] Platinum-carbon catalyst is a carrier catalyst that loads platinum onto activated carbon. It is a type of precious metal catalyst. In the field of fuel cells, platinum-carbon catalyst is particularly important. It can be used for chemical reactions such as hydrogen oxidation, methanol oxidation, formic acid oxidation, and oxygen reduction. It is a commonly used material in hydrogen fuel cells and water electrolysis reactions. Although platinum-carbon catalyst has a high catalytic efficiency, its cost is relatively high, mainly due to the high price of platinum itself and the high price of carbon black as a carbon carrier, and the complicated preparation process.

[0061] One aspect of the present application provides a method for preparing a platinum iron carbon catalyst using waste rubber powder. The method uses waste rubber as a carbon source and a hydrogen source, reduces the cost of the catalyst from the raw material level, simplifies the preparation process, and effectively reduces the preparation cost. The method is simple and easy to mass produce. It does not require the use of organic solvents and strong acids and alkalis, and is environmentally friendly. At the same time, the method can be analogized to the field of high-value recycling of other types of organic solid waste raw materials, and has a relatively broad application potential.

[0062] In one embodiment, the waste rubber powder comes from waste tire rubber powder. The stock of waste tires is large, and the recycling work is relatively easy to carry out. In addition, the carbon-hydrogen ratio of waste tire rubber powder is higher, which is more conducive to providing the hydrogen and carbon source required for reduction and loading.

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

[0064] The first waste rubber powder is subjected to pyrolysis treatment 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 comprises a platinum salt and an iron salt; the molar ratio of total cations in the metal salt to total carbon atoms in the pyrolytic carbon is (0.1-0.5):1;

[0066] heating the first mixture under stirring to obtain a sol;

[0067] The sol is dried and then calcined to obtain a catalyst precursor;

[0068] Mixing a second waste rubber powder 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 is subjected to microwave radiation treatment 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] Passing a first inert gas into the first waste rubber powder at a first temperature for a first time to obtain the pyrolytic carbon;

[0072] Wherein, the first temperature is 550°C to 650°C, and the first time is 2h to 6h;

[0073] Optionally, the flow rate of the inert gas is 150 mL / min~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] Stirring the first mixture at a first stirring speed and a second temperature for a second time to obtain the sol;

[0078] Wherein, the first stirring speed is 600 rpm to 1000 rpm, the second temperature is 50° C. to 70° C., 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] Wherein, after the sol is dried, a dry gel is obtained, comprising:

[0081] Rotating and evaporating the sol at a third temperature for a third time under a first vacuum degree to obtain a wet gel;

[0082] Drying the wet gel at a fourth temperature for a fourth time to obtain a dry gel;

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

[0084] The fourth temperature is 70° C. to 90° C., and the fourth time is 12 h to 24 h.

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

[0086] treating the xerogel at a fifth temperature for a fifth time to obtain the catalyst precursor;

[0087] The fifth temperature is 330° C. to 450° C., and the fifth time is 2 h to 4 h.

[0088] In one embodiment, subjecting the second mixture to microwave radiation treatment to obtain a platinum-carbon catalyst comprises the following steps:

[0089] Passing a second inert gas into the second mixture under the first microwave power for a sixth time to obtain the platinum-carbon catalyst;

[0090] The first microwave power is 400W~1000W, and the sixth time is 10min~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 comprises at least one of ferric nitrate, ferrous sulfate and ferric chloride;

[0094] (3) the complexing agent comprises at least one of citric acid, disodium ethylenediaminetetraacetic acid, acetylacetone, nitrilotriacetic acid, oxalic acid, glycine and polyvinylpyrrolidone;

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

[0096] On the other hand, the present application provides a platinum-iron-carbon catalyst prepared by the method for preparing a platinum-iron-carbon catalyst using waste rubber powder as described above. The method uses a sol-gel combustion method to accurately control the content and proportion of various metal components in the catalyst, and allows the metal components to be evenly dispersed. The method also uses the high carbon-hydrogen ratio of waste rubber heat to decompose the waste rubber into pyrolytic carbon and pyrolytic hydrogen in a short time through microwave radiation heating, and can achieve the reduction of platinum and iron active particles and the generation of carbon in one step. At the same time, the active particles of the catalyst are embedded in the carbon carrier, which improves the bonding strength between the metal particles and the carbon carrier. The prepared platinum-iron-carbon catalyst has good uniformity, strong anti-reverse polarity performance, high activity and good electronic conductivity.

[0097] In another aspect of the present application, there is provided a use of the platinum iron carbon catalyst described above in the preparation of a fuel cell catalyst.

[0098] The technical solution of the present application is aimed at the problems of the current catalyst layer materials of solid polymer membrane electrolyte fuel cells, such as complex preparation methods, environmental unfriendliness of the preparation methods, and high cost of carbon carrier raw materials. A method for preparing platinum iron carbon catalyst using waste rubber powder is provided. The method uses waste rubber as a carbon source and a hydrogen source and adopts a cheap and readily available carbon source, thereby reducing the preparation cost of the platinum carbon catalyst and realizing the high-value conversion and recycling of fossil resources.

[0099] The method of preparing platinum iron carbon catalyst using waste rubber powder in the present application simplifies the preparation process compared with the prior art, does not require the use of dangerous reagents such as strong acids and strong bases, saves costs, is environmentally friendly, and is easy to scale up.

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

[0101] The following are some specific embodiments.

[0102] For experimental parameters not specified in the following specific embodiments, reference is made to the instructions given in the present application document, and reference may also be made to experimental manuals in the art or other experimental methods known in the art, or to experimental conditions recommended by manufacturers.

[0103] The raw materials and reagents involved in the following specific examples can be obtained from commercial sources, or can be prepared by those skilled in the art according to known methods.

[0104] The waste rubber powder used in the embodiments of the present application is sourced from waste tire rubber powder, which is purchased from Shaanxi Hongrui Rubber Products.

[0105] Example 1

[0106] (1) Take 50 g of waste tire rubber powder and place it in a pyrolysis reactor. 2 (200 mL / min), pyrolyzed at 550 °C for 6 h to obtain pyrolytic carbon;

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

[0108] (3) heating and stirring the first mixture at 600 rpm and 50° C. for 90 min to obtain a sol;

[0109] (4) Using a rotary vacuum evaporation method (0.01 MPa, 70°C) to evaporate the water in the sol to obtain a wet gel, the evaporation time is about 0.3 h;

[0110] (5) The wet gel was placed in a vacuum drying oven and dried at 80°C to obtain a dry gel for about 18 hours;

[0111] (6) placing the dry gel in a tubular furnace and calcining it at 330 °C for 4 h to obtain a fluffy catalyst precursor;

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

[0113] (8) The second mixture is placed in a microwave radiation reactor and N 2 , stop passing N after the air is exhausted 2 , treated with microwave radiation at 800 W for 15 min, and taken out after the reactor was cooled to room temperature to obtain platinum carbon iron catalyst S1.

[0114] Example 2

[0115] (1) Place 10 g of waste tire rubber powder in a pyrolysis reactor and introduce N 2 (200 ml / min), pyrolysis at 650℃ for 3h to obtain waste tire pyrolysis carbon;

[0116] (2) mixing pyrolytic carbon (0.36 mol based on 4.4 g) with chloroplatinic acid (0.06 mol), ferric nitrate nonahydrate (0.05 mol), citric acid (0.9 mol) and deionized water to obtain a 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) Using a rotary vacuum evaporation method (0.03 MPa, 65 °C) to evaporate the water in the sol to obtain a wet gel, the evaporation time is about 0.5 h;

[0119] (5) The wet gel was placed in a vacuum drying oven and dried at 80°C to obtain a dry gel for about 18 hours;

[0120] (6) placing the dry gel in a tubular furnace and calcining it at 450 °C for 3.5 h to obtain a fluffy catalyst precursor;

[0121] (7) taking another 0.4 g of waste tire rubber powder and mixing it with the catalyst precursor to obtain a second mixture, wherein the second mixture contains 10 w% of waste tire rubber powder;

[0122] (8) The second mixture is placed in a microwave radiation reactor and N2 , stop passing N after the air is exhausted 2 , treated with microwave radiation at 700 W for 20 min, and taken out after the reactor was cooled to room temperature to obtain platinum carbon iron catalyst S2.

[0123] Example 3

[0124] (1) Place 10 g of waste tire rubber powder in a pyrolysis reactor and introduce N 2 (200 ml / min), pyrolysis at 620℃ for 3.5h to obtain waste tire pyrolysis carbon;

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

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

[0127] (4) Using a rotary vacuum evaporation method (0.05 MPa, 60°C) to evaporate the water in the sol to obtain a wet gel, the evaporation time is about 1 h;

[0128] (5) The wet gel was placed in a vacuum drying oven and dried at 80°C to obtain a dry gel for about 18 hours;

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

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

[0131] (8) The second mixture is placed in a microwave radiation reactor and N 2 , stop passing N after the air is exhausted 2 , treated with microwave radiation at 1000 W for 10 min, and taken out after the reactor was cooled to room temperature to obtain platinum carbon iron catalyst S3.

[0132] Example 4

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

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

[0135] (3) heating and stirring the first mixture at 800 rpm and 70°C for 30 min to obtain a sol;

[0136] (4) Using a rotary vacuum evaporation method (0.05 MPa, 60°C) to evaporate the water in the sol to obtain a wet gel, the evaporation time is about 1 h;

[0137] (5) The wet gel was placed in a vacuum drying oven and dried at 80°C to obtain a dry gel for about 18 hours;

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

[0139] (7) taking another 1 g of waste tire rubber powder and mixing it with the catalyst precursor to obtain a second mixture, wherein the second mixture contains 18w% of waste tire rubber powder;

[0140] (8) The second mixture is placed in a microwave radiation reactor and N 2 , stop passing N after the air is exhausted 2 , treated with microwave radiation at 900 W for 12 min, and taken out after the reactor was cooled to room temperature to obtain platinum carbon iron catalyst S4.

[0141] Comparative Example 1

[0142] (1) Place 10 g of waste tire rubber powder in a pyrolysis reactor and introduce N 2 (200 ml / min), pyrolysis at 600℃ for 3 h to obtain waste tire pyrolysis carbon;

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

[0144] (3) heating and stirring the first mixture at 900 rpm and 60° C. for 40 min to obtain a sol;

[0145] (4) Using a rotary vacuum evaporation method (0.05 MPa, 60°C) to evaporate the water in the sol to obtain a wet gel, the evaporation time is about 1 h;

[0146] (5) The wet gel was placed in a vacuum drying oven and dried at 80°C to obtain a dry gel for about 18 hours;

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

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

[0149] (8) The second mixture is placed in an electrically heated fixed bed reactor and N 2 , stop passing N after the air is exhausted 2 , heated at 800 °C for 10 min, and taken out after the reactor was cooled to room temperature to obtain platinum carbon iron catalyst D1.

[0150] Comparative Example 2

[0151] (1) Place 10 g of waste tire rubber powder in a pyrolysis reactor and introduce N 2 (200 ml / min), pyrolysis at 600℃ for 3 h to obtain waste tire pyrolysis carbon;

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

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

[0154] (4) Using a rotary vacuum evaporation method (0.03 MPa, 60 °C) to evaporate the water in the sol to obtain a wet gel, the evaporation time is about 1 h;

[0155] (5) The wet gel was placed in a vacuum drying oven and dried at 90°C to obtain a dry gel for about 18 hours;

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

[0157] (7) taking another 0.5 g of waste tire rubber powder and mixing it with the catalyst precursor to obtain a second mixture, wherein the second mixture contains 10 w% of waste tire rubber powder;

[0158] (8) The second mixture is placed in an electrically heated fixed bed reactor and N 2 , stop passing N after the air is exhausted 2 , heat treatment at 750 ℃ ​​for 10 minutes, and take out after the reactor is cooled to room temperature to obtain platinum carbon iron catalyst D2.

[0159] Comparative Example 3

[0160] (1) Place 10 g of waste tire rubber powder in a pyrolysis reactor and introduce N 2 (200 ml / min), pyrolysis at 600℃ for 3 h to obtain waste tire pyrolysis carbon;

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

[0162] (3) heating and stirring the first mixture at 900 rpm and 60° C. for 50 min to obtain a sol;

[0163] (4) Using a rotary vacuum evaporation method (0.05 MPa, 55 °C) to evaporate the water in the sol to obtain a wet gel, the evaporation time is about 1 h;

[0164] (5) The wet gel was placed in a vacuum drying oven and dried at 90°C to obtain a dry gel for about 20 hours;

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

[0166] (7) taking another 2 g of waste tire rubber powder and mixing it with the catalyst precursor to obtain a second mixture, wherein the second mixture contains 50w% of waste tire rubber powder;

[0167] (8) The second mixture is placed in an electrically heated fixed bed reactor and N 2 , stop passing N after the air is exhausted 2 , heat treatment at 800 ℃ for 10 minutes, and take out after the reactor is cooled to room temperature to obtain platinum carbon iron catalyst D3.

[0168] 2. Application of the platinum-carbon-iron catalyst of the above embodiment in preparing a battery

[0169] (1) Appearance

[0170] The transmission electron microscope image of Example 1 is as follows Figure 1 ,according to Figure 1 A, B, and C are electron microscope images of different sampling sites. From these images, it can be seen that the active metal particles are embedded in the surface of the carbon carrier, forming a strong bond between the active particles and the carbon carrier.

[0171] (2) Catalyst test results

[0172] The platinum-carbon-iron catalysts (platinum-carbon-iron catalysts S1-S4, D1) prepared in the above-mentioned embodiments and comparative examples were tested respectively using a rotating disk electrode system to obtain corresponding test data. 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 to S3 of Examples 1 to 3 reached 0.926 V, 0.921 V and 0.917 V, and the calculated catalyst mass activity reached 0.386 A / mg to 0.541 A / mg; the half-wave potential of the catalyst S4 of Example 4 was 0.901 V, and the mass activity was 0.241; the half-wave potential of the platinum carbon iron catalysts D1 to D3 of Comparative Examples 1 to 3 was only 0.706 V to 0.89 V, and the mass activity was 0.150 A / mg to 0.175 A / mg. By comparing the catalyst characterization results of Examples 1 to 4 and Comparative Examples 1 to 3, it can be seen that the platinum carbon iron catalyst obtained by the preparation method of the present application has a higher electrochemical catalytic activity.

[0176] All documents mentioned in this application are cited as references in this application, just as each document is cited as reference separately. Unless they conflict with the application purpose and / or technical solution of this application, the cited documents involved in this application are cited with all contents and all purposes. When the cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the cited documents are involved in this application, the examples and preferred methods of the cited relevant technical features can also be incorporated into this application as references, but are limited to the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be modified adaptively according to the description of this application.

[0177] The technical features of the above-mentioned implementation modes and examples can be combined in any appropriate manner. To make the description concise, not all possible combinations of the technical features in the above-mentioned implementation modes 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 above-described embodiments only express several implementation methods of the present application, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can also be made, which all belong to the protection scope of the present application. In addition, it should be understood that after reading the above-mentioned teaching content of the present application, those skilled in the art can make various changes or modifications to the present application, and the equivalent forms obtained also fall within the protection scope of the present application. It should also be understood that the technical solutions obtained by those skilled in the art on the basis of the technical solutions provided in the present application through logical analysis, reasoning or limited experiments are all within the protection scope of the claims attached to the present application. Therefore, the protection scope of the patent of the present application shall be based on the attached claims, and the description 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 is subjected to pyrolysis treatment 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 comprises a platinum salt and an 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; heating the first mixture under stirring to obtain a sol; The sol is dried to obtain a dry gel, and the dry gel is calcined to obtain a catalyst precursor; Mixing a second waste rubber powder 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 is subjected to microwave radiation treatment to obtain the platinum iron carbon catalyst.

2. The method for preparing a platinum iron carbon catalyst using waste rubber powder according to claim 1, characterized in that: The first waste rubber powder is subjected to pyrolysis treatment to obtain pyrolytic carbon, comprising: Passing a first inert gas into the first waste rubber powder, treating the first waste rubber powder at a first temperature for a first time, to obtain the pyrolytic carbon; Wherein, the first temperature is 550°C to 650°C, and the first time is 2h to 6h; Optionally, the flow rate of the inert gas is 150 mL / min~250 mL / min.

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

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

6. The method for preparing platinum iron carbon catalyst using waste rubber powder according to claim 5, characterized in that: The dry gel is calcined to obtain the catalyst precursor, comprising: treating the xerogel at a fifth temperature for a fifth time to obtain the catalyst precursor; The fifth temperature is 330° C. to 450° C., and the fifth time is 2 h to 4 h.

7. The method for preparing platinum iron carbon catalyst using waste rubber powder according to claim 1 or 2, characterized in that: The second mixture is subjected to microwave radiation treatment to prepare a platinum carbon iron catalyst, comprising the following steps: Passing a second inert gas into the second mixture, and heating the mixture under the first microwave power for a sixth time, to obtain the platinum-carbon-iron catalyst; The first microwave power is 400W~1000W, and the sixth time is 10min~20min.

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

9. A platinum iron carbon catalyst obtained 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 has both electrocatalytic performance and thermal catalytic performance.

10. Use of the platinum iron carbon catalyst according to claim 9, characterized in that: For preparing a solid polymer membrane electrolyte fuel cell; and / or, As a dehydrogenation catalyst for thermal catalytic hydrogen production from organic waste.

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