A continuous rapid batch production device and method of platinum carbon catalyst

Abstract

A kind of continuous quick batch production device and method of platinum carbon catalyst, it relates to the preparation device and method of fuel cell catalyst, it is to solve the technical problems of high cost, cannot continuous production of existing carbon-supported platinum catalyst production method, the device includes successively connected liquid supply system, first microwave reactor, intermediate collection system, transmission pump, second microwave reactor and receiving container;First microwave reactor and second microwave reactor are same in structure, including serpentine pipe reactor and microwave source transmitter.Catalyst preparation method: the raw material liquid containing carbon powder and chloroplatinic acid is input into the first serpentine pipe reactor of first microwave reactor, the temperature of first serpentine pipe reactor is controlled using microwave reactor, then input into intermediate collection system, then input into second microwave reactor and flow into receiving container after reaction.Catalyst particle size is 2-5nm, particle is uniform and not agglomerated, the performance and stability of catalyst are improved.It can be used in catalysis field.

Description

TECHNICAL FIELD

[0001] The present application relates to a device and method for preparing a fuel cell catalyst, and in particular to a device and method for continuously producing a high-activity and high-durability platinum-carbon catalyst using a microwave method. BACKGROUND

[0002] Currently, hydrogen fuel cells (PEMFC) are attracting much attention, and their performance mainly depends on the performance of the catalytic layer in the core component membrane electrode. Therefore, developing a low-cost, high-performance, and long-life catalyst is the key to the commercialization of PEMFC. Carbon-supported platinum (Pt / C) catalyst is a widely used catalyst. Porous carbon material with high specific surface area is used as a carrier to adsorb and embed nano-Pt particles on the surface of the porous carbon to improve the dispersion of the metal platinum, thereby improving the catalytic activity of the catalyst. The size and morphology of the Pt particles determine the performance of the catalyst. Fine and uniformly dispersed Pt particles increase the specific surface area of Pt, increase the active sites, and improve the utilization rate of the catalyst. Therefore, it is necessary to develop a fast and effective process to produce a catalyst with high catalytic activity and good stability, significantly reduce the cost of hydrogen fuel cells, and promote the commercialization process. In recent years, a lot of effort has been devoted to research on catalyst preparation methods at home and abroad, and many methods and technologies for preparing fuel cell catalysts have been proposed, such as the common colloidal method, impregnation reduction method, electrodeposition method, and ion exchange method, which have achieved good results. However, most of them are still at the laboratory stage due to equipment scaling problems.

[0003] Currently, the batch production of platinum-based catalysts mostly uses hydrothermal reaction method (one-pot method) for synthesis. This production method is high in cost and low in efficiency, and the synthesized catalyst is expensive and has uneven performance, which is not conducive to the further development of the industry. The existing microwave continuous production method is relatively complex to control, and the step control is not accurate enough for batch production of high-performance and long-life platinum-carbon catalysts. SUMMARY

[0004] The present application is to solve the technical problems of high cost and non-continuous production of the existing carbon-supported platinum (Pt / C) catalyst production method, and to provide a continuous and rapid batch production device and method for high-performance and long-life platinum-carbon catalyst. The device of the present application is a microwave production device for high-activity and high-durability platinum-carbon catalysts, which can continuously produce, is simple to operate, has high productivity, and is low in cost. The method can prepare high-quality platinum / carbon catalysts with uniform particles, high catalytic activity, and good durability, and has high production efficiency, which can be used for large-scale batch production.

[0005] The continuous and rapid batch production device for platinum-carbon catalysts of the present application comprises a liquid supply system 1, a first microwave reactor 2, an intermediate collection system 3, a transfer pump 4, a second microwave reactor 5, and a receiving container 6.

[0006] The first microwave reactor 2 is composed of a first coiled pipe reactor 2-1, a first microwave source emitter 2-2, a first microwave reaction cavity 2-3 and a first box 2-4; the first coiled pipe reactor 2-1 and the first microwave source emitter 2-2 are arranged in the first microwave reaction cavity 2-3, and the first microwave source emitter 2-2 is arranged below the first coiled pipe reactor 2-1; the first microwave reaction cavity 2-3 is fixed in the first box 2-4; a first liquid inlet 2-1-1 and a first liquid outlet 2-1-2 of the first coiled pipe reactor 2-1 extend out of the first microwave reaction cavity 2-3; the first liquid inlet 2-1-1 is connected with the liquid supply system 1; and the first liquid outlet 2-1-2 is connected with the intermediate collection system 3.

[0007] The second microwave reactor 5 has the same structure as the first microwave reactor 2; the second microwave reactor 5 is composed of a second coiled pipe reactor 5-1, a second microwave source emitter 5-2, a second microwave reaction cavity 5-3 and a second box 5-4; the second coiled pipe reactor 5-1 and the second microwave source emitter 5-2 are arranged in the second microwave reaction cavity 5-3, and the second microwave source emitter 5-2 is arranged below the second coiled pipe reactor 5-1; the second microwave reaction cavity 5-3 is fixed in the second box 5-4; a second liquid inlet 5-1-1 and a second liquid outlet 5-1-2 of the second coiled pipe reactor 5-1 extend out of the second microwave reaction cavity 5-3; the intermediate collection system 3 is connected with the second liquid inlet 5-1-1 through the transmission pump 4; and the second liquid outlet 5-1-2 is connected with the receiving container 6.

[0008] Further, the liquid supply system 1 is composed of an argon gas cylinder 1-1, a stirring table 1-2, a storage tank 1-3 and a peristaltic pump 1-4; the storage tank 1-3 is placed on the stirring table 1-2; the argon gas cylinder 1-1 is connected with the storage tank 1-3; and the storage tank 1-3 is connected with the first liquid inlet 2-1-1 of the first microwave reactor 2 through the peristaltic pump 1-4.

[0009] Further, the intermediate collection system 3 is composed of a collection kettle 3-1, a constant pressure funnel 3-2, a condenser 3-3 and a support 3-4; the collection kettle 3-1 has a feeding port 3-1-1 and a gas outlet 3-1-2 at the upper end, and has a discharging port 3-1-3 at the lower end; a stirrer 3-1-4 is arranged in the collection kettle 3-1; the constant pressure funnel 3-2 is arranged on the feeding port 3-1-1 of the collection kettle 3-1; and the condenser 3-3 is arranged on the gas outlet 3-1-2 of the collection kettle 3-1; the first liquid outlet 2-1-2 of the first microwave reactor 2 is connected with the constant pressure funnel 3-2.

[0010] Further, a jacket 3-1-5 is arranged on the outer wall of the collection kettle 3-1, and water can be passed through the jacket 3-1-5 to perform cold water bath cooling.

[0011] Further, temperature detectors are arranged at the first liquid inlet 2-1-1 and the first liquid outlet 2-1-2.

[0012] Further, temperature detectors are arranged at the second liquid inlet 5-1-1 and the second liquid outlet 5-1-2.

[0013] Further, the first box 2-4 is provided with a switch 2-4-1, a manual power adjusting knob 2-4-2, an operation display screen 2-4-3, and a real-time power display screen 2-4-4.

[0014] Further, universal wheels are arranged at the bottom of the bracket 3-4 for facilitating movement.

[0015] The method for preparing the platinum-carbon catalyst by using the continuous rapid batch production device of the platinum-carbon catalyst is performed according to the following steps:

[0016] I. Preparation of raw materials:

[0017] (1) Carbon powder treatment: The porous carbon powder is placed on a screen rack in an autoclave, and super-pure water is added under the screen rack. The autoclave is heated to 2-3 MPa and maintained for 5-6 hours. Then, the carbon powder is taken out and placed in a vacuum drying box with a temperature of 80℃ for vacuum drying for 2-3 hours. In this step, the carbon powder is treated with high-pressure steam on the screen rack to clean the pores of the carbon powder, which is beneficial for subsequent loading. Then, the carbon powder is vacuum dried to avoid residual water.

[0018] (2) Preparation of raw material solution: The porous carbon powder is added to ethylene glycol and ultrasonically mixed uniformly. Then, the ethylene glycol solution of chloroplatinic acid (H2PtCl6) is added under stirring. After stirring uniformly, the pH value is adjusted to 11-12.5 by using the ethylene glycol solution of sodium hydroxide. Then, argon is introduced to remove oxygen in the mixed solution to obtain the raw material solution.

[0019] II. Continuous microwave reaction:

[0020] (1) The raw material solution in the feeding system is input into the first snake coil type reactor 2-1 of the first microwave reactor 2. The temperature of the first snake coil type reactor 2-1 is controlled to be 100-130℃ by using the first microwave source emitter 2-2. The residence time of the raw material solution in the first microwave reactor 2 is 3s-8min.

[0021] (2) The material flowing out of the first microwave reactor 2 is input into the intermediate collection system 3. The material is stirred and kept at a temperature of 100-130℃ in the intermediate collection system 3 for 10-30min.

[0022] (3) The material is inputted into the second coiled pipe reactor 5-1 of the second microwave reactor 5 by the transmission pump 4, and the temperature of the second coiled pipe reactor 5-1 is controlled by the second microwave source emitter 5-2 to be 140-180℃, and the residence time of the material in the second microwave reactor 5 is 3s-8min;

[0023] (4) The material flowing out of the second microwave reactor 5 is inputted into the receiving container 6, and after being cooled to room temperature, the pH value is adjusted to 0.5-2 by using the ethylene glycol solution of nitric acid (HNO3), and then stirred for 10-12h, so that the reduced platinum carbon particles are completely adsorbed on the porous carbon to obtain a platinum carbon solution;

[0024] (5) Pure water with a temperature of 90-100℃ is added to the platinum carbon solution, and the filter cake is obtained by repeatedly adding hot water and filtering until the pH value of the filtrate reaches neutral or the residual anion content reaches the standard; the filter cake is vacuum dried at a temperature of 80℃ for 3-4h to obtain a dry powder;

[0025] III. The dry powder is heat treated at a temperature of 200-300℃ for 1-2h in an argon atmosphere or a hydrogen-argon mixed gas atmosphere, cooled to room temperature and taken out to obtain a platinum carbon catalyst.

[0026] Further, the concentration of chloroplatinic acid (H2PtCl6) in the ethylene glycol solution of chloroplatinic acid in step one (2) is 0.05-0.5mol / L;

[0027] Further, the concentration of sodium hydroxide in the ethylene glycol solution of sodium hydroxide in step two (2) is 0.5-6mol / L;

[0028] Further, when the argon gas is introduced to remove oxygen in the mixed solution in step two (2), the gas introduction time is 1-1.2h;

[0029] Further, the concentration of the porous carbon powder in the raw material solution in step two (2) is 1.5-4.5g / L; and the concentration of chloroplatinic acid (H2PtCl6) is 3.95-11.85g / L;

[0030] Further, the type of the carbon powder in step one (1) is XC-72, Ketjen black ECP600JD, Ketjen black ECP300 or BP2000;

[0031] Further, the following steps are used to replace the carbon powder treatment in step one (1):

[0032] (1) Carbon powder treatment: disperse the porous carbon black in 30wt% hydrogen peroxide solution, under stirring, heat to 90-100℃ and keep for 1h; then filter and wash the carbon black, and put it into a vacuum drying oven at 80℃ for 2h to remove water, and take it out after cooling to room temperature.

[0033] Further, the carbon powder treatment in step (1) is replaced by the following steps:

[0034] (1) Carbon powder treatment: put the porous carbon powder on a screen rack in an autoclave, and add ultrapure water under the screen rack; heat the autoclave to 2-3MPa and keep for 5-6h; then take out the carbon powder and put it into a vacuum drying oven at 80℃ for 2-3h; then mix the carbon powder with the doping source, and transfer it to a porcelain boat, and put it into a tube furnace, keep it in argon atmosphere at 650-900℃ for 2h, and take it out after cooling to room temperature; wherein the doping source is a nitrogen source or a sulfur source, the nitrogen source is urea or melamine, and the sulfur source is thiourea or titanium disulfide.

[0035] Further, in step (2), the anion content meets the standard, wherein the anion is chloride ion, and the standard is that the chloride ion content is less than 10 -6 mol / L.

[0036] Further, in step (3), the volume percentage of hydrogen in the hydrogen-argon mixed gas is 5%-10%.

[0037] The present application uses microwave radiation heating, which can quickly and efficiently reduce various metal nanoparticles, greatly shortening the time for preparing the catalyst. In the process of reducing metal nanoparticles, the reaction solution is heated by microwave, and the chemical state metal (for example, Pt Ⅵ in hexachloroplatinate) reacts with the solvent ethylene glycol to be reduced into metal elementary substance (Pt 0 ) nanoparticles; the ethylene glycol is oxidized to form glyoxal, glycolic acid, etc., and the oxidation product of ethylene glycol can also have a stabilizing effect on the metal particles generated in the reaction process, and the stabilizing mechanism is as follows: after the chemical state metal platinum (Pt Ⅳ ) is reduced into zero-valent platinum (Pt 0 ), the glycolate ions in the solution are tightly adsorbed on the surface of the metal particles to form a double-layer structure, so that the Pt particles are negatively charged. Due to the electrostatic repulsion between the negatively charged Pt colloidal particles, these Pt particles can exist stably in the solution, effectively preventing the agglomeration of metal particles. In addition, compared with the traditional hydrothermal heating preparation method, this microwave continuous preparation process also has the advantages of fast heating speed and uniform heating, which can promote the formation of a large number of initial crystal nuclei in the reaction, and the finally synthesized metal nanoparticles have good dispersibility, small particle size and narrow particle size distribution range.

[0038] Compared with the prior art, the continuous rapid batch production device and method of the high-performance long-life platinum-carbon catalyst of the application has at least the following beneficial effects:

[0039] (1) Before starting the microwave continuous flow production of the platinum-carbon catalyst, the carbon powder is pretreated (high-temperature steam treatment or nitrogen doping), the ash in the carbon powder is removed, the pore structure and pore size of the carbon powder are improved, the mesopores beneficial to the support are increased, and the hydrophilicity of the surface of the support is enhanced, which is beneficial to the dispersion and anchoring of the platinum particles in the subsequent process, and provides a basis for realizing the high performance and long life of the platinum-carbon catalyst;

[0040] (2) The microwave reduction process uses ethylene glycol as a dispersion medium, which is both a dispersant and a reducing agent, achieving good reduction effect and avoiding the trouble of complex solvent post-treatment, and the subsequent waste liquid treatment is more simple and environmentally friendly;

[0041] (3) In the process of microwave preparation of the catalyst:

[0042] ① In the first microwave reactor 2, Pt Ⅵ is reduced to elemental Pt 0 by alcohol under alkaline conditions at 100℃-140℃, and part of the nucleation is completed;

[0043] ② In the intermediate collection system 3, the solution is kept at 100℃-130℃ for 10-30min, and the nucleation and gestation are continued;

[0044] ③ In the second microwave reactor 5, the solution after gestation is heated to 140℃-180℃ by microwave, and the unreacted Pt Ⅵ in the solution is completely reduced by sufficient alcohol, so that the platinum crystal nucleus grows rapidly at the specific support pore end and reaches the expected particle size.

[0045] The whole process realizes accurate temperature control within ±1℃ by fine-tuning the microwave power, reduces the influence of temperature fluctuation in the reduction process on the size of the platinum particle growth, and prolongs the nucleation (gestation) time of the crystal by subsection microwave, which plays a key role in controlling the particle size of the platinum particles and is the key to realizing the high performance of the platinum-carbon catalyst.

[0046] The final heat treatment step eliminates the residual alcohol and other impurities in the catalyst, ensures the purity of the catalyst, reduces the influence of impurities on the catalyst, and can better improve the performance of the catalyst. Moreover, appropriate low-temperature heat treatment can improve the crystallinity of the platinum particles, which can further improve the performance and stability of the catalyst. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is a structural schematic diagram of the continuous rapid batch production device of the platinum-carbon catalyst of the application;

[0048] Figure 2 is a structural schematic diagram of the tank 2-4;

[0049] Figure 3 is a structural schematic diagram of the collection tank 3-1;

[0050] Figure 4 is a scanning electron microscope image of the platinum carbon catalyst obtained in Example 2;

[0051] Figure 5 is a scanning electron microscope image of the platinum carbon catalyst obtained in Example 3;

[0052] Figure 6 is an XRD spectrum of the platinum carbon catalyst obtained in Examples 2 and 3;

[0053] Figure 7 is a CV curve of the platinum carbon catalyst obtained in Example 2;

[0054] Figure 8 is a SCV curve of the platinum carbon catalyst obtained in Example 2;

[0055] Figure 9 is a power density curve of the platinum carbon catalyst obtained in Example 2;

[0056] Figure 10 is a CV curve of the platinum carbon catalyst obtained in Example 3;

[0057] Figure 11 is a SCV curve of the platinum carbon catalyst obtained in Example 3;

[0058] Figure 12 is a CV curve of the platinum carbon catalyst prepared in Example 3 before and after 30000 cycles;

[0059] Figure 13 is a SCV curve of the platinum carbon catalyst prepared in Example 3 before and after 30000 cycles;

[0060] Figure 14 is a comparison of CV curves of the platinum carbon catalyst prepared in Example 2 and Example 4;

[0061] Figure 15 is a comparison of SCV curves of the platinum carbon catalyst prepared in Example 2 and Example 4.

[0062] In the figure: 1 is a liquid supply system, 1-1 is an argon cylinder, 1-2 is a stirring table, 1-3 is a storage tank, 1-4 is a peristaltic pump, 2 is a first microwave reactor, 2-1 is a first coiled pipe reactor, 2-1-1 is a first liquid inlet, 2-1-2 is a first liquid outlet, 2-2 is a first microwave source emitter, 2-3 is a first microwave reaction cavity, 2-4 is a first box, 3 is a collection system, 3-1 is a collection kettle, 3-1-1 is a feed inlet, 3-1-2 is a gas outlet, 3-1-3 is a discharge port, 3-1-4 is a stirrer, 3-1-5 is a jacket, 3-2 is a constant pressure funnel, 3-3 is a condenser, 3-4 is a support, 4 is a transfer pump, 5 is a second microwave reactor, 5-1 is a second coiled pipe reactor, 5-1-1 is a second liquid inlet, 5-1-2 is a second liquid outlet, 5-2 is a second microwave source emitter, 5-3 is a second microwave reaction cavity, 5-4 is a second box, and 6 is a receiving container. DETAILED DESCRIPTION

[0063] The beneficial effects of the present application are verified by the following examples.

[0064] Example 1: The continuous rapid batch production device of the platinum carbon catalyst in this example is composed of a liquid supply system 1, a first microwave reactor 2, an intermediate collection system 3, a transfer pump 4, a second microwave reactor 5, and a receiving container 6.

[0065] The first microwave reactor 2 is composed of a first coiled pipe reactor 2-1, a first microwave source emitter 2-2, a first microwave reaction cavity 2-3, and a first box 2-4. The first coiled pipe reactor 2-1 and the first microwave source emitter 2-2 are arranged in the first microwave reaction cavity 2-3, and the first microwave source emitter 2-2 is arranged below the first coiled pipe reactor 2-1. The first microwave reaction cavity 2-3 is fixed in the first box 2-4. The first liquid inlet 2-1-1 and the first liquid outlet 2-1-2 of the first coiled pipe reactor 2-1 extend out of the first microwave reaction cavity 2-3. The first liquid inlet 2-1-1 is connected to the liquid supply system 1, and the first liquid outlet 2-1-2 is connected to the intermediate collection system 3.

[0066] The structure of the second microwave reactor 5 is the same as that of the first microwave reactor 2. The second microwave reactor 5 consists of a second coiled reactor 5-1, a second microwave source transmitter 5-2, a second microwave reaction chamber 5-3, and a second housing 5-4. The second coiled reactor 5-1 and the second microwave source transmitter 5-2 are located inside the second microwave reaction chamber 5-3, with the second microwave source transmitter 5-2 positioned below the second coiled reactor 5-1. The second microwave reaction chamber 5-3 is fixed inside the second housing 5-4. The second inlet 5-1-1 and the second outlet 5-1-2 of the second coiled reactor 5-1 extend outside the second microwave reaction chamber 5-3. The intermediate collection system 3 is connected to the second inlet 5-1-1 via a transfer pump 4. The second outlet 5-1-2 is connected to the receiving container 6. Temperature detectors are installed at the first inlet 2-1-1 and the first outlet 2-1-2.

[0067] The liquid supply system 1 consists of an argon cylinder 1-1, a stirring table 1-2, a storage tank 1-3, and a peristaltic pump 1-4. The first storage tank 1-3 and the second storage tank 1-4 are placed on the stirring table 1-2. The argon cylinder 1-1 is connected to the first storage tank 1-3. The first storage tank 1-3 and the second storage tank 1-4 are connected to the inlet of the peristaltic pump 1-5 through a three-way valve 1-6. The outlet of the peristaltic pump 1-5 is connected to the liquid inlet 2-1-1 of the first microwave reactor 2. Temperature detectors are installed at the second liquid inlet 5-1-1 and the second liquid outlet 5-1-2.

[0068] The intermediate collection system 3 consists of a collection vessel 3-1, a constant pressure funnel 3-2, a condenser 3-3, and a support 3-4. The upper end of the collection vessel 3-1 has a feed inlet 3-1-1 and a gas outlet 3-1-2, and the lower end has a discharge outlet 3-1-3. A stirrer 3-1-4 is installed inside the collection vessel 3-1. The constant pressure funnel 3-2 is installed on the feed inlet 3-1-1 of the collection vessel 3-1, and the condenser 3-3 is installed on the gas outlet 3-1-2 of the collection vessel 3-1. The outer wall of the collection vessel 3-1 has a jacket 3-1-5, which can be filled with water for cooling in a cold water bath. The first liquid outlet 2-1-2 of the first microwave reactor 2 is connected to the constant pressure funnel 3-2.

[0069] Example 2: A method for preparing a platinum-carbon catalyst using the continuous, rapid, and large-scale production apparatus of the platinum-carbon catalyst in Example 1, comprising the following steps:

[0070] I. Raw material preparation:

[0071] (1) Carbon powder treatment: Put the porous carbon powder of model Ketjen Black ECP600JD on the screen frame in the autoclave, and add ultrapure water under the screen frame. Heat the autoclave to 3 MPa and keep for 6 h. Then take out the carbon powder and put it into a watch glass, and then put the watch glass into a vacuum drying oven at a temperature of 80°C for vacuum drying for 2 h. In this step, the carbon powder on the screen frame is treated with high-pressure steam to make the pores of the cleaned carbon powder conducive to subsequent loading, and then vacuum drying is performed to avoid residual moisture;

[0072] (2) Preparation of raw material solution: weigh 240 mg of carbon powder into 400 mL of ethylene glycol, and put the solution into an ultrasonic device for ultrasonic treatment for 2 h, and then move it to a stirring table for stirring for 2 h. Then add an ethylene glycol solution of chloroplatinic acid with a concentration of 0.5 mol / L at a carbon / platinum mass ratio of 1:1 (platinum loading 50%), and continue to stir for 1 h. Then add an ethylene glycol solution of sodium hydroxide with a concentration of 1 mol / L to adjust the pH of the solution to 12. Then pass argon for 1 h to remove oxygen from the mixture to obtain the raw material solution;

[0073] II. Continuous microwave reaction:

[0074] (1) The raw material solution in the feed system storage tank 1-3 is input into the first snake coil type reactor 2-1 of the first microwave reactor 2 through the peristaltic pump 1-4, and the first microwave source emitter 2-2 is used to control the temperature of the first snake coil type reactor 2-1 to T1 = 130°C, and the residence time of the raw material solution in the first microwave reactor 2 is 32 s;

[0075] (2) The material flowing out of the first microwave reactor 2 enters the collection kettle 3-1 of the intermediate collection system 3, and the stirring speed of the stirrer 3-1-4 is 500 rpm / min, and the temperature of the collection kettle 3-1 is 130°C, and the temperature is kept for 20 min, and the nucleation is carried out;

[0076] (3) The material is input into the second snake coil type reactor 5-1 of the second microwave reactor 5 through the transmission pump 4, and the second microwave source emitter 5-2 is used to control the temperature of the second snake coil type reactor 5-1 to 160°C, and the residence time of the material in the second microwave reactor 5 is 32 s;

[0077] (4) The material flowing out of the second microwave reactor 5 enters the receiving container 6, and after cooling to room temperature, the pH is adjusted to 2 with an ethylene glycol solution of nitric acid (HNO3), and then stirred for 12 h to make the reduced platinum carbon particles completely adsorbed on the porous carbon to obtain a platinum carbon solution;

[0078] (5) Assemble the suction filtration device, and heat pure water to 100°C in advance. Pour the platinum-carbon solution into the suction filtration bottle, add 1 L of the prepared pure water, and perform suction filtration. Repeat the suction filtration until the suction filtrate is neutral. End the suction filtration, and obtain the filter cake. Vacuum dry the filter cake at 80°C for 3 h, and then cool to room temperature to obtain the dry powder;

[0079] III. Heat treat the dry powder at 200°C for 2 h under an argon atmosphere, cool to room temperature, and take out to obtain the platinum-carbon catalyst (Pt / C).

[0080] Example 3: A method for preparing a platinum-carbon catalyst using the continuous rapid batch production device of the platinum-carbon catalyst of Example 1, which is performed according to the following steps:

[0081] I. Raw material preparation

[0082] (1) Carbon powder treatment: Place the porous carbon powder of model KETJENBLACK ECP600JD on the screen frame in the autoclave, and add ultrapure water under the screen frame. Heat the autoclave to 3 MPa and maintain for 6 h. Then take out the carbon powder and place it in a watch glass. Place the watch glass in a vacuum drying box at 80°C and vacuum dry for 2 h. In this step, the carbon powder is treated with high-pressure steam on the screen frame to clean the pores of the carbon powder, which facilitates subsequent loading. Then, vacuum dry to avoid residual water. Then, grind and mix 500 mg of carbon powder with 400 mg of melamine, transfer to a porcelain boat, and place in a tube furnace. Maintain at 900°C under an argon atmosphere for 2 h, cool to room temperature, and take out for standby use.

[0083] (2) Preparation of raw material solution: Weigh 240 mg of carbon powder and disperse it in 400 mL of ethylene glycol. Place the solution in an ultrasonic device and ultrasonicate for 1 h. Then, transfer to a stirring table and stir for 1 h. Then, add an ethylene glycol solution of chloroplatinic acid (H2PtCl6) with a concentration of 0.5 mol / L at a carbon / platinum mass ratio of 1:1 (platinum loading of 50%), and continue to stir for 1 h. Then, add an ethylene glycol solution of sodium hydroxide with a concentration of 1 mol / L to adjust the pH of the solution to 12. Then, pass argon for 1 h to remove oxygen from the mixture to obtain the raw material solution.

[0084] II. Continuous microwave reaction:

[0085] (1) Transfer the raw material solution in the feed system storage tanks 1-3 to the first snake coil reactor 2-1 of the first microwave reactor 2 through the peristaltic pump 1-4. The temperature of the first snake coil reactor 2-1 is T1 = 130°C, and the residence time of the raw material solution in the first microwave reactor 2 is 32 s.

[0086] (2) The material flowed out from the first microwave reactor 2 enters the collection tank 3-1 of the intermediate collection system 3, the stirring speed of the stirrer 3-1-4 is 500 rpm / min, the temperature of the collection tank 3-1 is 130℃, and the material is incubated for 20 min under stirring at constant temperature;

[0087] (3) The material is input into the second microwave reactor 5 by the transfer pump 4, the temperature of the second microwave reactor 5 is 170℃, and the residence time of the material in the second microwave reactor 5 is 32 s;

[0088] (4) The material flowed out from the second microwave reactor 5 enters the receiving container 6, and after being cooled to room temperature, the pH is adjusted to 1.5 by using a nitric acid (HNO3) ethylene glycol solution, and then the material is stirred for 12 h, so that the reduced platinum carbon particles are completely adsorbed onto the porous carbon to obtain a platinum carbon solution;

[0089] (5) The suction filtration equipment is assembled, pure water is heated to 100℃ in advance, the platinum carbon solution is poured into the suction filtration bottle, 1 L of the heated pure water is added, and suction filtration is performed until the suction filtrate reaches neutral, the suction filtration is stopped, and a filter cake is obtained; the filter cake is vacuum dried at a temperature of 80℃ for 3 h, and then cooled to room temperature to obtain a dry powder;

[0090] III. The dry powder is heat treated under an argon atmosphere at a temperature of 210℃ for 2 h, cooled to room temperature, and taken out to obtain a platinum carbon catalyst (Pt / C).

[0091] The scanning electron microscope (SEM) photograph of the platinum carbon catalyst obtained in Example 2 is shown in FIG. 2, and the scanning electron microscope (SEM) photograph of the platinum carbon catalyst obtained in Example 3 is shown in FIG. 3. Figure 4 Figure 5 It can be seen from FIG. 2 and FIG. 3 that the Pt nanoparticles in the platinum carbon catalyst prepared by the segmented microwave method are uniformly distributed on the surface of the carrier, the average particle size is maintained at 2.8-3.5 nm, and there is no obvious agglomeration phenomenon. Figure 4 Figure 5 It can be seen from FIG. 4 and FIG. 5 that the nitrogen element doped in the carbon carrier of the platinum carbon catalyst is more conducive to the dispersion of platinum, and the Pt particles in the prepared Pt / C-N catalyst are uniform and less agglomerated.

[0092] The XRD spectrum of the platinum carbon catalyst obtained in Example 2 and 3 is shown in FIG. 6, and the XRD spectrum of the platinum carbon catalyst obtained in Example 4 is shown in FIG. 7. Figure 6 Figure 6 It can be seen from FIG. 6 and FIG. 7 that the Pt / C catalyst and the Pt / C-N catalyst prepared by the method both exhibit the diffraction characteristics of the typical polycrystalline Pt face-centered cubic (fcc) crystal structure. The diffraction peaks at about 39°, 46° and 68° are respectively attributed to the diffraction peaks of Pt (111), (200) and (220), which almost correspond to the standard card, indicating the formation of Pt nanocrystals.

[0093] ​​​Preparation of sample for CV curve test: 2 mg of Pt / C catalyst prepared in Example 2, 0.485 mL of ethanol, 0.485 mL of isopropanol and 0.03 mL of Nafion ionomer were mixed by ultrasonic for 40 min to obtain catalyst ink. CV curve test: 10 uL of catalyst ink was dropped on the surface of smooth glassy carbon electrode by using a pipette, and a uniform film was formed after drying, ready for electrochemical test. RDE test was carried out at 25°C using Shanghai Chenhua CHI760e. A three-electrode system was used for testing in 0.5 mol / L sulfuric acid solution, with glassy carbon rotating disc electrode as working electrode, mercury sulfate as reference electrode and platinum wire as counter electrode. The potential range for testing was -0.66 V to 0.39 V, and the electrochemical scanning speed was 50 mV / s. The CV curve was obtained by scanning, and the electrochemical active area was calculated by hydrogen adsorption method (ECSA). The CV curve of the Pt / C catalyst obtained in Example 2 is shown in Figure 7 From Figure 7 it can be seen that the electrochemical active area of the Pt / C catalyst prepared in Example 2 reached 80 m 2 / g.

[0094] Preparation of sample for SCV curve test: 2 mg of Pt / C catalyst prepared in Example 2, 0.485 mL of ethanol, 0.485 mL of isopropanol and 0.03 mL of Nafion ionomer were mixed by ultrasonic for 40 min to obtain catalyst ink. SCV curve test: 10 uL of catalyst ink was dropped on the surface of smooth glassy carbon electrode by using a pipette, and a uniform film was formed after drying, ready for electrochemical test. RDE test was carried out at 25°C using Shanghai Chenhua CHI760e. A three-electrode system was used for testing in 0.5 mol / L sulfuric acid solution, with glassy carbon rotating disc electrode as working electrode, mercury sulfate as reference electrode and platinum wire as counter electrode. Oxygen was passed into the solution for 20 min before testing to saturate the solution with oxygen, and the measurement was carried out at a potential of -0.66 V to 0.39 V, with a scanning speed of 50 mV / s and a rotating speed of 1600 rpm. The SCV curve was obtained by scanning. The SCV curve of the Pt / C catalyst obtained in Example 2 is shown in Figure 8 From Figure 8 it can be seen that the half-wave potential of the Pt / C catalyst prepared in Example 2 reached 0.895 V.

[0095] The sample for power density curve test was prepared by ultrasonic spraying, and the test was carried out at 25°C using membrane electrode 850e fuel cell test system. The test conditions were cell temperature 75°C, humidity 75%, back pressure 200 kPa, and flow rate using metering ratio, anode 1.5: cathode 2.5. The power density curve of the Pt / C catalyst obtained in Example 2 is shown in Figure 9 From Figure 9 it can be seen that the power density of the catalyst reached 0.1 mg cm-2 and 0.3 mg cm -2 Spraying was carried out for the membrane electrode to test the performance of 5x5 battery under the condition of current density of 2.4 A cm -2 , and the specific power output was 1.452 W cm -2 .

[0096] The platinum carbon catalyst obtained in Example 3 was used to prepare a test sample in the same way as the platinum carbon catalyst of Example 2, and the same test method was used for testing. The CV curve of the platinum carbon catalyst obtained in Example 3 is shown in Figure 10 , and it can be seen from Figure 10 that the electrochemical active area of the Pt / C-N catalyst prepared in Example 3 reached 105 m 2 / g; the SCV curve of the platinum carbon catalyst obtained in Example 3 is shown in Figure 11 , and it can be seen from Figure 11 that the half-wave potential of the Pt / C-N catalyst prepared in Example 3 reached 0.906 V, indicating that after the carbon powder was doped with melamine, the presence of nitrogen elements enhanced the stability of the carbon body structure, better anchored the platinum particles, and the prepared Pt / C-N catalyst had more excellent performance.

[0097] The CV curves of the platinum carbon catalyst prepared in Example 3 before and after 30000 cycles are shown in Figure 12 , and it can be seen from Figure 12 that the electrochemical active area of the catalyst prepared in Example 3 attenuated only by 20% after 3 million cycles.

[0098] The SCV curves of the platinum carbon catalyst prepared in Example 3 before and after 30000 cycles are shown in Figure 13 , and it can be seen from Figure 13 that the half-wave potential of the catalyst prepared in Example 3 attenuated only by 5 mV after 3 million cycles, and the mass activity attenuation was only 15%, indicating that the catalyst prepared by this method had good stability.

[0099] Example 4: The difference between this example and Example 2 is that the microwave reaction in Step 2 is different, and the operation in Step 2 is replaced by the following steps:

[0100] II. Continuous microwave reaction:

[0101] (1) The raw material liquid in the feed system storage tank 1-3 is input into the first snake coil type reactor 2-1 of the first microwave reactor 2 through the peristaltic pump 1-4, and the temperature of the first snake coil type reactor 2-1 is T1=170℃, and the residence time of the raw material liquid in the first microwave reactor 2 is 32s;

[0102] (2) The material flowed out from the first microwave reactor 2 directly enters the receiving container 6, and after being cooled to room temperature, the pH is adjusted to 1.5 by using a nitric acid (HNO3) ethylene glycol solution, and then stirring for 12 h, so that the reduced platinum carbon particles are completely adsorbed on the porous carbon to obtain a platinum carbon solution;

[0103] (3) The suction filtration equipment is assembled, pure water is heated to 100 ℃ in advance, the platinum carbon solution is poured into the suction filtration bottle, 1 L of the heated pure water is added, suction filtration is performed, and the suction filtration is repeatedly performed until the suction filtration liquid reaches neutral, the suction filtration is ended, and a filter cake is obtained; the filter cake is vacuum dried at a temperature of 80 ℃ for 3 h, and then is cooled to room temperature to obtain a dry powder;

[0104] The other steps and parameters are the same as those in Example 2.

[0105] The CV curve comparison diagram of the platinum carbon catalysts prepared in Example 2 and Example 4 is shown in Figure 14 , and Figure 14 It can be seen that the electrochemical active area of the Pt / C catalyst prepared in Example 2 reaches 80 m 2 / g, and the electrochemical area of the Pt / C catalyst prepared in Example 4 is only 65 m 2 / g; compared with the effect of Example 4, the effect is poor, because Example 4 only undergoes one microwave heating, without the intermediate heat preservation process, so that the growth of platinum particles is not uniform enough, and not enough platinum nanoparticles are exposed on the surface of the carbon carrier, which affects the catalytic performance.

[0106] The SCV curve comparison diagram of the platinum carbon catalysts prepared in Example 2 and Example 4 is shown in Figure 15 , and Figure 15 It can be seen that the half-wave potential of the Pt / C catalyst prepared in Example 2 reaches 0.895 V, and the half-wave potential of the Pt / C catalyst prepared in Example 4 reaches 0.882 V, which indicates that the Pt / C catalyst produced by the series microwave heating has more excellent performance, and compared with the effect of Example 4, the effect is poor, because Example 4 only undergoes one microwave heating, without the intermediate heat preservation process, so that the growth of platinum particles is not uniform enough, and not enough platinum nanoparticles are exposed on the surface of the carbon carrier, which affects the catalytic performance.

[0107] As can be seen from the above examples, the microwave radiation heating is used in the present application, and various metal nanoparticles can be quickly and efficiently reduced, so that the time for preparing the catalyst is greatly shortened. In the process of reducing the metal nanoparticles, the reaction liquid is heated by the microwave, the chemical state metal (i.e., Pt Ⅵ in the hexachloroplatinic acid) reacts with the solvent ethylene glycol, and is reduced into the metal element (Pt 0) nanoparticles; ethylene glycol is oxidized to glyoxal, glycolic acid, etc., and the oxidation products of ethylene glycol can also stabilize the metal particles generated in the reaction process, and the stabilization mechanism is that: when the combined state of platinum (Pt Ⅳ ) is reduced to zero-valent platinum (Pt 0 ), glycolate ions in the solution are tightly adsorbed on the surface of the metal particles to form a double-layer structure, so that the Pt particles are negatively charged. Due to the electrostatic repulsion between the negatively charged Pt colloidal particles, these Pt particles can exist stably in the solution, effectively preventing the agglomeration between the metal particles. In addition, compared with the traditional hydrothermal heating preparation method, the microwave continuous preparation process also has the advantages of fast heating speed and uniform heating, which can promote the formation of a large number of initial crystal nuclei in the reaction, and the finally synthesized metal nanoparticles have good dispersity, small particle size and narrow particle size distribution range. The present application can prepare platinum-carbon catalysts with high activity and high durability.

Claims

1. A continuous and rapid batch production apparatus for platinum-carbon catalysts, characterized in that... The device includes a liquid supply system (1), a first microwave reactor (2), an intermediate collection system (3), a transfer pump (4), a second microwave reactor (5), and a receiving container (6). The first microwave reactor (2) consists of a first coiled reactor (2-1), a first microwave source transmitter (2-2), a first microwave reaction chamber (2-3), and a first housing (2-4). The first coiled reactor (2-1) and the first microwave source transmitter (2-2) are located inside the first microwave reaction chamber (2-3), and the first microwave source transmitter (2-2) is located below the first coiled reactor (2-1). The first microwave reaction chamber (2-3) is fixed inside the first housing (2-4). The first inlet (2-1-1) and the first outlet (2-1-2) of the first coiled reactor (2-1) extend outside the first microwave reaction chamber (2-3). The first inlet (2-1-1) is connected to the liquid supply system (1). The first outlet (2-1-2) is connected to the intermediate collection system (3). The structure of the second microwave reactor (5) is the same as that of the first microwave reactor (2); the second microwave reactor (5) consists of a second coil reactor (5-1), a second microwave source transmitter (5-2), a second microwave reaction chamber (5-3), and a second housing (5-4); the second coil reactor (5-1) and the second microwave source transmitter (5-2) are located inside the second microwave reaction chamber (5-3), and the second microwave source transmitter (5-2) is located below the second coil reactor (5-1), and the second microwave reaction chamber (5-3) is fixed inside the second housing (5-4); the second inlet (5-1-1) and the second outlet (5-1-2) of the second coil reactor (5-1) extend outside the second microwave reaction chamber (5-3); the intermediate collection system (3) is connected to the second inlet (5-1-1) through a transfer pump (4); the second outlet (5-1-2) is connected to the receiving container (6); The liquid supply system (1) consists of an argon cylinder (1-1), a stirring table (1-2), a storage tank (1-3), and a peristaltic pump (1-4); the storage tank (1-3) is placed on the stirring table (1-2); the argon cylinder (1-1) is connected to the storage tank (1-3); the storage tank (1-3) is connected to the first liquid inlet (2-1-1) of the first microwave reactor (2) through the peristaltic pump (1-4); The intermediate collection system (3) consists of a collection vessel (3-1), a constant pressure funnel (3-2), a condenser (3-3), and a support (3-4). The upper end of the collection vessel (3-1) has a feed inlet (3-1-1) and a gas outlet (3-1-2), and the lower end has a discharge outlet (3-1-3). A stirrer (3-1-4) is installed inside the collection vessel (3-1). The constant pressure funnel (3-2) is installed on the feed inlet (3-1-1) of the collection vessel (3-1), and the condenser (3-3) is installed on the gas outlet (3-1-2) of the collection vessel (3-1). The first liquid outlet (2-1-2) of the first microwave reactor (2) is connected to the constant pressure funnel (3-2).

2. The continuous and rapid batch production apparatus for a platinum-carbon catalyst according to claim 1, characterized in that, The outer wall of the collecting vessel (3-1) is fitted with a jacket (3-1-5).

3. The continuous and rapid batch production apparatus for a platinum-carbon catalyst according to claim 1, characterized in that, The first housing (2-4) is equipped with a switch (2-4-1), a manual power adjustment knob (2-4-2), an operation display screen (2-4-3), and a real-time power display screen (2-4-4).

4. A method for preparing a platinum-carbon catalyst using the continuous, rapid, and large-scale production apparatus for the platinum-carbon catalyst as described in claim 1, characterized in that... This method is performed in the following steps: I. Raw material preparation: (1) Toner treatment: Place the porous toner on the screen rack in the autoclave and add ultrapure water under the screen rack; heat the autoclave to 2-3 MPa and maintain it for 5-6 hours; then take out the toner and put it into a vacuum drying oven at 80°C for 2-3 hours; in this step, the toner is placed on the screen rack and treated with high pressure steam to clean the pores of the toner for subsequent loading, and then vacuum dehydrated to avoid moisture residue; (2) Preparation of raw material solution: Porous carbon powder is added to a mixed solution of ethylene glycol and isopropanol and ultrasonically mixed evenly. Then, under stirring conditions, an ethylene glycol solution of chloroplatinic acid (H2PtCl6) is added and stirred evenly. The pH value is adjusted to 11~12.5 with an ethylene glycol solution of sodium hydroxide and then argon gas is introduced to remove oxygen in the mixture to obtain the raw material solution. II. Continuous Microwave Reaction: (1) Input the raw material liquid in the feeding system into the first serpentine tube reactor (2-1) of the first microwave reactor (2), and use the first microwave source transmitter (2-2) to control the temperature of the first serpentine tube reactor (2-1) to 100℃~130℃, and the residence time of the raw material liquid in the first microwave reactor (2) is 3s~8min; (2) The material flowing out of the first microwave reactor (2) enters the intermediate collection system (3), and the material is kept warm and stirred in the intermediate collection system (3) at a temperature of 100℃~130℃ for 10~30 minutes; (3) The material is fed into the second serpentine reactor (5-1) of the second microwave reactor (5) by the transfer pump (4). The temperature of the second serpentine reactor (5-1) is controlled by the second microwave source transmitter (5-2) to be 140~180℃. The residence time of the material in the second microwave reactor (5) is 3s~8min. (4) The material flowing out from the second microwave reactor (5) enters the receiving container (6), and after cooling to room temperature, the pH is adjusted to 0.5~2 with ethylene glycol solution of nitric acid (HNO3), and then stirred for 10~12h to allow the reduced platinum carbon particles to be completely adsorbed onto the porous carbon to obtain a platinum carbon solution. (5) Add pure water at a temperature of 90℃~100℃ to the platinum carbon solution, filter by suction, and repeatedly add hot water for suction filtration until the pH value of the filtrate reaches neutral or the residual anion content meets the standard, and obtain filter cake; vacuum dry the filter cake at a temperature of 80℃ for 3~4h to obtain dried powder.

3. Heat-treat the dried powder in an argon atmosphere or a hydrogen-argon mixture at a temperature of 200℃~300℃ for 1~2 hours, cool it to room temperature and remove it to obtain the platinum-carbon catalyst.

5. The method for preparing platinum-carbon catalyst using the continuous, rapid, and batch production apparatus for platinum-carbon catalyst according to claim 4, characterized in that, In step one (2), the concentration of chloroplatinic acid in the ethylene glycol solution of chloroplatinic acid is 0.05~0.5mol / L.

6. The method for preparing platinum-carbon catalyst using a continuous, rapid, and batch production apparatus according to claim 4 or 5, characterized in that, In step 2 (2), the concentration of porous carbon powder in the raw material liquid is 1.5~4.5 g / L; the concentration of chloroplatinic acid (H2PtCl6) is 3.95~11.85 g / L.

7. The method for preparing platinum-carbon catalyst using a continuous, rapid, and batch production apparatus according to claim 4 or 5, characterized in that, The toner treatment in step one (1) can be replaced by the following steps: (1) Carbon powder treatment: Disperse porous carbon black in a 30% hydrogen peroxide solution and heat it to 90~100 ℃ under stirring and keep it for 1h; then filter and wash the carbon black, and put it into a vacuum drying oven at 80℃ for 2h to remove moisture. After cooling to room temperature, take it out for use.

8. The method for preparing platinum-carbon catalyst using a continuous, rapid, and batch production apparatus according to claim 4 or 5, characterized in that, The toner treatment in step one (1) can be replaced by the following steps: (1) Carbon powder treatment: Place the porous carbon powder on the screen rack in the autoclave and add ultrapure water under the screen rack; heat the autoclave to 2~3MPa and maintain it for 5~6h; then take out the carbon powder and put it into a vacuum drying oven at 80℃ for vacuum drying for 2~3h; then grind and mix the carbon powder with the doping source and transfer it to a ceramic boat, put it into a tube furnace, and maintain it in an argon atmosphere at 650~900℃ for 2h. After cooling to room temperature, take it out for use; the doping source is a nitrogen source or a sulfur source. The nitrogen source is urea or melamine, and the sulfur source is thiourea or titanium disulfide.

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