A method of hot working and forming a multi-modal pore structure platinum alloy electrode

Abstract

The application belongs to the technical field of electrode heat processing treatment, and particularly discloses a heat processing forming method of a multi-modal pore structure platinum alloy electrode, which adopts a staged heat processing treatment, first carbonizes a transition metal-based precursor for heat treatment, then selects a nitrogen and phosphorus pore forming agent to be mixed for heat treatment in sequence, then performs layer-by-layer spraying low-temperature heat treatment, and finally performs high-temperature high-pressure heat treatment for single electrode forming manufacturing. The heat processing forming method of the multi-modal pore structure platinum alloy electrode is adopted, parameters of a gradual heat treatment process are regulated and controlled, the multi-modal pore structure of the platinum alloy electrode is constructed, and the long-life platinum alloy electrode is developed through the combination of the layer-by-layer spraying low-temperature heat treatment and the high-temperature high-pressure heat treatment.

Description

Technical Field

[0001] This invention relates to the field of electrode thermal processing technology, and in particular to a thermal forming method for a platinum alloy electrode with a multimodal porous structure. Background Technology

[0002] Platinum alloy electrodes are widely used electrode materials in many electrochemical applications, favored for their excellent physical and chemical properties. Platinum and its alloys possess excellent electrical conductivity, making them suitable for various electrochemical reactions. Platinum alloys exhibit extremely high corrosion resistance in a variety of chemical environments, enabling long-term use under harsh conditions such as strong acids and alkalis. Platinum alloy electrodes remain stable under high temperatures and pressures, and are not easily oxidized or decomposed. Platinum alloys possess good catalytic activity, promoting certain chemical reactions, particularly in fuel cells and water electrolysis. Platinum alloys have high mechanical strength and toughness, capable of withstanding certain mechanical stresses and impacts.

[0003] Platinum alloy electrodes are a key component of proton exchange membrane fuel cells (PEMFCs), used to catalyze the reaction of hydrogen and oxygen. In the water electrolysis process for hydrogen production, platinum alloy electrodes serve as both the anode and cathode, promoting the water splitting reaction. Platinum alloy electrodes are widely used in various chemical and biosensors, such as pH sensors and gas sensors. In medical devices such as pacemakers and nerve stimulators, platinum alloy electrodes are widely used due to their biocompatibility and corrosion resistance. In electroplating processes and electrochemical synthesis, platinum alloy electrodes are used to provide stable current and catalytic activity.

[0004] High-precision platinum alloy electrodes represent a new generation of electrode materials following pure platinum electrodes. Current technologies often employ a room-temperature spraying process to coat a slurry of platinum alloy powder onto an intermediate layer, followed by air drying to form the electrode. However, electrodes obtained using this process suffer from low bonding strength, easy peeling, and poor mass transfer, resulting in poor electrocatalytic performance and failing to meet the demands of the new energy sector for high-end electrode materials. Therefore, a staged thermal processing method is employed to control the grain size and crystal facet ratio of the electrode material, optimizing the electrode's pore structure and fundamentally improving its electrocatalytic performance. Furthermore, controlling the electrode composite process, performing layer-by-layer spraying with low-temperature heat treatment combined with high-temperature, high-pressure heat treatment to achieve single-electrode forming is an essential strategy to ensure electrode bonding strength. Summary of the Invention

[0005] The purpose of this invention is to provide a hot-working forming method for a multimodal porous platinum alloy electrode. By controlling the parameters of the step-by-step heat treatment process, the multimodal porous structure of the platinum alloy electrode can be constructed. By combining layer-by-layer spraying low-temperature heat treatment and high-temperature and high-pressure heat treatment, a long-life platinum alloy electrode can be developed.

[0006] To achieve the above objectives, the present invention provides a hot working forming method for a platinum alloy electrode with a multimodal porous structure, comprising the following steps:

[0007] S1. Dissolve copper nitrate trihydrate and benzoic acid in deionized water and ethanol respectively, and sonicate for 0.5 h to prepare solution A and solution B;

[0008] S2. Mix the two solutions from step S1, sonicate for 0.5 h, add polyvinylpyrrolidone dispersant, and sonicate for another 1 h to form solution C.

[0009] S3. Transfer the solution C from step S2 into a 100 mL standard hydrothermal reactor, place it in an oven, heat it for 12 h, and after the reaction is complete, cool it naturally to room temperature, centrifuge it for 10 min, collect the precipitate, wash it with a mixed solution of deionized water and ethanol, and heat dry it to obtain a blue copper-based organic framework precursor powder.

[0010] S4. Grind the precursor powder from step S3 thoroughly in a mortar, transfer it into a corundum boat, place it in a tube furnace, introduce inert gas, and perform high-temperature pyrolysis to obtain black copper / carbon material powder.

[0011] S5. Mix the black copper / carbon material from step S4 with one of melamine, urea, or dicyandiamide, transfer it to a micro ball mill, grind and mix for 0.5 hours to obtain a mechanically mixed material, place it in a tube furnace, introduce inert gas, and perform high-temperature pyrolysis to obtain black copper / nitrogen-carbon material powder.

[0012] S6. Take the copper / nitrogen-carbon material from step S5 and mix it with sodium dihydrogen phosphate or sodium hypophosphite. Transfer the mixture to a micro ball mill and grind and mix for 0.5 hours to obtain a mechanically mixed material. Place the mixture in a tube furnace, introduce an inert gas, and perform high-temperature pyrolysis to obtain black copper / nitrogen-phosphorus-carbon material powder.

[0013] S7. Take the copper / nitrogen-phosphorus-carbon material from step S6 and disperse it in a mixed solution of deionized water and ethylene glycol or deionized water and ascorbic acid. Disperse it ultrasonically for 0.5 h, add potassium hypochlorous acid or chloroplatinic acid, and further sonicate for 0.5 h to form solution D.

[0014] S8. Transfer the solution D from step S7 into a 100 mL standard hydrothermal reactor, place it in an oven, heat it for 12 h, and after the reaction is complete, cool it naturally to room temperature, centrifuge it for 10 min, collect the precipitate, wash it with a mixed solution of deionized water and ethanol, freeze dry it to obtain black platinum alloy material powder.

[0015] S9. Disperse the black platinum alloy material powder from step S8 in a mixed solution of deionized water and isopropanol, add Nafion binder, sonicate three times, and further oscillate for 20 minutes in a vortex stirrer to obtain a uniformly dispersed ink paste containing platinum metal.

[0016] S10. The ink paste containing platinum metal from step S9 is applied to conductive carbon paper in three rotational spraying processes, and then dried at low temperature to form a uniform catalytic layer.

[0017] S11. The conductive carbon paper loaded with the catalyst layer from step S10 is combined with the proton exchange membrane layer and subjected to high temperature and high pressure treatment to form a multimodal porous platinum alloy electrode.

[0018] Preferably, in step S1, the mass ratio of copper nitrate trihydrate to benzoic acid is 3:2, and the volume ratio of deionized water to ethanol is 1:1; in step S2, the mass ratio of polyvinylpyrrolidone dispersant added to copper nitrate trihydrate is 1:1; in step S3, the heating temperature is 140°C, the volume ratio of deionized water to ethanol is 1:1, and the drying temperature is 80°C.

[0019] Preferably, in step S4, the inert gas is argon, the high-temperature pyrolysis is pyrolysis at 600℃ for 2 hours, and the heating rate is 10℃ / min.

[0020] Preferably, in step S5, the mass ratio of the black carbon material to one of melamine, urea, and dicyandiamide is 1:1, the inert gas is argon, the high-temperature pyrolysis is performed at 550-650℃ for 4 hours, and the heating rate is 10℃ / min.

[0021] Preferably, in step S6, the mass ratio of copper / nitrogen-carbon material to sodium dihydrogen phosphate or sodium hypophosphite is 1:1.5, the inert gas is argon, the high-temperature pyrolysis is pyrolysis at 700-750℃ for 2 hours, and the heating rate is 10℃ / min.

[0022] Preferably, in step S7, the volume ratio of deionized water to ethylene glycol or ascorbic acid is 1:1.5-2, and the amount of potassium chloroplatinate or potassium hypochloroplatinate added is 5% of the mass of the copper / nitrogen-phosphorus-carbon material.

[0023] Preferably, in step S8, the heating temperature is 120°C, the volume ratio of deionized water to ethanol is 1:0.5-1, and the freeze-drying temperature is -40°C.

[0024] Preferably, in step S9, the volume ratio of deionized water to isopropanol is 1:4, the mass fraction of Nafion adhesive is 5%, and the volume ratio of its addition to the volume of polyvinylpyrrolidone dispersant in step S2 is 1:0.01. Ultrasonic treatment is performed for 0.5 hours at 0.5-hour intervals, for a total of three times.

[0025] Preferably, in step S10, the platinum content in the platinum-containing ink paste is 0.15 mg. pt / cm 2 Rotary spraying involves placing conductive carbon paper in a 200 rpm, 40°C rotary sprayer and spraying it with a spray gun. The spraying is done layer by layer at 0.5 h intervals, accumulating three coats.

[0026] Preferably, in step S11, the area ratio of the catalyst layer to the proton exchange membrane layer is 1:1, and the high temperature and high pressure treatment is 130-150℃, hot pressing at 10-13 MPa for 3-5 minutes.

[0027] The advantages and beneficial effects of the hot working forming method for the multi-modal porous structure platinum alloy electrode of the present invention are as follows:

[0028] 1. The platinum alloy electrode forming process of the present invention adopts a graded heat treatment. First, the transition metal base precursor is subjected to carburization heat treatment, then sodium dihydrogen phosphate or sodium hypophosphite is selected for mixed heat treatment, followed by layer-by-layer spraying low-temperature heat treatment, and finally high-temperature and high-pressure heat treatment for single electrode forming manufacturing.

[0029] 2. The platinum alloy electrode forming process of the present invention achieves multimodal pore structure control of the electrode through graded heat treatment. First, the selection of appropriate pore size control agent, the control of its proportion, and the adjustment of heat treatment temperature realize the micro, meso, and macropore characteristics of the electrode micropore structure. Second, the layer-by-layer spraying low-temperature heat treatment realizes the construction of the layered pore structure of the electrode.

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0031] Figure 1 The images show the XRD patterns of the multimodal porous platinum alloy electrodes prepared in Examples 1-3 of this invention, where (a) is Example 1, (b) is Example 2, and (c) is Example 3.

[0032] Figure 2 The pore size distribution diagram is shown for the platinum-copper / nitrogen-phosphorus-carbon-600 electrode prepared in Example 2 of this invention.

[0033] Figure 3 The SEAD diagram of the platinum-copper / nitrogen-phosphorus-carbon-600 electrode prepared in Example 2 of this invention;

[0034] Figure 4 The polarization curve and peak power density curve of the platinum-copper / nitrogen-phosphorus-carbon-600 electrode prepared in Example 2 of the present invention are shown. Detailed Implementation

[0035] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0037] Unless otherwise defined, all reagents, equipment and other materials used in this invention are commercially available.

[0038] Example 1

[0039] A hot forming method for a platinum alloy electrode with a multimodal porous structure includes the following steps:

[0040] S1. Weigh 3.6g of copper nitrate trihydrate (Cu(NO3)2·3H2O) and dissolve it in 16mL of deionized water. Disperse it by sonication for 0.5h to form solution A. Weigh 2.4g of benzotricarboxylic acid (H3BTC) and dissolve it in 16mL of ethanol. Disperse it by sonication for 0.5h to form solution B.

[0041] S2. Mix solution A and solution B from step S1, sonicate for 0.5 h, add 3.6 g of polyvinylpyrrolidone dispersant, and sonicate for another 1 h to form solution C;

[0042] S3. Transfer solution C to a 100 mL standard hydrothermal reactor and place it in a 140 °C oven for 12 h. After the reaction is complete, allow it to cool naturally to room temperature, centrifuge at 12000 rpm for 10 min, collect the precipitate, wash it with a mixture of 5 mL deionized water and 5 mL ethanol for a total of 3 washes, and dry it in an 80 °C oven for 8 h to obtain a blue copper-based organic framework precursor powder.

[0043] S4. Take 300mg of the blue precursor powder from step S3 and grind it thoroughly in a mortar. Transfer it to a corundum boat, place it in a tube furnace, introduce inert argon gas (Ar), and pyrolyze it at 600℃ for 2h at a heating rate of 10℃ / min to obtain black copper / carbon material powder.

[0044] S5. Take 200mg of black copper / carbon material from step S4 and mix it with 200mg of melamine. Transfer the mixture to a micro ball mill and grind and mix for 0.5h to obtain a mechanically mixed material. Place the mixture in a tube furnace, introduce inert gas Ar, and pyrolyze it at 550℃ for 4h at a heating rate of 10℃ / min to obtain black copper / nitrogen-carbon material powder.

[0045] S6. Take 200mg of copper / nitrogen-carbon material from step S5 and mix it with 300mg of sodium dihydrogen phosphate. Transfer the mixture to a micro ball mill and grind and mix for 0.5h to obtain a mechanically mixed material. Place the mixture in a tube furnace, introduce inert gas Ar, and pyrolyze it at 700℃ for 2h at a heating rate of 10℃ / min to obtain black copper / nitrogen-phosphorus-carbon material powder.

[0046] S7. Take 50 mg of copper / nitrogen-phosphorus-carbon material from step S6 and disperse it in a mixed solution of 10 mL deionized water and 15 mL ethylene glycol. Disperse it ultrasonically for 0.5 h, add 2.5 mg of potassium hypochlorous acid platinum, and further sonicate for 0.5 h to form solution D.

[0047] S8. Transfer the solution D from step S7 into a 100 mL standard hydrothermal reactor, place it in an oven at 120 °C, and heat it for 12 h. After the reaction is complete, cool it naturally to room temperature, centrifuge it at 12000 rpm for 10 min, collect the precipitate, wash it with a mixed solution of 10 mL deionized water and 5 mL ethanol, wash it three times in total, and freeze dry it in a freeze dryer at -40 °C for 6 h to obtain black platinum alloy material powder.

[0048] S9. Disperse the 5mg black platinum alloy material powder from step S8 in a mixed solution of 180μL deionized water and 720μL isopropanol, add 100μL Nafion binder, and sonicate in an ultrasonic cell disruptor for 0.5h every 0.5h for a total of 3 times. Then, further oscillate in a vortex stirrer for 20min to obtain a uniformly dispersed ink paste containing platinum metal.

[0049] S10. Take the ink paste containing platinum metal from step S9 (platinum content is 0.15 mg). pt / cm 2 Spray 200 μL each time, three times, onto a low-temperature (40℃) conductive carbon paper rotating at a constant speed of 200 rpm (1 cm). 2 ), and each time at 0.5h interval, a uniform catalyst layer is formed;

[0050] S11, Place the conductive carbon paper (1cm) loaded with the catalyst layer from step S10... 2 ) and proton exchange membrane (Nafion 117 membrane, 1cm) 2 The platinum alloy electrode (platinum-copper / nitrogen-phosphorus-carbon-550) with a multimodal porous structure was formed by hot pressing at 130℃ and 10MPa for 3 minutes.

[0051] Example 2

[0052] A hot forming method for a platinum alloy electrode with a multimodal porous structure includes the following steps:

[0053] S1. Weigh 4.8g of copper nitrate trihydrate (Cu(NO3)2·3H2O) and dissolve it in 20mL of deionized water. Disperse it by sonication for 0.5h to form solution A. Weigh 3.2g of benzotricarboxylic acid (H3BTC) and dissolve it in 20mL of ethanol. Disperse it by sonication for 0.5h to form solution B.

[0054] S2. Mix solution A and solution B, sonicate for 0.5 h, add 4.8 g of polyvinylpyrrolidone dispersant, and sonicate for another 1 h to form solution C;

[0055] S3. Transfer solution C to a 100 mL standard hydrothermal reactor and place it in a 140 °C oven for 12 h. After the reaction is complete, allow it to cool naturally to room temperature, centrifuge at 12000 rpm for 10 min, collect the precipitate, wash it with a mixture of 10 mL deionized water and 10 mL ethanol for a total of 3 washes, and dry it in an 80 °C oven for 10 h to obtain a blue copper-based organic framework precursor powder.

[0056] S4. Take 400mg of the blue precursor powder from step S3 and grind it thoroughly in a mortar. Transfer it to a corundum boat, place it in a tube furnace, introduce inert gas Ar, and pyrolyze it at 600℃ for 2h at a heating rate of 10℃ / min to obtain black copper / carbon material powder.

[0057] S5. Take 300mg of black copper / carbon material from step S4 and mix it with 300mg of urea. Transfer the mixture to a micro ball mill and grind and mix for 0.5h to obtain a mechanically mixed material. Place the mixture in a tube furnace, introduce inert gas Ar, and pyrolyze it at 600℃ for 4h at a heating rate of 10℃ / min to obtain black copper / nitrogen-carbon material powder.

[0058] S6. Take 300mg of copper / nitrogen-carbon material from step S5 and mix it with 450mg of sodium dihydrogen phosphate. Transfer the mixture to a micro ball mill and grind and mix for 0.5h to obtain a mechanically mixed material. Place the mixture in a tube furnace, introduce inert gas Ar, and pyrolyze it at 700℃ for 2h at a heating rate of 10℃ / min to obtain black copper / nitrogen-phosphorus-carbon material powder.

[0059] S7. Take 100 mg of copper / nitrogen-phosphorus-carbon material from step S6 and disperse it in a mixed solution of 20 mL deionized water and 30 mL ethylene glycol. Disperse it ultrasonically for 0.5 h, add 5 mg of potassium hypochlorous acid platinum, and further sonicate for 0.5 h to form solution D.

[0060] S8. Transfer the solution D from step S7 into a 100 mL standard hydrothermal reactor, place it in an oven at 120 °C, and heat it for 12 h. After the reaction is complete, allow it to cool naturally to room temperature, centrifuge at 12000 rpm for 10 min, collect the precipitate, wash it with a mixed solution of 20 mL deionized water and 10 mL ethanol, wash it three times in total, and freeze-dry it in a freeze dryer at -40 °C for 8 h to obtain black platinum alloy material powder.

[0061] S9. Disperse 10 mg of black platinum alloy material powder from step S8 in a mixed solution of 180 μL deionized water and 720 μL isopropanol, add 100 μL of Nafion binder, and sonicate for 0.5 h at 0.5 h intervals in an ultrasonic cell disruptor for a total of 3 times. Then, further oscillate in a vortex stirrer for 20 min to obtain a uniformly dispersed ink paste containing platinum metal.

[0062] S10. Take the ink paste containing platinum metal from step S9 (platinum content is 0.15 mg). pt / cm 2 Spray 100 μL each time, three times, onto a low-temperature (40°C) conductive carbon paper rotating at a constant speed of 200 rpm (1 cm). 2 ), and each time at 0.5h interval, a uniform catalyst layer is formed;

[0063] S11, Place the conductive carbon paper (1cm) loaded with the catalyst layer from step S10... 2 ) and proton exchange membrane (Nafion 117 membrane, 1cm) 2 The platinum alloy electrode (platinum-copper / nitrogen-phosphorus-carbon-600) with a multimodal porous structure was formed by hot pressing at 130℃ and 10MPa for 3 minutes.

[0064] Example 3

[0065] A hot forming method for a platinum alloy electrode with a multimodal porous structure includes the following steps:

[0066] S1. Weigh 5.4g of copper nitrate trihydrate (Cu(NO3)2·3H2O) and dissolve it in 30mL of deionized water. Disperse it by sonication for 0.5h to form solution A. Weigh 3.6g of benzotricarboxylic acid (H3BTC) and dissolve it in 30mL of ethanol. Disperse it by sonication for 0.5h to form solution B.

[0067] S2. Mix solution A and solution B from step S1, sonicate for 0.5 h, add 5.4 g of polyvinylpyrrolidone dispersant, and sonicate for another 1 h to form solution C;

[0068] S3. Transfer the solution C from step S2 into a 100 mL standard hydrothermal reactor, place it in an oven at 140 °C, and heat it for 12 h. After the reaction is complete, allow it to cool naturally to room temperature, centrifuge at 12000 rpm for 10 min, collect the precipitate, wash it with a mixed solution of 20 mL deionized water and 20 mL ethanol, wash it three times in total, and dry it in an oven at 80 °C for 12 h to obtain a blue copper-based organic framework precursor powder.

[0069] S4. Take 500mg of the blue precursor powder from step S3 and grind it thoroughly in a mortar. Transfer it to a corundum boat, place it in a tube furnace, introduce inert gas Ar, and pyrolyze it at 600℃ for 2h at a heating rate of 10℃ / min to obtain black copper / carbon material powder.

[0070] S5. Take 400mg of black carbon material from step S4 and mix it with 400mg of dicyandiamide. Transfer the mixture to a micro ball mill and grind and mix for 0.5h to obtain a mechanically mixed material. Place the mixture in a tube furnace, introduce inert gas Ar, and pyrolyze it at 650℃ for 4h at a heating rate of 10℃ / min to obtain black copper / nitrogen-carbon material powder.

[0071] S6. Take 500mg of copper / nitrogen-carbon material from step S5 and mix it with 750mg of sodium hypophosphite. Transfer the mixture to a micro ball mill and grind and mix for 0.5h to obtain a mechanically mixed material. Place the mixture in a tube furnace, introduce inert gas Ar, and pyrolyze it at 750℃ for 2h at a heating rate of 10℃ / min to obtain black copper / nitrogen-phosphorus-carbon material powder.

[0072] S7. Take 150 mg of copper / nitrogen-phosphorus-carbon material from step S6 and disperse it in a mixed solution of 20 mL deionized water and 40 mL ascorbic acid. Disperse it ultrasonically for 0.5 h, add 10 mg of potassium hypochlorous acid, and further sonicate for 0.5 h to form solution D.

[0073] S8. Transfer the solution D from step S7 into a 100 mL standard hydrothermal reactor, place it in an oven at 120 °C, and heat it for 12 h. After the reaction is complete, allow it to cool naturally to room temperature, centrifuge at 12000 rpm for 10 min, collect the precipitate, wash it with a mixed solution of 20 mL deionized water and 20 mL ethanol, wash it three times in total, and freeze-dry it in a freeze dryer at -40 °C for 10 h to obtain black platinum alloy material powder.

[0074] S9. Disperse the 20mg black platinum alloy material powder from step S8 in a mixed solution of 360μL deionized water and 540μL isopropanol, add 100μL Nafion binder, and sonicate in an ultrasonic cell disruptor for 0.5h every 0.5h for a total of 3 times. Then, further oscillate in a vortex stirrer for 20min to obtain a uniformly dispersed ink paste containing platinum metal.

[0075] S10. Take the ink paste containing platinum metal from step S9 (platinum content is 0.15 mg). pt / cm 2 Spray 100 μL each time, three times, onto a low-temperature (40℃) conductive carbon paper rotating at a constant speed of 200 rpm (2 cm). 2 ), and each time at 0.5h interval, a uniform catalyst layer is formed;

[0076] S11, Place the conductive carbon paper (2cm) loaded with the catalyst layer from step S10... 2 ) and proton exchange membrane (Nafion 117 membrane, 2cm) 2 The platinum alloy electrode (platinum-copper / nitrogen-phosphorus-carbon-650) with a multimodal porous structure was formed by hot pressing at 150℃ and 13MPa for 5 minutes.

[0077] Comparative Example 1

[0078] A hot forming method for a platinum alloy electrode includes the following steps:

[0079] Steps S1-S9 are the same as in Example 2;

[0080] S10. Take the platinum-containing ink paste from step S9 (platinum content is 0.15 mg) pt / cm 2 Spray 100 μL each time, three times, onto a statically laid conductive carbon paper (1 cm thick). 2 ), and each time at 0.5h interval, a uniform catalyst layer is formed;

[0081] S11, Place the conductive carbon paper (1cm) loaded with the catalyst layer from step S10... 2 ) and proton exchange membrane (Nafion 117 membrane, 1cm) 2 The platinum alloy electrode (platinum-copper / nitrogen-phosphorus-carbon-600-S) with a multimodal porous structure was formed by hot pressing at 80℃ and 10MPa for 3 minutes.

[0082] The platinum alloy electrodes prepared in Examples 1-3 and Comparative Example 1 were installed in a mold with a serpentine gas flow channel. Peak power density tests were conducted at an operating temperature of 80°C, relative humidity of 100%, anode-cathode gas flow rate of 2:1, and back pressure of 1 bar. The values ​​of their respective peak power densities are shown in Table 1.

[0083] Table 1 Peak Power Density Test Values

[0084] project Peak power density Example 1 <![CDATA[203mW·cm -2 ]]> Example 2 <![CDATA[243mW·cm -2 ]]> Example 3 <![CDATA[212mW·cm -2 ]]> Comparative Example 1 <![CDATA[176mW·cm -2 ]]>

[0085] As shown in Table 1, the peak power density of the multimodal porous platinum alloy electrodes prepared in Examples 1-3 remained between 200 and 240 mW·cm⁻¹. -2 Within this range, the peak power density of Comparative Example 1 is below 180 mW·cm⁻¹. -2 This indicates that layer-by-layer spraying and low-temperature heat treatment are more conducive to the uniform dispersion of active materials on the electrode surface, thereby ensuring high battery power density.

[0086] Figure 1 The XRD patterns of Examples 1-3 of this invention show that the diffraction peaks of the multimodal porous platinum alloy electrodes prepared by different heat treatments are all located between the diffraction peaks of pure Pt (JCPDS04-0802) and Cu (JCPDS04-0836). This indicates that the transition metal-based precursors obtained by different heat treatments in sulfuric acid medium are easy to undergo metal substitution with high-valence platinum, and then alloy.

[0087] Figure 2 The image shows the pore size distribution of the platinum-copper / nitrogen-phosphorus-carbon-600 electrode prepared in Example 2. The results show that the layer-by-layer rotary spraying process is beneficial to the formation of the layered pore structure of the electrode. With appropriate pore size control agents and heat treatment, the electrode can achieve the coexistence of micropores, mesopores and macropores, thereby ensuring sufficient accessibility of reactants and rapid electron exchange on the electrode surface.

[0088] Figure 3 The SEAD diagram of the platinum-copper / nitrogen-phosphorus-carbon-600 electrode prepared in Example 2 shows that after high-temperature and high-pressure treatment, the crystallinity of all alloy crystal planes is low, and the electrode has a certain degree of disorder and more deformation, which is beneficial to better electrocatalysis.

[0089] Figure 4 The polarization curves and peak power density curves of the platinum-copper / nitrogen-phosphorus-carbon-600 electrode prepared in Example 2 are shown. The results indicate that the open-circuit voltage of the electrode is 0.82 V and the peak power density is 243 mW·cm⁻¹. -2 The peak power surface density of the electrodes prepared in Examples 1 and 3 and Comparative Example 1 is higher than that of the electrodes prepared in Comparative Example 1, which shows that different heat treatment processes have different effects on the control of electrode pore structure, and the optimal pore structure ratio has the best electrocatalytic performance.

[0090] The platinum alloy electrodes prepared in Example 2 and Comparative Example 1 were placed into a mold with a serpentine gas flow channel, and impedance tests were performed under the following conditions: operating temperature 80°C, relative humidity 100%, anode-cathode gas flow rate 2:1, and back pressure 1 bar. The test results are shown in Table 2.

[0091] Table 2 Test Results

[0092] project Peak power density Example 2 <![CDATA[0.303Ω / cm 2 ]]> Comparative Example 1 <![CDATA[0.413Ω / cm 2 ]]>

[0093] As shown in Table 2, the impedance of the electrode in Comparative Example 1 is relatively large. This is attributed to the fact that the electrode obtained by hot pressing under conventional 80°C conditions has poor bonding between the catalyst particles and Nafion, which in turn leads to a decrease in the proton conductivity in the catalyst layer.

[0094] Therefore, the present invention adopts the above-mentioned hot processing forming method for a multimodal porous structure platinum alloy electrode, and realizes the construction of a multimodal porous structure of platinum alloy electrode by adjusting the parameters of the step-by-step heat treatment process; and realizes the development of long-life platinum alloy electrode by combining layer-by-layer spraying low-temperature heat treatment and high-temperature high-pressure heat treatment.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method of hot worked forming of a multi-modal pore structure platinum alloy electrode, characterized by, Comprise the following steps: S1, take the copper nitrate trihydrate and benzene tricarboxylic acid are dissolved in deionized water and ethanol respectively, ultrasonic dispersion 0.5h, configuration solution A and solution B; S2, the two solutions of step S1 are mixed, ultrasonic mixing 0.5h, add polyvinylpyrrolidone dispersant, further ultrasonic treatment 1h, form solution C; S3, solution C of step S2 is transferred into 100ml standard hydrothermal kettle, placed in oven, heating treatment 12h, after reaction is completed, natural cooling to room temperature, centrifugal treatment 10min, collect the precipitate, with the mixed solution of deionized water and ethanol is washed, hot drying treatment, get blue copper-based organic framework precursor powder; S4, the precursor powder of step S3 is ground in a mortar, transfer into corundum boat, placed in tube furnace, inert gas is imported, high temperature pyrolysis, get black copper / carbon material powder; S5, the black copper / carbon material of step S4 is mixed with one of melamine, urea, dicyandiamide, transfer into micro ball mill, grinding mixing 0.5h, get mechanical mixing material, placed in tube furnace, inert gas is imported, high temperature pyrolysis, get black copper / nitrogen-carbon material powder; S6, take the copper / nitrogen-carbon material of step S5 and sodium dihydrogen phosphate or sodium hypophosphite are mixed, transfer into micro ball mill, grinding mixing 0.5h, get mechanical mixing material, placed in tube furnace, inert gas is imported, high temperature pyrolysis, get black copper / nitrogen phosphorus-carbon material powder; S7, take the copper / nitrogen phosphorus-carbon material of step S6 is dispersed in the mixed solution of deionized water and ethylene glycol or deionized water and ascorbic acid, ultrasonic dispersion 0.5h, add potassium hypochlorite or chloroplatinic acid, further ultrasonic treatment 0.5h, form solution D; S8, solution D of step S7 is transferred into 100ml standard hydrothermal kettle, placed in oven, heating treatment 12h, after reaction is completed, natural cooling to room temperature, centrifugal treatment 10min, collect the precipitate, with the mixed solution of deionized water and ethanol is washed, freeze drying treatment, get black platinum alloy material powder; S9, the black platinum alloy material powder of step S8 is dispersed in the mixed solution of deionized water and isopropanol, add Nafion adhesive, ultrasonic treatment three times, in vortex agitator, further oscillation 20min, get the uniform dispersion of ink slurry containing platinum metal; S10, the ink slurry containing platinum metal in step S9 is sprayed on the conductive carbon paper by multiple rotations, and the content of platinum in the ink slurry containing platinum metal is 0.15 mg pt / cm 2 The spray rotation is that the conductive carbon paper is placed in a 200 rpm, 40℃ rotator for spray gun spraying, the interval is 0.5 h, the spray is performed layer by layer, the accumulation is three times, low-temperature drying treatment is performed, and a uniform catalytic layer is formed. S11, the conductive carbon paper of step S10 loaded with catalytic layer is compounded with proton exchange membrane layer, the area ratio of catalytic layer and proton exchange membrane layer is 1:1, high temperature, high pressure treatment 130-150 DEG C, 10-13Mpa under hot pressing 3-5min, form multimodal pore structure platinum alloy electrode.

2. A method of hot working and forming a multi-modal pore structure platinum alloy electrode according to claim 1, characterized in that: In step S1, the mass ratio of copper nitrate trihydrate and benzene tricarboxylic acid is 3:2, the volume ratio of deionized water and ethanol is 1:1; in step S2, the added amount of polyvinylpyrrolidone dispersant is 1:1 with the mass ratio of copper nitrate trihydrate; in step S3, the heating temperature is 140 DEG C, the volume ratio of deionized water and ethanol is 1:1, and the drying temperature is 80 DEG C.

3. A method of hot working and forming a multi-modal pore structure platinum alloy electrode according to claim 1, characterized in that: In step S4, the inert gas is argon, the high-temperature pyrolysis is pyrolysis at 600 DEG C for 2h, and the heating rate is 10 DEG C / min.

4. A method of hot working and forming a multi-modal pore structure platinum alloy electrode according to claim 1, characterized in that: In step S5, the mass ratio of the black carbon material to one of melamine, urea, and dicyandiamide is 1:1, the inert gas is argon, the high-temperature pyrolysis is pyrolysis at 550-650 DEG C for 4h, and the heating rate is 10 DEG C / min.

5. A method of hot working and forming a multi-modal pore structure platinum alloy electrode according to claim 1, characterized in that: In step S6, the mass ratio of the copper / nitrogen-carbon material to sodium dihydrogen phosphate or sodium hypophosphite is 1:1.5, the inert gas is argon, the high-temperature pyrolysis is pyrolysis at 700-750 DEG C for 2h, and the heating rate is 10 DEG C / min.

6. A method of hot working and forming a multi-modal pore structure platinum alloy electrode according to claim 1, characterized by: In step S7, the volume ratio of deionized water to ethylene glycol or ascorbic acid is 1:1.5-2, and the amount of potassium chloroplatinate or potassium hypochloroplatinate added is 5% of the mass of the copper / nitrogen-phosphorus-carbon material.

7. A method of hot working and forming a multi-modal pore structure platinum alloy electrode according to claim 1, characterized by: In step S8, the heating temperature is 120 DEG C, the volume ratio of deionized water to ethanol is 1:0.5-1, and the freeze-drying temperature is -40 DEG C.

8. A method of hot working and forming a multi-modal pore structure platinum alloy electrode according to claim 1, characterized by: In step S9, the volume ratio of deionized water to isopropyl alcohol is 1:4, the mass fraction of the Nafion binder is 5%, the volume ratio of the amount of the Nafion binder added to the volume of the polyvinylpyrrolidone dispersant in step S2 is 1:0.01, the ultrasonic treatment is performed for 0.5h every 0.5h, and the cumulative ultrasonic treatment is three times.

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