An acetylene black supported iridium-palladium alloy catalyst, a preparation method, application and device thereof

Abstract

The application relates to the technical field of water electrolysis catalyst materials, and discloses an acetylene black loaded iridium-palladium alloy catalyst as well as a preparation method, application and device thereof. The preparation method comprises the following steps: acid treatment of acetylene black with a nitric acid solution, washing until neutral, and then dispersing in an alcohol solvent to obtain an acetylene black suspension; mixing an iridium precursor and a palladium precursor, adding the suspension under ultrasonic assistance, and stirring and adsorbing; cooling the obtained mixture to 0-5 DEG C, quickly adding a sodium borohydride solution for a reduction reaction, and then continuing the reaction after the temperature is increased to room temperature; and finally filtering, washing and drying. The obtained catalyst has the advantages of small particle size (2-5 nm), high alloy uniformity (atomic level distribution), excellent catalytic performance (eta 10 = 278 mV) and good stability (100h attenuation < 5%), significantly reduces the iridium consumption and the catalyst cost, and is suitable for a PEM water electrolysis hydrogen production system.

Description

Technical Field

[0001] This invention belongs to the field of electrolytic water catalytic materials technology, specifically relating to an acetylene black supported iridium-palladium alloy catalyst and its preparation method, application and apparatus. Background Technology

[0002] Proton exchange membrane (PEM) water electrolysis technology is considered one of the green hydrogen production technologies most closely coupled with renewable energy sources due to its advantages such as high current density, fast dynamic response, and high hydrogen purity. In this system, the oxygen evolution reaction (OER) at the anolyte, due to its slow four-electron transfer kinetics, has become a key bottleneck restricting electrolysis efficiency. Currently, iridium-based catalysts (such as IrO2) are the only practical anolyte catalysts that possess both high activity and long-term stability under the acidic operating environment of a PEM electrolyzer. However, iridium's abundance in the Earth's crust is extremely low (approximately 0.001 ppm), and its price is extremely high, resulting in high catalyst costs for PEM electrolyzers, severely hindering its large-scale commercialization. Therefore, how to significantly reduce the amount of iridium used while ensuring catalytic performance and stability is a core scientific problem that urgently needs to be solved in the field of PEM water electrolysis.

[0003] To reduce the cost of iridium-based catalysts, researchers have focused on three main directions: first, alloying iridium with inexpensive metals (such as Pd, Ru, and Ni) to enhance intrinsic activity through electronic structure modulation, thereby reducing the amount of iridium used; second, nano-sizing and highly dispersing the active components on a support to increase the density of active sites; and third, using support materials with high specific surface area, high conductivity, and corrosion resistance to improve metal utilization and catalyst structural stability. Among these, the iridium-palladium (IrPd) alloy is considered one of the most promising alloy systems due to its high lattice matching and the proximity of the d-band center of Pd to that of Ir.

[0004] Despite numerous reports on IrPd alloy catalysts, existing preparation methods still face the following technical bottlenecks: First, while traditional high-temperature alloying treatments (typically >500℃) can promote alloy phase formation, they easily lead to severe sintering of metal particles (particle size >10 nm) and induce compositional segregation, forming a core-shell structure rather than a homogeneous alloy, thus failing to fully utilize the synergistic electronic effects of the alloy. Second, due to Pd... 2+ The reduction potential of / Pd (+0.951 V vs. SHE) is significantly higher than that of IrCl6. 2-In the reaction with Ir (+0.86 V vs. SHE), Pd is preferentially reduced under conventional reduction conditions, easily forming a heterogeneous structure rich in Pd cores and Ir shells, leading to a decrease in intrinsic catalytic activity. Furthermore, the carbon support is prone to corrosion during high-temperature processing, causing metal particle detachment and agglomeration, severely impairing the long-term stability of the catalyst. In addition, some existing methods rely on multi-step reactions, complex equipment, or expensive reagents, resulting in cumbersome processes and difficulties in large-scale production. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention aims to provide an acetylene black supported iridium-palladium alloy catalyst and its preparation method, application and apparatus, so as to solve the technical problems of low alloying degree, easy sintering of particles, component segregation and carrier corrosion caused by the difference in reduction kinetics and high temperature heat treatment in the preparation process of iridium-palladium alloy catalysts in the prior art.

[0006] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a method for preparing an acetylene black supported iridium-palladium alloy catalyst, comprising the following steps: S1, Carrier pretreatment: Acetylene black is acid-treated with nitric acid solution, washed until neutral, and then dispersed in alcohol solvent to obtain acetylene black suspension; S2, Impregnation Adsorption: The iridium precursor solution and the palladium precursor solution are mixed and added to the acetylene black suspension under ultrasonic assistance. The mixture is stirred and adsorbed to obtain an acetylene black mixture loaded with iridium and palladium precursors. S3, Low-temperature reduction alloying: The acetylene black mixture obtained from S2 is cooled to 0-5℃, and sodium borohydride solution is rapidly added under vigorous stirring to carry out the reduction reaction. Then, the reaction system is heated to room temperature to continue the reaction, and the crude reduced catalyst is obtained. S4, Post-processing: The crude catalyst obtained in S3 is filtered, washed, and dried to obtain the acetylene black supported iridium-palladium alloy catalyst.

[0007] A further improvement of the present invention is that the mass concentration of the nitric acid solution in S1 is 3-7 wt%, the acid treatment temperature is 50-70°C, and the treatment time is 4-8 hours.

[0008] A further improvement of the present invention is that the alcohol solvent in S1 is isopropanol or ethanol.

[0009] A further improvement of the present invention is that the iridium precursor in S2 is chloroiridium acid, and the palladium precursor is chloropalladium acid or palladium chloride; the molar ratio of iridium to palladium is (3:1)-(1:3).

[0010] A further improvement of the present invention is that the ultrasonic assistance power in S2 is 200-400W, the ultrasonic time is 30-60 minutes, and the stirring and adsorption time is 4-6 hours.

[0011] A further improvement of the present invention is that the rapid addition time in S3 is 1-3 minutes, and the molar amount of sodium borohydride is 5-15 times the total molar amount of iridium and palladium.

[0012] A further improvement of the present invention is that the concentration of the sodium borohydride solution in S3 is 0.1-0.5M.

[0013] Secondly, the present invention also provides an acetylene black supported iridium-palladium alloy catalyst, obtained by the above preparation method. The catalyst includes an acetylene black support and iridium-palladium alloy nanoparticles supported on the acetylene black support. The total loading of iridium and palladium in the catalyst is 20-40 wt%, the average particle size of the iridium-palladium alloy nanoparticles is 2-5 nm, and the Ir and Pd elements are uniformly distributed in a single particle.

[0014] Thirdly, the present invention also provides the application of the acetylene black supported iridium-palladium alloy catalyst as described above as an anode catalyst in proton exchange membrane water electrolysis for hydrogen production.

[0015] Fourthly, the present invention also provides a proton exchange membrane water electrolysis device, wherein the anode catalyst layer comprises the above-mentioned acetylene black supported iridium-palladium alloy catalyst.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for preparing an iridium-palladium alloy catalyst supported on acetylene black. First, pretreatment of acetylene black with nitric acid introduces oxygen-containing functional groups onto the support surface, significantly enhancing its hydrophilicity and anchoring ability to the metal precursor, laying the foundation for the highly dispersed loading of the subsequent active components. Second, ultrasonic-assisted impregnation adsorption is used to uniformly disperse the iridium and palladium precursors within the support pores. Combined with forced synchronous reduction by rapidly adding sodium borohydride at a low temperature of 0-5℃, atomic migration and particle agglomeration are effectively suppressed, avoiding component segregation caused by differences in reduction kinetics. This results in alloy nanoparticles with Ir and Pd uniformly distributed at the atomic level within individual particles, with an average particle size of only 2-5 nm and a uniform distribution. Due to the highly uniform alloy structure and fine particle size, the obtained catalyst exhibits excellent catalytic performance in the acidic oxygen evolution reaction (OER), with a value of 10 mA / cm². 2The overpotential at current density is as low as 275-285mV, the mass activity is up to 3.3 times that of commercial IrO2, the Tafel slope is only 40-45mV / dec, and it also has excellent stability, with an activity decay of less than 5% after 100 hours of constant current testing. In addition, the entire preparation process is completed under low temperature conditions, without the need for complex equipment or expensive reagents, making the process green and economical and suitable for large-scale production.

[0017] This invention also provides an acetylene black-supported iridium-palladium alloy catalyst. The catalyst uses acetylene black as a support, which, after nitric acid pretreatment, has a surface rich in oxygen-containing functional groups. This effectively anchors the iridium-palladium alloy nanoparticles, ensuring a high degree of dispersion of the active components. The average particle size of the iridium-palladium alloy nanoparticles is only 2-5 nm, and Ir and Pd elements are uniformly distributed within each particle, without core-shell structure or segregation. This fully leverages the electronic synergistic effect of the alloy, significantly improving the intrinsic catalytic activity. The total loading of iridium and palladium in the catalyst is 20-40 wt%, effectively controlling the amount of precious metals while ensuring excellent catalytic performance and reducing catalyst costs.

[0018] The aforementioned acetylene black supported iridium-palladium alloy catalyst was used as an anode catalyst in proton exchange membrane water electrolysis for hydrogen production. Utilizing its small size, high alloying degree, and uniform atomic distribution characteristics, it exhibited excellent catalytic activity and stability in the acidic oxygen evolution reaction, which could significantly reduce the anode overpotential, improve electrolysis efficiency, reduce the amount of precious metal iridium used, lower the manufacturing cost of the electrolyzer, and promote the large-scale application of green hydrogen production technology.

[0019] The proton exchange membrane water electrolysis device uses the aforementioned acetylene black supported iridium-palladium alloy catalyst as the main active component of the anode catalyst layer. Thanks to the high intrinsic activity and excellent stability of the catalyst, the device exhibits low energy consumption and high efficiency during operation, and has good long-term operational stability. It effectively reduces the amount of precious metals used and system maintenance costs, and has good economic benefits and commercial application prospects. Detailed Implementation

[0020] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0021] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0022] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0023] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0024] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0025] This invention provides a method for preparing an acetylene black supported iridium-palladium alloy catalyst, comprising the following steps: S1, Carrier Pretreatment: Acetylene black is acid-treated with a 3-7 wt% nitric acid solution at 50-70℃ for 4-8 hours to introduce oxygen-containing functional groups such as carboxyl and hydroxyl groups onto its surface, enhancing its hydrophilicity and anchoring ability to metal precursors. After washing to neutrality, it is dispersed in isopropanol or ethanol to obtain an acetylene black suspension. The BET specific surface area of ​​the carrier after treatment increases from 65 m² / g to 85-90 m² / g, and the pore volume increases by about 20%. S2, Impregnation Adsorption: Using chloroiridium acid and chloropalladium acid as metal sources, a mixed solution is prepared with an Ir:Pd molar ratio of (3:1)-(1:3). The mixed solution is added to the acetylene black suspension using an equal-volume impregnation method under ultrasonic assistance with a power of 200-400W. The mixture is ultrasonically treated for 30-60 minutes and then stirred and adsorbed for 4-6 hours to uniformly disperse the precursor in the carrier pores, thus obtaining an acetylene black mixture loaded with iridium and palladium precursors. S3, Low-Temperature Reduction Alloying: The acetylene black mixture obtained in S2 is cooled to 0-5℃, and a sodium borohydride solution is rapidly added within 1-3 minutes under vigorous stirring to carry out a reduction reaction. The concentration of the sodium borohydride solution is 0.1-0.5M, and the molar amount of sodium borohydride is 5-15 times the total molar amount of iridium and palladium. The low-temperature condition inhibits atomic migration, forcing iridium and palladium ions to be reduced simultaneously, avoiding component segregation caused by differences in reduction kinetics. The reaction mechanism is as follows: IrCl6 2 +3BH4 +12H₂O→Ir+3B(OH)₃+6Cl +21H2 PdCl4 2 +2BH4 +8H₂O→Pd+2B(OH)₃+4Cl +14H2 After the reduction reaction is complete, the reaction system is heated to room temperature to continue the reaction, and the crude reduced catalyst is obtained. S4, Post-processing: The crude catalyst obtained in S3 is filtered, washed until no chloride ions are detected, washed with ethanol, and vacuum dried at 50-70℃ for 10-14 hours to obtain the acetylene black supported iridium-palladium alloy catalyst.

[0026] The present invention also provides an acetylene black supported iridium-palladium alloy catalyst, which is obtained by the above preparation method. The catalyst includes an acetylene black support and iridium-palladium alloy nanoparticles supported on the acetylene black support. The total loading of iridium and palladium in the catalyst is 20-40 wt%, the average particle size of the iridium-palladium alloy nanoparticles is 2-5 nm, and the Ir and Pd elements are uniformly distributed in a single particle.

[0027] The present invention also provides an application of the acetylene black supported iridium-palladium alloy catalyst as described above as an anode catalyst in proton exchange membrane water electrolysis for hydrogen production.

[0028] The present invention also provides a proton exchange membrane electrolysis water device, wherein the anode catalyst layer comprises the above-mentioned acetylene black supported iridium palladium alloy catalyst, proton conducting resin and film forming aid, and the anode catalyst layer is coated on the anode side of the proton exchange membrane, and together with the cathode catalyst layer and the proton exchange membrane, constitutes a membrane electrode assembly.

[0029] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0030] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" represents weight percentage, "parts" represents parts by weight, and "ratio" represents weight proportion.

[0031] Example 1 Step 1: Place 200.0 mg of acetylene black in a 250 mL round-bottom flask, add 40.0 mL of 5 wt% nitric acid solution, and place the flask in a 60°C water bath. Stir mechanically at 500 rpm for 6 hours for acid treatment. After the reaction is complete, cool to room temperature and filter using a 0.22 μm polyethersulfone membrane. Wash with deionized water until the conductivity of the filtrate is below 10 μS / cm. Transfer the washed wet filter cake to a 100 mL beaker, add 50.0 mL of isopropanol, and sonicate using a 400W ultrasonic probe for 30 minutes to obtain an acetylene black suspension.

[0032] Step 2: Using chloroiridium acid (H2IrCl6·6H2O, Ir content 35%) and chloropalladium acid (H2PdCl4, Pd content 40%) as precursors, and calculating based on an Ir:Pd molar ratio of 1:1 and a total iridium and palladium loading of 30wt% of the acetylene black mass, 85.7 mg of chloroiridium acid and 75.0 mg of chloropalladium acid were weighed and dissolved in 10.0 mL of a 1:1 mixture of water and isopropanol to obtain a precursor mixture solution. Under 400W ultrasonic assistance, the precursor mixture solution was added dropwise to the acetylene black suspension at a rate of 1 mL / min. After the addition was complete, ultrasonication was continued for 30 minutes, followed by stirring at 800 rpm for 4 hours at room temperature to obtain an acetylene black mixture loaded with iridium and palladium precursors.

[0033] Step 3: Transfer the above acetylene black mixture to a 250 mL three-necked flask and cool it to 0°C in an ice bath. While vigorously stirring at 1200 rpm, rapidly add 10.0 mL of a pre-prepared sodium borohydride solution within 1 minute. The molar amount of sodium borohydride in this solution is 10 times the total molar amount of iridium and palladium (53.4 mg), and the concentration is 0.1 M. After the reduction reaction is complete, remove the ice bath and allow the reaction system to naturally warm to room temperature. Continue stirring for 2 hours to obtain the crude reduced catalyst.

[0034] Step 4: The reduced crude catalyst was filtered using a Buchner funnel, washed with deionized water until no white precipitate was detected by 0.1M silver nitrate, and then washed three times with 50 mL of anhydrous ethanol each time. The washed solid product was placed in a vacuum drying oven at 60℃ and dried for 12 hours, then ground through a 400-mesh sieve to obtain the acetylene black supported iridium-palladium alloy catalyst.

[0035] The obtained catalyst was subjected to electrochemical performance testing in 0.5 M H₂SO₄ electrolyte at 25 °C. The working electrode was a glassy carbon electrode (5 mm in diameter), and the catalyst loading was 0.2 mg / cm³. 2 The reference electrode is a saturated calomel electrode, and the counter electrode is a platinum sheet (1×1 cm). 2The linear scan voltammetry test was conducted at a scan rate of 1 mV / s with 90% iR compensation, and a measurement of 10 mA / cm² was obtained. 2 The overpotential at the current density was 278 mV; the cyclic voltammetry scan range was 0.4–1.4 V vs. RHE, with a scan rate of 50 mV / s; the electrochemical impedance spectroscopy (EIS) test frequency range was 100 kHz–0.1 Hz, with an amplitude of 5 mV. The calculated Tafel slope was 42 mV / dec, and the electrochemical active area was 85 m². 2 / g, the mass activity at 1.55V is 1.25 A / mgIr. At 1 A / cm 2 After 100 hours of constant current testing, the voltage rise was less than 15 mV; after 10,000 cycles in the 0.6–1.6 V vs. RHE range, the voltage rose to 10 mA / cm². 2 The overpotential increases by 12 mV at the current density.

[0036] Example 2 Step 1: Place 200.0 mg of acetylene black in a 250 mL round-bottom flask, add 40.0 mL of 5 wt% nitric acid solution, and place the flask in a 60°C water bath. Stir mechanically at 500 rpm for 6 hours for acid treatment. After the reaction is complete, cool to room temperature and filter using a 0.22 μm polyethersulfone membrane. Wash with deionized water until the conductivity of the filtrate is below 10 μS / cm. Transfer the washed wet filter cake to a 100 mL beaker, add 50.0 mL of isopropanol, and sonicate using a 400W ultrasonic probe for 30 minutes to obtain an acetylene black suspension.

[0037] Step 2: Using chloroiridium acid (H2IrCl6·6H2O, Ir content 35%) and chloropalladium acid (H2PdCl4, Pd content 40%) as precursors, and calculating based on an Ir:Pd molar ratio of 3:1 and a total iridium and palladium loading of 30wt% of the acetylene black mass, 128.6 mg of chloroiridium acid and 37.5 mg of chloropalladium acid were weighed and dissolved in 10.0 mL of a 1:1 mixture of water and isopropanol to obtain a precursor mixture solution. Under 400W ultrasonic assistance, the precursor mixture solution was added dropwise to the acetylene black suspension at a rate of 1 mL / min. After the addition was complete, ultrasonication was continued for 30 minutes, followed by stirring at 800 rpm for 4 hours at room temperature to obtain an acetylene black mixture loaded with iridium and palladium precursors.

[0038] Step 3: Transfer the above acetylene black mixture to a 250 mL three-necked flask and cool it to 0°C in an ice bath. While stirring vigorously at 1200 rpm, rapidly add 10.0 mL of a pre-prepared sodium borohydride solution within 1 minute. The molar amount of sodium borohydride in this solution is 10 times the total molar amount of iridium and palladium, and the concentration is 0.1 M. After the reduction reaction is complete, remove the ice bath and allow the reaction system to naturally warm to room temperature. Continue stirring for 2 hours to obtain the crude reduced catalyst.

[0039] Step 4: The reduced crude catalyst was filtered using a Buchner funnel, washed with deionized water until no white precipitate was detected by 0.1M silver nitrate, and then washed three times with 50 mL of anhydrous ethanol each time. The washed solid product was placed in a vacuum drying oven at 60℃ and dried for 12 hours, then ground through a 400-mesh sieve to obtain the acetylene black supported iridium-palladium alloy catalyst.

[0040] The obtained catalyst was subjected to electrochemical performance testing in 0.5 M H₂SO₄ electrolyte at 25 °C. The working electrode was a glassy carbon electrode (5 mm in diameter), and the catalyst loading was 0.2 mg / cm³. 2 The reference electrode is a saturated calomel electrode, and the counter electrode is a platinum sheet (1×1 cm). 2 The linear scan voltammetry test was conducted at a scan rate of 1 mV / s with 90% iR compensation, and a measurement of 10 mA / cm² was obtained. 2 The overpotential at the current density is 285 mV, and the mass activity at 1.55 V is 0.98 A / mgIr. Transmission electron microscopy characterization shows that the average particle size of the catalyst is 3.5 nm.

[0041] Example 3 Step 1: Place 200.0 mg of acetylene black in a 250 mL round-bottom flask, add 40.0 mL of 5 wt% nitric acid solution, and place the flask in a 60°C water bath. Stir mechanically at 500 rpm for 6 hours for acid treatment. After the reaction is complete, cool to room temperature and filter using a 0.22 μm polyethersulfone membrane. Wash with deionized water until the conductivity of the filtrate is below 10 μS / cm. Transfer the washed wet filter cake to a 100 mL beaker, add 50.0 mL of isopropanol, and sonicate using a 400W ultrasonic probe for 30 minutes to obtain an acetylene black suspension.

[0042] Step 2: Using chloroiridium acid (H2IrCl6·6H2O, Ir content 35%) and chloropalladium acid (H2PdCl4, Pd content 40%) as precursors, and calculating based on an Ir:Pd molar ratio of 1:3 and a total iridium and palladium loading of 30wt% of the acetylene black mass, 42.9 mg of chloroiridium acid and 112.5 mg of chloropalladium acid were weighed and dissolved in 10.0 mL of a 1:1 mixture of water and isopropanol to obtain a precursor mixture solution. Under 400W ultrasonic assistance, the precursor mixture solution was added dropwise to the acetylene black suspension at a rate of 1 mL / min. After the addition was complete, ultrasonication was continued for 30 minutes, followed by stirring at 800 rpm for 4 hours at room temperature to obtain an acetylene black mixture loaded with iridium and palladium precursors.

[0043] Step 3: Transfer the above acetylene black mixture to a 250 mL three-necked flask and cool it to 0°C in an ice bath. While stirring vigorously at 1200 rpm, rapidly add 10.0 mL of a pre-prepared sodium borohydride solution within 1 minute. The molar amount of sodium borohydride in this solution is 10 times the total molar amount of iridium and palladium, and the concentration is 0.1 M. After the reduction reaction is complete, remove the ice bath and allow the reaction system to naturally warm to room temperature. Continue stirring for 2 hours to obtain the crude reduced catalyst.

[0044] Step 4: The reduced crude catalyst was filtered using a Buchner funnel, washed with deionized water until no white precipitate was detected by 0.1M silver nitrate, and then washed three times with 50 mL of anhydrous ethanol each time. The washed solid product was placed in a vacuum drying oven at 60℃ and dried for 12 hours, then ground through a 400-mesh sieve to obtain the acetylene black supported iridium-palladium alloy catalyst.

[0045] The obtained catalyst was subjected to electrochemical performance testing in 0.5 M H₂SO₄ electrolyte at 25 °C. The working electrode was a glassy carbon electrode (5 mm in diameter), and the catalyst loading was 0.2 mg / cm³. 2 The reference electrode is a saturated calomel electrode, and the counter electrode is a platinum sheet (1×1 cm). 2 The linear scan voltammetry test was conducted at a scan rate of 1 mV / s with 90% iR compensation, and a measurement of 10 mA / cm² was obtained. 2 The overpotential at the current density was 292 mV, and the mass activity at 1.55 V was 0.86 A / mgIr. Transmission electron microscopy characterization showed that the average particle size of the catalyst was 3.8 nm.

[0046] Example 4 Step 1: Place 200.0 mg of acetylene black in a 250 mL round-bottom flask, add 40.0 mL of 5 wt% nitric acid solution, and place the flask in a 60°C water bath. Stir mechanically at 500 rpm for 6 hours for acid treatment. After the reaction is complete, cool to room temperature and filter using a 0.22 μm polyethersulfone membrane. Wash with deionized water until the conductivity of the filtrate is below 10 μS / cm. Transfer the washed wet filter cake to a 100 mL beaker, add 50.0 mL of isopropanol, and sonicate using a 400W ultrasonic probe for 30 minutes to obtain an acetylene black suspension.

[0047] Step 2: Using chloroiridium acid (H2IrCl6·6H2O, Ir content 35%) and chloropalladium acid (H2PdCl4, Pd content 40%) as precursors, and calculating based on an Ir:Pd molar ratio of 1:1 and a total iridium and palladium loading of 30wt% of the acetylene black mass, 85.7 mg of chloroiridium acid and 75.0 mg of chloropalladium acid were weighed and dissolved in 10.0 mL of a 1:1 mixture of water and isopropanol to obtain a precursor mixture solution. Under 400W ultrasonic assistance, the precursor mixture solution was added dropwise to the acetylene black suspension at a rate of 1 mL / min. After the addition was complete, ultrasonication was continued for 30 minutes, followed by stirring at 800 rpm for 4 hours at room temperature to obtain an acetylene black mixture loaded with iridium and palladium precursors.

[0048] Step 3: Transfer the above acetylene black mixture to a 250 mL three-necked flask and cool it to 0°C in an ice bath. While vigorously stirring at 1200 rpm, rapidly add 10.0 mL of a pre-prepared sodium borohydride solution within 1 minute. The molar amount of sodium borohydride in this solution is 5 times the total molar amount of iridium and palladium (26.7 mg), and the concentration is 0.1 M. After the reduction reaction is complete, remove the ice bath and allow the reaction system to naturally warm to room temperature. Continue stirring for 2 hours to obtain the crude reduced catalyst.

[0049] Step 4: The reduced crude catalyst was filtered using a Buchner funnel, washed with deionized water until no white precipitate was detected by 0.1M silver nitrate, and then washed three times with 50 mL of anhydrous ethanol each time. The washed solid product was placed in a vacuum drying oven at 60℃ and dried for 12 hours, then ground through a 400-mesh sieve to obtain the acetylene black supported iridium-palladium alloy catalyst.

[0050] The obtained catalyst was subjected to electrochemical performance testing in 0.5 M H₂SO₄ electrolyte at 25 °C. The working electrode was a glassy carbon electrode (5 mm in diameter), and the catalyst loading was 0.2 mg / cm³. 2 The reference electrode is a saturated calomel electrode, and the counter electrode is a platinum sheet (1×1 cm). 2The linear scan voltammetry test was conducted at a scan rate of 1 mV / s with 90% iR compensation, and a measurement of 10 mA / cm² was obtained. 2 The overpotential at the current density was 281 mV. Transmission electron microscopy characterization showed that the average particle size of the catalyst was 3.6 nm. The residual chloride ion content in the catalyst was detected to be 35 ppm.

[0051] Example 5 Step 1: Place 200.0 mg of acetylene black in a 250 mL round-bottom flask, add 40.0 mL of 5 wt% nitric acid solution, and place the flask in a 60°C water bath. Stir mechanically at 500 rpm for 6 hours for acid treatment. After the reaction is complete, cool to room temperature and filter using a 0.22 μm polyethersulfone membrane. Wash with deionized water until the conductivity of the filtrate is below 10 μS / cm. Transfer the washed wet filter cake to a 100 mL beaker, add 50.0 mL of isopropanol, and sonicate using a 400W ultrasonic probe for 30 minutes to obtain an acetylene black suspension.

[0052] Step 2: Using chloroiridium acid (H2IrCl6·6H2O, Ir content 35%) and chloropalladium acid (H2PdCl4, Pd content 40%) as precursors, and calculating based on an Ir:Pd molar ratio of 1:1 and a total iridium and palladium loading of 30wt% of the acetylene black mass, 85.7 mg of chloroiridium acid and 75.0 mg of chloropalladium acid were weighed and dissolved in 10.0 mL of a 1:1 mixture of water and isopropanol to obtain a precursor mixture solution. Under 400W ultrasonic assistance, the precursor mixture solution was added dropwise to the acetylene black suspension at a rate of 1 mL / min. After the addition was complete, ultrasonication was continued for 30 minutes, followed by stirring at 800 rpm for 4 hours at room temperature to obtain an acetylene black mixture loaded with iridium and palladium precursors.

[0053] Step 3: Transfer the above acetylene black mixture to a 250 mL three-necked flask and cool it to 0°C in an ice bath. While vigorously stirring at 1200 rpm, rapidly add 10.0 mL of a pre-prepared sodium borohydride solution within 1 minute. The molar amount of sodium borohydride in this solution is 15 times the total molar amount of iridium and palladium (80.1 mg), and the concentration is 0.1 M. After the reduction reaction is complete, remove the ice bath and allow the reaction system to naturally warm to room temperature. Continue stirring for 2 hours to obtain the crude reduced catalyst.

[0054] Step 4: The reduced crude catalyst was filtered using a Buchner funnel, washed with deionized water until no white precipitate was detected by 0.1M silver nitrate, and then washed three times with 50 mL of anhydrous ethanol each time. The washed solid product was placed in a vacuum drying oven at 60℃ and dried for 12 hours, then ground through a 400-mesh sieve to obtain the acetylene black supported iridium-palladium alloy catalyst.

[0055] The obtained catalyst was subjected to electrochemical performance testing in 0.5 M H₂SO₄ electrolyte at 25 °C. The working electrode was a glassy carbon electrode (5 mm in diameter), and the catalyst loading was 0.2 mg / cm³. 2 The reference electrode is a saturated calomel electrode, and the counter electrode is a platinum sheet (1×1 cm). 2 The linear scan voltammetry test was conducted at a scan rate of 1 mV / s with 90% iR compensation, and a measurement of 10 mA / cm² was obtained. 2 The overpotential at the current density was 279 mV. Transmission electron microscopy characterization showed that the average particle size of the catalyst was 3.3 nm. The residual chloride ion content in the catalyst was detected to be 8 ppm.

[0056] Comparative Example 1 Step 1: Place 200.0 mg of acetylene black in a 250 mL round-bottom flask, add 40.0 mL of 5 wt% nitric acid solution, and place the flask in a 60°C water bath. Stir mechanically at 500 rpm for 6 hours for acid treatment. After the reaction is complete, cool to room temperature and filter using a 0.22 μm polyethersulfone membrane. Wash with deionized water until the conductivity of the filtrate is below 10 μS / cm. Transfer the washed wet filter cake to a 100 mL beaker, add 50.0 mL of isopropanol, and sonicate using a 400W ultrasonic probe for 30 minutes to obtain an acetylene black suspension.

[0057] Step 2: Using chloroiridium acid (H2IrCl6·6H2O, Ir content 35%) and chloropalladium acid (H2PdCl4, Pd content 40%) as precursors, and calculating based on an Ir:Pd molar ratio of 1:1 and a total iridium and palladium loading of 30wt% of the acetylene black mass, 85.7 mg of chloroiridium acid and 75.0 mg of chloropalladium acid were weighed and dissolved in 10.0 mL of a 1:1 mixture of water and isopropanol to obtain a precursor mixture solution. Under 400W ultrasonic assistance, the precursor mixture solution was added dropwise to the acetylene black suspension at a rate of 1 mL / min. After the addition was complete, ultrasonication was continued for 30 minutes, followed by stirring at 800 rpm for 4 hours at room temperature to obtain an acetylene black mixture loaded with iridium and palladium precursors.

[0058] Step 3: The acetylene black mixture loaded with iridium and palladium precursors is placed in a tube furnace and heated to 500°C at a rate of 5°C / min under a mixed atmosphere of hydrogen and nitrogen with a volume ratio of 5:95. The mixture is held at this temperature for 2 hours for high-temperature reduction, and then naturally cooled to room temperature to obtain the crude reduced catalyst.

[0059] Step 4: Filter the reduced crude catalyst using a Buchner funnel, wash with deionized water until no white precipitate is detected by 0.1M silver nitrate, then wash three times with 50 mL of anhydrous ethanol each time. Place the washed solid product in a vacuum drying oven at 60℃ for 12 hours, grind it through a 400-mesh sieve to obtain the catalyst.

[0060] Transmission electron microscopy (TEM) characterization showed that the catalyst had an average particle size of 8.5 nm. Electrochemical performance was tested in 0.5 M H₂SO₄ electrolyte at 25 °C, using a glassy carbon electrode (5 mm in diameter) as the working electrode and a catalyst loading of 0.2 mg / cm³. 2 The reference electrode is a saturated calomel electrode, and the counter electrode is a platinum sheet (1×1 cm). 2 The linear scan voltammetry test was conducted at a scan rate of 1 mV / s with 90% iR compensation, and the measured value was 10 mA / cm². 2 The overpotential at the current density was 305 mV. Energy dispersive spectroscopy analysis showed that the catalyst particles exhibited a distinct core-shell structure, with palladium enriched in the core region and iridium enriched in the outer shell region.

[0061] Comparative Example 2 Step 1: Place 200.0 mg of acetylene black in a 250 mL round-bottom flask, add 40.0 mL of 5 wt% nitric acid solution, and place the flask in a 60°C water bath. Stir mechanically at 500 rpm for 6 hours for acid treatment. After the reaction is complete, cool to room temperature and filter using a 0.22 μm polyethersulfone membrane. Wash with deionized water until the conductivity of the filtrate is below 10 μS / cm. Transfer the washed wet filter cake to a 100 mL beaker, add 50.0 mL of isopropanol, and sonicate using a 400W ultrasonic probe for 30 minutes to obtain an acetylene black suspension.

[0062] Step 2: Using palladium chloropalladium acid (H₂PdCl₄, Pd content 40%) as the palladium precursor, 75.0 mg of palladium chloropalladium acid was weighed and dissolved in 5.0 mL of a 1:1 mixture of water and isopropanol. Under 400W ultrasonic assistance, the palladium precursor solution was added dropwise to the acetylene black suspension at a rate of 1 mL / min. After the addition was complete, ultrasonication continued for 30 minutes, followed by stirring at 800 rpm for 2 hours at room temperature. The resulting mixture was transferred to a 250 mL three-necked flask and placed in a 60°C water bath. Under vigorous stirring at 1200 rpm, 5.0 mL of a pre-prepared sodium borohydride solution (10 times the molar amount of palladium, concentration 0.1 M) was rapidly added within 1 minute. After the reduction reaction was complete, stirring continued for 2 hours to obtain a palladium-loaded acetylene black mixture.

[0063] Step 3: Using chloroiridium acid (H2IrCl6·6H2O, Ir content 35%) as the iridium precursor, 85.7 mg of chloroiridium acid was weighed according to an Ir:Pd molar ratio of 1:1 and dissolved in 5.0 mL of a 1:1 mixture of water and isopropanol. Under 400W ultrasonic assistance, the iridium precursor solution was added dropwise to the above-mentioned palladium-loaded acetylene black mixture at a rate of 1 mL / min. After the addition was complete, ultrasonication was continued for 30 minutes, followed by stirring at 800 rpm for 2 hours at room temperature. The resulting mixture was transferred to a 250 mL three-necked flask and cooled to 0°C in an ice bath. Under vigorous stirring at 1200 rpm, 5.0 mL of a pre-prepared sodium borohydride solution was rapidly added within 1 minute. The molar amount of sodium borohydride in this solution was 10 times that of iridium, and the concentration was 0.1 M. After the reduction reaction was completed, the ice bath was removed, and the reaction system was allowed to naturally warm to room temperature. Stirring was continued for 2 hours to obtain the crude reduced catalyst.

[0064] Step 4: Filter the reduced crude catalyst using a Buchner funnel, wash with deionized water until no white precipitate is detected by 0.1M silver nitrate, then wash three times with 50 mL of anhydrous ethanol each time. Place the washed solid product in a vacuum drying oven at 60℃ for 12 hours, grind it through a 400-mesh sieve to obtain the catalyst.

[0065] Transmission electron microscopy (TEM) characterization showed that the catalyst had an average particle size of 6.8 nm. Electrochemical performance was tested in 0.5 M H₂SO₄ electrolyte at 25 °C, using a glassy carbon electrode (5 mm in diameter) as the working electrode and a catalyst loading of 0.2 mg / cm³. 2 The reference electrode is a saturated calomel electrode, and the counter electrode is a platinum sheet (1×1 cm). 2 The linear scan voltammetry test was conducted at a scan rate of 1 mV / s with 90% iR compensation, and the measured value was 10 mA / cm². 2 The overpotential at the current density was 298 mV. Energy dispersive spectroscopy analysis showed that the palladium content in the catalyst particles decreased gradually from the core to the shell, while the iridium content increased gradually.

[0066] Comparative Example 3 Commercial iridium dioxide (IrO2) catalysts can be purchased directly without further processing.

[0067] The electrochemical performance of a commercial iridium dioxide catalyst was tested in 0.5 M H₂SO₄ electrolyte at 25 °C. The working electrode was a glassy carbon electrode (5 mm in diameter), and the catalyst loading was 0.2 mg / cm³. 2 The reference electrode is a saturated calomel electrode, and the counter electrode is a platinum sheet (1×1 cm). 2The linear scan voltammetry test was conducted at a scan rate of 1 mV / s with 90% iR compensation, and a measurement of 10 mA / cm² was obtained. 2 The overpotential at current density is 320 mV, and the mass activity at 1.55 V is 0.38 A / mgIr. At 1 A / cm 2 After 100 hours of constant current testing, the catalyst activity decreased by 18%.

[0068] In summary, compared with the comparative examples, the acetylene black supported iridium-palladium alloy catalyst provided by this invention exhibits significant advantages in terms of particle size, alloy uniformity, electrocatalytic activity, and stability. Comparative Example 1, employing a high-temperature reduction process, resulted in severe sintering of the metal particles (average particle size reaching 8.5 nm) and the formation of a distinct core-shell structure, with severe component segregation. Its 10 mA / cm²... 2 The overpotential at the current density was as high as 305 mV, and the catalytic performance was significantly inferior to that of the embodiments of the present invention. Comparative Example 2 deposited palladium and iridium separately through a stepwise reduction strategy. Although it did not undergo high-temperature treatment, due to the failure to achieve simultaneous reduction of iridium and palladium, the particles still exhibited an elemental gradient distribution, with an average particle size of 6.8 nm and an overpotential of 298 mV. Similarly, a homogeneous alloy structure was not formed, and the catalytic activity and noble metal utilization efficiency were inferior to those of the present invention. Comparative Example 3, although a commercial iridium dioxide catalyst is a commonly used anode catalyst in the field, had an overpotential as high as 320 mV, a mass activity of only 0.38 A / mgIr, and an activity decay of 18% after 100 hours of stability testing, all of which were significantly inferior to the catalyst obtained by the present invention. In contrast, the present invention uses acid-treated acetylene black as a support, combined with ultrasonic-assisted impregnation and low-temperature rapid simultaneous reduction process, which effectively suppressed the component segregation caused by the difference in reduction kinetics, and achieved atomic-level uniform distribution of iridium and palladium in individual particles, with an average particle size controlled at 2~5 nm and 10 mA / cm². 2 With an overpotential as low as 275~292 mV, a mass activity of up to 1.25 A / mgIr, and a constant current decay of less than 5% after 100 hours, this invention achieves excellent catalytic performance and long-term stability while reducing the amount of iridium used, fully demonstrating the outstanding progress of this invention in catalyst structure design, preparation process and comprehensive performance.

[0069] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing an acetylene black supported iridium-palladium alloy catalyst, characterized in that, Includes the following steps: S1, Carrier pretreatment: Acetylene black is acid-treated with nitric acid solution, washed until neutral, and then dispersed in alcohol solvent to obtain acetylene black suspension; S2, Impregnation Adsorption: The iridium precursor solution and the palladium precursor solution are mixed and added to the acetylene black suspension under ultrasonic assistance. The mixture is stirred and adsorbed to obtain an acetylene black mixture loaded with iridium and palladium precursors. S3, Low-temperature reduction alloying: The acetylene black mixture obtained from S2 is cooled to 0-5℃, and sodium borohydride solution is rapidly added under vigorous stirring to carry out the reduction reaction. Then, the reaction system is heated to room temperature to continue the reaction, and the crude reduced catalyst is obtained. S4, Post-processing: The crude catalyst obtained in S3 is filtered, washed, and dried to obtain the acetylene black supported iridium-palladium alloy catalyst.

2. The method for preparing an acetylene black supported iridium-palladium alloy catalyst according to claim 1, characterized in that, The nitric acid solution in S1 has a mass concentration of 3-7 wt%, an acid treatment temperature of 50-70℃, and a treatment time of 4-8 hours.

3. The method for preparing an acetylene black supported iridium-palladium alloy catalyst according to claim 1, characterized in that, The alcohol solvent mentioned in S1 is isopropanol or ethanol.

4. The method for preparing an acetylene black supported iridium-palladium alloy catalyst according to claim 1, characterized in that, The iridium precursor in S2 is chloroiridium acid, and the palladium precursor is chloropalladium acid or palladium chloride; the molar ratio of iridium to palladium is (3:1)-(1:3).

5. The method for preparing an acetylene black supported iridium-palladium alloy catalyst according to claim 1, characterized in that, The ultrasonic-assisted power described in S2 is 200-400W, the ultrasonic time is 30-60 minutes, and the stirring and adsorption time is 4-6 hours.

6. The method for preparing an acetylene black supported iridium-palladium alloy catalyst according to claim 1, characterized in that, The rapid addition time described in S3 is 1-3 minutes, and the molar amount of sodium borohydride is 5-15 times the total molar amount of iridium and palladium.

7. The method for preparing an acetylene black supported iridium-palladium alloy catalyst according to claim 1, characterized in that, The concentration of the sodium borohydride solution in S3 is 0.1-0.5M.

8. An acetylene black supported iridium-palladium alloy catalyst, characterized in that, The catalyst is obtained by the preparation method according to any one of claims 1-7, wherein the catalyst comprises an acetylene black support and iridium-palladium alloy nanoparticles supported on the acetylene black support, wherein the total loading of iridium and palladium in the catalyst is 20-40 wt%, the average particle size of the iridium-palladium alloy nanoparticles is 2-5 nm, and the Ir and Pd elements are uniformly distributed in a single particle.

9. The application of the acetylene black supported iridium-palladium alloy catalyst as described in claim 8 as an anode catalyst in proton exchange membrane water electrolysis for hydrogen production.

10. A proton exchange membrane water electrolysis device, characterized in that, Its anode catalyst layer comprises the acetylene black supported iridium-palladium alloy catalyst as described in claim 8.