A poly-aniline electrodeposited modified pyrochlore composite electrocatalyst and application thereof

Abstract

The application discloses a pyrochlore composite electrocatalyst modified by polyaniline electrodeposition, and a neutral electrodeposition electrolyte is obtained by dissolving aniline monomers and anhydrous sodium sulfate in deionized water; powder-shaped Y2Ru2O7, Ketjen black and 5 wt% Nafion solution are dispersed in an organic solvent, ultrasonic mixing is carried out to obtain slurry, the slurry is uniformly coated on the surface of a carbon paper electrode, and drying is carried out to obtain a working electrode loaded with a pyrochlore substrate; the working electrode loaded with the pyrochlore substrate is placed in the neutral electrodeposition electrolyte in step (1), polyaniline is deposited on the surface of the working electrode through constant current electrodeposition, and water washing is carried out to obtain the pyrochlore composite electrocatalyst modified by polyaniline electrodeposition; the catalyst obtained by the application not only can improve the catalytic activity of the pyrochlore on the oxygen evolution reaction, but also can obviously enhance the stability; under a current density of 10 mA, the oxygen evolution overpotential is 220-240 mV; through chronopotentiometry test, the stable running time is increased from 22 h before modification to 90 h.

Description

Technical Field

[0001] This invention belongs to the technical field of organic-inorganic hybrid materials and electrocatalytic materials, specifically relating to a method for preparing a polyaniline electrodeposition modified pyrochlore composite acidic oxygen evolution electrocatalyst. Background Technology

[0002] Proton exchange membrane (PEM) water electrolysis is compatible with renewable energy sources such as wind and solar power, produces high-purity hydrogen, and can operate at high current densities, making it a mainstream and efficient hydrogen production route. However, its anodic oxygen evolution reaction (OER) is a slow reaction with four-electron kinetics, and the anode is exposed to a strongly acidic and corrosive environment for extended periods. Most non-precious metal oxides are easily dissolved and deactivated, with only ruthenium and iridium-based oxides exhibiting stable catalytic capabilities. Pyrochlore (A₂B₂O₇) is a type of metal oxide with a unique crystal structure. Its lattice contains abundant oxygen vacancies and moduloizable metal cations. By controlling the composition of the metal elements at the A and B sites, the electronic structure and catalytic performance can be optimized, demonstrating good OER catalytic potential. Furthermore, pyrochlore possesses certain chemical and thermal stability, giving it a basis for application in acidic environments. Y and Ru both exhibit high activity and high catalytic performance in electrocatalysis, and are relatively inexpensive; therefore, Y₂Ru₂O₇ has a very promising future in acidic OER water electrolysis for hydrogen production.

[0003] However, pure-phase pyrochlore has two major drawbacks: 1) its intrinsic conductivity is limited and its charge transfer rate is slow; 2) during long-term electrolysis in strong acid, the surface Ru active sites continue to dissolve and are lost, and the catalyst decays rapidly, which cannot meet the requirements of long-term industrial operation.

[0004] Conductive polymer polyaniline (PANI) possesses reversible redox properties, excellent proton conductivity, and good acid corrosion resistance. Coating ultrathin PANI layers with metal oxides can simultaneously improve conductivity and resistance to leaching. Existing PANI composite oxide preparation techniques mostly employ in-situ chemical polymerization, which suffers from uncontrollable polymer layer thickness, localized thick film blockage of active sites, and poor coating uniformity. Furthermore, current technologies lack specific electrodeposition techniques for pyrochlore substrates, and there are no published patents on electrodeposition techniques on pyrochlore surfaces. To address these shortcomings, this invention proposes a precise constant current electrodeposition modification process to prepare composite electrocatalysts with simultaneously improved activity and stability.

[0005] Patent 1 (CN118754219B) discloses a surface modification method for pyrochlore oxide and its application, belonging to the field of inorganic materials technology. The surface modification method for pyrochlore oxide provided by this invention includes the following steps: surface modification treatment of pyrochlore oxide with ascorbic acid to obtain surface-modified pyrochlore oxide. This invention utilizes the dual-functionality of ascorbic acid, namely its acidity and reducing properties, to modify the surface of pyrochlore oxide, etching the passivation layer on its surface to expose sites with high catalytic activity. Furthermore, after surface treatment, tensile strain occurs on its crystal surface, generating a large amount of lattice distortion. This change in the distance between lattice atoms alters the energy levels of its outer electrons, significantly improving the electrochemical reactivity of the pyrochlore oxide material. The surface-modified pyrochlore oxide obtained by this invention has wide applications as a catalyst, especially in the electrolysis of water to produce hydrogen. While this patent shares the same synthetic concept as this invention, it uses ascorbic acid processing, whereas this patent uses polyaniline, and the composite method is also different. Summary of the Invention

[0006] To address the shortcomings of current high-temperature solid-phase pure A2B2O7 technology, such as insufficient conductivity, severe ruthenium active component dissolution, and poor long-term stability, and to overcome the limitations of chemical polymerization, uneven polyaniline coating during high-current electrodeposition, thick film obscuring catalytic active sites, and strong acid electrolytes damaging the pyrochlore crystal structure, this invention provides a fully quantifiable and reproducible polyaniline electrodeposition-modified pyrochlore composite acidic oxygen evolution electrocatalyst. The preparation process allows for precise control of the polyaniline film thickness, simultaneously optimizing the acidic oxygen evolution catalytic activity and anti-dissolution stability. The specific technical solution is as follows: This invention provides a polyaniline electrodeposition-modified pyrochlore composite electrocatalyst, prepared by the following method: (1) Dissolve aniline monomer and anhydrous sodium sulfate in deionized water, stir and let stand to remove bubbles to obtain a neutral electrodeposition electrolyte; the molar ratio of aniline monomer to anhydrous sodium sulfate is 1:5. (2) Powdered Y2Ru2O7, Ketjen black, and 5 wt% Nafion solution are dispersed in an organic solvent and ultrasonically mixed to obtain a slurry. The slurry is uniformly coated on the surface of a carbon paper electrode and dried to obtain a working electrode supported on a pyrochlore substrate. The mass ratio of pyrochlore to Ketjen black is 5:2, and the mass-to-volume ratio of powdered Y2Ru2O7 to the 5 wt% Nafion solution is 100-250 g / L. The volume of the slurry, based on the surface area of ​​the carbon paper electrode, is 40 μL / cm². 2 -60ul / cm 2 (Preferred 40 μL / cm²); (3) The working electrode loaded with pyrochlore substrate is placed in the neutral electrodeposition electrolyte described in step (1), and polyaniline is deposited on the surface of the working electrode by constant current electrodeposition. After washing with water, the polyaniline electrodeposition modified pyrochlore composite electrocatalyst is obtained.

[0007] Furthermore, the volume of deionized water in step (1) is 5 L / mol based on the amount of aniline monomer.

[0008] Furthermore, the organic solvent mentioned in step (2) is ethanol.

[0009] Furthermore, the volume of the organic solvent in step (2) is 196–200 μL based on the mass of the pyrochlore powder. mg - ¹.

[0010] Furthermore, the mass-to-volume ratio of the powdered Y2Ru2O7 in step (2) to the 5 wt% Nafion solution is 100 g / L.

[0011] Furthermore, the constant current electrodeposition in step (3) is carried out in a three-electrode system, with the working electrode of the loaded pyrochlore substrate as the anode, the platinum sheet as the counter electrode, and the saturated Ag / AgCl electrode as the reference electrode.

[0012] Furthermore, the current density of the constant current electrodeposition in step (3) is 0.1-1 mA / cm² (preferably 0.5 mA / cm²), and the deposition time is 300-700 s (preferably 300 s).

[0013] This invention also provides the application of a polyaniline electrodeposition-modified pyrochlore composite electrocatalyst in the oxygen evolution reaction of water electrolysis.

[0014] Furthermore, the application employs a three-electrode system, with the electrocatalyst as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode. The water electrolysis and oxygen evolution reaction is carried out in an acidic electrolyte (preferably 0.5 M H2SO4).

[0015] Technical effects: This invention employs a constant current method to modify the surface of pyrochlore by electrodeposition of polyaniline. The resulting catalyst not only enhances the catalytic activity of pyrochlore for the oxygen evolution reaction (OER) but also significantly improves its stability. At a current density of 10 mA, its OER overpotential is 220–240 mV; and according to chronopotential testing, its stable operating time is increased from 22 h before modification to 90 h. Attached Figure Description

[0016] Figure 1LSV curves of Examples 1, 2, and 3 and the precursor pyrochlore

[0017] Figure 2 Example 2: Stability Comparison with Precursor Pyrochlore

[0018] Figure 3 Example 2: XRD comparison with the precursor pyrochlore

[0019] Figure 4 Infrared comparison of Example 2 and its precursor pyrochlore

[0020] Figure 5 Contact angle test of precursor pyrochlore

[0021] Figure 6 Contact angle test in Example 2

[0022] Figure 7 Example 2: TEM and lattice pattern

[0023] Figure 8 Diffraction rings of Example 2 Detailed Implementation

[0024] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be considered as specific limitations of the invention.

[0025] Example 1

[0026] I. Reagents and Instruments

[0027] Reagents: Nafion D520 5 wt% perfluorosulfonic acid dispersion, anhydrous ethanol (Sinopharm AR grade), conductive carbon black (Ketjen Black) Vulcan XC-72, deionized water (self-made), anhydrous sodium sulfate Na2SO4, CAS: 7757-82-6 (Aladdin), aniline monomer C6H7N, CAS: 62-53-3 (Sinopharm), RuCl3·3H2O (Sinopharm Group), Y(NO3)3·6H2O (Aladdin Reagent), anhydrous citric acid CAS: 77-92-9 (Sinopharm)

[0028] Instruments: beakers, standard three-electrode electrolytic cell, saturated Ag / AgCl electrode, 1 cm × 1 cm platinum sheet electrode, electronic analytical balance (accuracy 0.1 mg), magnetic stirrer, oil bath, corundum crucible, muffle furnace (Carbolite), high-temperature oven.

[0029] II. Experimental Procedures

[0030] (1) Using deionized water as solvent, accurately weigh 0.093 g (0.01 mol) of aniline monomer and 0.71 g (0.05 mol) of anhydrous sodium sulfate, add 50 ml of deionized water and stir until the solid is completely dissolved; after stirring for 10 min, let stand for 15 min to remove air bubbles inside the solution to obtain a neutral electrodeposition electrolyte, which should be prepared and used immediately. Accurately weigh RuCl3·3H2O, Y(NO3)3·6H2O, and citric acid 0.01307 g, 0.01915 g, and 0.28818 g respectively; add 25 ml of deionized water and 100 μl of ethylene glycol, stir in an oil bath at 80℃ for 8 h, then heat at 110℃ in a high-temperature oven for 8 h, and finally heat to 700℃ at 5℃ / min in a muffle furnace, hold for 6 h, then heat to 1050℃ at 5℃ / min, hold for 12 h to prepare pyrochlore powder (Y2Ru2O7).

[0031] (2) Prepare electrodes from pyrochlore powder. Mix 5 mg of pyrochlore, 2 mg of Ketjen black, 50 μL of 5 wt% Nafion, and 980 μL of ethanol until homogeneous. Sonicate the mixture for 1 h. Then, pipette 10 μL of the mixture and evenly drop it onto a 1 cm thick surface. The surface of the 1 cm carbon paper electrode was dried under an oven lamp for 30 min. The process of dripping and drying 10 μL of slurry was repeated four times to obtain the working electrode loaded with the pyrochlore substrate.

[0032] (3) Constant current electrodeposition setup: a standard three-electrode electrolytic cell, with the working electrode being the YRO carbon paper electrode prepared in step 2, the counter electrode being a 1 cm × 1 cm platinum sheet electrode, and the reference electrode being a saturated Ag / AgCl electrode; all three electrodes were immersed in the electrodeposition electrolyte prepared in step 1; the electrochemical workstation was set to a constant deposition current density of 0.5 mA·cm. - ², with a deposition time of 300s, a composite electrode of polyaniline-coated pyrochlore was prepared; (4) Cleaning and drying: After electrodeposition, remove the electrode and rinse the electrode surface three times with ultrapure water to remove residual aniline and sodium sulfate electrolyte.

[0033] III: Experimental Testing

[0034] All electrochemical tests in this embodiment were performed using the same instrument: the Shanghai Chenhua CHI660E electrochemical workstation. All electrochemical tests employed a three-electrode system. The electrode system used the PAN@YRO electrode prepared in this embodiment as the working electrode, with an immersion area of ​​1 cm² in the electrolyte. The electrode was 1 cm thick, the counter electrode was a Pt sheet, and the reference electrode was an Ag / AgCl reference electrode. The test electrolyte was 50 ml of 0.5 M H₂SO₄ strong acid solution. All potentials were uniformly calibrated to the reversible hydrogen electrode (RHE) potential. OER tests were performed. Figure 1 The black line represents the LSV curve measured in Example 1, and the green line represents the LSV curve of YRO. Analysis of the LSV curves shows that the overpotential corresponding to a 10 mA charge density of pyrochlore is 250 mV, while the overpotential corresponding to a 10 mA charge density of PAN@YRO is 240 mV.

[0035] Example 2

[0036] I. Reagents and Instruments

[0037] Reagents: Nafion D520 5 wt% perfluorosulfonic acid dispersion, anhydrous ethanol (Sinopharm AR grade), conductive carbon black (Ketjen Black) Vulcan XC-72, deionized water (self-made), anhydrous sodium sulfate Na2SO4, CAS: 7757-82-6 (Aladdin), aniline monomer C6H7N, CAS: 62-53-3 (Sinopharm), RuCl3·3H2O (Sinopharm Group), Y(NO3)3·6H2O (Aladdin Reagent), anhydrous citric acid CAS: 77-92-9 (Sinopharm)

[0038] Instruments: beakers, standard three-electrode electrolytic cell, saturated Ag / AgCl electrode, 1 cm × 1 cm platinum sheet electrode, electronic analytical balance (accuracy 0.1 mg), magnetic stirrer, oil bath, corundum crucible, muffle furnace (Carbolite), high-temperature oven.

[0039] II. Experimental Procedures

[0040] (1) Using deionized water as solvent, accurately weigh 0.093 g (0.01 mol) of aniline monomer and 0.71 g (0.05 mol) of anhydrous sodium sulfate, add 50 ml of deionized water and stir until the solid is completely dissolved; after stirring for 10 min, let stand for 15 min to remove air bubbles inside the solution to obtain a neutral electrodeposition electrolyte, which should be prepared and used immediately. Accurately weigh RuCl3·3H2O, Y(NO3)3·6H2O, citric acid 0.01307 g, 0.01915 g, and 0.28818 g respectively; add 25 ml of deionized water and 100 ul of ethylene glycol, stir in an oil bath at 80℃ for 8 h, then heat at 110℃ in a high-temperature oven for 8 h, and finally heat to 700℃ at 5℃ / min in a muffle furnace and hold for 6 h, then heat to 1050℃ at 5℃ / min and hold for 12 h to prepare pyrochlore powder.

[0041] (2) Prepare electrodes from pyrochlore powder. Mix 5 mg of pyrochlore, 2 mg of Ketjen black, 50 μL of 5 wt% Nafion, and 980 μL of ethanol evenly, sonicate for 1 h, and then pipette 10 μL of the slurry and evenly drop it onto a 1 cm thick surface. The 1cm carbon paper electrode surface was dried under an oven lamp for 30 minutes. The process of dripping and drying 10ul of slurry was repeated four times to obtain a working electrode loaded with a pyrochlore substrate.

[0042] (3) Constant current electrodeposition setup: A standard three-electrode electrolytic cell was used, with the working electrode being the YRO carbon paper electrode prepared in step 2, the counter electrode being a 1 cm × 1 cm platinum sheet electrode, and the reference electrode being a saturated Ag / AgCl electrode; all three electrodes were immersed in the electrodeposition electrolyte prepared in step 1; the electrochemical workstation was set to a constant deposition current density of 0.5 mA. cm -2 A composite electrode with polyaniline-coated pyrochlore was prepared by setting the deposition time to 300 s. (4) Cleaning and drying: After electrodeposition, remove the electrode and rinse the electrode surface three times with ultrapure water to remove residual aniline and sodium sulfate electrolyte.

[0043] III: Experimental Testing

[0044] All electrochemical tests in this embodiment were performed using the same instrument: the Shanghai Chenhua CHI660E electrochemical workstation. All electrochemical tests employed a three-electrode system. The electrode system used the PAN@YRO electrode prepared in this embodiment as the working electrode, with an immersion area of ​​1 cm² in the electrolyte. The electrode was 1 cm thick, the counter electrode was a Pt sheet, and the reference electrode was an Ag / AgCl reference electrode. The test electrolyte was 50 ml of 0.5 M H2SO4 strong acid solution. All potentials were uniformly calibrated to the reversible hydrogen electrode (RHE) potential. OER and stability tests were performed. Figure 1 The red line represents the LSV curve measured in Example 2, and the green line represents the LSV curve of YRO. Analysis of the LSV curves shows that the overpotential corresponding to a 10 mA voltage density of pyrochlore is 250 mV, and the overpotential corresponding to a 10 mA voltage density of PAN@YRO is 220 mV. Figure 2 As shown in the stability test chart, by comparing the time points at which the stability abruptly changes, it can be seen that the original pyrochlore has a stability of 22 h, while the stability reaches 90 h after attaching polyaniline.

[0045] X-ray diffraction (XRD) involves pressing a powder sample into a pellet, using an X-ray diffractometer, setting the scanning angle range and scanning rate, acquiring diffraction signals, and obtaining the diffraction pattern. Figure 3The phase composition and crystal structure were analyzed. XRD comparison revealed that the crystal structure remained unchanged, and combined with other tests, it can be concluded that the synthesized polyaniline is amorphous polyaniline.

[0046] Fourier transform infrared spectroscopy (FT-IR) was performed by grinding and mixing the catalyst powder with potassium bromide and pressing it into a thin sheet; the measurement was conducted using a Fourier transform infrared spectrometer at wavenumbers of 4000-400 cm⁻¹. - ¹; Obtain infrared absorption spectra Figure 4 The functional groups and chemical bonds on the sample surface were analyzed. Analysis of the functional groups revealed the presence of the C=C bond characteristic of polyaniline, confirming the successful synthesis of polyaniline.

[0047] The powder sample was pressed into a flat, thin sheet, and a contact angle meter was used. A measured amount of deionized water was dropped onto the sample surface, and the camera captured images of the YRO droplet and the Pan@yro droplet. Figure 5 Figure 6 The hydrophilicity and hydrophobicity of the sample surface were evaluated. Through comparison, it was found that the hydrophobicity changed, becoming more hydrophobic, consistent with the generally hydrophobic characteristics of polyaniline, thus proving the successful synthesis of polyaniline.

[0048] The microstructure of the sample was observed using transmission electron microscopy (TEM, high-resolution HRTEM); high-resolution imaging was used to obtain lattice fringes images. Figure 7 The grain size and crystal plane information were analyzed. By comparison, it can be seen that amorphous coarse lines appear near the pyrochlore lattice striations, which corresponds to the XRD results, indicating the presence of amorphous polyaniline.

[0049] Diffraction rings are obtained by selecting a specific region of the sample and collecting selected area electron diffraction data in a transmission electron microscope (TEM). Figure 8 This is used to determine the polycrystalline / single-crystal characteristics of a sample and to calibrate its crystal planes. Diffraction analysis clearly reveals the crystal planes of pyrochlore, proving that the pyrochlore lattice is unaffected and that it is an amorphous polyaniline.

[0050] Example 3

[0051] I. Reagents and Instruments

[0052] Reagents: Nafion D520 5 wt% perfluorosulfonic acid dispersion, anhydrous ethanol (Sinopharm AR grade), conductive carbon black (Ketjen Black) Vulcan XC-72, deionized water (self-made), anhydrous sodium sulfate Na2SO4, CAS: 7757-82-6 (Aladdin), aniline monomer C6H7N, CAS: 62-53-3 (Sinopharm), RuCl3·3H2O (Sinopharm Group), Y(NO3)3·6H2O (Aladdin Reagent), anhydrous citric acid CAS: 77-92-9 (Sinopharm)

[0053] Instruments: beakers, standard three-electrode electrolytic cell, saturated Ag / AgCl electrode, 1 cm × 1 cm platinum sheet electrode, electronic analytical balance (accuracy 0.1 mg), magnetic stirrer, oil bath, corundum crucible, muffle furnace (Carbolite), high-temperature oven.

[0054] II. Experimental Procedures

[0055] (1) Using deionized water as solvent, accurately weigh 0.093 g (0.01 mol) of aniline monomer and 0.71 g (0.05 mol) of anhydrous sodium sulfate, add 50 ml of deionized water and stir until the solid is completely dissolved; after stirring for 10 min, let stand for 15 min to remove air bubbles inside the solution to obtain a neutral electrodeposition electrolyte, which should be prepared and used immediately. Accurately weigh RuCl3·3H2O, Y(NO3)3·6H2O, 0.01307 g, 0.01915 g, and 0.28818 g of citric acid, respectively; add 25 ml of deionized water and 100 μl of ethylene glycol, stir in an oil bath at 80℃ for 8 h, then heat at 110℃ in a high-temperature oven for 8 h, and finally heat to 700℃ at 5℃ / min in a muffle furnace and hold for 6 h, then heat to 1050℃ at 5℃ / min and hold for 12 h to prepare pyrochlore powder.

[0056] (2) Prepare electrodes from pyrochlore powder. Mix 5 mg of pyrochlore, 2 mg of Ketjen black, 50 μL of 5 wt% Nafion, and 980 μL of ethanol evenly, sonicate for 1 h, and then pipette 10 μL of the slurry and evenly drop it onto a 1 cm thick surface. The surface of a 1cm carbon paper electrode was dried under an oven lamp for 30 minutes. The process of dripping 10ul of slurry onto the electrode and drying it was repeated four times to obtain a working electrode loaded with a pyrochlore substrate.

[0057] (3) Constant current electrodeposition setup: A standard three-electrode electrolytic cell was used, with the working electrode being the YRO carbon paper electrode prepared in step 2, the counter electrode being a 1 cm × 1 cm platinum sheet electrode, and the reference electrode being a saturated Ag / AgCl electrode; all three electrodes were immersed in the electrodeposition electrolyte prepared in step 3; the electrochemical workstation was set to a constant deposition current density of 0.5 mA·cm⁻¹. - ², with a deposition time of 300s, a composite electrode of polyaniline-coated pyrochlore was prepared; (4) Cleaning and drying: After electrodeposition, remove the electrode and rinse the electrode surface three times with ultrapure water to remove residual aniline and sodium sulfate electrolyte.

[0058] III: Experimental Testing

[0059] All electrochemical tests in this embodiment were performed using the same instrument: the Shanghai Chenhua CHI660E electrochemical workstation. All electrochemical tests employed a three-electrode system. The electrode system used the PAN@YRO electrode prepared in this embodiment as the working electrode, with an immersion area of ​​1 cm² in the electrolyte. The electrode was 1 cm thick, the counter electrode was a Pt sheet, and the reference electrode was an Ag / AgCl reference electrode. The test electrolyte was 50 ml of 0.5 M H₂SO₄ strong acid solution. All potentials were uniformly calibrated to the reversible hydrogen electrode (RHE) potential. OER tests were performed. Figure 1 The blue line represents the LSV curve measured in Example 3, and the green line represents the LSV curve of YRO. The overpotential corresponding to a 10 mA charge density of pyrochlore is 250 mV, and the overpotential corresponding to a 10 mA charge density of PAN@YRO is 230 mV.

Claims

1. A polyaniline electrodeposition-modified pyrochlore composite electrocatalyst, characterized in that, Prepared by the following method: (1) Dissolve aniline monomer and anhydrous sodium sulfate in deionized water, stir and let stand to remove bubbles to obtain a neutral electrodeposition electrolyte; the molar ratio of aniline monomer to anhydrous sodium sulfate is 1:

5. (2) Powdered Y2Ru2O7, Ketjen black, and 5 wt% Nafion solution are dispersed in an organic solvent and ultrasonically mixed to obtain a slurry. The slurry is uniformly coated on the surface of a carbon paper electrode and dried to obtain a working electrode supported on a pyrochlore substrate. The mass ratio of pyrochlore to Ketjen black is 5:2, and the mass-to-volume ratio of powdered Y2Ru2O7 to the 5 wt% Nafion solution is 100-250 g / L. The volume of the slurry, based on the surface area of ​​the carbon paper electrode, is 40 μL / cm². 2 -60ul / cm 2 ; (3) The working electrode loaded with pyrochlore substrate is placed in the neutral electrodeposition electrolyte described in step (1), and polyaniline is deposited on the surface of the working electrode by constant current electrodeposition. After washing with water, the polyaniline electrodeposition modified pyrochlore composite electrocatalyst is obtained.

2. The polyaniline electrodeposition-modified pyrochlore composite electrocatalyst as described in claim 1, characterized in that, The volume of deionized water in step (1) is 5 L / mol based on the amount of aniline monomer.

3. The polyaniline electrodeposition-modified pyrochlore composite electrocatalyst as described in claim 1, characterized in that, The organic solvent mentioned in step (2) is ethanol.

4. The polyaniline electrodeposition-modified pyrochlore composite electrocatalyst as described in claim 1, characterized in that, The volume of the organic solvent in step (2) is 196–200 μL based on the mass of the pyrochlore powder. mg - ¹.

5. The polyaniline electrodeposition-modified pyrochlore composite electrocatalyst as described in claim 1, characterized in that, The mass-to-volume ratio of the powdered Y2Ru2O7 in step (2) to the 5 wt% Nafion solution is 100 g / L.

6. The polyaniline electrodeposition-modified pyrochlore composite electrocatalyst as described in claim 1, characterized in that, The constant current electrodeposition in step (3) is carried out in a three-electrode system, with the working electrode of the loaded pyrochlore substrate as the anode, the platinum sheet as the counter electrode, and the saturated Ag / AgCl electrode as the reference electrode.

7. The polyaniline electrodeposition-modified pyrochlore composite electrocatalyst as described in claim 1, characterized in that, The current density of the constant current electrodeposition in step (3) is 0.1-1 mA / cm², and the deposition time is 300-700 s.

8. The application of the polyaniline electrodeposition modified pyrochlore composite electrocatalyst as described in claim 1 in the oxygen evolution reaction of water electrolysis.

9. The application as described in claim 8, characterized in that, The application employs a three-electrode system, with the electrocatalyst as the working electrode, a platinum sheet as the counter electrode, and Ag / AgCl as the reference electrode. The water electrolysis and oxygen evolution reaction is carried out in an acidic electrolyte.

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