A Ce-doped Ir-based composite catalyst, its preparation method, and its application as an anode catalyst for proton exchange membrane water electrolysis.

Abstract

This invention discloses a Ce-doped Ir-based composite catalyst, its preparation method, and its application as an anode catalyst for proton exchange membrane water electrolysis. It belongs to the technical field of anode catalysts for proton exchange membrane water electrolysis. This invention uses an ethylene glycol reflux method to load iridium clusters onto a Ce salt support. Simultaneously, due to the strongly acidic environment of the reflux system, the Ce salt support gradually dissolves and leaches in situ during the reaction, ultimately forming Ce-doped IrO. x Composite catalyst (Ir(Ce)O) x Doped Ce elements and IrO x The strong electron transfer between them, and the special structure that promotes the formation of materials during the in-situ leaching of Ce, enable this catalyst to exhibit good activity and stability in proton exchange membrane water electrolysis hydrogen production equipment.

Description

Technical Field

[0001] This invention belongs to the field of proton exchange membrane water electrolysis anode catalyst technology, specifically relating to a Ce-doped Ir-based composite catalyst, its preparation method, and its application as a proton exchange membrane water electrolysis anode catalyst. Background Technology

[0002] Proton exchange membrane electrolysis (PEMWE) technology shows great promise in synergistic use with intermittent renewable energy sources to convert excess electricity into chemical energy stored in hydrogen bonds. (Wang, H.; Li, X.; Zhang, G.; Gu, Z.; Chen, H.; Wei, G.; Shen, S.; Cheng, J.; Zhang, J., Recent Progress in Balancing the Activity, Durability, and Low Ir Content for Ir-Based OxygenEvolution Reaction Electrocatalysts in Acidic Media. Small 2024.) However, the high overpotential at the anode leads to slow oxygen evolution reaction (OER) kinetics, severely limiting hydrogen production efficiency. Compared to non-precious metal and ruthenium (Ru)-based catalysts, iridium (Ir)-based catalysts generally represent the optimal balance between activity and stability. However, they are still limited by their lower mass activity and the current scarcity of Ir resources. Furthermore, under high electrolysis voltages (>1.6V) and harsh acidic corrosion conditions, Ir-based catalysts inevitably undergo structural deformation and fail, further hindering the large-scale production and application of PEMWE. (Wang, Y.; Yan, H.; Fu, H., Recent advances and modulation tactics in Ru-and Ir-based electrocatalysts for PEMWE anodes atlarge current densities. eScience 2024.) Currently, researchers have developed various strategies to construct efficient Ir-based nanomaterials. For example, introducing foreign metal doping into Ir-based catalysts has proven to be an effective method. For instance, Xing et al. used the ethylene glycol reflux method with TiB2 as a sacrificial template to prepare a Ti-inverse-doped Ti-IrOx / Ir catalyst. The Ir-O-Ti structure in this catalyst achieved a synergistic enhancement of OER activity and stability. In PEMWE, the total voltage at a current density of 2 A cm-2 was only 1.774 V (Wang, Y.; Ma, R.; Shi, Z.; Wu, H.; Hou, S.; Wang, Y.; Liu, C.; Ge, J.; Xing, W., Inverse doping IrOx / Ti with weakened Ir-O interaction towardstable and efficient acidic oxygen evolution. Chem 2023, 9 (10), 2931-2942.). In the Nd-doped IrO2 catalyst developed by Wang et al., the long-range ordered structure of Nd was broken to induce a strain effect. The resulting Nd-O-Ir bond adjusted the electronic structure of Ir, leading to a decrease in the d-band center and thus weakening the adsorption of intermediates on Ir sites. This not only resulted in a lower overpotential but also improved performance at 50 mA cm⁻¹. -2 It exhibits superior durability at current densities (Wang, Y.; Qin, Y.; Wen, R.; Wang, L.; Dou, M.; Wang, F., High-Performance Low-Iridium Catalyst for Water Oxidation: Breaking Long-Ranged Order of IrO2 by Neodymium Doping. Small 2024, 20 (42).).

[0003] Although the above works have all improved the mass activity of Ir sites in catalysts to some extent by introducing non-noble metal elements, their application in PEMWE remains limited. Currently commonly used doping elements such as Ti and Mn have limited properties and are difficult to further provide charge to the active Ir sites through M (metal)-Ir-O bonds under high potential and strong acid conditions, leading to the oxidation and dissolution of Ir sites and the structural collapse of the catalyst. In contrast, cerium (Ce... 3+ / Ce 4+The flexible valence change capability enables flexible charge transfer for Ir during the OER process, accommodating excess electrons of Ir at low potentials, promoting the formation of higher valence Ir, and enhancing the catalytic activity of the catalyst; at the same time, under long-term, high-potential testing conditions, the electron buffering effect of Ce sites significantly enhances the dissolution energy barrier of Ir atoms, thereby achieving a synergistic improvement in catalyst activity and stability. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0006] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a Ce-doped Ir-based composite catalyst, wherein the catalyst uses trace amounts of Ce as an electron pool to exchange electrons with the active site Ir. The atomic ratio of Ce to Ir is 0.6 to 0.01:1.

[0007] Another object of the present invention is to provide a method for preparing a Ce-doped Ir-based composite catalyst.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: including, Ce salt and surfactant are dispersed in ethylene glycol solution and ultrasonically dispersed and mixed to obtain the first suspension; Ir precursor was added to the first suspension and stirred to obtain the second suspension; The second suspension was heated in an oil bath and refluxed to obtain the third suspension. The third suspension was centrifuged, washed, and freeze-dried to obtain a Ce-doped Ir-based composite catalyst.

[0009] In a preferred embodiment of the method for preparing the Ce-doped Ir-based composite catalyst of the present invention, the Ce salt is selected from one or more of cerium dioxide, cerium oxalate, cerium chloride, cerium nitrate, cerium sulfate, and cerium octanoate; and the surfactant is selected from hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, or polyvinylpyrrolidone.

[0010] CeO2 includes commercial CeO2 or CeO2 obtained by thermal decomposition of commercial cerium nitrate.

[0011] In a preferred embodiment of the preparation method of the Ce-doped Ir-based composite catalyst of the present invention, the mass ratio of the surfactant to the Ce salt is 1~10:1.

[0012] In a preferred embodiment of the preparation method of the Ce-doped Ir-based composite catalyst of the present invention, the mass-volume ratio of the Ce salt to ethylene glycol is 1 mg:10 ml to 1 mg:1 ml.

[0013] 2. As a preferred embodiment of the preparation method of the Ce-doped Ir-based composite catalyst of the present invention, wherein the Ir precursor is selected from one or more of chloroiridium acid, iridium chloride, iridium acetylacetonate, iridium acetate, potassium chloroiridium, sodium chloroiridium, iridium oxide, strontium iridium, barium iridium, lithium iridium, potassium iridium, and praseodymium iridium, and the mass ratio of Ir to Ce salt in the Ir precursor is 0.2 to 1:1.

[0014] In a preferred embodiment of the preparation method of the Ce-doped Ir-based composite catalyst of the present invention, the ultrasonic dispersion and mixing time is 0.5~3 h.

[0015] In a preferred embodiment of the preparation method of the Ce-doped Ir-based composite catalyst of the present invention, the stirring time for the mixing is 0.5 to 3 h.

[0016] In a preferred embodiment of the preparation method of the Ce-doped Ir-based composite catalyst of the present invention, the oil bath heating and reflux is performed at a temperature of 120 ℃ to 180 ℃ for a time of 1 h to 6 h.

[0017] Another object of the present invention is to provide an application of a Ce-doped Ir-based composite catalyst as an anode catalyst for proton exchange membrane water electrolysis.

[0018] Beneficial effects of this invention: (1) Ce-doped IrO provided by the present invention x A method for preparing a composite material proton exchange membrane anode catalyst for water electrolysis was developed, achieving Ce-IrO-toluene exchange via a simple ethylene glycol reflux process. x The synthesis method is simple and convenient, and has relatively mature operating techniques. It can obtain the target catalyst without calcination or gasification, and does not produce toxic or harmful gases during the reaction. The entire reaction process is short, safe, low-energy, and environmentally friendly.

[0019] (2) During the ethylene glycol reflux process, Ir first accumulates and grows on the Ce salt surface. In the strongly acidic environment, the Ce salt acts as a sacrificial template, gradually dissolving and leaching in situ, resulting in a catalyst structure rich in defects. At the same time, the remaining trace amount of stable cerium in the catalyst acts as an electron pool during the reaction, flexibly exchanging electrons with the active site Ir, which makes the catalyst exhibit good catalytic activity and stability compared to IrO without Ce doping. x The overpotential of the composite material was reduced by approximately 40 mV.

[0020] (3) Using this catalyst as the anode to assemble a water electrolysis device, the catalyst exhibits excellent electrocatalytic activity and stability, 2 Acm -2 At current density, the potential is only 1.69 V, and at 2 A cm⁻¹... -2 Stability tests were conducted at current density, and the performance showed almost no degradation within 1000 h, indicating that this catalyst has extremely broad application prospects. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 Transmission electron microscopy image of the Ce-doped Ir-based composite catalyst prepared in Example 1 of this invention; Figure 2 The transmission electron microscopy elemental distribution scan results are shown for the Ce-doped Ir-based composite catalyst prepared in Example 1 of this invention. Figure 3 The results of the activity test of the Ce-doped Ir-based composite catalyst prepared in Example 1 of this invention in a three-electrode system are shown. Figure 4 The results of stability tests on the Ce-doped Ir-based composite catalyst prepared in Example 1 of this invention in a three-electrode system are shown. Figure 5 The results are the activity test results of a proton exchange membrane electrolyzer assembled using the Ce-doped Ir-based composite catalyst prepared in Example 1 of this invention as the anode. Figure 6 The results show the stability test results of a proton exchange membrane electrolyzer assembled using the Ce-doped Ir-based composite catalyst prepared in Example 1 of this invention as the anode. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0025] Unless otherwise specified, all raw materials used in this invention are commercially available in the field.

[0026] Example 1 This embodiment provides a method for preparing a Ce-doped Ir-based composite catalyst. CeO2 is used as an example of Ce salt, and chloroiridic acid is used as an example of Ir salt. The specific experimental steps and parameters are as follows: 75 mg CeO2 and 415 mg cetyltrimethylammonium bromide (CTAB) were placed in a round-bottom flask, 150 ml of ethylene glycol was added, and the mixture was sonicated for about 1 h to disperse it evenly, thus obtaining the first suspension. In this experimental scheme, the mass ratio of CeO2 to surfactant CATB was 1:5.5, and the mass-volume ratio of CeO2 to ethylene glycol was 1 mg:2 ml. Add 1.59 ml of chloroiridium acid (35 mg) to the first suspension. Ir ml -1 The mixture was stirred at room temperature for about 2 hours to obtain a second suspension. In this experimental scheme, the mass ratio of Ir to CeO2 was 0.74:1. The second suspension was heated in an oil bath and refluxed at a temperature of 160 °C for 3 h to obtain the third suspension. The third suspension was centrifuged, washed, and freeze-dried to obtain a Ce-doped Ir-based composite catalyst, which can be used as an anode catalyst for proton exchange membrane water electrolysis.

[0027] The Ce-doped Ir-based composite catalyst of Example 1 was characterized by transmission electron microscopy, and the results are as follows: Figure 1 As shown, the lattice fringes in the obtained catalyst correspond to IrO2 and CeO2, respectively.

[0028] Elemental mapping analysis was performed on the Ce-doped Ir-based composite catalyst of Example 1, and the results are as follows: Figure 2 As shown, the catalyst contains Ce, Ir, and O elements simultaneously, confirming the successful synthesis of Ce-doped Ir-based composite catalysts, where the atomic ratio of Ce to Ir elements is 0.01:1.

[0029] The activity of the Ce-doped Ir-based composite catalyst from Example 1 was tested in a three-electrode system. The test temperature was 30 °C, the electrolyte was 0.5 M H₂SO₄ solution, the reference electrode was an Hg / HgSO₄ electrode (with a potential of approximately 0.701 mV), and the counter electrode was a carbon rod. The results are as follows: Figure 3 As shown. The three-electrode system assembled with this catalyst at a catalyst loading of 0.5 mg cm⁻¹ -2 Under these conditions, it reaches 10 mA cm -2 The catalyst requires a current density of only 237 mV and exhibits high metal utilization and good catalytic activity.

[0030] The stability of the Ce-doped Ir-based composite catalyst of Example 1 was tested in a three-electrode system, and the results are as follows: Figure 4 As shown. The three-electrode system assembled with this catalyst at a catalyst loading of 2 mg cm⁻¹ -2 Under these conditions, at 10 mAcm -2 The catalyst exhibited excellent catalytic stability after more than 1000 hours of stability testing at the specified current density, with almost no performance degradation.

[0031] The Ce-doped Ir-based composite catalyst from Example 1 was used as the anode spray-coated membrane electrode and assembled into a water electrolysis device for performance testing. The results are as follows: Figure 5 As shown. The proton exchange membrane water electrolysis device assembled with this catalyst as the anode has an anode Ir loading of 0.416 mg / cm³. -2 Under the condition that the current density is 2 A cm⁻¹ -2 The electrolytic cell voltage was 1.697 V and the current density was 3 A cm⁻¹. -2 The electrolytic cell voltage was 1.81 V, indicating that the catalyst exhibited high utilization of precious metals and good catalytic activity.

[0032] Stability tests were conducted using the Ce-doped Ir-based composite catalyst from Example 1 as the anode in an assembled electrolytic cell. The results are as follows: Figure 6 As shown. At 1 A cm -2 At the specified current density, the electrolytic cell assembled with the above-mentioned supported catalyst as the anode operated stably for over 2000 hours, with a voltage decay rate of approximately -1.59 μV / h. -1and in 2 A cm -2 Stability tests were conducted continuously at current density, and the system operated stably for over 1000 hours with a voltage decay rate of approximately -20.58 μV / h. -1 This indicates that the catalyst exhibits good catalytic stability in the electrolytic cell system.

[0033] Example 2 The difference between this embodiment and Example 1 is that the amount of cetyltrimethylammonium bromide (CATB) in the first suspension is adjusted to 200 mg, so that the mass ratio of CeO2 to surfactant CATB is 1:2.7. The remaining steps and processes are the same as in Example 1. The Ce-doped Ir-based composite catalyst of this embodiment can be used as an anode catalyst for proton exchange membrane water electrolysis.

[0034] Example 3 Weigh 132 mg of cerium chloride heptahydrate and 300 mg of hexadecyltrimethylammonium chloride into a round-bottom flask, add 200 ml of ethylene glycol, and sonicate for about 1 h to disperse evenly to obtain the first suspension. In this experimental scheme, the mass ratio of CeCl3·7H2O to surfactant CATB is 1:2.3, and the mass-volume ratio of CeCl3·7H2O to ethylene glycol is 1 mg:1.5 ml. Add 1.59 ml of chloroiridium acid (35 mg) to the first suspension. Ir ml -1 The mixture was stirred at room temperature for about 3 hours to obtain a second suspension. In this experimental design, the mass ratio of Ir to Ce salt was 0.42:1. The second suspension was heated in an oil bath and refluxed at a temperature of 180°C for 3 hours to obtain the third suspension. The third suspension was centrifuged, washed, and freeze-dried to obtain a Ce-doped Ir-based composite catalyst, which can be used as an anode catalyst for proton exchange membrane water electrolysis.

[0035] Example 4 75 mg CeO2 and 400 mg cetyltrimethylammonium bromide were placed in a round-bottom flask, 100 ml of ethylene glycol was added, and the mixture was sonicated for about 2 h to disperse it evenly, thus obtaining the first suspension. In this experimental scheme, the mass ratio of CeO2 to surfactant CATB was 1:5.3, and the mass-volume ratio of CeO2 to ethylene glycol was 1 mg:1.3 ml. Add 1.59 ml of chloroiridium acid (35 mg) to the first suspension. Ir ml -1 The mixture was stirred at room temperature for about 3 hours to obtain a second suspension. In this experimental scheme, the mass ratio of Ir to CeO2 was 0.74:1. The second suspension was heated in an oil bath and refluxed at a temperature of 140°C for 3 hours to obtain the third suspension. The third suspension was centrifuged, washed, and freeze-dried to obtain a Ce-doped Ir-based composite catalyst, which can be used as an anode catalyst for proton exchange membrane water electrolysis.

[0036] Example 5 140 mg of cerium nitrate hexahydrate and 400 mg of cetyltrimethylammonium bromide were placed in a round-bottom flask, and 150 ml of ethylene glycol was added. The mixture was sonicated for about 2 hours to disperse the precipitate evenly, resulting in the first suspension. In this experimental design, the mass ratio of Ce(NO3)3·6H2O to surfactant CATB was 1:2.85, and the mass-to-volume ratio of Ce(NO3)3·6H2O to ethylene glycol was 1 mg:1.07 ml. Add 1 ml of chloroiridium acid (35 mg Ir ml) to the first suspension. -1 The mixture was stirred at room temperature for about 3 hours to obtain a second suspension. In this experimental scheme, the mass ratio of Ir to Ce(NO3)3·6H2O was 0.74:1. The second suspension was heated in an oil bath and refluxed at a temperature of 160°C for 3 hours to obtain the third suspension. The third suspension was centrifuged, washed, and freeze-dried to obtain a Ce-doped Ir-based composite catalyst, which can be used as an anode catalyst for proton exchange membrane water electrolysis.

[0037] Example 6 Weigh 132 mg of cerium chloride heptahydrate and 400 mg of hexadecyltrimethylammonium chloride into a round-bottom flask, add 200 ml of ethylene glycol, and sonicate for about 2 h to disperse evenly to obtain the first suspension. In this experimental scheme, the mass ratio of CeCl3·7H2O to surfactant CATB is 1:3.0, and the mass-volume ratio of CeCl3·7H2O to ethylene glycol is 1 mg:1.5 ml. Add 2.5 ml of chloroiridium acid (35 mg) to the first suspension. Ir ml -1 The mixture was stirred at room temperature for about 2 hours to obtain a second suspension. In this experimental scheme, the mass ratio of Ir to CeCl3·7H2O was 0.66:1. The second suspension was heated in an oil bath and refluxed at a temperature of 110°C for 3 hours to obtain the third suspension. The third suspension was centrifuged, washed, and freeze-dried to obtain a Ce-doped Ir-based composite catalyst, which can be used as an anode catalyst for proton exchange membrane water electrolysis.

[0038] Example 7 Weigh 132 mg of cerium chloride heptahydrate and 415 mg of hexadecyltrimethylammonium chloride into a round-bottom flask, add 200 ml of ethylene glycol, and sonicate for about 1.5 h to disperse evenly to obtain the first suspension. In this experimental scheme, the mass ratio of CeCl3·7H2O to surfactant CATB is 1:3.1, and the mass-volume ratio of CeCl3·7H2O to ethylene glycol is 1 mg:1.5 ml. Add 2.0 ml of chloroiridium acid (35 mg) to the first suspension. Ir ml -1 The mixture was stirred at room temperature for about 3 hours to obtain a second suspension. In this experimental scheme, the mass ratio of Ir to CeCl3·7H2O was 0.53:1. The second suspension was heated in an oil bath and refluxed at a temperature of 170°C for 3 hours to obtain the third suspension. The third suspension was centrifuged, washed, and freeze-dried to obtain a Ce-doped Ir-based composite catalyst, which can be used as an anode catalyst for proton exchange membrane water electrolysis.

[0039] The Ce-doped Ir-based composite catalysts prepared in Examples 2 to 7 were tested for activity in a three-electrode system and for activity and stability in a single cell. The results were similar to those in Example 1.

[0040] Comparative Example 1 This comparative example provides a method for preparing an Ir-based composite catalyst without Ce doping, specifically: 415 mg of cetyltrimethylammonium bromide was placed in a round-bottom flask, 300 ml of ethylene glycol was added, and the mixture was sonicated for 1.5 h to disperse it evenly, thus obtaining the first suspension. Add 2.0 ml of chloroiridium acid (35 mg) to the first suspension. Ir ml -1 The mixture was stirred at room temperature for about 2 hours to obtain a second suspension. The second suspension was heated in an oil bath and refluxed at a temperature of 170 °C for 3 h to obtain the third suspension. The third suspension was centrifuged, washed, and freeze-dried to obtain the Ir-based composite catalyst of this comparative example.

[0041] The activity of the Ir-based composite catalyst obtained in this comparative example was tested in a three-electrode system with a catalyst loading of 0.5 mg / cm³. -2 Under these conditions, it reaches 10 mA cm -2 The overpotential at the current density was 279 mV, indicating a significant decrease in activity compared to Example 1. The three-electrode system assembled with this catalyst at a catalyst loading of 2 mg cm⁻¹...-2 Under the condition of 10mA cm -2 The stability test at the current density was only about 100 hours, and the performance degraded significantly.

[0042] Comparative Example 2 200 mg of cetyltrimethylammonium bromide was placed in a round-bottom flask, 200 ml of ethylene glycol was added, and the mixture was sonicated for 1.5 h to disperse it evenly, thus obtaining the first suspension. Add 5.5 ml of chloroiridium acid (35 mg) to the first suspension. Ir ml -1 The mixture was stirred at room temperature for about 3 hours to obtain a second suspension. The second suspension was heated in an oil bath and refluxed at a temperature of 170°C for 3 hours to obtain the third suspension. The third suspension was centrifuged, washed, and freeze-dried to obtain the Ir-based composite catalyst of this comparative example.

[0043] The activity of the Ir-based composite catalyst obtained in this comparative example was tested in a three-electrode system with a catalyst loading of 0.5 mg / cm³. -2 Under these conditions, it reaches 10 mA cm -2 The overpotential at the current density was similar to that of Comparative Example 1, but its activity decreased significantly compared to Example 1. The three-electrode system assembled with this catalyst at a catalyst loading of 2 mg cm⁻¹... -2 Under these conditions, at 10 mA cm -2 The stability test at the current density was only about 100 hours, and the performance degraded significantly.

[0044] Comparative Example 3 300 mg of cetyltrimethylammonium bromide was placed in a round-bottom flask, 100 ml of ethylene glycol was added, and the mixture was sonicated for 2 h to disperse it evenly, thus obtaining the first suspension. Add 1.59 ml of chloroiridium acid (35 mg) to the first suspension. Ir ml -1 The mixture was stirred at room temperature for about 2 hours to obtain a second suspension. The second suspension was heated in an oil bath and refluxed at a temperature of 160 °C for 3 h to obtain the third suspension. The third suspension was centrifuged, washed, and freeze-dried to obtain the Ir-based composite catalyst of this comparative example.

[0045] The activity of the Ir-based composite catalyst obtained in this comparative example was tested in a three-electrode system with a catalyst loading of 0.5 mg / cm³. -2 Under these conditions, it reaches 10 mA cm -2The overpotential at the current density was similar to that of Comparative Example 1, but its activity decreased significantly compared to Example 1. The three-electrode system assembled with this catalyst at a catalyst loading of 2 mg cm⁻¹... -2 Under these conditions, at 10 mA cm -2 The stability test at the current density was only about 100 hours, and the performance degraded significantly.

[0046] Furthermore, in the experimental schemes of Comparative Examples 1 to 3, the mass of CTAB and the volume of ethylene glycol added had no significant effect on the performance of the obtained catalyst. They could be adjusted appropriately according to the amount of chloroiridium acid added and the volume of the container used during the reaction. For example, in a 500 ml round-bottom flask, the amount of CTAB could be controlled between 200 and 600 mg, and the volume of ethylene glycol could be controlled between 50 and 400 ml.

[0047] Comparative Example 4 The difference between this comparative example and Example 1 is that the amount of hexadecyltrimethylammonium bromide (CTAB) was adjusted to 800 mg, so that the mass ratio of CeO2 to surfactant CATB was 1:10.7. The remaining steps and processes were the same as in Example 1, and the Ce-doped Ir-based composite catalyst of this comparative example was obtained.

[0048] The Ce-doped Ir-based composite catalyst obtained in this comparative example was tested for activity in a three-electrode system with a catalyst loading of 0.5 mg / cm³. -2 Under these conditions, it reaches 10 mA cm -2 The overpotential at the current density of Example 1 was much higher than that in Example 1, with an overpotential of approximately 283 mV. This is because in this comparative example, too much surfactant was added during the synthesis process. On the one hand, surfactants are prone to agglomeration during the synthesis process, affecting the reaction process. On the other hand, a large amount of surfactant residue may remain in the subsequent washing process, thus affecting the performance of the catalyst.

[0049] Comparative Example 5 The difference between this comparative example and Example 1 is that the oil bath heating temperature of the second suspension was adjusted to 80 °C, while the remaining steps and processes were the same as in Example 1, to obtain the Ce-doped Ir-based composite catalyst of this comparative example.

[0050] The oxygen evolution reaction (OER) activity of the Ce-doped Ir-based composite catalyst prepared in this comparative example was tested in a three-electrode system. The catalyst loading was 0.5 mg cm⁻¹. -2 Under these conditions, it reaches 10 mA cm -2The overpotential at the current density was approximately 290 mV, significantly lower than the activity of the catalyst obtained in Example 1. This is primarily because the oil bath reflux temperature was too low during the synthesis process in this comparative example. Under these low-temperature conditions, ethylene glycol struggled to generate a sufficient reducing atmosphere, leading to insufficient reduction of the Ir precursor and inhibiting the effective incorporation and uniform dispersion of Ce species. This negatively impacted the formation of the active phase of the catalyst, ultimately resulting in a significantly increased overpotential.

[0051] Comparative Example 6 The difference between this comparative example and Example 1 is that the amount of CeO2 was adjusted to 20 mg, so that the mass ratio of CeO2 to surfactant CATB was 1:20.75, the mass-volume ratio of CeO2 to ethylene glycol was 1 mg:7.5 ml, and the mass ratio of Ir to CeO2 was 2.78:1. The remaining steps and processes were the same as in Example 1, thus obtaining the Ce-doped Ir-based composite catalyst of this comparative example.

[0052] The oxygen evolution reaction (OER) activity of the Ce-doped Ir-based composite catalyst prepared in this comparative example was tested in a three-electrode system. The catalyst loading was 0.5 mg cm⁻¹. -2 Under these conditions, it reaches 10 mA cm -2 The overpotential at the current density was approximately 281 mV, significantly lower than the activity of the catalyst obtained in Example 1. The main reason for this is that the amount of CeO2 precursor added during the synthesis of this comparative example was too small. Under ethylene glycol reflux conditions, the system could not provide sufficient Ce ions to participate in the IrO2 reaction. x Substrate doping and reconstruction. This leads to Ce in IrO x The effective doping rate in the crystal lattice is extremely low, Ir(Ce)O x Solid solutions or complex oxide phases are difficult to form sufficiently, failing to effectively regulate the covalent nature of Ir-O bonds and stabilize lattice oxygen, thus resulting in increased overpotential and decreased activity.

[0053] Comparative Example 7 The difference between this comparative example and Example 1 is that the amount of ethylene glycol was adjusted to 30 ml, so that the mass-volume ratio of CeO2 to ethylene glycol was 2.5 mg:1 ml; the remaining steps and processes were the same as in Example 1, and the Ce-doped Ir-based composite catalyst of this comparative example was obtained.

[0054] The oxygen evolution reaction (OER) activity of the Ce-doped Ir-based composite catalyst prepared in this comparative example was tested in a three-electrode system. The catalyst loading was 0.5 mg cm⁻¹. -2 Under these conditions, it reaches 10 mA cm -2The overpotential at the current density was approximately 297 mV, significantly lower than the activity of the catalyst obtained in Example 1. The main reason for this is the insufficient amount of ethylene glycol solvent added during the comparative synthesis. This resulted in a severely insufficient reducing atmosphere generated under reflux conditions, preventing the Ir precursor from being fully reduced and hindering the formation of highly active low-valence Ir or IrO. x On the one hand, insufficient ethylene glycol content significantly restricts the uniform dispersion of Ce and Ir precursors in the liquid phase. Excessively high local concentrations during synthesis easily lead to component aggregation and uneven distribution, increasing particle size and resulting in the burial of numerous active sites, thus significantly reducing the effective electrochemical active area. Under the combined effect of these two adverse factors, the catalyst's overpotential increases dramatically, and the OER activity decreases markedly.

[0055] In summary, this application utilizes Ce salt in a strongly acidic environment as a sacrificial template for gradual dissolution and in-situ leaching, resulting in a catalyst structure rich in defects, which enhances the oxygen evolution catalytic activity of the catalyst. At the same time, the remaining trace amount of stable Ce element in the catalyst acts as an electron pool during the reaction, flexibly exchanging electrons with the active site Ir, inhibiting the metal dissolution and structural collapse caused by excessive oxidation of the active site Ir during the catalytic process. This results in a synergistic enhancement of catalytic activity and stability of the catalyst.

[0056] The Ce-doped IrO provided by this invention x (Ir(Ce)O) x The catalyst can be prepared using a simple ethylene glycol reflux process, eliminating the need for complex high-temperature calcination steps. The process is simple, the conditions are mild, and it is easier to scale up. Regarding catalytic performance, the Ir(Ce)O prepared in this invention exhibits superior catalytic properties. x The catalyst exhibits significantly improved stability: it can operate stably for more than 1200 h in a three-electrode test system with almost no performance degradation; while the similar catalyst described in document 1 only maintains stability for about 100 h under the same test conditions, and the potential rises significantly and the degradation is faster.

[0057] Furthermore, the catalyst of this invention can be directly applied to membrane electrode (MEA) systems and exhibits excellent durability under actual operating conditions. At 80°C and 2 A cm⁻¹, -2 Under harsh operating conditions, the present invention Ir(Ce)O x The catalyst can operate stably for over 1000 hours with an extremely low decay rate. In contrast, the long-term stability of similar Ce-doped catalysts under similar conditions has not been reported in the prior art, or is far lower than that of this invention. Therefore, this invention not only simplifies the preparation process but also significantly improves the electrochemical stability of the catalyst, possessing outstanding practical application value and industrialization potential. It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. 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 be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A Ce-doped Ir-based composite catalyst, characterized in that: The catalyst uses trace amounts of Ce as an electron pool to exchange electrons with the active site Ir. The atomic ratio of Ce to Ir is 0.6 to 0.01:

1.

2. The method for preparing the Ce-doped Ir-based composite catalyst as described in claim 1, characterized in that: include, Ce salt and surfactant are dispersed in ethylene glycol solution and ultrasonically dispersed and mixed to obtain the first suspension; Ir precursor was added to the first suspension and stirred to obtain the second suspension; The second suspension was heated in an oil bath and refluxed to obtain the third suspension. The third suspension was centrifuged, washed, and freeze-dried to obtain a Ce-doped Ir-based composite catalyst.

3. The method for preparing the Ce-doped Ir-based composite catalyst as described in claim 2, characterized in that: The Ce salt is selected from one or more of cerium dioxide, cerium oxalate, cerium chloride, cerium nitrate, cerium sulfate, and cerium octanoate; the surfactant is selected from hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, or polyvinylpyrrolidone.

4. The method for preparing the Ce-doped Ir-based composite catalyst as described in claim 3, characterized in that: The mass ratio of the surfactant to Ce salt is 1~10:

1.

5. The method for preparing the Ce-doped Ir-based composite catalyst as described in claim 2, characterized in that: The mass-to-volume ratio of Ce salt to ethylene glycol is 1 mg:10 ml to 1 mg:1 ml.

6. The method for preparing the Ce-doped Ir-based composite catalyst as described in claim 4, characterized in that: The Ir precursor is selected from one or more of chloroiridium acid, iridium chloride, iridium acetylacetonate, iridium acetate, potassium chloroiridium, sodium chloroiridium, iridium oxide, strontium iridium, barium iridium, lithium iridium, potassium iridium, and praseodymium iridium. The mass ratio of Ir to Ce salt in the Ir precursor is 0.2 to 1:

1.

7. The method for preparing the Ce-doped Ir-based composite catalyst as described in claim 2, characterized in that: The ultrasonic dispersion and mixing time is 0.5~3 h.

8. The method for preparing the Ce-doped Ir-based composite catalyst as described in claim 2, characterized in that: The mixing time is 0.5 to 3 hours.

9. The method for preparing the Ce-doped Ir-based composite catalyst as described in claim 2, characterized in that: The oil bath is heated and refluxed, with a reflux temperature of 120 ℃~180 ℃ and a reflux time of 1 h~6 h.

10. The application of the Ce-doped Ir-based composite catalyst as described in claim 1 as an anode catalyst for proton exchange membrane water electrolysis.

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