O-IrO X Catalyst materials, methods of making and use

Abstract

The application belongs to the technical field of catalyst and electrochemical energy material, and discloses O-IrO x Catalyst material, preparation method and application. The catalyst material is obtained by hydrothermal reconstruction of SrCo 0.9 Ir 0.1 O 2.52 Precursor material, has local topological invariance structure, contains edge limited non-bonding oxygen. The application realizes enrichment and reconstruction of iridium atoms on the surface of the catalyst through the topological reconstruction strategy of the SrCo 0.9 Ir 0.1 O 2.52 Precursor, when the iridium loading amount is only 0.05 mg / cm 2 (about 1 / 10 of the loading amount of a commercial catalyst), the cell voltage performance of 3 A / cm 2 Lower 1.72 V can be achieved, which significantly reduces the amount of noble metal and the cost of hydrogen production.

Description

Technical Field

[0001] This invention relates to the field of catalysts and electrochemical energy materials, specifically to O-IrO. x Catalyst materials, preparation methods, and applications. Background Technology

[0002] Proton exchange membrane electrolysis (PEMWE) technology is considered one of the most promising technological pathways for producing high-purity green hydrogen due to its advantages of high current density, fast response characteristics, and the ability to directly utilize pure water as an electrolyte. In PEMWE systems, the slow kinetics of the oxygen evolution reaction (OER) at the anode, involving a complex four-electron transfer process, is a key bottleneck limiting the overall efficiency of the electrolyzer.

[0003] Currently, iridium-based oxides (such as IrO2) are the only practical OER catalysts that can simultaneously meet the requirements of strongly acidic operating environments and long-term operational stability. However, the abundance of iridium in the Earth's crust is extremely low (approximately 0.001 ppm), with an annual mining volume of only about 7-8 tons, resulting in high prices and limited supply. For commercial applications, PEMWE systems typically require an anode loading of approximately 1-2 mg / cm³. 2 The use of precious metal catalysts significantly increases the cost of hydrogen production and limits the large-scale deployment of the technology. Therefore, developing OER catalysts that can maintain high performance with ultra-low iridium loading has become a key technological challenge in this field.

[0004] From a catalytic mechanism perspective, existing iridium-based oxides mainly follow the adsorbate evolution mechanism (AEM), which involves a proton-electron coupling transfer step from *OH to O to *OOH to O2. The formation of the *OOH intermediate is characterized by a high intrinsic kinetic energy barrier (theoretical overpotential of approximately 0.37 V), fundamentally limiting catalytic activity. Although the lattice oxygen oxidation mechanism (LOM) can bypass the *OOH formation step by allowing lattice oxygen to directly participate in OO coupling, significantly improving reactivity, this mechanism relies on the redox of bulk lattice oxygen, which is limited at high current densities. - The rate of diffusion replenishment to the bulk catalyst phase is much lower than the rate of lattice oxygen consumption, leading to irreversible oxygen vacancy formation and crystal structure collapse, resulting in poor long-term stability.

[0005] To enhance the activity of the AEM pathway or reduce the amount of precious metals used, various modification strategies have been developed, including heteroelement doping, lattice stress modulation, and amorphization. These strategies introduce oxygen vacancies or unbonded oxygen species (O2) into the bulk phase. NBTo enhance the covalent nature of metal-oxygen bonds and thus activate lattice oxygen, the above methods lack control over the spatial distribution of active oxygen species. Oxygen defects are mainly distributed in the bulk phase of the catalyst rather than the surface active region, making it difficult to avoid excessive consumption of lattice oxygen and structural degradation even under high current density operating conditions. In addition, existing technologies often require a trade-off between catalytic activity and long-term stability, making it difficult to achieve simultaneous improvement of both.

[0006] In view of this, the present invention is proposed. Summary of the Invention

[0007] The present invention aims to solve at least one of the above technical problems, and provides O-IrO x Catalyst materials, preparation methods, and applications.

[0008] To achieve the above objectives, the first technical solution adopted by the present invention is as follows: O-IrO x Catalyst material, the catalyst material being hydrothermally reconstructed from SrCo 0.9 Ir 0.1 O 2.52 The precursor material is obtained and has a locally topologically invariant structure containing edge-confined unbonded oxygen.

[0009] Preferably, the catalyst material in the proton exchange membrane electrolyzer has an iridium loading of 0.05 mg. Ir / cm 2 At 3A / cm 2 The cell voltage at the current density is no higher than 1.72 V, and the iridium loading is 0.4 mg. Ir / cm 2 At 1 A / cm 2 Operating stability at current density exceeds 4200 hours.

[0010] Preferably, the catalyst material has an iridium-rich active surface structure, with a surface iridium content higher than the bulk iridium content.

[0011] Preferably, the catalyst material has a low crystallinity structure or contains a low crystallinity / crystalline heterogeneous interface.

[0012] The second technical solution adopted in this invention is: O-IrO x Methods for preparing catalyst materials include: Preparation of SrCo 0.9 Ir 0.1 O 2.52 Perovskite precursor; The precursor was dispersed in a dilute nitric acid solution and subjected to a hydrothermal reaction, selectively dissolving strontium and cobalt while retaining the iridium-oxygen framework, thus confining unbonded oxygen at the catalyst edge to obtain the O-IrO. x Catalyst materials.

[0013] Preferably, the precursor preparation method adopts the sol-gel method, using citric acid and ethylenediaminetetraacetic acid as complexing agents to form a sol under conditions of pH 7-10 and 60-120°C, and then drying at 160-250°C and annealing at 600-1000°C to obtain the precursor.

[0014] Preferably, the concentration of the dilute nitric acid solution is 0.05–0.1 mol / L, the hydrothermal reaction temperature is 100–180°C, and the reaction time is 6–12 hours.

[0015] Preferably, the dispersion is subjected to ultrasonic treatment, followed by hydrothermal reaction, and then washing and drying to obtain the final product.

[0016] The third technical solution adopted in this invention is: O-IrO x Application of catalyst materials in electrocatalytic oxygen evolution reaction.

[0017] Preferably, the application is as an anode catalyst in a proton exchange membrane water electrolyzer for hydrogen production by water electrolysis.

[0018] Compared with the prior art, the present invention has the following beneficial effects: To address the problem of excessively high iridium loading in existing PEMWE anode catalysts, this invention utilizes SrCo... 0.9 Ir 0.1 O 2.52 The precursor topology reconstruction strategy enabled the enrichment and reconstruction of iridium atoms on the catalyst surface, even with an iridium loading of only 0.05 mg / cm³. 2 (At approximately 1 / 10 of the loading of commercial catalysts) 3 A / cm can be achieved. 2 The cell voltage performance at 1.72 V is better than the U.S. Department of Energy's (DOE) 2026 target (3 A / cm). 2 At 1.8 V, with a loading of 0.5 mg / cm² 2 This significantly reduced the amount of precious metals used and the cost of hydrogen production.

[0019] To address the activity limitation caused by the slow kinetics of OOH formation in the traditional AEM mechanism, this invention utilizes the Local Topological Invariance (LBTI) strategy to construct confined unbonded oxygen (O2) at the catalyst edge. NB At low potentials, it acts as an oxygen redox center driving direct OO coupling, bypassing the *OOH intermediate formation step, thereby achieving a speed of 10 mA / cm². 2An ultra-low overpotential of 201 mV was achieved at a current density, breaking through the theoretical kinetic limitations of the AEM mechanism.

[0020] To address the structural collapse and poor stability caused by excessive consumption of bulk lattice oxygen in the LOM mechanism, this invention confines unbonded oxygen to the edges rather than the bulk phase and establishes a potential-dependent dual-center adaptive mechanism: at high potentials, in-plane Ir sites are activated as metal redox centers to assist OER, suppressing excessive consumption of lattice oxygen and the formation of oxygen vacancies. This strategy enables the catalyst to operate at 1 A / cm². 2 It operates stably for over 4200 hours in a pure water electrolysis environment at current density, solving the trade-off between activity and stability.

[0021] This invention employs a two-step method combining sol-gel and dilute nitric acid hydrothermal reconstruction to prepare catalysts. The process conditions are mild and controllable, with good repeatability, avoiding high temperature and high pressure or complex post-processing steps, and has good potential for industrial-scale production. Attached Figure Description

[0022] Figure 1 SCIO as a precursor, and O-IrO prepared in Example 1 x Polarization curves of C-IrO2 (Commercial-IrO2); Figure 2 Preparation of O-IrO at different nitric acid concentrations in Examples 1-3 x Polarization curves of the sample; Figure 3 O-IrO was prepared under different hydrothermal reaction conditions for Examples 1, 4, and 5. x Polarization curves of the sample; Figure 4 O-IrO was prepared under different hydrothermal reaction conditions in Examples 1, 6, and 7. x Polarization curves of the sample; Figure 5 SCIO as a precursor, and O-IrO prepared in Example 1 x Durability curves of C-IrO2 (Commercial-IrO2) on three electrodes; Figure 6 for O-IrO x -2 Durability curves on three electrodes; Figure 7 for O-IrO x -3 Durability curves on three electrodes; Figure 8 for O-IrO x -4 Durability curves on three electrodes; Figure 9 for O-IrO x-5 Durability curves on three electrodes; Figure 10 for O-IrO x -6 Durability curves on three electrodes; Figure 11 for O-IrO x -7 Durability curves on three electrodes; Figure 12 O-IrO with different Ir loading x The PEMWE polarization curves of the anode catalyst are shown. Figure 13 O-IrO prepared in Example 1 x PEMWE for the anode catalyst at 1 A / cm 2 Constant current potential curve under current density; Figure 14 for O-IrO x HAADF-STEM image; Inset: Corresponding Fast Fourier Transform (FFT) pattern showing exposed crystal planes; Figure 15 The total energy of the Ir-OO-Ir structural unit located at the lattice edge and bulk phase, calculated by DFT. Figure 16 This is a schematic diagram of the edge-bounded Ir-OO-Ir region. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without specified manufacturers are all commercially available conventional products.

[0024] The first embodiment of the present invention provides O-IrO x Catalyst material, the catalyst material being hydrothermally reconstructed from SrCo 0.9 Ir 0.1 O 2.52 The precursor material is obtained and has a locally topologically invariant structure containing edge-confined unbonded oxygen.

[0025] The catalyst material provided in this invention is designed based on a local topological invariance (LBTI) strategy. Unlike traditional single redox processes, LBTI design achieves an adaptive control mechanism. This strategy intrinsically introduces unbonded oxygen (O₂) confined to the edge. NBThis spatial confinement is key: by confining unbonded oxygen to the catalyst edge rather than the bulk phase, it prevents OH from forming at high current densities. - The slow replenishment of oxygen cannot match the rapid consumption of oxygen in the bulk lattice, thus avoiding the formation of a large number of oxygen vacancies and structural collapse.

[0026] Local topological invariance (LBTI) refers to the selective dissolution of some metal elements (Sr, Co) in the precursor while retaining the main metal-oxygen framework (Ir-O), enabling the catalyst to maintain a specific topological connection relationship during atomic rearrangement, forming a structural feature where the edge is enriched with unbonded oxygen while the bulk phase remains relatively intact.

[0027] During the electrocatalytic oxygen evolution reaction, in the low potential region, the unbonded oxygen (O2) confined at the edge... NB As an oxygen redox center, it can drive oxygen production through a direct OO coupling pathway, which differs from the pathway involving the *OOH intermediate in the traditional adsorbate evolution mechanism (AEM), thus breaking through the inherent kinetic limitations of the AEM mechanism. In the high potential region, the in-plane Ir sites of the catalyst are activated as metal redox centers, which assist the oxygen evolution reaction while suppressing the excessive consumption of lattice oxygen and maintaining the integrity of the crystal structure, thus solving the common stability problem of the lattice oxygen oxidation mechanism (LOM).

[0028] The unbonded oxygen (O) NB Oxygen species that have not formed stable chemical bonds with metals are highly reactive. Edge confinement refers to the fact that these reactive oxygen species are mainly distributed at the edge sites of the catalyst, rather than in the bulk lattice. This distribution is achieved through a hydrothermal reconstruction process using specific precursors.

[0029] In terms of specific performance, the catalyst material in the proton exchange membrane electrolyzer has an iridium loading of 0.05 mg. Ir / cm 2 At 3 A / cm 2 The cell voltage at the current density is no higher than 1.72 V, and the iridium loading is 0.4 mg. Ir / cm 2 At 1A / cm 2 The catalyst exhibits operational stability exceeding 4200 hours at current density. These performance indicators demonstrate that the catalyst achieves both high activity and high durability at ultra-low iridium loading. Notably, the cell voltage not exceeding 1.72 V is superior to the US Department of Energy (DOE) 2026 target (3 A / cm²). 2 At 1.8 V, with an iridium loading of 0.5 mg Ir / cm 2 This indicates that the catalyst has significant advantages in practical PEMWE devices.

[0030] The catalyst material possesses an iridium-rich active surface structure, meaning the surface iridium content is higher than the bulk iridium content. This is achieved through the selective dissolution of strontium and cobalt during hydrothermal reconstruction, leading to the enrichment of iridium atoms on the surface. This surface-enriched structure improves the atomic utilization of the noble metal, enabling high catalytic activity even with ultra-low bulk iridium content.

[0031] Regarding the crystallinity of the catalyst, it can be a low-crystallinity structure or contain low-crystallinity / crystalline heterogeneous interfaces. This structural feature is beneficial for providing more edge active sites and defect sites, thereby enhancing catalytic activity.

[0032] The second embodiment of the present invention provides O-IrO x Methods for preparing catalyst materials include: Preparation of SrCo 0.9 Ir 0.1 O 2.52 Perovskite precursor; The precursor was dispersed in a dilute nitric acid solution and subjected to a hydrothermal reaction, selectively dissolving strontium and cobalt while retaining the iridium-oxygen framework, thus confining unbonded oxygen at the catalyst edge to obtain the O-IrO. x Catalyst materials.

[0033] Preferably, the precursor preparation method adopts the sol-gel method, using citric acid and ethylenediaminetetraacetic acid as complexing agents to form a sol under conditions of pH 8-9 and 80-100℃, and then drying at 180-220℃ and annealing at 700-900℃.

[0034] The core of the preparation method in this embodiment lies in achieving a topological transformation from a three-dimensional perovskite precursor to an iridium-rich active surface structure through hydrothermal reconstruction. 0.9 Ir 0.1 O 2.52 The precursor has a specific stoichiometric ratio, in which iridium is uniformly dispersed at a low concentration (10% molar ratio) in the lattice of cobalt and strontium. Under hydrothermal conditions of dilute nitric acid, strontium and cobalt are selectively dissolved due to their high solubility, while the iridium-oxygen bonds are relatively stable and retained, forming an iridium oxide structure with edge-confined unbonded oxygen. This process is called local topological invariance reconstruction, which achieves the exposure and reconstruction of active sites through the dissolution of some elements while maintaining the stability of the overall framework.

[0035] Precursor preparation can be achieved using various methods, with the sol-gel method being a preferred option. This method uses citric acid and ethylenediaminetetraacetic acid as complexing agents to form a sol at pH 7–10 and 60–120°C. The sol is then dried at 160–250°C and annealed at 600–1000°C to obtain the precursor. It should be noted that the sol-gel method is only one exemplary means of preparing a homogeneous mixed oxide precursor. Other methods capable of achieving homogeneous mixing at the elemental molecular level, such as co-precipitation and solid-state reaction methods, can also be used for precursor preparation, as long as SrCo can be obtained. 0.9 Ir 0.1 O 2.52 The phase composition is sufficient.

[0036] In the hydrothermal reconstruction step, the concentration of the dilute nitric acid solution, the reaction temperature, and the reaction time have a crucial impact on the morphology and performance of the final catalyst. Preferably, the concentration of the dilute nitric acid solution is 0.05–0.1 mol / L, the hydrothermal reaction temperature is 100–180 °C, and the reaction time is 6–12 hours. The selection of these parameters is based on a balance between the dissolution rate and the degree of reconstruction: too low an acid concentration or temperature may lead to insufficient dissolution and failure to form an iridium-rich surface; too high an acid concentration or temperature may lead to excessive structural collapse.

[0037] During the dispersion of the precursor, ultrasonic treatment helps to achieve uniform dispersion of the precursor in dilute nitric acid and avoids agglomeration. After the hydrothermal reaction, the product is washed to remove residual ions and dried to obtain the final product. Washing and drying are routine post-treatment steps for catalysts. The number of washes, drying temperature (50–80°C), and time (12–36 hours) can be adjusted according to actual operating conditions. The selection of these parameters does not have a decisive impact on the essential characteristics of the catalyst.

[0038] O-IrO prepared by the above method x The catalyst material has all the features described in the first embodiment, including a locally topologically invariant structure and edge-confined unbonded oxygen.

[0039] The third embodiment of the present invention provides O-IrO x Application of catalyst materials in the electrocatalytic oxygen evolution reaction. In particular, they are used as anode catalysts in proton exchange membrane water electrolyzers for hydrogen production.

[0040] In the PEMWE system, the aforementioned catalyst material is coated on the anode side, and together with the Pt / C catalyst at the cathode, it is sprayed onto both sides of a proton exchange membrane (such as a Nafion 212 or Nafion 115 membrane) to form a membrane electrode assembly (MEA). During electrolysis, water is oxidized at the anode to produce oxygen and protons. The protons migrate through the proton exchange membrane to the cathode, where they combine with electrons to generate hydrogen.

[0041] Because this catalyst material can withstand ultra-low iridium loading (e.g., 0.05 mg) Ir / cm 2 High activity and long lifespan can be achieved under ideal conditions, and its application in practical PEMWE devices can significantly reduce hydrogen production costs and improve the economics and sustainability of the system. The stability of the catalyst in a pure water electrolysis environment indicates that it is suitable for large-scale production of high-purity green hydrogen.

[0042] The following provides several specific embodiments for O-IrO x The preparation and properties of the catalyst materials are described in detail.

[0043] Example 1 Strontium nitrate (5 mmol), cobalt nitrate (4.5 mmol), and iridium chloride (0.5 mmol) were weighed and dissolved in 50 mL of deionized water. Citric acid (15 mmol) and ethylenediaminetetraacetic acid (10 mmol) were added, and the mixture was stirred magnetically for 30 minutes. The pH was adjusted to 8, and the mixture was stirred continuously at 90 °C for 2 hours to form a transparent sol. The sol was dried in a vacuum oven at 200 °C for 24 hours. The dried gel was then ground and annealed at 800 °C for 4 hours in air to obtain the precursor SrCo. 0.9 Ir 0.1 O 2.52 (SCIO).

[0044] 200 mg of the precursor was dispersed in 60 mL of 0.07 mol / L nitric acid solution and sonicated for 30 minutes. The solution was then transferred to a polytetrafluoroethylene (PTFE) reactor and hydrothermally reacted at 150 °C for 6 hours. After cooling, filtration, washing three times, and drying at 60 °C for 24 hours, O-IrO was obtained. x .

[0045] Example 2 The preparation method is the same as in Example 1, except that the concentration of the nitric acid solution is 0.05 mol / L, and the catalyst material O-IrO is prepared. x -2.

[0046] Example 3 The preparation method is the same as in Example 1, except that the concentration of the nitric acid solution is 0.1 mol / L, and the catalyst material O-IrO is prepared. x -3.

[0047] Example 4 The preparation method is the same as in Example 1, except that the concentration of the nitric acid solution is 0.05 mol / L and the hydrothermal reaction temperature is 100℃, thus preparing the catalyst material O-IrO. x -4.

[0048] Example 5 The preparation method is the same as in Example 1, except that the concentration of the nitric acid solution is 0.1 mol / L and the hydrothermal reaction temperature is 180℃, thus preparing the catalyst material O-IrO. x -5.

[0049] Example 6 The preparation method is the same as in Example 1, except that the concentration of the nitric acid solution is 0.05 mol / L and the hydrothermal reaction time is 9 hours, thus preparing the catalyst material O-IrO. x -6.

[0050] Example 7 The preparation method is the same as in Example 1, except that the concentration of the nitric acid solution is 0.1 mol / L and the hydrothermal reaction time is 12 hours, thus preparing the catalyst material O-IrO. x -7.

[0051] Comparative Example 1 In this comparative example, C-IrO2 was a commercial iridium oxide catalyst purchased from Sigma-Aldrich, with an Ir content greater than 84.5%.

[0052] Comparative Example 2 This comparative example uses the precursor SCIO prepared in Example 1.

[0053] Test case (A) Three-electrode anodic oxygen evolution performance test The anodic oxygen evolution performance of the catalyst samples prepared in Examples 1-7 and the comparative examples above was tested using a three-electrode system. The electrode coated with the catalyst sample was used as the working electrode, the saturated calomel electrode as the reference electrode, and the platinum wire as the counter electrode. The electrolyte was a 0.5M H2SO4 solution saturated with oxygen. Before the test, high-purity oxygen was bubbled into the electrolyte for at least 30 min to reach saturation. A linear scan test was performed at a scan rate of 1 mV / s.

[0054] Experimental results are as follows Figures 1-4 As shown. Among them, Figure 1 The polarization curves of Example 1 are compared with those of Comparative Example 1 (commercial C-IrO2) and Comparative Example 2 (SCIO precursor). Figure 1 As shown, the O-IrO prepared in Example 1 x At a reference current density of 10 mA / cm 2 Under these conditions, it exhibits an ultra-low overpotential of only 201 mV, which is significantly lower than that of SCIO (352 mV) in Comparative Example 2 and C-IrO2 (330 mV) in Comparative Example 1, indicating that the catalytic activity is greatly improved after hydrothermal reconstruction.

[0055] Figure 2The polarization curves of samples prepared with different dilute nitric acid concentrations were compared to investigate the effect of nitric acid concentration on catalytic activity (corresponding to Examples 1, 2, and 3, with concentrations of 0.07 mol / L, 0.05 mol / L, and 0.1 mol / L, respectively). The results showed that the O-IrO prepared in Example 1 (0.07 mol / L) exhibited better catalytic activity. x At a reference current density of 10 mA / cm 2 At this concentration, an ultra-low overpotential of only 201 mV was observed; the overpotential of Example 2 (0.05 mol / L) was 253 mV; and the overpotential of Example 3 (0.1 mol / L) was 295 mV. Nitric acid concentration significantly affected the degree of remodeling and the exposure of surface active sites, with 0.07 mol / L being the optimal concentration.

[0056] Figure 3 Polarization curves of samples prepared under different hydrothermal reaction conditions were compared (corresponding to Examples 1, 4, and 5). The results show that Example 1, at 10 mA / cm², exhibited the best polarization performance. 2 The overpotential in Example 1 was 201 mV; the overpotential in Example 4 was 263 mV; and the overpotential in Example 5 was 266 mV. Example 1 exhibited the best catalytic activity, indicating that within the range of dilute nitric acid concentration (0.05–0.1 mol / L) and hydrothermal reaction temperature (100–180 °C), the combination of 0.07 mol / L and 150 °C is more conducive to the formation of a highly active edge-confined structure.

[0057] Figure 4 Polarization curves of samples prepared under different hydrothermal reaction conditions were compared (corresponding to Examples 1, 6, and 7). The results show that Example 1, at 10 mA / cm², exhibited the best polarization performance. 2 The overpotential in Example 1 was 201 mV; the overpotential in Example 6 was 273 mV; and the overpotential in Example 7 was 283 mV. Example 1 exhibited the best catalytic activity, indicating that within the range of 0.05–0.1 mol / L nitric acid concentration and hydrothermal reaction time of 6–12 h, the combination of 0.07 mol / L and 6 h is more conducive to the formation of a highly active edge-confined structure.

[0058] (B) Three-electrode durability test Using the same three-electrode system as (A), in oxygen-saturated 0.5M H2SO4, at 10 mA / cm -2 A constant current was applied to perform a durability test, and the working electrode potential was recorded every 10 hours.

[0059] Experimental results are as follows Figure 5-11 As shown, the O-IrO prepared in Examples 1-7 x The catalyst materials all exhibit excellent stability, with degradation ranging from 70 to 80 mV after 2000 hours of testing.

[0060] (C) Performance testing of proton exchange membrane electrolyzer O-IrO was processed in an assembled proton exchange electrolyzer. x Performance tests were conducted using a spray coating process, applying Pt / C with different loadings (0.05, 0.1, 0.2, 0.4 mg). Ir / cm 2 )O-IrO x A membrane array (MEA) is formed by spraying coatings onto both sides of a Nafion 212 film. A single cell is assembled using titanium felt as a diffusion layer, with Pt / C as the cathode and O-IrO as the cathode. x It is the anode, named O-IrO x ||Pt / C catalyst. Furthermore, the test temperature was 80℃, and the electrolyte was pure water.

[0061] Experimental results are as follows Figure 12 As shown, the membrane electrode assembled with the catalyst prepared in Example 1 exhibits excellent performance under low loading conditions, with an Ir loading of 0.05 mg. Ir / cm 2 At 3 A / cm 2 A cell voltage of 1.72 V was achieved at a current density, significantly better than the U.S. Department of Energy's (DOE) 2026 target (3 A / cm²). 2 At 1.8 V, with an iridium loading of 0.5 mg Ir / cm 2 ).

[0062] (D) Stability test of proton exchange membrane electrolyzer MEAs were prepared using the same process as in (C), employing a Nafion 115 membrane, at 40°C and 1 A / cm. 2 Long-term stability tests were conducted under constant current conditions, and the cell voltage was recorded every 1 hour.

[0063] Experimental results are as follows Figure 13 As shown, the O-IrO prepared in Example 1 x The catalyst in pure water can reach 1 A / cm -2 It has been running stably for over 4200 hours, demonstrating excellent stability.

[0064] (E) Structural characterization analysis The O-IrO prepared in Example 1 x High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) was used to characterize the crystal planes and resolve their information. Figure 14 Combining multi-region analysis with Fast Fourier Transform (FFT) plots along the

[010] zone axis (inset) shows that O-IrO x High exposure to IrO2 (200), ( )and( ) crystal plane; where ( )and( They possess the same properties in rutile IrO2 and belong to the same crystal plane family. For O-IrO... x HAADF-STEM characterization of multiple randomly selected regions of the sample revealed that this type of polycrystalline facet exposure is a common feature. The measured interplanar spacing (d) (200) = 0.206nm, d {101} = 0.239 nm) Compared to the standard rutile phase IrO2 (0.224 nm and 0.258 nm in PDF#86-0330), it shrinks significantly. This is essentially due to the high-valence state Ir induced by the edge-confined Ir-OO-Ir structural unit and the shortened Ir–O bond.

[0065] Figure 15 The total energy of the Ir-OO-Ir structural unit located at the lattice edge and in the bulk phase, calculated by DFT, is given. The total energy of the system containing the edge-site Ir-OO-Ir structural unit is −312.6 eV, which is 5.7 eV lower than its corresponding bulk structure. This significant energy difference indicates that anchoring the Ir-OO-Ir structural unit at the edge site is thermodynamically more advantageous, strongly demonstrating that the LBTI strategy can be effectively implemented in O-IrO x (200) Intrinsic crystal planes introduce edge O NB (Ir-OO-Ir) structural units. These are highly reactive O... NB Species are expected to be activated as redox centers during the OER process, thereby overcoming the low activity bottleneck of C-IrO2 caused by the metal-centric AEM mechanism.

[0066] Figure 16 The diagram shows the edge-confined Ir-OO-Ir region, illustrating the spatial distribution characteristics of edge-confined unbonded oxygen on the catalyst surface.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. O-IrO x Catalyst material, characterized in that, The catalyst material is obtained by hydrothermal restructuring of SrCo 0.9 Ir 0.1 O 2.52 The precursor material is obtained, having a local topological invariance structure, containing edge-limited non-bonding oxygen.

2. The O-IrO as described in claim 1 x Catalyst material, characterized in that, The catalyst material was used in a proton exchange membrane electrolyzer with an iridium loading of 0.05 mg. Ir / cm 2 At 3 A / cm 2 The cell voltage at the current density is no higher than 1.72 V, and the iridium loading is 0.4 mg. Ir / cm 2 At 1 A / cm 2 Operating stability at current density exceeds 4200 hours.

3. The O-IrO as described in claim 1 x Catalyst material, characterized in that, The catalyst material has an iridium-rich active surface structure, with a surface iridium content higher than the bulk iridium content.

4. The O-IrO as described in claim 1 x Catalyst material, characterized in that, The catalyst material has a low crystallinity structure or contains a low crystallinity / crystalline heterogeneous interface.

5. The O-IrO as described in any one of claims 1 to 4 x The method for preparing catalyst materials is characterized by, include: Preparation of SrCo 0.9 Ir 0.1 O 2.52 Perovskite precursor; The precursor was dispersed in a dilute nitric acid solution and subjected to a hydrothermal reaction, selectively dissolving strontium and cobalt while retaining the iridium-oxygen framework, thus confining unbonded oxygen at the catalyst edge to obtain the O-IrO. x Catalyst materials.

6. The preparation method according to claim 5, characterized in that, The precursor preparation method employs a sol-gel method, using citric acid and ethylenediaminetetraacetic acid as complexing agents to form a sol under conditions of pH 7–10 and 60–120°C, which is then dried at 160–250°C and annealed at 600–1000°C.

7. The preparation method according to claim 5, characterized in that, The concentration of the dilute nitric acid solution is 0.05–0.1 mol / L, the hydrothermal reaction temperature is 100–180℃, and the reaction time is 6–12 hours.

8. The preparation method according to claim 5, characterized in that, The product is obtained by ultrasonic treatment during dispersion, followed by hydrothermal reaction, washing, and drying.

9. The O-IrO as described in any one of claims 1 to 4 x Catalyst material or O-IrO prepared by the method described in any one of claims 5 to 8 x Application of catalyst materials in electrocatalytic oxygen evolution reaction.

10. The application as described in claim 9, characterized in that, The application is as an anode catalyst in a proton exchange membrane water electrolyzer for hydrogen production through water electrolysis.

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