Hollow iridium oxide nanosphere catalyst as well as preparation method and application thereof
Hollow iridium oxide nanosphere catalysts were prepared by template-free self-assembly, which solved the problems of iridium resource scarcity and structural instability in the PEMWE anode catalyst layer, and achieved efficient and stable catalytic performance and reduced production costs.
Patent Information
- Application Number
- CN202511336435.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-18
- Publication Date
- 2025-11-14
AI Technical Summary
The high iridium loading in the existing PEMWE anode catalyst layer leads to resource scarcity and structural instability, making large-scale deployment difficult. Traditional methods of reducing thickness result in island effects and increased resistance.
Hollow iridium oxide nanosphere catalysts were prepared using a template-free self-assembly method. This simplified the process, reduced the amount of iridium used, and maintained the catalyst layer thickness and structural integrity.
It achieves efficient and stable catalytic performance, reduces production costs and material consumption, and is suitable for large-scale industrial production.
Smart Images
Figure CN120943310A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a hollow iridium oxide nanosphere catalyst, its preparation method, and its application. Background Technology
[0002] Proton exchange membrane water electrolyzers (PEMWEs) have become a key component of sustainable energy systems, efficiently converting intermittent renewable energy sources (such as solar and wind power) into storable hydrogen energy, thereby enabling hydrogen production. The core performance of PEMWEs lies in the oxygen evolution reaction (OER) at the anode, a four-electron transfer process with a high kinetic barrier, accounting for approximately 30% to 50% of the system's total energy loss.
[0003] Currently, the PEMWE anode catalyst layer used in industry typically consists of IrO2 nanoparticles with sizes ranging from several nanometers to tens of nanometers. To achieve the activity and stability requirements for industrial applications, this catalyst layer usually needs to have a strength of 2–4 mg·cm⁻¹. -2 The iridium loading and thickness are 5-10 μm. However, given the extreme scarcity of iridium resources and the potential supply-demand imbalance in the future, significantly reducing the iridium loading in the anode catalyst layer is of great significance for promoting the large-scale deployment of PEMWE.
[0004] While reducing the thickness of conventional IrO2 nanocatalyst layers to decrease iridium loading is a direct strategy, this method has inherent limitations. For example, when the iridium loading is below 0.5 mg·cm⁻¹... -2 When the anode catalyst layer is too thin, it is difficult to maintain the continuity and integrity of its structure. This easily leads to the formation of electron-isolated IrO2 nanoclusters (i.e., the "island effect"), creating electrochemically inactive regions and causing a significant increase in in-plane resistivity due to the interruption of electron conduction pathways. Under the actual operating conditions of PEMWE, the aggregation kinetics of catalyst particles accelerate, further exacerbating the island effect.
[0005] To reduce iridium loading while maintaining catalyst layer thickness, hollow iridium oxide (IrO2) nanoparticles have emerged as a promising solution to circumvent the island effect. This strategy aims to develop novel oxygen evolution reaction electrocatalysts by reducing iridium loading density, thereby addressing both excessive iridium loading and structural integrity. In recent years, Sun K, Liang X, Wang X, et al. Highly Efficient and Durable Anode Catalyst Layer Constructed with Deformable Hollow IrOx Nanospheres in Low‐Iridium PEM Water Electrolyzer[J]. Angewandte Chemie International Edition, 2025, 64(21). reported a method for preparing hollow iridium oxide using silica as a template, demonstrating excellent performance in a low-iridium-loaded anode catalyst layer (10.1002 / anie.202504531). However, this synthetic route is cumbersome, requiring the introduction and removal of a template, which is not only complex but also unfavorable for economically feasible large-scale preparation. Summary of the Invention
[0006] To address the aforementioned problems in the existing technology, this application provides a hollow iridium oxide nanosphere catalyst, its preparation method, and its application. A highly active and stable hollow iridium oxide nanosphere catalyst is synthesized through template-free self-assembly.
[0007] To address the above problems, the present invention provides the following technical solution: In a first aspect, this application provides a method for preparing a hollow iridium oxide nanosphere catalyst, comprising the following steps: S1. Dissolve the iridium-based precursor in water, then add an inorganic strong base and heat to react; S2. Add an inorganic strong acid to adjust the pH of the mixture obtained in step S1 to neutral or acidic, and then mix and react. S3. After washing and drying the product obtained in step S2, hollow iridium oxide nanosphere catalyst is obtained.
[0008] In one embodiment of this application, the iridium-based precursor is selected from at least one of K2IrCl6, IrCl3, Na2IrCl6, and H2IrCl6.
[0009] In one embodiment of this application, the water is selected from ultrapure water.
[0010] In one embodiment of this application, the inorganic strong base is selected from at least one of NaOH, KOH, and LiOH.
[0011] In one embodiment of this application, the ratio of iridium-based precursor, water, and inorganic strong base is 2-3 g:1 L:2-3 g.
[0012] In one embodiment of this application, the temperature of the heating reaction is 50°C-100°C.
[0013] In one embodiment of this application, the heating reaction time is 0.5-2 h.
[0014] In one embodiment of this application, the temperature of the heating reaction is 60°C-90°C.
[0015] In one embodiment of this application, the heating reaction time is 1 hour.
[0016] In one embodiment of this application, the inorganic strong acid is selected from at least one of hydrochloric acid, sulfuric acid, nitric acid, and perchloric acid.
[0017] In one embodiment of this application, an inorganic strong acid is added to adjust the pH of the mixture obtained in step S1 to acidic, and the mixture reacts.
[0018] In one embodiment of this application, the acidity is adjusted to 3 to 6.9.
[0019] In one embodiment of this application, the concentration of the inorganic strong acid is 0.5 mmol / L-2 mmol / L.
[0020] In one embodiment of this application, the concentration of the inorganic strong acid is 1 mmol / L.
[0021] In one embodiment of this application, the temperature of the mixing reaction is 50°C-70°C.
[0022] In one embodiment of this application, the mixing reaction time is 5-10 h.
[0023] In one embodiment of this application, the temperature of the mixing reaction is 60°C.
[0024] In one embodiment of this application, the mixing reaction time is 8 hours.
[0025] Secondly, this application provides a hollow iridium oxide nanosphere catalyst prepared by the above-mentioned preparation method.
[0026] In one embodiment of this application, the hollow iridium oxide nanosphere catalyst has a particle size of 50-70 nm.
[0027] Thirdly, this application provides the application of hollow iridium oxide nanosphere catalysts as oxygen evolution reaction catalysts in PEM water electrolysis.
[0028] Compared with the prior art, the technical solution provided in this application has the following beneficial effects: 1) The preparation method of hollow iridium oxide nanosphere catalyst provided in this application eliminates the steps of introducing and removing templates, reduces the complexity of operation, and simplifies the process flow; 2) The preparation method of the hollow iridium oxide nanosphere catalyst provided in this application improves the generation efficiency, meets the industrial needs of large-scale generation, and has good scalability; 3) The preparation method of the hollow iridium oxide nanosphere catalyst provided in this application simplifies the process flow, reduces the consumption of raw materials and energy, and lowers the production cost; 4) The hollow iridium oxide nanosphere catalyst prepared by the method of this application exhibits excellent electrochemical performance and stability in PEMWE. Attached Figure Description
[0029] Figure 1 The image shows the X-ray diffraction (XRD) pattern of the hollow iridium oxide nanosphere catalyst prepared in Example 1 of this invention. Figure 2 This is a high-resolution transmission electron microscope (HRTEM) image of the hollow iridium oxide nanosphere catalyst prepared in Example 1 of the present invention. The scale bar in the image is 50 nm. Figure 3 The image shows a scanning electron microscope (SEM) image of the hollow iridium oxide nanosphere catalyst prepared in Example 2 of this invention at pH=3, with the scale bar at 500 nm. Figure 4 The image shows a scanning electron microscope (SEM) image of the hollow iridium oxide nanosphere catalyst prepared in Example 3 of this invention at pH=5, with the scale bar at 500 nm. Figure 5 This is a three-electrode curve of the hollow iridium oxide nanosphere catalyst prepared in Example 1 of the present invention; Figure 6 The PEMWE performance diagram of the hollow iridium oxide nanosphere catalyst prepared in Example 1 of this invention is shown. Figure 7 This is a particle size distribution diagram of the hollow iridium oxide nanosphere catalyst prepared in Example 2 of the present invention at pH=3; Figure 8 This is a particle size distribution diagram of the hollow iridium oxide nanosphere catalyst prepared in Example 3 of the present invention at pH=5. Detailed Implementation
[0030] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.
[0031] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. The range defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range.
[0032] Unless otherwise stated, when this invention relates to percentages between liquids, it is volume / volume percentage; when this invention relates to percentages between liquids and solids, it is volume / weight percentage; when this invention relates to percentages between solids and liquids, it is weight / volume percentage; the rest are weight / weight percentage. Example 1
[0033] A method for preparing a hollow iridium oxide nanosphere catalyst, specifically comprising: S1. Dissolve 2.1 g K2IrCl6 in 1 L of ultrapure water, then add 2.8 g NaOH and stir continuously at 60 °C for 1 h; S2. Adjust the pH to 7 using 1 M HClO4 and react at 60°C for 8 h; S3. After washing and drying the product obtained from step S2, the desired catalyst is obtained.
[0034] like Figure 1 As shown, no obvious diffraction peaks were observed in the XRD pattern, indicating that the prepared catalyst had an amorphous structure.
[0035] like Figure 2 As shown in the HRTEM image, the prepared catalyst exhibits a distinct hollow nanosphere structure.
[0036] like Figure 5 As shown in the three-electrode curve, the overpotential of the prepared catalyst is 270 mV.
[0037] like Figure 6 As shown, the prepared catalyst exhibits excellent performance under PEMWE at a current density of 1 A / cm². 2 At that time, its voltage was only 1.63 V; at a current density of 2 A / cm 2 At that time, its voltage was only 1.76 V; at a current density of 3 A / cm 2 At that time, its voltage was only 1.85 V. Example 2
[0038] A method for preparing a hollow iridium oxide nanosphere catalyst, specifically comprising: S1. Dissolve 1.05 g H2IrCl6 in 0.5 L of ultrapure water, then add 1.5 g NaOH and stir continuously at 90 °C for 1 h; S2. Adjust the pH to 3 using 1 M HNO3 and react at 60°C for 8 h; S3. After washing and drying the product obtained from step S2, the desired catalyst is obtained.
[0039] like Figure 3 As shown, the catalyst prepared at pH=3 has a hollow nanosphere structure. Example 3
[0040] A method for preparing a hollow iridium oxide nanosphere catalyst, specifically comprising: S1. Dissolve 1.37 g Na2IrCl6 in 0.5 L of ultrapure water, then add 1.2 g NaOH and stir continuously at 80 °C for 1 h; S2. Adjust the pH to 5 using 1 M H2SO4 and react at 60°C for 8 h; S3. After washing and drying the product obtained from step S2, the desired catalyst is obtained.
[0041] like Figure 4 As shown, the catalyst prepared at pH=5 has a hollow nanosphere structure.
[0042] Preparation method of membrane electrode assembly: The catalyst is ultrasonically sprayed onto the Nafion 115 membrane, and the anode is coated with IrO2 catalyst or commercial IrO2 (0.3 mg / cm³). 2 The cathode is treated with 50% Pt / C (0.1 mg / cm³). 2 ).
[0043] Preparation of slurry for anode catalyst: 0.5 g lrO2 was dispersed in 24 mL ultrapure water, 24 mL isopropanol and 1.2 g Nafion solution, and stirred at 13500 rpm for 1 h using an emulsifying shear machine to obtain a uniform ink.
[0044] Preparation of cathode catalyst slurry: 0.5 g Pt / C (50%) was dispersed in 12 mL of ultrapure water, 36 mL of isopropanol and 4.5 g of Nafion solution, and stirred at 16500 rpm for 1 h using an emulsifying shear press to obtain a uniform ink.
[0045] To fabricate the membrane electrode assembly, an anode catalyst layer and a cathode catalyst layer with an area of 25 cm² were prepared on both sides of an N115 membrane using ultrasonic spraying. 2 The loading rates were 0.3 mg / cm³. 2 and 0.1 mg / cm2 .
[0046] PEMWE Assembly: A titanium felt (0.25 mm thick) was electroplated with platinum (0.5 μm) and used as a porous transport layer (PTL) on the anode. For the cathode, Toray's YLS-30T carbon paper was used as the PTL. The PTLs of the anode, membrane electrode, and cathode were then assembled into a single-cell test.
[0047] The present application has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application.
Claims
1. A method for preparing a hollow iridium oxide nanosphere catalyst, characterized in that, Includes the following steps: S1. Dissolve the iridium-based precursor in water, then add an inorganic strong base and heat to react; S2. Add an inorganic strong acid to adjust the pH of the mixture obtained in step S1 to neutral or acidic, and then mix and react. S3. After washing and drying the product obtained in step S2, hollow iridium oxide nanosphere catalyst is obtained.
2. The method for preparing hollow iridium oxide nanosphere catalyst according to claim 1, characterized in that, The iridium-based precursor is selected from at least one of K2IrCl6, IrCl3, Na2IrCl6, and H2IrCl6.
3. The method for preparing the hollow iridium oxide nanosphere catalyst according to claim 1, characterized in that, The inorganic strong base is selected from at least one of NaOH, KOH, and LiOH.
4. The method for preparing the hollow iridium oxide nanosphere catalyst according to claim 1, characterized in that, The ratio of the iridium-based precursor, water, and inorganic strong base is 2-3 g:1 L:2-3 g.
5. The method for preparing the hollow iridium oxide nanosphere catalyst according to claim 1, characterized in that, The heating reaction temperature is 50℃-100℃, and the heating reaction time is 0.5-2 h.
6. The method for preparing the hollow iridium oxide nanosphere catalyst according to claim 1, characterized in that, The inorganic strong acid is selected from at least one of hydrochloric acid, sulfuric acid, nitric acid, and perchloric acid.
7. The method for preparing the hollow iridium oxide nanosphere catalyst according to claim 1, characterized in that, The temperature of the mixing reaction is 50℃-70℃, and the time of the mixing reaction is 5-10 h.
8. The method for preparing the hollow iridium oxide nanosphere catalyst according to claim 7, characterized in that, The mixing reaction was carried out at a temperature of 60°C for 8 hours.
9. The hollow iridium oxide nanosphere catalyst prepared by the preparation method according to any one of claims 1-8, wherein the particle size of the hollow iridium oxide nanosphere catalyst is 50-70 nm.
10. The application of the hollow iridium oxide nanosphere catalyst according to claim 9 as an oxygen evolution reaction catalyst in PEM water electrolysis.