Amorphous carrier supported iridium catalyst, its preparation method and application
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHANGCHUN INSTITUTE OF APPLIED CHEMISTRY CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2025-01-09
- Publication Date
- 2026-06-19
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Figure CN119932608B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst technology, specifically relating to an amorphous supported iridium catalyst, its preparation method, and its application. Background Technology
[0002] The dual carbon goals of "carbon peaking" and "carbon neutrality" have greatly promoted the rapid development of hydrogen energy. Proton exchange membrane electrolysis (PEMWE) technology, due to its rapid response to fluctuating and intermittent renewable energy sources (such as solar and wind power), has significant application prospects in the field of green hydrogen production. However, the PEMWE anode is located in a strongly acidic environment with a high oxidation potential, and the oxygen evolution reaction (OER) has a high energy barrier, requiring the use of large amounts of precious metal iridium (Ir)-based catalysts. However, Ir is scarce in the Earth's crust and its high cost limits the application of PEMWE in practical production. Therefore, developing anode OER catalysts with low Ir loading is crucial for reducing the cost of PEMWE technology and realizing its large-scale application.
[0003] Using transition metal oxides (such as TiO2, Nb2O5, ZrO2, etc.) as supports to load Ir is an effective way to reduce the amount of precious metals used, and there has been considerable research on this topic. For example, the Hyun-Seok Cho team developed IrO supported on Zr2ON2. x Nanoparticle catalyst, at 0.4 mg Ir cm -2 At loading levels of [specific catalyst name], it exhibited membrane electrode performance superior to that of commercial catalysts. (Lee, C.; Shin, K.; Park, Y.; Yun, YH; Doo, G.; Jung, GH; Kim, M.; Cho, WC; Kim, CH; Lee, HM; Kim, HY; Lee, S.; Henkelman, G.; Cho, HS, Catalyst-Support Interactions in Zr2ON2-Supported IrO2) xElectrocatalysts to Break the Trade-Off Relationship Between the Activity and Stability in the Acidic Oxygen Evolution Reaction. Advanced Functional Materials 2023, 33(25). Shuang Ma Andersen's team used a microwave-assisted polyol synthesis method to prepare antimony-doped tin oxide (ATO) supported metallic Ir nanoparticles (Ir-NPs), achieving efficient dispersion of Ir on the support and demonstrating that the ATO support can effectively modulate the electronic activity sites of Ir during the reaction, achieving an electron-rich state of Ir sites, thereby inhibiting the oxidative dissolution of Ir. (Ali Khan, I.; Morgen, P.; Gyergyek, S.; Sharma, R.; Ma Andersen, S., Reduced valence state of iridium supported on antimony doped tin oxide as a highly active and robust oxygen evolution reaction electrocatalyst for proton exchange membrane-based electrolysis. Applied Surface Science 2024, 646.) Xu et al. formed a Mn-O-Ir coordination structure through a hydrothermal-redox reaction, driving strong anchoring of Ir species on a MnO2 substrate. The significant electronegativity difference between Mn and Ir atoms promoted the redistribution of electrons within the Mn-O-Ir coordinated structure, thereby achieving the stability of the catalyst in acidic OER. (Weng, Y.; Wang, K.; Li, S.; Wang, Y.; Lei, L.; Zhuang, L.; Xu, Z., High-Valence-Manganese Driven Strong Anchoring of Iridium Species for RobustAcidic WaterOxidation. Adv Sci (Weinh) 2023, 10 (8), e2205920.)
[0004] Although the above supported catalysts improve the dispersion of Ir and reduce the amount of precious metals required to some extent, the electron transfer between the support and the active Ir site is limited. The weak support-metal interaction (MSI) is usually insufficient to suppress the aggregation and oxidative dissolution of Ir species under high-potential, long-term testing conditions, leading to a loss of catalyst performance. In contrast, amorphous metal oxides typically have abundant unsaturated metal bonds. The unsaturated electronic configuration promotes more flexible orbital coupling, accelerates charge transfer between the metal oxide and the active site, and further enhances the support-metal interaction. Summary of the Invention
[0005] 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.
[0006] To address the problem that existing proton exchange membrane electrolysis (PEMWE) anode-supported catalysts suffer from weak interactions between the metal oxide support and the supported Ir, thus failing to effectively utilize metal-support interactions to enhance intrinsic activity and stability, this invention provides an amorphous zirconia-supported Ir catalyst. Due to the unique substrate confinement effect of the amorphous support, the Ir particle size can be reduced, thereby increasing the utilization rate of precious metals. Furthermore, the amorphous configuration can induce and enhance MSI (Medium Suspension Injection), thereby regulating the electronic structure of Ir, increasing the electron density of Ir sites, and inhibiting excessive oxidation of Ir during the catalytic process. This effectively improves the utilization rate of surface catalytic active centers and reduces the amount of precious metals required. The prepared amorphous support-supported Ir catalyst exhibits excellent catalytic activity and stability in electrolysis equipment, effectively solving the aforementioned problems.
[0007] In view of the problems existing in the above and / or prior art, the present invention is proposed.
[0008] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing an amorphous support-supported iridium catalyst.
[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solutions, including:
[0010] A hydrothermal reaction was carried out between a metallic zirconium salt and a metallic strontium salt to obtain a zirconium-containing precursor, SrZrO3.
[0011] After washing and drying, the precursor SrZrO3 was stirred with Ir salt in an aqueous solution to obtain a mixed solution;
[0012] The mixed solution undergoes a secondary hydrothermal reaction to obtain an amorphous supported iridium catalyst.
[0013] In a preferred embodiment of the preparation method of the amorphous support-supported iridium catalyst of the present invention, the zirconium salt includes one or more of zirconium oxychloride octahydrate, zirconium nitrate, and calcium chloride; and the strontium salt includes one or more of strontium nitrate, strontium chloride, and strontium acetate.
[0014] In a preferred embodiment of the preparation method of the amorphous support-supported iridium catalyst of the present invention, the molar ratio of the zirconium salt to the strontium salt is 0.5 to 1.5:1.
[0015] In a preferred embodiment of the preparation method of the amorphous support-supported iridium catalyst of the present invention, the primary hydrothermal reaction is carried out at a hydrothermal temperature of 110–200°C, for a hydrothermal time of 12–36 h, and at a heating rate of 3–5°C / min.
[0016] As a preferred embodiment of the preparation method of the amorphous support supported iridium catalyst of the present invention, the Ir salt includes 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, or praseodymium iridium.
[0017] In a preferred embodiment of the preparation method of the amorphous support-supported iridium catalyst of the present invention, the molar ratio of Zr element in the precursor SrZrO3 to Ir element in the Ir salt is 0.4 to 4:1.
[0018] In a preferred embodiment of the preparation method of the amorphous support-supported iridium catalyst of the present invention, the stirring time is 5 to 24 hours.
[0019] In a preferred embodiment of the preparation method of the amorphous support-supported iridium catalyst of the present invention, the secondary hydrothermal reaction is carried out at a hydrothermal temperature of 120–200°C, for a hydrothermal time of 12–36 h, and at a heating rate of 3–5°C / min.
[0020] Another objective of this invention is to overcome the shortcomings of the prior art and provide an amorphous supported iridium catalyst, wherein the amorphous supported iridium catalyst uses amorphous zirconium oxide as a support and loads Ir clusters thereon.
[0021] The mass ratio of the Ir clusters to the amorphous zirconium oxide support is 0.2 to 4:1.
[0022] The third objective of this invention is to overcome the shortcomings of the prior art and provide an application of an amorphous support-supported iridium catalyst in the proton exchange membrane water electrolysis reaction.
[0023] The three-electrode system assembled with the iridium catalyst supported on the amorphous support at a catalyst loading of 0.5 mg / cm³ 2 Under these conditions, it reaches 10 mA / cm 2 The current density is <371mV;
[0024] At 10mA / cm 2 Stable operating time at current density >150h, voltage decay <80mV.
[0025] Beneficial effects of this invention:
[0026] (1) The method for preparing the amorphous zirconia-supported Ir proton exchange membrane electrolysis anode catalyst provided by the present invention achieves the loading of Ir clusters on the amorphous support through a two-step hydrothermal process. This synthesis method is simple and convenient, and the target catalyst can be obtained without calcination or gas transmission. Moreover, no toxic or harmful gases are generated during the reaction process, and the entire reaction process is safe, low in energy consumption, and environmentally friendly.
[0027] (2) The inhibitory effect of the amorphous support on the growth of the Ir supported layer helps to form a supported catalyst with Ir nanoclusters of smaller particle size. The prepared catalyst has a uniform distribution of Ir clusters with small particle size, which ensures a high utilization rate of noble metals. In addition, the unique amorphous support enhances the interaction between Ir clusters and ZrO. x Electron interactions between carriers.
[0028] (3) The catalyst prepared by the present invention exhibits good catalytic activity and stability. Compared with Ir supported on a commercial zirconia support with high crystallinity, its overpotential is reduced by about 100mV. With the same Ir loading, the mass activity is increased by about 2.5 times at 1.6V.
[0029] (4) At 10mA / cm 2 Stability tests were conducted at current density. The amorphous zirconia-supported Ir catalyst provided by this invention showed no significant performance degradation within 500 hours, while the potential of the commercially available zirconia-supported Ir catalyst increased rapidly within 100 hours. This indicates that the unique substrate confinement effect of the amorphous support and the enhanced MSI between the amorphous support and the supported Ir clusters effectively achieved a synergistic improvement in catalyst activity and stability. Attached Figure Description
[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying 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:
[0031] Figure 1Transmission electron microscopy (TEM) images and selected area electron diffraction (SED) images of the amorphous zirconia support-supported Ir proton exchange membrane anode catalyst for water electrolysis prepared in Example 1 of this invention;
[0032] Figure 2 The transmission electron microscopy (TEM) elemental distribution scan results of the Ir proton exchange membrane electrolysis anode catalyst supported on an amorphous zirconia support prepared in Example 1 of this invention;
[0033] Figure 3 The X-ray diffraction pattern of the amorphous zirconia support-supported Ir proton exchange membrane anode catalyst for water electrolysis prepared in Example 1 of this invention;
[0034] Figure 4 The amorphous zirconia-supported Ir proton exchange membrane anode catalyst for water electrolysis prepared in Example 1 of this invention, and the highly crystalline zirconia-supported Ir catalyst and iridium oxide catalyst prepared in the same manner, were used in 0.5 mol L... -1 Linear sweep voltammetry curve in sulfuric acid solution (left), Tafel slope curve (right);
[0035] Figure 5 The amorphous zirconia-supported Ir proton exchange membrane anode catalyst for water electrolysis prepared in Example 1 of this invention was used in 0.5 mol L... -1 Chemical impedance spectroscopy in sulfuric acid solution;
[0036] Figure 6 The amorphous zirconia-supported Ir proton exchange membrane anode catalyst for water electrolysis prepared in Example 1 of this invention, and the highly crystalline zirconia-supported Ir catalyst and iridium oxide catalyst prepared in the same manner, were tested at 10 mA cm⁻¹. -2 Chronopotential curves at current density and dissolution curves of the noble metal Ir during a 500-hour test (top right figure). Detailed Implementation
[0037] 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.
[0038] 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.
[0039] Secondly, the term "an 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 throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.
[0040] Unless otherwise specified, all raw materials used in this invention are common commercially available analytical grade chemicals.
[0041] Hydrated iridium chloride, with the chemical formula IrCl3 xH2O, has an Ir content ≥58%.
[0042] Example 1
[0043] This embodiment provides a method for preparing an iridium catalyst supported on an amorphous support, specifically as follows:
[0044] 0.529 g of strontium nitrate was weighed into a polytetrafluoroethylene liner, and 20 mL of approximately 10 M KOH was added and stirred until homogeneous. Then, 0.741 g of zirconium oxychloride octahydrate (i.e., the molar ratio of metallic zirconium salt to metallic strontium salt was 0.92:1) was added. The above raw materials were mixed and stirred for about 12 h. The stainless steel liner was then tightened and placed in an oven for hydrothermal treatment at 180 °C for 24 h, with a heating rate of 4 °C / min. After the reaction was completed, the mixture was washed three times by centrifugation with deionized water and dried in an oven at 55 °C to obtain a white precursor solid SrZrO3 containing zirconium and strontium elements.
[0045] 200 mg of SrZrO3 precursor containing zirconium and strontium and 263 mg of hydrated iridium chloride were dissolved in 20 ml of deionized water (the molar ratio of Zr in the SrZrO3 precursor to Ir in the Ir salt was 1:1). The mixture was ultrasonically dispersed for 1 h and stirred for about 12 h. The mixture was then transferred to a polytetrafluoroethylene (PTFE) liner, and a stainless steel outer liner was screwed on and placed in an oven. The mixture was hydrothermally heated at 150 °C for 12 h at a heating rate of 4 °C / min. After the reaction was complete, the mixture was washed three times with deionized water and dried in an oven at 55 °C to obtain an amorphous zirconium oxide supported catalyst with Ir nanoclusters.
[0046] The Ir proton exchange membrane anode catalyst for water electrolysis supported on the amorphous zirconia support of Example 1 was characterized by transmission electron microscopy, and the results are as follows: Figure 1 As shown, it can be seen that the Ir nanoclusters in the obtained catalyst are dispersed on the surface of the amorphous zirconium oxide support.
[0047] Elemental mapping analysis was performed on the amorphous zirconia-supported Ir proton exchange membrane anode catalyst for water electrolysis in Example 1. The results are as follows: Figure 2 As shown, the catalyst contains Zr, Ir, and O elements simultaneously, confirming the synthesis of the amorphous support and the effective loading of Ir.
[0048] X-ray diffraction characterization was performed on the amorphous zirconia support of Example 1, and the results are as follows: Figure 3 As shown, the prepared carrier has an amorphous structure.
[0049] X-ray diffraction characterization was performed on the amorphous zirconia-supported Ir proton exchange membrane anode catalyst for water electrolysis in Example 1. The results are as follows: Figure 3 As shown, the prepared supported catalyst only showed X-ray diffraction peaks corresponding to elemental Ir, proving the successful loading of Ir and that the support still maintains an amorphous structure.
[0050] The performance of the Ir proton exchange membrane anode catalyst supported on the amorphous zirconia support in Example 1 was tested in a three-electrode system, and the results are as follows: Figure 4 , Figure 5 As shown. The three-electrode system assembled with this catalyst at a catalyst loading of 0.5 mg / cm³ 2 Under these conditions, it reaches 10 mA / cm 2 The catalyst requires a current density of only 264 mV and exhibits high metal utilization and good catalytic activity.
[0051] The stability of the Ir proton exchange membrane anode catalyst for water electrolysis supported on the amorphous zirconia support of Example 1 was tested in a three-electrode system, and the results are as follows: Figure 6 As shown. The catalyst was dropped onto carbon paper at a catalyst loading of 2 mg / cm³. 2 Under the condition of 10 mA / cm 2 The catalyst can operate stably for more than 500 hours at a current density with a voltage decay of about 40mV, indicating that the catalyst exhibits good catalytic stability in the electrolytic cell system.
[0052] Example 2
[0053] The difference between this embodiment and Example 1 is that the molar ratio of Zr element in the precursor SrZrO3 to Ir element in the Ir salt is adjusted to 1.5:1. The rest of the preparation process is the same as in Example 1, and an amorphous zirconia supported catalyst loaded with Ir nanoclusters is obtained.
[0054] Example 3
[0055] The difference between this embodiment and Example 1 is that the molar ratio of Zr element in the precursor SrZrO3 to Ir element in the Ir salt is adjusted to 2:1. The rest of the preparation process is the same as in Example 1, and an amorphous zirconia supported catalyst loaded with Ir nanoclusters is obtained.
[0056] Example 4
[0057] The difference between this embodiment and Example 1 is that the molar ratio of Zr element in the precursor SrZrO3 to Ir element in the Ir salt is adjusted to 0.4:1. The rest of the preparation process is the same as in Example 1, and an amorphous zirconia supported catalyst loaded with Ir nanoclusters is obtained.
[0058] Example 5
[0059] The difference between this embodiment and Example 1 is that the molar ratio of Zr element in the precursor SrZrO3 to Ir element in the Ir salt is adjusted to 0.25:1. The rest of the preparation process is the same as in Example 1, and an amorphous zirconia supported catalyst loaded with Ir nanoclusters is obtained.
[0060] Comparative Example 1
[0061] The difference between this comparative example and Example 1 is that the molar ratio of Zr element in the precursor SrZrO3 to Ir element in the Ir salt is adjusted to 6:1. The rest of the preparation process is the same as in Example 1, and an amorphous zirconium oxide supported catalyst loaded with Ir nanoclusters is obtained.
[0062] The performance of the materials prepared in the above embodiments was tested, and the comparison results with those of Example 1 are shown in Table 1.
[0063] Table 1
[0064] overpotential Stable running time Voltage attenuation Example 1 264mV >500h 40mV Example 2 281mV <400h 50mV Example 3 312mV <200h 60mV Example 4 371mV <200h 70mV Example 5 341mV <200h 70mV Comparative Example 1 414mV <10h 100mV
[0065] As shown in the table above, adjusting the molar ratio of Zr in the precursor SrZrO3 to Ir in the Ir salt significantly affects the performance of the amorphous zirconia-supported catalyst with Ir nanoclusters. This is because after the hydrothermal reaction, a large number of iridium clusters supported on the amorphous support agglomerate, leading to a reduction in the number of active sites, decreasing the intrinsic activity of the noble metal Ir, resulting in poor conductivity of the metal oxide support, and inhibiting the expression of catalyst activity. According to the results in the table above, the optimal technical effect can be obtained when the molar ratio of Zr in the precursor SrZrO3 to Ir in the Ir salt is 1:1.
[0066] Example 6
[0067] The difference between this embodiment and Example 1 is that the temperature of the secondary hydrothermal reaction is adjusted to 110°C, while the rest of the preparation process is the same as in Example 1, resulting in an amorphous zirconia supported catalyst loaded with Ir nanoclusters.
[0068] Example 7
[0069] The difference between this embodiment and Example 1 is that the temperature of the secondary hydrothermal reaction is adjusted to 130°C, while the rest of the preparation process is the same as in Example 1, resulting in an amorphous zirconia-supported catalyst loaded with Ir nanoclusters.
[0070] Example 8
[0071] The difference between this embodiment and Example 1 is that the temperature of the secondary hydrothermal reaction is adjusted to 170°C, while the rest of the preparation process is the same as in Example 1, resulting in an amorphous zirconia supported catalyst loaded with Ir nanoclusters.
[0072] Example 9
[0073] The difference between this embodiment and Example 1 is that the temperature of the secondary hydrothermal reaction is adjusted to 200°C, while the rest of the preparation process is the same as in Example 1, resulting in an amorphous zirconia supported catalyst loaded with Ir nanoclusters.
[0074] The performance of the materials prepared in the above embodiments was tested, and the results compared with those of Example 1 are shown in Table 2.
[0075] Table 2
[0076] overpotential Stable running time Voltage attenuation Example 1 264mV >500h 40mV Example 6 304mV <300h 80mV Example 7 281mV <200h 50mV Example 8 290mV <300h 50mV Example 9 284mV - -
[0077] Note: "-" indicates no data.
[0078] As shown in the table above, adjusting the temperature of the second hydrothermal reaction significantly affects the performance of the amorphous zirconia-supported catalyst with Ir nanoclusters. This is because at lower reaction temperatures, the Sr element in the precursor SrZrO3 is difficult to dissolve, inhibiting the formation of the amorphous zirconia support; at higher reaction temperatures, the formed amorphous zirconia-supported iridium catalyst degrades under high temperature and high pressure reaction conditions, ultimately making it difficult to obtain the target amorphous zirconia-supported iridium catalyst. According to the results in the table above, the optimal technical effect can be obtained when the second hydrothermal reaction temperature in this invention is 150℃.
[0079] Example 10
[0080] The difference between this embodiment and Example 1 is that the iridium salt is changed to potassium hexachloroiridate, while the rest of the preparation process is the same as in Example 1, to obtain an amorphous zirconia supported catalyst with Ir nanoclusters.
[0081] The performance of the materials prepared in the above embodiments was tested, and the results compared with those of Example 1 are shown in Table 2.
[0082] Table 2
[0083] overpotential Stable running time Voltage attenuation Example 1 264mV >500h 40mV Example 10 304mV - -
[0084] Note: "-" indicates no data.
[0085] As shown in the table above, when the iridium salt is hydrated iridium trichloride, the solution exhibits strong acidity. Under these conditions, the precursor SrZrO3 undergoes in-situ dissolution, and the leaching of Sr induces amorphous ZrO. x The formation of the support: When the iridium salt is potassium hexachloroiridate, the solution is neutral. Even with the addition of hydrochloric acid to adjust the pH, the formation of the amorphous support is more difficult, the chloride ion content is higher, and it is easier for the chloride ion to coordinate with Ir, thus inhibiting Ir-ZrO. x Catalyst formation. Therefore, adjusting the type of iridium salt significantly affects the performance of amorphous zirconia-supported catalysts with Ir nanoclusters. In this invention, the best technical effect can be obtained when the iridium salt is hydrated iridium chloride.
[0086] Comparative Example 2
[0087] 109 mg of commercial zirconium dioxide and 132 mg of iridium chloride hydrate were weighed and dissolved in 20 ml of deionized water. The mixture was ultrasonically dispersed for 1 h and stirred at room temperature for about 12 h. The mixture was then transferred to a polytetrafluoroethylene (PTFE) liner, and a stainless steel outer liner was screwed on and placed in an oven. The mixture was hydrothermally heated at 150 °C for 12 h at a heating rate of approximately 4 °C / min. After the reaction was complete, the mixture was washed three times with deionized water and dried in an oven at 55 °C to obtain a highly crystalline zirconium oxide supported catalyst with Ir nanoclusters.
[0088] The activity and stability of the Ir proton exchange membrane anode catalyst supported on the highly crystalline zirconia support of Comparative Example 1 were tested using a three-electrode system. The results are as follows: Figure 4 As shown, it is at 10 mA / cm 2 The overpotential at the current density is 365 mV. The catalyst was dropped onto carbon paper at a catalyst loading of 2 mg / cm³. 2 Under these conditions, the catalyst was tested at 10 mA / cm 2 Stability tests were conducted at current density, and its performance rapidly declined within 100 hours. Compared to Example 1, both activity and stability decreased significantly.
[0089] Comparative Example 3
[0090] 109 mg of commercial zirconium dioxide and 263 mg of iridium chloride hydrate were weighed and dissolved in 20 ml of deionized water. The mixture was ultrasonically dispersed for 1 h and stirred at room temperature for about 5 h. The mixture was then transferred to a polytetrafluoroethylene (PTFE) liner, and a stainless steel outer liner was screwed on and placed in an oven. The mixture was hydrothermally heated at 120 °C for 12 h at a heating rate of approximately 4 °C / min. After the reaction was complete, the mixture was washed three times with deionized water and dried in an oven at 55 °C to obtain a highly crystalline zirconium oxide supported catalyst with Ir nanoclusters.
[0091] The activity and stability of the Ir proton exchange membrane electrolysis anode catalyst supported on the highly crystalline zirconia support of Comparative Example 2 were tested using a three-electrode system. The overpotential of the catalyst at a current density of 10 mA / cm was 314 mV. The stability of the catalyst at a current density of 10 mA / cm was also tested. Its performance rapidly declined within 100 h, similar to Example 6. Compared with Example 1, both the activity and stability decreased significantly.
[0092] Comparative Example 4
[0093] 109 mg of commercial zirconium dioxide and 89 mg of iridium chloride hydrate were weighed and dissolved in 20 ml of deionized water. The mixture was ultrasonically dispersed for 1 h and stirred at room temperature for about 10 h. The mixture was then transferred to a polytetrafluoroethylene (PTFE) liner, and a stainless steel outer liner was screwed on and placed in an oven. The mixture was hydrothermally heated at 170 °C for 12 h at a heating rate of approximately 4 °C / min. After the reaction was complete, the mixture was washed three times with deionized water and dried in an oven at 55 °C to obtain a highly crystalline zirconium dioxide supported catalyst with Ir nanoclusters.
[0094] The activity and stability of the Ir proton exchange membrane electrolysis anode catalyst supported on the highly crystalline zirconia support of Comparative Example 3 were tested using a three-electrode system. The overpotential at a current density of 10 mA / cm was 395 mV. The stability of the catalyst was tested at a current density of 10 mA / cm. Its performance rapidly declined within 100 h. Compared with Example 1, both the activity and stability decreased significantly.
[0095] The performance of the materials prepared in the above comparative example was tested, and the results compared with those of Example 1 are shown in Table 3.
[0096] Table 3
[0097] overpotential Stable running time Voltage attenuation Example 1 264mV ＞500h 40mV Comparative Example 2 365mV ＜150h 30mV Comparative Example 3 314mV ＜150h 30mV Comparative Example 4 395mV ＜150h 30mV
[0098] In summary, addressing the technical problems of low precious metal utilization and poor activity and stability in existing proton exchange membrane water electrolysis anode catalysts, this invention provides an amorphous zirconia-supported Ir catalyst, its preparation method, and its application in a three-electrode system, belonging to the field of catalyst and its preparation technology. Specifically, it includes an amorphous zirconia-supported Ir nanocluster catalyst. This invention first prepares a zirconium-containing precursor via a hydrothermal method, and then prepares an amorphous zirconia catalyst loaded with Ir clusters via a second hydrothermal method. The confinement effect of the amorphous surface of the support ensures that the Ir nanoclusters loaded on the support surface are small in size, improving the utilization rate of precious metals. Furthermore, the enhanced support-metal inter-catalyst effect enables the catalyst to exhibit good activity and stability in a proton exchange membrane water electrolysis hydrogen production device. Transmission electron microscopy and X-ray diffraction spectroscopy characterization show that the support exhibits an amorphous structure. When the anode catalyst is used in a three-electrode system for activity and stability testing, this supported catalyst not only shows high activity but also maintains good stability during long-term testing. Therefore, the amorphous zirconia-supported Ir catalyst has the advantages of high metal utilization and excellent activity and stability during the oxygen evolution test.
[0099] 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 process for the preparation of an amorphous support supported iridium catalyst, characterized by: include, A hydrothermal reaction was carried out between a metallic zirconium salt and a metallic strontium salt to obtain a zirconium-containing precursor, SrZrO3. After washing and drying, the precursor SrZrO3 was stirred with Ir salt in an aqueous solution to obtain a mixed solution; The mixed solution undergoes a secondary hydrothermal reaction to obtain an amorphous supported iridium catalyst. The molar ratio of Zr element in the precursor SrZrO3 to Ir element in the Ir salt is 0.25~2:1; The stirring time is 5~24 h; The secondary hydrothermal reaction is wherein the hydrothermal temperature is 120~200 ºC, the hydrothermal time is 12~36 h, and the heating rate is 3~5℃ / min; The amorphous supported iridium catalyst prepared by the method uses amorphous zirconium oxide as a support, on which Ir clusters are loaded; wherein, the mass ratio of the Ir clusters to the amorphous zirconium oxide support is 0.2~4:
1. The application of the amorphous supported iridium catalyst in the proton exchange membrane water electrolysis reaction is described in a three-electrode system assembled with the amorphous supported iridium catalyst at a catalyst loading of 0.5 mg / cm³. 2 Under these conditions, it reaches 10 mA / cm 2 The current density is <371 mV; At 10 mA / cm 2 Stable operating time at current density >150 h, voltage decay <80 mV.
2. The method for preparing the amorphous supported iridium catalyst as described in claim 1, characterized in that: The zirconium salt includes one or more of zirconium oxychloride octahydrate, zirconium nitrate, and calcium chloride; the strontium salt includes one or more of strontium nitrate, strontium chloride, and strontium acetate.
3. The method for preparing the amorphous supported iridium catalyst as described in claim 1, characterized in that: The molar ratio of the zirconium salt to the strontium salt is 0.5 to 1.5:
1.
4. The method of claim 1, wherein the amorphous support is selected from the group consisting of silica, alumina, titania, zirconia, ceria, and mixtures thereof. The hydrothermal reaction is wherein the hydrothermal temperature is 110~200 ºC, the hydrothermal time is 12~36 h, and the heating rate is 3~5℃ / min.
5. The method for preparing the amorphous supported iridium catalyst as described in claim 1, characterized in that: The Ir salt includes one or more of the following: iridium chloroiridium, iridium chloride, iridium acetylacetonate, iridium acetate, potassium iridium chloroiridium, sodium iridium chloroiridium, iridium oxide, strontium iridium, barium iridium, lithium iridium, potassium iridium, or praseodymium iridium.