Local amorphous porous iridium oxide and its preparation and application in OER catalysis

Abstract

The present invention belongs to the field of electrode materials for electrolytic water hydrogen production, and specifically relates to locally amorphous porous iridium oxide, its preparation and application in OER catalysis. Among them, the preparation method of the locally amorphous porous iridium oxide is as follows: A mixed raw material of an iridium source, an organic-inorganic synergistic regulator, and a sodium-based composite salt is subjected to calcination treatment, and then subjected to rapid quenching treatment to obtain the locally amorphous porous iridium oxide; the organic-inorganic synergistic regulator includes La inorganic matter and an organic matter of formula 1 () with a weight ratio of 1 to 10:10 to 50; the sodium-based composite salt includes sodium nitrate and sodium chloride; in formula 1, R is H, an alkyl group or a substituted alkyl group. The material prepared by the preparation method of the present invention has excellent performance under high temperature conditions and can operate stably under frequent start-stop and large current conditions.

Description

Technical Field

[0001] The present invention belongs to the field of catalytic materials, and particularly relates to the field of OER catalysis. Background Art

[0002] With the global energy structure transforming towards green and low-carbon, proton exchange membrane water electrolysis for hydrogen production (PEMWE) technology has become one of the core research directions in the hydrogen energy field due to its high efficiency, rapid response, and cleanliness. However, the high overpotential of the oxygen evolution reaction (OER) at the anode of water electrolysis and the insufficient stability of the catalyst are still the key bottlenecks restricting its large-scale application. Currently, iridium oxide (IrO2) is regarded as an ideal OER catalyst due to its excellent catalytic activity and stability in acidic environments, but problems such as its high cost, low atomic utilization rate, and limited active sites caused by its crystal phase structure need to be urgently solved. Therefore, modifying iridium oxide to improve its catalytic activity and realizing its application in proton exchange membrane electrolyzers is of great significance.

[0003] Currently, most commercial iridium-based catalyst materials are rutile-phase crystalline iridium dioxide prepared by the Adams method, which are large in size, prone to agglomeration, and have a small number of active sites. Moreover, the proton exchange membrane (PEM) prepared using commercial iridium dioxide catalysts has insufficient activity, resulting in a high iridium loading in the electrolyzer.

[0004] In response to the problems faced by iridium-based catalyst materials, some optimization schemes such as doping and structural modification have also been proposed in the prior art. For example, the Chinese patent document with the publication number CN116463672A discloses a phosphorus-doped iridium dioxide and its preparation method and application. Another example is that the Chinese patent document with the publication number CN109107570A discloses a scheme for an SrIrO3 catalyst with high OER catalytic performance.

[0005] In summary, although the existing doping processes can optimize the iridium lattice and help improve performance and reduce costs, the existing materials mainly consist of crystalline phases. The crystalline phase IrO2 has a stable crystal structure and can operate stably under high currents, but the crystalline phase IrO2 has low activity due to insufficient active sites. And amorphizing the crystalline phase IrO2 through the existing structural modification processes will result in the amorphous morphology of the amorphous phase being prone to dissolution and structural collapse under high-temperature conditions with frequent start-stop and high-current conditions, leading to performance degradation and being unable to adapt to high-density current operation and frequent start-stop under industrial conditions. Therefore, designing a local amorphous porous iridium oxide with a crystalline phase forming a skeleton to support the amorphous phase is of profound significance for realizing the industrial application of PEM water electrolysis. Summary of the Invention

[0006] Aiming at the problem of unsatisfactory catalytic activity of existing iridium oxides, the first object of the present invention is to provide a preparation method of locally amorphous porous iridium oxides, aiming to prepare an OER catalytic active material with local amorphousness and excellent activity.

[0007] The second object of the present invention is to provide the locally amorphous porous iridium oxides prepared by the above preparation method and their application in OER catalysis.

[0008] The third object of the present invention is to provide a device containing the locally amorphous porous iridium oxides.

[0009] Most of the iridium oxides synthesized by the prior art are rutile-phase iridium dioxide crystal materials, which also have deficiencies such as a small number of active sites and low mass activity. For the amorphous modification of iridium oxides in the prior art, dissolution and structural collapse are likely to occur under frequent start-stop and high-current conditions, resulting in performance degradation. And under industrial conditions, the working temperature is usually ≥60°C, and the iridium oxides synthesized by the prior art will be deactivated more rapidly under high-temperature conditions. In view of this problem, through in-depth research, the present invention provides the following improvement solutions:

[0010] A preparation method of locally amorphous porous iridium oxides, comprising calcining a mixed raw material of an iridium source, an organic-inorganic synergistic regulator (also simply referred to as a synergistic regulator or a regulator in the present invention), and a sodium-based composite salt, and then performing a rapid cooling treatment to obtain the locally amorphous porous iridium oxides.

[0011] The organic-inorganic synergistic regulator includes La inorganic substances and organic substances of formula 1 with a weight ratio of 1~10:10~50; the sodium-based composite salt includes sodium nitrate and sodium chloride.

[0012] Formula 1

[0013] In formula 1, R is H, an alkyl group or a substituted alkyl group with C1~C6; the substituted alkyl group is a group with at least one substituent selected from mercapto, hydroxyl, carboxyl, amino, imino, thiophene group, and pyranyl group on the alkyl group with C1~C6.

[0014] The present invention innovatively uses the organic-inorganic regulator and the sodium-based composite salt to jointly assist the calcination treatment of the iridium source, and further cooperates with the rapid cooling treatment. In this way, synergy can be unexpectedly achieved, which can effectively regulate the physical and chemical structure of iridium oxides, and a material with a brand-new physical and chemical structure with a rutile-phase oxide as a porous skeleton and an amorphous component in-situ grown on the surface can be prepared. Research shows that the material with the characteristics prepared by the preparation method of the present invention has good conductivity, its mass activity in a three-electrode system is better than that of the existing IrO2 catalyst, it has excellent performance under high-temperature conditions, and it can operate stably under frequent start-stop and high-current conditions.

[0015] In the present invention, the iridium source includes at least one of iridium chlorate, iridium trichloride, and iridium acetylacetonate.

[0016] In the present invention, the organic-inorganic synergistic regulator with the described ratio is innovatively adopted, which can help regulate the crystal and amorphous morphologies of iridium oxide, and improve the crystal framework support structure and the morphology and bonding interface of locally grown amorphous. In addition, combining it with the sodium-based composite salt of the described components helps to further optimize the composite interface and distribution effect between the amorphous and the crystal.

[0017] Among the organic-inorganic synergistic regulators, the La inorganic substance includes at least one of lanthanum nitrate, lanthanum chloride, lanthanum acetate, lanthanum sulfate, and lanthanum bromide.

[0018] In Formula 1, R is H or a substituted alkyl group, and the substituted alkyl group is a substituted alkyl group with at least one substituent of mercapto or carboxyl on the alkyl carbon chain of C1-C6.

[0019] Preferably, Formula 1 includes at least one of Formula 1a and Formula 1b. Among them, Formula 1a is a compound of Formula 1 in which R is a mercapto-substituted alkyl group. Formula 1b is a compound of Formula 1 in which R is a carboxyl-substituted alkyl group. The mercapto-substituted alkyl group is, for example, a compound with a mercapto substituent on the alkyl group of C1-C6. The carboxyl-substituted alkyl group is, for example, a compound with a carboxyl substituent on the alkyl group of C1-C6.

[0020] Research in the present invention shows that combining Formula 1a with other components and preparation processes of the present invention helps to further facilitate the preparation of the crystal-amorphous material and helps to improve the start-stop and high-temperature stability of the prepared material.

[0021] More preferably, Formula 1 includes Formula 1a and Formula 1b with a weight ratio of 1:0.5-2.

[0022] Research in the present invention also shows that adopting the combined Formula 1 can further optimize the physical and chemical structure of the prepared material and helps to further improve the start-stop and high-temperature stability of the prepared material.

[0023] Preferably, in the organic-inorganic synergistic regulator, the weight ratio of the La inorganic substance to the organic substance of Formula 1 is 1:3-6. Research shows that at this preferred ratio, it helps to further strengthen the synergistic effect of the organic-inorganic synergistic regulator in constructing the crystal-amorphous, and helps to further strengthen the high-temperature stability and start-stop stability of the material.

[0024] In the present invention, in the sodium-based composite salt, the weight ratio of sodium nitrate to sodium chloride is 60-100:10-40; further, it can be 8-9.5:1.

[0025] In the present invention, the weight ratio of the iridium source, the organic-inorganic synergistic regulator, and the sodium-based composite salt is 5 to 20:5 to 20:100 to 300; further, it can be 8 to 12:5 to 15:200.

[0026] In the present invention, the mixed raw materials can be obtained by mixing the respective raw materials in solid phase or liquid phase. For example, as an alternative solution, the iridium source, the organic-inorganic synergistic regulator, and the sodium-based composite salt are mixed in liquid phase and the pH is adjusted to 7 ± 0.5, followed by desolvation treatment to obtain the mixed raw materials. Research in the present invention shows that by adopting this liquid-phase mixing method, the synergy between components can be further enhanced, which helps to further improve the prepared local amorphous porous iridium oxide and helps to improve the high-temperature and start-stop stability of the material.

[0027] In the present invention, the atmosphere in the calcination stage is an oxygen-containing atmosphere. The oxygen-containing atmosphere can be, for example, oxygen, a mixed gas of oxygen and an inert gas, or can be air.

[0028] In the present invention, the calcination temperature is 300 to 550 °C; further, it can be 400 to 500 °C, and more preferably 420 to 460 °C. Research shows that at the preferred calcination temperature, it is further beneficial for the preparation of the crystal-amorphous material and helps to improve the high-temperature and start-stop stability of the prepared material.

[0029] In the present invention, the calcination time is 0.5 to 4 h; further, it can be 1 to 2 h.

[0030] In the present invention, innovatively, the calcination product assisted by the organic-inorganic synergistic regulator and the sodium-based composite salt is subjected to rapid cooling treatment, which helps to further optimize the amorphous-crystal composite interface and helps to improve the stability and performance of the material.

[0031] In the present invention, the calcined product can be brought into contact with a cooling medium while it is hot to achieve rapid cooling treatment. In the present invention, as an implementable solution, the temperature difference when the calcined product contacts the cooling medium can be more than 200 °C. In addition, the calcined product can be directly brought into contact with the cooling medium, or the heat-conducting container loaded with the calcined product can be directly brought into contact with the cooling medium while it is hot.

[0032] In the present invention, the medium for rapid cooling treatment is at least one of a solid, a liquid, or a gas with a temperature lower than 50 °C. For example, considering cost, the cooling medium can be water. In addition, cold gas can also be introduced for gas cooling.

[0033] The present invention also provides a local amorphous porous iridium oxide prepared by the above preparation method, which includes rutile-phase iridium dioxide and locally grown amorphous-phase iridium dioxide supported by the rutile-phase iridium dioxide as a framework.

[0034] The preparation method described in the present invention can produce a material with completely new physical and chemical characteristics, and the material with such characteristics prepared by the preparation method can unexpectedly and effectively improve the performance of iridium oxide.

[0035] The present invention also provides an application of the locally amorphous porous iridium oxide prepared by the preparation method as an OER catalytic material. In the present invention, based on the good OER performance of the material, a device for electrolyzing water can be prepared based on this.

[0036] The present invention also provides an OER catalytic device, which comprises the locally amorphous porous iridium oxide prepared by the preparation method, or is prepared from the locally amorphous porous iridium oxide.

[0037] The OER catalytic device described in the present invention can be, for example, a conventional device for producing hydrogen by electrolyzing water, and further can be a device for producing hydrogen by electrolyzing water with a proton exchange membrane.

[0038] Beneficial effects

[0039] The present invention innovatively uses the organic-inorganic regulator and sodium-based composite salt in combination for the roasting of the iridium source, and further cooperates with rapid cooling treatment, which helps to prepare an iridium oxide with a rutile phase-amorphous composite phase.

[0040] The preparation method described in the present invention can prepare an iridium oxide with a completely new physical and chemical structure, and the iridium oxide with such characteristics prepared by the preparation method can unexpectedly take into account excellent OER performance. For example, this material has excellent performance under high-temperature conditions and can operate stably under conditions of frequent start-stop and large current. Description of the drawings

[0041] Figure 1 TEM images of the catalyst prepared in Example 1, where (a) is a low-resolution transmission electron microscopy image; (b) is a high-resolution transmission electron microscopy image;

[0042] Figure 2 Transmission electron microscopy images of the material prepared in Comparative Example 1, where (a) is a low-resolution transmission electron microscopy image; (b) is a high-resolution transmission electron microscopy image;

[0043] Figure 3 X-ray diffraction patterns of the iridium oxide nanomaterials prepared in Example 1, Example 2-D, and Comparative Example 1;

[0044] Figure 4 Three-electrode system performance diagrams of the iridium oxide nanomaterials prepared in some cases and Comparative Example 1;

[0045] Figure 5 Stability test diagrams of the three-electrode systems of Example 1, Comparative Example 1, and commercial IrO2;

[0046] Figure 6 Performance graphs of the iridium oxide catalysts prepared in Example 1 and Comparative Example 1 for PEM electrolysis devices; wherein, (a) is a graph showing the relationship between voltage and current of the iridium oxide catalysts prepared in Example 1 and Comparative Example 1 for PEM electrolysis devices; (b) is a graph showing the decomposition of the polarization voltage loss of the iridium oxide catalyst prepared in Example 1 for PEM electrolysis devices; (c) is a graph comparing the overpotential losses of the iridium oxide catalysts prepared in Example 1 and Comparative Example 1 for PEM electrolysis devices; (d) is a graph showing the stability test of the iridium oxide catalyst prepared in Example 1 for PEM electrolysis devices. Detailed implementation manners

[0047] The following specific examples are intended to further illustrate the content of the present invention in detail, rather than further limiting the protection scope of the claims of the present invention.

[0048] The reagents involved in the following examples are commercial reagent products directly purchased from the market if not otherwise specified.

[0049] Example 1

[0050] Step 1: Weigh 0.1 g of iridium source (iridium trichloride hydrate), dissolve 2 g of sodium-based composite salt (including 1.8 g of sodium nitrate and 0.2 g of sodium chloride) in 5 ml of water, stir for 10 min, ultrasonicate for 15 min, add 59 mg of co-regulator (including 50 mg of Formula 1 (in this case, Formula 1A, whose structure is ), and 9 mg of lanthanum nitrate), ultrasonicate again for 15 min, adjust the pH of the solution to 7 with sodium hydroxide to obtain Solution A. Transfer the final Solution A to a glass test tube and evaporate it to dryness at 110 °C (marked as T1) for 12 hours. After cooling to room temperature, collect the product and ball mill it for 30 min to collect the mixture;

[0051] Step 2:

[0052] Calcine the mixture in a muffle furnace in an air atmosphere at 450 °C for 1 h. Place the crucible containing the mixed melt obtained after firing in the muffle furnace at the bottom into water at 5 - 15 °C for rapid quenching treatment until the melt crystallizes into a block. Wash the obtained crystalline product with water and ethanol multiple times and then dry it to obtain a partially amorphous porous iridium oxide catalyst (also referred to as the catalyst).

[0053] The TEM of the prepared catalyst is shown in Figure 1 , Figure 1 It can be seen from (a) of Figure 1 that the prepared catalyst has a porous morphology, and it can be seen from the high-resolution TEM of (b) of

[0054] The XRD of the prepared catalyst is shown in Figure 3 , and it can be seen that the prepared catalyst is composed of rutile-phase IrO2 and amorphous-phase IrOx.

[0055] Test:

[0056] I. Electrochemical detection

[0057] The prepared catalyst was used for the oxygen evolution reaction in an acidic environment. A three-electrode test system was adopted, with a Pt sheet as the counter electrode and a saturated calomel electrode as the reference electrode; 2 mg of the catalyst was weighed and dispersed in a mixed solvent of 400 μL of water and ethanol (vwater: vethanol = 1:3), and ultrasonic treatment was carried out to obtain a uniformly dispersed slurry. A certain amount of the slurry was evenly dropped on the surface of a 5 mm glassy carbon electrode as the working electrode, and the loading was 0.25 mg / cm 2 , for testing. 0.5 M sulfuric acid solution was selected as the electrolyte, and linear sweep voltammetry was used to test the electrochemical data. The scanning rate was 5 mV / s. At 60°, the long-term stability of the OER reaction was tested at a current density of 10 mA / cm 2 . The results of the electrochemical detection are shown in Figures 4 to 5 .

[0058] In order to detect the performance of the catalyst and simulate industrial production conditions, the anodic current was tested at 60 °C, and it was restarted after pausing for 1 h every 24 h. After testing for 100 h, the test results of the activity decay rate are shown in Table 1 and Table 2.

[0059] II. Preparation of membrane electrode and PEM test

[0060] The prepared catalyst was sprayed on the surface of the Nifion115 membrane as the anode catalyst, and 60% commercial Pt / C was used as the cathode. 20 mg of the prepared catalyst was weighed and dispersed in a mixed solution containing 1 ml of 5% Nifion solution and 1 ml of isopropanol, and the mixture was stirred evenly for 30 min using a mixing stirrer. Subsequently, 1 ml of isopropanol was added to the mixed solution and stirred evenly again for 30 min using the mixing stirrer. The slurry was washed out with a mixed solution of 1 ml of water and 1 ml of isopropanol and ultrasonicated for 30 min to be evenly dispersed. The slurry was sprayed on the anode side of the Nifion115 membrane using a manual spray gun, and the catalyst loading was 1 mg / cm 2 . The prepared membrane electrode was assembled into a PEM, and the electrochemical data was tested after activation for 1 h at a current density of 1 A / cm 2 . After the temperature was raised to 60 °C, the stable performance of the catalyst was measured at a current density of 1 A / cm 2 . The test results of the electrolyzed water performance of the material are shown in Figure 6 .

[0061] Example 2

[0062] Compared with Example 1, the only difference is that the type and composition of the co-regulator are changed. The experimental groups are as follows:

[0063] Group A: Using Formula 1B ( ) as Formula 1;

[0064] Group B: Using Formula 1C ( ) as Formula 1;

[0065] Group C: Replacing the lanthanum nitrate with lanthanum chloride;

[0066] Group D: Controlling the weight ratio of Formula 1 to lanthanum nitrate to be 10:3;

[0067] Other operations and parameters are the same as those in Example 1.

[0068] Example 3

[0069] Compared with Example 1, the only difference is the conditions in Step 1. The experimental groups are as follows:

[0070] Group A: Changing the proportion of the sodium-based composite salt and the weight ratio of Ir, co-regulator and sodium-based composite salt (weight ratio of sodium nitrate to sodium chloride is 8.5:1) to 8:12:200;

[0071] Group B: Conducting conventional solid-phase grinding on the iridium source, co-regulator and sodium-based composite salt to obtain a mixture.

[0072] Other operations and parameters are the same as those in Example 1.

[0073] Example 4

[0074] Compared with Example 1, the only difference is that the calcination temperature in Step 2 is changed to 500 °C and the calcination time is 1.5 h. Other operations and parameters are the same as those in Example 1.

[0075] Example 5

[0076] Compared with Example 1, the only difference is that after the calcination is completed, air cooling treatment (air-based rapid cooling) is carried out through normal-temperature air. Other operations and parameters are the same as those in Example 1.

[0077] Comparative Example 1

[0078] Compared with Example 1, the only difference is that no co-regulator is added. Other operations and parameters are the same as those in Example 1. The TEM and XRD of the material are shown in Figure 2 and Figure 3 .

[0079] It can be seen from the TEM images that the catalyst synthesized without adding the co - regulator has an aggregated particulate morphology. The results of XRD show that the catalyst synthesized in Comparative Example 1 is rutile - phase IrO₂.

[0080] Comparative Example 2

[0081] Compared with Example 1, the only difference is that in the co - regulator, lanthanum nitrate is not added, and the total amount of the co - regulator and other operations and parameters are the same as those in Example 1.

[0082] Comparative Example 3

[0083] Compared with Example 1, the only difference is that in the co - regulator, Comparative Formula A ( ) is used to replace Formula 1, and other operations and parameters are the same as those in Example 1.

[0084] Comparative Example 4

[0085] Compared with Example 1, the only difference is that in the co - regulator, Comparative Formula B ( ) is used to replace Formula 1, and other operations and parameters are the same as those in Example 1.

[0086] Comparative Example 5

[0087] Compared with Example 1, the only difference is that in the co - regulator, the ratio of Formula 1 to lanthanum nitrate is 1:3, and the total amount of the co - regulator and other operations and parameters are the same as those in Example 1.

[0088] Comparative Example 6

[0089] Compared with Example 1, the only difference is that in the co - regulator, cobalt nitrate is used to replace lanthanum nitrate, and the total amount of the co - regulator and other operations and parameters are the same as those in Example 1.

[0090] Comparative Example 7

[0091] Compared with Example 1, the only difference is that the sodium - based composite salt is not added, and other operations and parameters are the same as those in Example 1.

[0092] Comparative Example 8

[0093] Compared with Example 1, the only difference is that a single sodium nitrate is used to replace the sodium - based composite salt, and the dosage of the sodium - based composite salt and other operations and parameters are the same as those in Example 1.

[0094] Comparative Example 9

[0095] Compared with Example 1, the only difference is that a single sodium chloride is used to replace the sodium - based composite salt, and the dosage of the sodium - based composite salt and other operations and parameters are the same as those in Example 1.

[0096] Comparative Example 10

[0097] Compared with Example 1, the difference is only that after the calcination is completed, it is cooled with the furnace (slow cooling), and other operations and parameters are the same as those in Example 1.

[0098] The calculation results of the overpotential of the catalysts prepared in each example and each comparative example at a constant temperature of 60 °C and the activity decay rate after 100 h of start-stop test every 24 h are listed in Tables 1 and 2.

[0099]

[0100]

[0101] It can be seen from Example 1 and Comparative Examples 1-10 in Tables 1 and 2 that the combined use of the organic-inorganic regulator and the sodium-based composite salt in the calcination of the iridium source, further combined with the quenching treatment, helps to prepare an iridium oxide with a rutile phase-amorphous composite phase.

[0102] It can be seen from Example 1 and Example 2 that using Formula 1A as Formula 1 can be combined with the process of the present invention, and better synergy can be obtained, which helps to further improve the frequent start-stop and high-temperature stability of the battery.

[0103] It can be seen from Example 1 and Example 3 that using the liquid-phase mixing process described in the present invention helps to further optimize the component and process synergy, and helps to further improve the frequent start-stop and high-temperature stability of the battery.

Claims

1. A preparation method of a local amorphous porous iridium oxide, characterized in that, A mixed raw material of an iridium source, an organic-inorganic synergistic regulator, and a sodium-based composite salt is subjected to calcination treatment, and then quenching treatment is carried out to obtain the local amorphous porous iridium oxide; The organic-inorganic synergistic regulator includes La inorganic substances and an organic substance of Formula 1 with a weight ratio of 1-10:10-50; the sodium-based composite salt includes sodium nitrate and sodium chloride; the La inorganic substances include at least one of lanthanum nitrate, lanthanum chloride, lanthanum acetate, lanthanum sulfate, and lanthanum bromide; Formula 1 In Formula 1, R is H, an alkyl or substituted alkyl of C1-C6; the substituted alkyl is a group with at least one substituent selected from mercapto, hydroxyl, carboxyl, amino, thiophene, and pyranyl on the alkyl of C1-C6.

2. The preparation method of the local amorphous porous iridium oxide according to claim 1, characterized in that, The iridium source includes at least one of chloroiridic acid, iridium trichloride, and iridium acetylacetonate.

3. The preparation method of the local amorphous porous iridium oxide according to claim 1, characterized in that, In the said Formula 1, R is H or a substituted alkyl, and the substituted alkyl is a substituted alkyl with at least one substituent selected from mercapto and carboxyl on the alkyl carbon chain of C1-C6.

4. The preparation method of the local amorphous porous iridium oxide according to claim 1, characterized in that, In the sodium-based composite salt, the weight ratio of sodium nitrate to sodium chloride is 60-100:10-40.

5. The preparation method of the local amorphous porous iridium oxide according to any one of claims 1 to 4, characterized in that, The iridium source, the organic-inorganic synergistic regulator, and the sodium-based composite salt are mixed in liquid phase and the pH is adjusted to 7±0.5, and then desolvation treatment is carried out to obtain the mixed raw material; The weight ratio of the iridium source, the organic-inorganic synergistic regulator, and the sodium-based composite salt is 5-20:5-20:100-300.

6. The preparation method of the local amorphous porous iridium oxide according to claim 1, characterized in that, The atmosphere in the calcination stage is an oxygen-containing atmosphere; The calcination temperature is 300-550°C; The calcination time is 0.5-4 h.

7. The preparation method of the local amorphous porous iridium oxide according to claim 1, wherein, The medium for quenching treatment is at least one of a solid, a liquid, or a gas with a temperature lower than 50°C.

8. A local amorphous porous iridium oxide prepared by the preparation method according to any one of claims 1 to 7, characterized in that, It includes rutile-phase iridium dioxide and locally grown amorphous-phase iridium dioxide supported by the rutile-phase iridium dioxide as a framework.

9. Use of the locally amorphous porous iridium oxide prepared by the preparation method according to any one of claims 1 to 7, characterized in that, Use it as an OER catalytic material.

10. An OER catalytic device, characterized in that, It includes the local amorphous porous iridium oxide prepared by the preparation method according to any one of claims 1-7, or is prepared from the said local amorphous porous iridium oxide.

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