Rapid preparation of short-range ordered iridium oxide by a mixed molten salt method for PEM water electrolysis

Abstract

The present invention discloses a method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method for PEM water electrolysis, belonging to the technical field of catalytic material preparation. This method can prepare short-range ordered iridium oxide within 20 minutes to 2 hours. By introducing a high-melting-point mixed molten salt as a reaction medium, the iridium salt is uniformly dispersed, effectively reducing agglomeration and improving the preparation efficiency; no morphology control template is required, simplifying the process and reducing costs; by adjusting the reaction parameters, the morphology and size of iridium oxide can be flexibly controlled, and the particle size of a single nanocrystal is 1.7 - 2.7 nm, forming a short-range ordered structure. This short-range ordered iridium oxide provides more active sites, enhances the structural stability, has good dispersibility, can be directly used as a catalyst slurry, and achieves high catalytic activity at an extremely low loading; when applied as a catalytic material for the anode of proton exchange membrane water electrolysis to produce hydrogen, it reduces the catalyst cost, improves the energy conversion efficiency, the electrolytic cell reaches a high current density at a lower voltage, and the performance is stable, which helps to promote the development of the green hydrogen economy.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalytic material preparation, and specifically relates to the rapid preparation of short-range ordered iridium oxide by a mixed molten salt method for PEM water electrolysis. Background Art

[0002] Proton exchange membrane (PEM) water electrolysis for hydrogen production technology is an efficient and environmentally friendly hydrogen production method. It uses a proton exchange membrane as an electrolyte and generates hydrogen and oxygen by electrolyzing water, and has broad application prospects in many fields such as renewable energy hydrogen production, energy storage, and transportation. In the proton exchange membrane (PEM) water electrolysis for hydrogen production technology, the efficiency and stability of the PEM water electrolysis for hydrogen production technology largely depend on the anode catalytic material of the electrolytic cell. The anode catalytic material needs to have excellent catalytic activity, outstanding stability, and excellent conductivity in order to effectively reduce the electrolysis energy consumption and improve the hydrogen production rate. Rutile-type iridium dioxide (IrO2) is the current commercial acidic oxygen evolution catalyst. Although it meets the requirements of PEM water electrolysis for hydrogen production to a certain extent, its preparation methods such as chemical vapor deposition (CVD), sol-gel method, and hydrothermal synthesis method have problems such as long preparation cycle, high energy consumption, and low product order, which limit its application in industrial production; although the IrO2 obtained by the existing preparation methods has certain catalytic activity, its performance is still not ideal and it is difficult to meet the growing demand for energy conversion efficiency. Therefore, developing new and efficient preparation methods for iridium oxide and exploring anode catalytic materials with better performance have become important research directions in the current PEM water electrolysis for hydrogen production technology.

[0003] In order to improve the catalytic activity, researchers have developed many new iridium-based oxide catalysts, including layered iridium-based oxides, amorphous iridium oxides (IrOx), and composite metal oxides. These new catalysts show higher intrinsic activity than IrO2 under laboratory conditions, bringing new hope to the PEM water electrolysis for hydrogen production technology. However, although the new iridium-based oxide catalysts perform well under laboratory conditions, they still face many challenges in practical applications. During the acidic oxygen evolution process, iridium ions in the iridium-based oxide catalyst are prone to desolvation, resulting in the destruction of the catalyst structure and the decline of performance; during long-term operation, its structure is prone to change, resulting in a rapid decline in catalytic activity. This instability limits the commercial application of the catalyst; although iridium oxide itself has certain conductivity, the conductivity of some iridium-based oxide catalysts is poor, affecting the electron transfer efficiency on the catalyst surface, thereby reducing the catalytic reaction rate and unable to meet the requirements of efficient water electrolysis for hydrogen production. These problems seriously limit the wide application of iridium-based oxide catalysts in the PEM water electrolysis for hydrogen production technology. Summary of the Invention

[0004] In view of the problems of low preparation efficiency of existing iridium-based oxide catalysts, insufficient stability and high oxidation overpotential of iridium-based oxides during the acidic oxygen evolution reaction (OER), the purpose of the present invention is to provide a method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method for PEM water electrolysis, and rapidly preparing short-range ordered iridium oxide by the mixed molten salt method.

[0005] To achieve the above object, the present invention is implemented by the following technical solutions:

[0006] The present invention provides a method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method, including:

[0007] Step 1: Add an iridium source precursor to the molten composite salt, mix, and then cool to obtain solid particles;

[0008] The molten composite salt is a molten composite salt of sodium carbonate and sodium nitrate;

[0009] Step 2: Wash and dry the solid particles obtained in Step 1 to obtain short-range ordered iridium oxide;

[0010] The particle size of the short-range ordered iridium oxide particles is 1.7 nm to 2.7 nm.

[0011] The molten composite salt is obtained by mixing and calcining sodium carbonate and sodium nitrate, and the mass ratio of sodium carbonate to sodium nitrate is 1:1 to 49.

[0012] Further, the mass ratio of sodium carbonate to sodium nitrate is 1:24 to 49.

[0013] The calcination temperature is 360 °C to 500 °C, and the calcination time is 20 min to 2 h.

[0014] Further, the calcination temperature is 360 °C to 450 °C, and the calcination time is 20 min to 1 h.

[0015] The iridium source precursor is any one of iridium trichloride hydrate, iridium trichloride, and iridium dioxide.

[0016] Further, the iridium source precursor is iridium trichloride hydrate.

[0017] The mass ratio of the iridium source precursor to the molten composite salt is 1:100 to 150.

[0018] Further, the mass ratio of the iridium source precursor to the molten composite salt is 1:125.

[0019] In Step 2, the drying is vacuum drying at 50 °C to 100 °C.

[0020] The short-range ordered iridium oxide obtained by the above method.

[0021] Use of the above-mentioned short-range ordered iridium oxide in preparing an anode catalytic material for hydrogen production by proton exchange membrane electrolysis of water.

[0022] The present invention provides a proton exchange membrane electrolysis water hydrogen production anode, comprising an anode carrier and an anode catalytic material loaded thereon, wherein the anode catalytic material is the above-mentioned short-range ordered iridium oxide.

[0023] The present invention provides a method for hydrogen production by proton exchange membrane electrolysis of water, using the above-mentioned proton exchange membrane electrolysis water hydrogen production anode, using a 0.1 M HClO4 solution as an electrolyte, and using a platinum mesh and an Ag / AgCl electrode as a counter electrode and a reference electrode, respectively.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The method for rapidly preparing short-range ordered iridium oxide by the mixed molten salt method provided by the present invention promotes the uniform dispersion of the iridium source in the reaction system by introducing a high-melting-point molten composite salt as a reaction medium, thereby effectively reducing the agglomeration phenomenon of the generated iridium oxide, making the product more uniform and delicate. The whole process can form a short-range ordered structure in only 20 min to 2 h, significantly improving the preparation efficiency and greatly reducing the preparation difficulty. The method of the present invention does not require the use of a morphology control template, simplifies the preparation process, and reduces the production cost. By adjusting the reaction temperature, time, and the amount of molten salt, the morphology and size of iridium oxide can be flexibly controlled, and the specific requirements of iridium oxide particles for different application scenarios can be met. The obtained short-range ordered iridium oxide particles have a particle size of 1.7 to 2.7 nm and form a short-range ordered structure, which is beneficial to improving its catalytic activity. The short-range ordered iridium oxide has excellent catalytic activity, stability, and electrical conductivity, making it have a broad application prospect in catalytic fields such as proton exchange membrane electrolysis water hydrogen production.

[0026] The short-range ordered iridium oxide obtained by the preparation method of the present invention has a short-range ordered structure that is beneficial to electron transport and the exposure of catalytic active sites. Compared with traditional disordered or low-ordered iridium oxide, the short-range ordered structure can provide more effective catalytic active sites, thereby improving catalytic activity; during the acidic oxygen evolution process, the ordered crystal structure can better resist the desolvation of iridium ions, reduce the destruction of the catalyst structure, and thus extend the service life of the catalyst, enhancing the structural stability of the catalyst; in the environment of PEM electrolytic water hydrogen production, the short-range ordered iridium oxide has stronger corrosion resistance, reducing the performance degradation of the catalyst caused by corrosion. The short-range ordered iridium oxide nanoparticles of the present invention have a particle size range of 1.7 - 2.7 nm, with good dispersibility, and can be directly used as a catalyst slurry for catalytic reactions. Compared with ordinary bulk catalysts, it can achieve high catalytic activity at extremely low loading amounts; it has good catalytic activity and stability. The catalyst exhibits a low overpotential of only 186 - 204 mV at a current density of 10 mA cm -2 and shows excellent stability in the durability test of 590 - 600 hours, having great commercial application potential.

[0027] The application of the short-range ordered iridium oxide provided by the present invention in the preparation of proton exchange membrane electrolytic water hydrogen production anode catalytic materials reduces the use cost of the catalyst, improves the energy conversion efficiency, and promotes the commercialization process of this technology; a proton exchange membrane electrolytic cell with short-range ordered iridium oxide as the anode catalyst can reach a relatively high current density at a lower voltage (showing a low overpotential of 186 - 204 mV at a current density of 10 mA cm -2 ), and the performance shows no obvious decline after running for 590 - 600 hours. This excellent catalytic performance makes the proton exchange membrane electrolytic water hydrogen production technology more competitive and helps to promote the development of the green hydrogen economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the X-ray diffraction (XRD) pattern of the short-range ordered iridium oxide of the present invention;

[0029] Figure 2 is the microscopic morphology diagram of the short-range ordered iridium oxide of the present invention. Among them, (a) is the scanning electron microscope image, and (b) is the transmission electron microscope image;

[0030] Figure 3 is the OER polarization curve and stability curve of the short-range ordered iridium oxide of the present invention in 0.1 M HClO4 solution. Among them, (a) is the OER polarization curve, and (b) is the stability curve at a constant current density of 10 mA cm -2 . DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition only for the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meanings understood by those skilled in the art for the present invention. In case of conflicts, the definitions in this specification shall prevail.

[0032] Definition and Explanation:

[0033] Overpotential: An important indicator for measuring the oxygen evolution reaction activity of a catalyst. The lower the overpotential, the higher the oxygen evolution reaction activity of the catalyst.

[0034] Example 1

[0035] This example provides a method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method, which specifically includes the following steps:

[0036] (1) Preparation of molten composite salt

[0037] Weigh 0.1 g of sodium carbonate and 4.9 g of sodium nitrate solids, mix them evenly, and place them in a muffle furnace at 360 °C. The heating program of the muffle furnace is as follows: the heating rate is 20 °C / min, and keep warm for 20 min to obtain a uniform molten composite salt.

[0038] (2) Preparation of short-range ordered iridium oxide

[0039] Weigh 40 mg of IrCl3·H2O, add it to the molten composite salt obtained in step (1), continue to heat for 5 min, and then naturally cool to room temperature; the product is washed with deionized water, filtered, and dried in vacuum at 80 °C to obtain 30 mg of short-range ordered iridium oxide.

[0040] Perform relevant performance tests on the short-range ordered iridium oxide prepared in this example:

[0041] Characterize the crystal structure of the short-range ordered iridium oxide sample in this example by X-ray diffraction (XRD), see Appendix Figure 1 As shown, there are two broad XRD peaks at approximately 34.4° and 59.9°, indicating that the iridium oxide (IrOx) in the sample prepared in this example presents a structure similar to an amorphous state. This structure means that atoms or molecules have a certain arrangement order at short distances, but lack a regular periodic arrangement at long distances. Therefore, it can be inferred that the iridium oxide sample in this example has a short-range ordered crystal structure.

[0042] Further investigate the microstructure of the short-range ordered iridium oxide sample in this example, specifically see Appendix Figure 2As shown. The scanning electron microscope (SEM) image shows that the surface of the short-range ordered iridium oxide sample in this embodiment consists of stacked nanoparticles; the transmission electron microscope (TEM) image further reveals the internal structure of the short-range ordered iridium oxide sample. The short-range ordered iridium oxide sample consists of a large number of short-range ordered grains. The particle size of a single grain is about 1.7 - 2.3 nm, and the particle size after stacking is 65 - 175 nm. There are a large number of grain boundaries (edge sites) between the grains. Due to the large number of grain boundaries between the grains and the short-range order of the grains themselves, the overall structure presents a highly disordered structure. This highly disordered structure is beneficial to mass transfer and energy conversion in catalytic reactions.

[0043] Oxygen evolution evaluation under acidic conditions: Weigh 5 mg of the short-range ordered iridium oxide nanoparticle solid powder and disperse it in 950 μL of an ethanol-water solution (the volume ratio of water to ethanol is 1:1); then add 50 μL of a perfluorosulfonic acid polymer solution (Nafion solution) and disperse it evenly in an ultrasonic machine to obtain a dispersion; measure 4 μL of the dispersion and drop it on a glassy carbon electrode (with an area of 0.071 cm 2 ), and after drying, it serves as the working electrode. The reference electrode and the counter electrode are a saturated silver chloride electrode and a platinum wire respectively. The electrolyte is a 0.1 M HClO4 solution. Set up a three-electrode system and conduct three-electrode tests on an electrochemical workstation (Chenhua 760E). The potential obtained with the saturated silver chloride electrode as the reference electrode is converted to the reversible hydrogen electrode potential (RHE) in the performance graph. With the converted E RHE as the abscissa and the corresponding current density or other performance indicators as the ordinate, plot the performance curve; set a constant current density of 10 mA cm -2 on the electrochemical workstation and conduct a long-term catalytic stability test on the short-range ordered iridium oxide in this embodiment. Continuously record the voltage change of the working electrode to evaluate the stability of the catalyst. For details, see Appendix Figure 3 as shown.

[0044] From the data in Appendix Figure 3 , it can be seen that at a current density of 10 mA cm -2 , the overpotential of the short-range ordered iridium oxide in this embodiment is only 186 mV, indicating its excellent oxygen evolution reaction activity; after a 600 h constant current density test, the voltage of the short-range ordered iridium oxide in this embodiment does not increase significantly, indicating that during the long-term catalytic reaction process, the activity of the short-range ordered iridium oxide does not decay significantly. It can be seen that the short-range ordered iridium oxide prepared by the present invention has excellent catalytic stability.

[0045] Example 2

[0046] This embodiment provides a method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method, which specifically includes the following steps:

[0047] (1) Preparation of molten composite salt

[0048] Weigh 0.1 g of sodium carbonate and 4.9 g of sodium nitrate solids. After mixing them evenly, place them in a muffle furnace at 500 °C. The heating program of the muffle furnace is as follows: the heating rate is 20 °C / min, and keep the temperature for 20 min to obtain a uniform molten composite salt.

[0049] (2) Preparation of short-range ordered iridium oxide

[0050] Weigh 40 mg of IrCl3·H2O and add it to the molten composite salt obtained in step (1). Continue heating for 5 min, and then naturally cool to room temperature; wash the product with deionized water, filter, and dry it in vacuum at 80 °C to obtain 30 mg of short-range ordered iridium oxide.

[0051] The particle size of a single nanocrystal is about 1.8 - 2.6 nm, and the particle size after packing is 70 - 181 nm. At a current density of 10 mA cm -2 , the overpotential of the short-range ordered iridium oxide in this embodiment is 200 mV, and it can work stably for 596 h.

[0052] Example 3

[0053] This embodiment provides a method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method, which specifically includes the following steps:

[0054] (1) Preparation of molten composite salt

[0055] Weigh 0.2 g of sodium carbonate and 4.8 g of sodium nitrate solids. After mixing them evenly, place them in a muffle furnace at 450 °C. The heating program of the muffle furnace is as follows: the heating rate is 20 °C / min, and keep the temperature for 60 min to obtain a uniform molten composite salt.

[0056] (2) Preparation of short-range ordered iridium oxide

[0057] Weigh 50 mg of iridium dioxide and add it to the molten composite salt obtained in step (1). Continue heating for 5 min, and then naturally cool to room temperature; wash the product with deionized water, filter, and dry it in vacuum at 100 °C to obtain 30 mg of short-range ordered iridium oxide.

[0058] The particle size of a single nanocrystal is about 1.8 - 2.5 nm, and the particle size after packing is 68 - 180 nm. At a current density of 10 mA cm -2 , the overpotential of the short-range ordered iridium oxide in this embodiment is 188 mV, and it can work stably for 597 h.

[0059] Example 4

[0060] This example provides a method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method, which specifically includes the following steps:

[0061] (1) Preparation of molten composite salt

[0062] Weigh 0.1 g of sodium carbonate and 4.9 g of sodium nitrate solids. After mixing them evenly, place them in a muffle furnace at 450 °C. The heating program of the muffle furnace is as follows: the heating rate is 20 °C / min, and keep warm for 60 min to obtain a uniform molten composite salt.

[0063] (2) Preparation of short-range ordered iridium oxide

[0064] Weigh 50 mg of iridium dioxide and add it to the molten composite salt obtained in step (1). Continue heating for 5 min, and then naturally cool to room temperature; the product is washed with deionized water, filtered, and dried in vacuum at 100 °C to obtain 30 mg of short-range ordered iridium oxide.

[0065] The particle size of a single nanocrystal is about 1.8 - 2.4 nm, and the particle size after stacking is 66 - 179 nm. At a current density of 10 mA cm -2 , the overpotential of the short-range ordered iridium oxide in this example is 189 mV, and it can work stably for 598 h.

[0066] Example 5

[0067] This example provides a method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method, which specifically includes the following steps:

[0068] (1) Preparation of molten composite salt

[0069] Weigh 2.5 g of sodium carbonate and 2.5 g of sodium nitrate solids. After mixing them evenly, place them in a muffle furnace at 360 °C. The heating program of the muffle furnace is as follows: the heating rate is 20 °C / min, and keep warm for 20 min to obtain a uniform molten composite salt.

[0070] (2) Preparation of short-range ordered iridium oxide

[0071] Weigh 40 mg of IrCl3·H2O and add it to the molten composite salt obtained in step (1). Continue heating for 5 min, and then naturally cool to room temperature; the product is washed with deionized water, filtered, and dried in vacuum to obtain 30 mg of short-range ordered iridium oxide.

[0072] The particle size of a single nanocrystal of the short-range ordered iridium oxide is about 1.7 - 2.4 nm, and the particle size after stacking is 65 - 176 nm. At a current density of 10 mA cm -2At a current density of, the overpotential of the short-range ordered iridium oxide in this embodiment is 187 mV, and it operates stably for 599 h.

[0073] Example 6

[0074] This embodiment provides a method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method, which specifically includes the following steps:

[0075] (1) Preparation of molten composite salt

[0076] Weigh 2.5 g of sodium carbonate and 2.5 g of sodium nitrate solids, mix them evenly and place them in a muffle furnace at 500 °C. The heating program of the muffle furnace is: the heating rate is 20 °C / min, and keep warm for 20 min to obtain a uniform molten composite salt.

[0077] (2) Preparation of short-range ordered iridium oxide

[0078] Weigh 40 mg of IrCl3·H2O, add it to the molten composite salt obtained in step (1), continue heating for 5 min, and then naturally cool to room temperature; the product is washed with deionized water, filtered, and dried in vacuum to obtain 30 mg of short-range ordered iridium oxide.

[0079] The particle size of a single nanocrystal of the short-range ordered iridium oxide is about 1.8 - 2.7 nm, and the particle size after stacking is 71 - 181 nm. At a current density of 10 mA cm -2 of, the overpotential of the short-range ordered iridium oxide in this embodiment is 201 mV, and it operates stably for 595 h.

[0080] Comparative Example 1

[0081] A method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method is provided, which specifically includes the following steps:

[0082] (1) Preparation of molten composite salt

[0083] Weigh 0.1 g of sodium chloride and 4.9 g of sodium nitrate solids, mix them evenly and place them in a muffle furnace at 360 °C. The heating program of the muffle furnace is: the heating rate is 20 °C / min, and keep warm for 20 min to obtain a uniform molten composite salt.

[0084] (2) Preparation of short-range ordered iridium oxide

[0085] Weigh 40 mg of IrCl3·H2O, add it to the molten composite salt obtained in step (1), continue heating for 5 min, and then naturally cool to room temperature; the product is washed with deionized water, filtered, and dried in vacuum at 80 °C to obtain 30 mg of short-range ordered iridium oxide.

[0086] The particle size of a single nanocrystal is about 2.5 nm, and the particle size after packing is 146 - 308 nm. At a current density of 10 mA cm -2 , the overpotential of the short-range ordered iridium oxide in this embodiment is 270 mV, and it can operate stably for 400 h.

[0087] Comparative Example 2

[0088] A method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method is provided, which specifically includes the following steps:

[0089] (1) Preparation of molten composite salt

[0090] Weigh 0.1 g of sodium chloride and 4.9 g of sodium nitrate solids, mix them evenly and place them in a muffle furnace at 500 °C. The heating program of the muffle furnace is: the heating rate is 20 °C / min, and keep warm for 20 min to obtain a uniform molten composite salt.

[0091] (2) Preparation of short-range ordered iridium oxide

[0092] Weigh 40 mg of IrCl3·H2O, add it to the molten composite salt obtained in step (1), continue heating for 5 min, and then naturally cool to room temperature; the product is washed with deionized water, filtered, and vacuum dried to obtain 30 mg of short-range ordered iridium oxide.

[0093] The particle size of a single nanocrystal is about 2.5 nm, and the particle size after packing is 93 - 282 nm. At a current density of 10 mA cm -2 , the overpotential of the short-range ordered iridium oxide in this embodiment is 306 mV, and it can operate stably for 383 h.

[0094] Comparative Example 3

[0095] A method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method is provided, which specifically includes the following steps:

[0096] (1) Preparation of molten composite salt

[0097] Weigh 2.5 g of sodium chloride and 2.5 g of sodium nitrate solids, mix them evenly and place them in a muffle furnace at 360 °C. The heating program of the muffle furnace is: the heating rate is 20 °C / min, and keep warm for 20 min to obtain a uniform molten composite salt.

[0098] (2) Preparation of short-range ordered iridium oxide

[0099] Weigh 40 mg of IrCl3·H2O, add it to the molten composite salt obtained in step (1), continue heating for 5 min, and then naturally cool to room temperature; the product is washed with deionized water, filtered, and vacuum dried to obtain 30 mg of short-range ordered iridium oxide.

[0100] The particle size of a single nanocrystal is about 2.5 nm, and the particle size after packing is 146 - 308 nm. At a current density of 10 mA cm -2 , the overpotential of the short-range ordered iridium oxide in this embodiment is 287 mV, and it can operate stably for 392 h.

[0101] Comparative Example 4

[0102] A method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method is provided, which specifically includes the following steps:

[0103] (1) Preparation of molten composite salt

[0104] Weigh 2.5 g of sodium chloride and 2.5 g of sodium nitrate solids, mix them evenly and place them in a muffle furnace at 500 °C. The heating program of the muffle furnace is: the heating rate is 20 °C / min, and keep warm for 20 min to obtain a uniform molten composite salt.

[0105] (2) Preparation of short-range ordered iridium oxide

[0106] Weigh 40 mg of IrCl3·H2O, add it to the molten composite salt obtained in step (1), continue to heat for 5 min, and then naturally cool to room temperature; the product is washed with deionized water, filtered, and vacuum dried to obtain 30 mg of short-range ordered iridium oxide.

[0107] The particle size of a single nanocrystal is about 2.6 nm, and the particle size after packing is 153 - 284 nm. At a current density of 10 mA cm -2 , the overpotential of the short-range ordered iridium oxide in this embodiment is 313 mV, and it can operate stably for 378 h.

[0108] Comparative Example 5

[0109] A method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method is provided, which specifically includes the following steps:

[0110] (1) Preparation of molten composite salt

[0111] Weigh 5 g of sodium nitrate solid, mix it evenly and place it in a muffle furnace at 360 °C. The heating program of the muffle furnace is: the heating rate is 20 °C / min, and keep warm for 20 min to obtain a uniform molten composite salt.

[0112] (2) Preparation of short-range ordered iridium oxide

[0113] Weigh 40 mg of IrCl3·H2O, add it to the molten composite salt obtained in step (1), continue to heat for 5 min, and then naturally cool to room temperature; the product is washed with deionized water, filtered, and vacuum dried to obtain 30 mg of short-range ordered iridium oxide.

[0114] The particle size of a single nanocrystal is about 2.0 nm, and the particle size after packing is 137 - 255 nm. At a current density of 10 mA cm -2 , the overpotential of the short-range ordered iridium oxide in this embodiment is 268 mV, and it can operate stably for 500 h.

[0115] Comparative Example 6

[0116] Weigh 5 mg of commercial IrO2 catalyst (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., purity ≥99.9%, CAS No.: 12030-49-8), disperse it in 950 μL of ethanol solution (the volume ratio of ethanol to water is 1:1), then add 50 μL of Nafion solution, and disperse it evenly in an ultrasonic machine; take 4 μL of the well-dispersed solution and drop it on a glassy carbon electrode with an area of 0.071 cm 2 . Use it as the working electrode, the reference electrode is a saturated silver chloride electrode, the counter electrode is a platinum wire, and the electrolyte is a 0.1 M HClO4 solution. Perform three-electrode tests on an electrochemical workstation (Chenhua 760E).

[0117] The average particle size after packing is not more than 5 μm. At a current density of 10 mA cm -2 , the overpotential of iridium oxide in Comparative Example 6 is 296 mV, and it can operate stably for 184 h.

[0118] The above content is only to illustrate the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method, characterized in that: include: Step 1: adding an iridium source precursor to a molten composite salt and mixing the mixture, followed by cooling to obtain solid particles; The molten composite salt is a molten composite salt of sodium carbonate and sodium nitrate; the molten composite salt is obtained by mixing and calcining sodium carbonate and sodium nitrate, and the mass ratio of sodium carbonate to sodium nitrate is 1:1-49; the calcination temperature is 360°C-500°C, and the calcination time is 20 min-2 h; the mass ratio of the iridium source precursor to the molten composite salt is 1:100-150; Step 2: washing the solid particles obtained in step 1 and drying them to obtain short-range ordered iridium oxide; The particle size of the short-range ordered iridium oxide particles is 1.7 nm to 2.7 nm.

2. The method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method according to claim 1, wherein The iridium source precursor is any one of iridium trichloride hydrate, iridium trichloride, and iridium dioxide.

3. The method for rapidly preparing short-range ordered iridium oxide by a mixed molten salt method according to claim 1, wherein In step 2, the drying is vacuum drying at 50°C to 100°C.

4. A method for producing hydrogen by electrolysis of water using a proton exchange membrane, characterized in that: The short-range ordered iridium oxide obtained by the method according to any one of claims 1 to 3 is used to prepare a proton exchange membrane water electrolysis hydrogen production anode catalytic material, a 0.1M HClO4 solution is used as the electrolyte, and a platinum mesh and an Ag / AgCl electrode are used as the counter electrode and the reference electrode, respectively.

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