Preparation method and application of iridium ruthenium nanoparticle modified superfine nanowire titanium oxide acidic water electrolysis catalyst

Abstract

The invention discloses a preparation method and application of an iridium ruthenium nanoparticle modified superfine nanowire titanium oxide acidic water electrolysis catalyst. By combining hydrothermal morphology regulation and control, molten salt mediated nanoparticle loading and component coordinated regulation and control, the catalytic performance and durability of the catalyst are remarkably improved (the oxygen evolution overpotential of the catalyst in 0.5 M H2SO4 and under the current density of 10 mAcm <-2 > is only 167 mV (vs.RHE), and the activity of the catalyst after continuous operation for 100 hours under the constant potential of 1.5 V is attenuated by 1t; compared with the traditional IrO2, the catalyst has the advantages that the catalyst is simple in preparation process and low in cost, the use amount of precious metal Ir can be remarkably reduced, the Ir loading capacity is reduced to 0.1 mg / cm < 2 > (reduced by 80% compared with that of traditional IrO2), the process economy is extremely high, the bottleneck that activity and durability of a traditional low-precious-metal catalyst are difficult to consider is remarkably broken through, and an efficient and low-cost solution is provided for green large-scale hydrogen energy preparation.

Description

Technical Field

[0001] The present invention belongs to the field of electrocatalysis technology, and relates to a preparation method and application of an iridium ruthenium nanoparticle modified ultrafine nanowire titanium oxide acidic electrolysis water catalyst, and specifically relates to a preparation method of the catalyst and its application in water electrolysis. Background Art

[0002] At present, the world is facing multiple challenges such as energy crisis, climate change and ecological environment deterioration. It is urgent to promote the innovation of clean energy technology. Proton exchange membrane water electrolysis (PEMWE) hydrogen production technology is regarded as the core path for large-scale production of green hydrogen due to its high current density operation capability, compact system design, wide operating adaptability and zero carbon emission characteristics. However, the PEMWE anode oxygen evolution reaction (OER) relies on ultra-high loading of precious metal catalysts (especially scarce iridium-based materials), resulting in high hydrogen production costs, which seriously restricts its industrialization process. Therefore, the development of acidic OER catalysts with high activity, long life and low precious metal usage has become a bottleneck problem that needs to be broken through in this field.

[0003] Among the existing anode catalysts, iridium (Ir)-based materials are considered the best choice because of their excellent catalytic activity and durability in strongly acidic media, but their extremely low crustal abundance (~0.001ppm) and high price limit their large-scale application. In contrast, although the cost of ruthenium (Ru)-based catalysts is significantly reduced, their structural instability at high acidic potentials can easily lead to dissolution and inactivation of active components. In recent years, the synergistic optimization strategy of balancing cost and performance by constructing an Ir-Ru bimetallic system has become a research hotspot. For example, Chinese patent CN118272863A discloses a manganese-doped iridium-ruthenium metal oxide nanorod catalyst, which adopts a hydrothermal synthesis combined with a multi-step ion replacement process: first, a metal organic framework (MOF) is formed by the coordination of isopropyl tribenzoic acid and manganese ions, and then the Ir / Ru component is introduced through multiple ion exchanges. The catalyst has a high catalytic activity at 10 mA cm -2 It exhibits a low overpotential of 203mV at a current density of 2.5 and can maintain stability for 40 hours without significant degradation. However, its preparation process involves complex organic ligands and multiple reactions, resulting in complex processes, high safety risks, and difficulty in large-scale production, making it difficult to meet commercial needs.

[0004] Although the current anode catalyst field has been gradually reducing the amount of precious metals iridium (Ir) and ruthenium (Ru), the extent of this reduction is still limited by the bottleneck of the activity-stability trade-off. To address this problem, there is an urgent need for a catalyst that uses less precious metals iridium (Ir) and ruthenium (Ru) while maintaining strong catalytic activity and durability. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings and deficiencies of the prior art by providing an iridium-ruthenium nanoparticle-modified ultrafine nanowire titanium oxide acidic water electrolysis catalyst, which addresses the issues of excessive iridium usage and the poor stability of ruthenium oxide. Furthermore, the present invention provides a method for preparing the iridium-ruthenium nanoparticle-modified ultrafine nanowire titanium oxide acidic water electrolysis catalyst. Finally, the present invention further provides the use of the iridium-ruthenium nanoparticle-modified ultrafine nanowire titanium oxide acidic water electrolysis catalyst in hydrogen production by water electrolysis.

[0006] The purpose of the present invention can be achieved by the following solutions:

[0007] In a first aspect, the present invention provides a method for preparing an iridium ruthenium nanoparticle-modified ultrafine nanowire titanium oxide acidic water electrolysis catalyst, comprising the following steps:

[0008] S1. Mix and dissolve a titanium source and sodium hydroxide, and then perform a hydrothermal reaction to obtain a sodium titanate precursor;

[0009] S2. After dissolving the sodium titanate precursor, performing ion exchange under acidic conditions, and obtaining a titanate precursor after washing and drying;

[0010] S3, dissolving the iridium source and the ruthenium source, and then adding molten salt to obtain a mixed solution;

[0011] S4, dissolving the titanate precursor in step S2, and then adding the mixed solution in step S3 dropwise to obtain an iridium ruthenium titanium precursor solution;

[0012] S5. Dry the iridium ruthenium titanium precursor solution in S4 and then calcine it to obtain.

[0013] As a preferred embodiment, in step S1, the titanium source includes at least one of titanium powder, titanium dioxide, and titanium trioxide. The titanium powder includes at least one of 300 mesh titanium powder and 60 mesh nano titanium powder.

[0014] As a preferred embodiment, in step S1, the concentration of sodium hydroxide is 1 to 3 mol / L.

[0015] As a preferred embodiment, in step S1, the molar ratio of the titanium source to sodium hydroxide is 1 to 3:1.

[0016] As a preferred embodiment, in step S1, the hydrothermal reaction is carried out under alkaline conditions, and the alkaline conditions are adjusted using an inorganic acid, preferably hydrochloric acid.

[0017] In some embodiments, the alkaline condition is pH=11.

[0018] As a preferred embodiment, in step S1, the hydrothermal reaction includes a first-stage hydrothermal reaction and a second-stage hydrothermal reaction; wherein the temperature of the first-stage hydrothermal reaction is 80°C to 120°C and the time is 4 to 8 hours; the temperature of the second-stage hydrothermal reaction is 160°C to 220°C and the time is 6 to 12 hours. By forming a hydroxyl-rich precursor in the first-stage hydrothermal reaction and then fixing the hydroxyl groups through the second-stage hydrothermal reaction, the surface active sites are increased, and the step-by-step hydrothermal reaction can also provide oxygen vacancies on the surface of titanium oxide. In the second-stage hydrothermal reaction, it is difficult to synthesize ultrafine nanowire morphology below 160°C, and the ultrafine nanowire morphology is prone to collapse above 220°C.

[0019] Traditional titanium oxide supports rely on templates for low-temperature synthesis, resulting in slow crystal growth, which can lead to dense rather than porous structures, reducing the support's specific surface area and hindering the formation of a large number of surface hydroxyl groups. The present invention utilizes a stepwise hydrothermal reaction to spontaneously form ultrafine nanowire structures with diameters of 3-8 nm, avoiding template limitations. The resulting titanium oxide support exhibits a high specific surface area, rich in hydroxyl functional groups, and possesses surface oxygen vacancies.

[0020] In some embodiments, the hydrothermal reaction is carried out in a high-pressure hydrothermal reactor.

[0021] As a preferred embodiment, in step S2, the acidic condition is adjusted by dropwise addition of an inorganic acid, wherein the inorganic acid comprises hydrochloric acid. In some embodiments, the acidic condition is pH=1.2.

[0022] Furthermore, the amount of the sodium titanate precursor and hydrochloric acid is 50 to 150 ml of dilute hydrochloric acid solution per 1 g of sodium titanate, and the concentration of the hydrochloric acid is 0.2 to 1 mol / L.

[0023] Furthermore, the dropping speed is 2 to 20 ml / min.

[0024] As a preferred embodiment, in step S2, the ion exchange time is 6 to 12 hours.

[0025] As a preferred embodiment, in step S3, the iridium source includes one or more iridium salts such as chloroiridic acid, iridium acetate, iridium bromide, and iridium acetylacetonate; the ruthenium source includes one or more ruthenium salts such as ruthenium trichloride, ammonium chlororuthenate, potassium chlororuthenate, and ruthenium acetylacetonate.

[0026] As a preferred embodiment, in step S3, the ratio of the amount of metal elements in the iridium source to that in the ruthenium source is 0.01 to 0.2:1, preferably 0.02:1.

[0027] As a preferred embodiment, in step S3, the molten salt includes one or more of chlorides, nitrates, phosphates, carbonates, and silicates. In some embodiments, the molten salt is sodium nitrate.

[0028] Traditionally, Ru and Ir loading methods rely on single-metal impregnation, making it difficult to achieve atomic-level synergistic effects. This invention utilizes a bimetallic design in a molten salt method to synergistically control the composition of Ru and Ir, resulting in Ir-Ru alloy particles with a particle size of 1.5±0.3nm. This optimizes OOH* adsorption, improves stability, and reduces Ru dissolution rate.

[0029] As a preferred embodiment, in step S3, the mass ratio of the molten salt to the sum of the masses of the iridium source, the ruthenium source and the titanate precursor is 10 to 30:1.

[0030] As a preferred embodiment, in step S4, the dropping speed is 0.5-5 mL / min; and the ratio of the amount of the metal element substances of the ruthenium source to the titanium source is 0.11-0.55:1.

[0031] As a preferred embodiment, in step S5, the drying temperature is 60°C to 100°C and the drying time is 6 to 12 hours.

[0032] As a preferred embodiment, the calcination temperature is 400° C. to 500° C. and the calcination time is 0.5 to 2.5 hours. In some embodiments, the drying and calcination are performed in a crucible, and washing is performed after calcination.

[0033] In a second aspect, the present invention provides an iridium ruthenium nanoparticle-modified ultrafine nanowire titanium oxide acidic water electrolysis catalyst obtained by the preparation method.

[0034] In a third aspect, the present invention provides an application of the iridium ruthenium nanoparticle modified ultrafine nanowire titanium oxide acidic water electrolysis catalyst in hydrogen production by water electrolysis.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The present invention significantly improves the catalytic performance and durability of the catalyst by combining hydrothermal morphology control, molten salt-mediated nanoparticle loading and component synergistic control (the catalyst is in 0.5M H2SO4 and at 10mA cm -2 The oxygen evolution overpotential at this current density is only 167 mV (vs. RHE), and the activity decay is less than 5% after 100 hours of continuous operation at a constant potential of 1.5 V. This can significantly reduce the amount of precious metal Ir used, reducing the Ir loading to 0.1 mg / cm 2(80% lower than traditional IrO2), with extremely high process economy, significantly breaking through the bottleneck of traditional low-precious metal catalysts that are difficult to balance activity and durability, and providing an efficient and low-cost solution for the large-scale preparation of green hydrogen energy.

[0037] 2. Hydrothermal morphology control: The present invention adopts a step-by-step hydrothermal synthesis method to precisely control the crystal growth dynamics of titanium oxide precursors to form an ultrafine nanowire structure with a diameter of 3-8nm. This structure not only has a high specific surface area (>180m 2 / g), multi-level porosity and rich hydroxyl functional groups, which expose abundant active sites and provide high-density anchoring sites for precious metal loading; it also has surface oxygen vacancies, which can form strong electronic coupling with Ir-Ru particles and optimize the electron transfer path by regulating the surface energy and oxygen vacancy concentration, forming a strong metal-support interaction (SMSI) and improving the charge transfer efficiency (EIS shows Rct = 2.1Ω·cm -2 ), improving the catalytic performance of the catalyst. Furthermore, an electron redistribution effect occurs between the substrate oxygen vacancies and the IrRu nanoparticles, significantly inhibiting the acidic dissolution of Ru (Ru loss rate measured by ICP is <0.5 μg / h), thus improving the durability of the catalyst.

[0038] 3. Molten salt-mediated nanoparticle loading: The present invention utilizes a high-temperature liquid phase environment (300-500°C) in a molten salt medium (such as the KNO3-NaNO3 eutectic system) to reduce the reaction activation energy, thereby achieving rapid decomposition of the iridium-ruthenium precursor and in-situ nucleation of nanoparticles (1-3nm), obtaining Ir-Ru alloy particles with a particle size of 1.5±0.3nm and a particle spacing of <2nm, forming a highly active site network; and with the help of the etching effect of molten salt ions on the nanowires, the particle-substrate interface bonding is enhanced, forming a strong metal-support interaction (SMSI), further improving the catalytic performance of the catalyst.

[0039] 4. Coordinated regulation of components: XANES analysis shows that the introduction of Ru shifts the d-band center of Ir by 0.15 eV (vs. pure Ir), promoting the adsorption optimization of OOH intermediates (ΔGOOH = 3.18 eV). At the same time, the inert lattice of Ir inhibits the excessive oxidation of Ru through interfacial charge transfer (Ru dissolution rate is reduced to 0.12 μg cm -2 h -1), synergistically improving the catalytic performance and durability of the catalyst; further, by optimizing the molar ratio of iridium, ruthenium, and titanium (Ir:Ru:Ti=1:100:909 to 1:5:9), the molar ratio of iridium to ruthenium is too low, making it difficult to form iridium-ruthenium nanoparticles, while too high a ratio easily agglomerates and makes it difficult to achieve uniform dispersion, both of which make it difficult to achieve the desired catalytic effect; low titanium content makes it difficult to provide sufficient active area to support precious metal particles, while high titanium content reduces activity and makes it difficult to achieve the optimal catalytic effect. Therefore, by balancing the synergistic effect of precious metal active site density and support stability, the catalyst achieves a current density of >200mA cm at 1.5V vs. RHE. -2 The oxygen evolution current density was 100, and the activity decay was <5% after 100 hours of stability test.

[0040] 5. The present invention provides a universal design paradigm for the development of low-cost, highly stable acidic OER catalysts through the three-in-one strategy of "morphology engineering-bimetallic synergy-interface strengthening". Its core idea can be extended to other transition metal supports and precious metal alloy systems, which is of milestone significance for promoting cost reduction and efficiency improvement in the green hydrogen industry. This work not only provides an innovative paradigm of "support engineering-bimetallic synergy" for the design of low-precious metal PEMWE anode catalysts, but its process compatibility can also be extended to other non-precious metal supports and precious metal combination systems, and has significant application potential in clean energy fields such as green hydrogen equipment and fuel cells. At the same time, the process of the present invention has strong compatibility (no need for complex atmosphere control, high-temperature calcination or complex post-processing), is suitable for large-scale production, and the single batch production capacity can reach kilograms; the obtained catalyst exhibits low polarization loss (<1.7V@1A / cm 2 ), which has the application potential of green hydrogen industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0042] Figure 1 This is a SEM image of the nano-catalyst titanate precursor prepared in Example 1;

[0043] Figure 2 This is the SEM image of the nanocatalyst prepared in Example 1;

[0044] Figure 3 This is the XRD pattern of the nanocatalyst prepared in Example 1;

[0045] Figure 4 The OER polarization curves of the nanocatalysts prepared in Example 1 and Comparative Examples 1, 3, 4, and 5 are shown;

[0046] Figure 5 The OER polarization curves of the nanocatalysts prepared in Example 1 and Comparative Example 2 are shown;

[0047] Figure 6 The OER polarization curves of the nanocatalysts prepared in Example 1 and Example 3;

[0048] Figure 7 The OER polarization curves of the nanocatalysts prepared in Example 1 and Comparative Examples 6-7 are shown;

[0049] Figure 8 The stability test results of the nanocatalysts prepared in Example 1 and Comparative Example 2 are shown;

[0050] Figure 9 This is the electron paramagnetic resonance (EPR) spectrum of the nanocatalyst prepared in Example 1. DETAILED DESCRIPTION

[0051] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The following examples are implemented under the premise of the technical solution of the present invention, provide detailed implementation methods and specific operating procedures, and will help those skilled in the art to further understand the present invention. It should be pointed out that the scope of protection of the present invention is not limited to the following embodiments, and a number of adjustments and improvements made under the premise of the concept of the present invention all fall within the scope of protection of the present invention.

[0052] Example 1

[0053] The iridium ruthenium nanoparticle-modified ultrafine nanowire titanium oxide acidic water electrolysis catalyst of this embodiment is prepared by a method comprising the following steps:

[0054] (1) 1.1 g of 60-mesh nano-titanium powder was evenly dispersed in 360 mL of deionized water, 40 ml of 2 mol / L NaOH solution was added, and 0.5 mol / L dilute hydrochloric acid was used to adjust the pH to 11. The solution was evenly dispersed in a polytetrafluoroethylene liner after stirring and mixing, and then placed in a stainless steel reactor, tightened, and placed in an oven. The program was set as follows: temperature 80 ° C, time 360 min (first stage hydrothermal reaction), temperature 220 ° C, time 480 min (second stage hydrothermal reaction), and the oven was taken out after cooling to room temperature to obtain the primary product sodium titanate precursor.

[0055] The reaction formula of the titanium powder and NaOH solution under hydrothermal conditions is:

[0056] Ti+2NaOH+H2O=Na2TiO3+2H2↑

[0057] (2) 3.2 g of sodium titanate precursor in (1) was added to deionized water, and the supernatant was removed. This operation was repeated three times. While stirring at a constant temperature, 0.5 mol / L dilute hydrochloric acid solution was added dropwise at a rate of 5 ml / min for ion exchange (PH = 1.2). The ion exchange time was 6 h. After washing with deionized water three times, the product was placed in a vacuum drying oven and dried for 8 hours to obtain a titanate precursor.

[0058] (3) 100 mg of anhydrous ruthenium chloride was fully dissolved in 5 ml of deionized water and stirred evenly, and then 223 μL of 0.05 mol / L iridium chloride solution was added dropwise to form an iridium-ruthenium mixed salt solution. 4 g of sodium nitrate was dissolved in 5 ml of deionized water and added dropwise to the above iridium-ruthenium mixed salt solution to form a mixed solution.

[0059] (4) Dissolve 100 mg of titanate precursor in 10 ml of deionized water and stir evenly, then dropwise add the mixed solution in (3) to obtain an iridium ruthenium titanium precursor solution and place it in a crucible.

[0060] (5) The crucible was placed in an oven for drying, and the program was set as follows: temperature 80 ° C, time 640 min. After the oven cooled to room temperature, it was taken out to obtain amorphous iridium ruthenium nanoparticle-modified nanowire titanium oxide, which was then placed in a muffle furnace for calcination, and the program was set as follows: temperature 450 ° C, time 120 min. After the muffle furnace cooled to room temperature, the crude product powder was collected and washed with deionized water three times to obtain the final product, iridium ruthenium nanoparticle-modified nanowire titanium oxide electrolysis catalyst.

[0061] Example 2

[0062] The only difference between the above method and Example 1 is that in step (1), the 60-mesh nano titanium powder is replaced with 300-mesh titanium powder.

[0063] Example 3

[0064] The only difference from Example 1 is that in step (3), the amounts of anhydrous ruthenium chloride used are set to 200 mg (1% Ir), 100 mg (2% Ir), 40 mg (5% Ir), and 20 mg (10% Ir), respectively.

[0065] Example 4

[0066] The only difference from Example 1 is that in step (4), the amount of titanate precursor is set to 100 mg, 60 mg, and 20 mg, respectively.

[0067] Comparative Example 1

[0068] The iridium ruthenium oxide acidic water electrolysis catalyst of this comparative example is prepared by a method comprising the following steps:

[0069] (1) Dissolve 100 mg of anhydrous ruthenium chloride in 5 ml of deionized water and stir evenly. Then, add 223 μL of 0.05 mol / L iridium chloride solution dropwise to form an iridium-ruthenium mixed salt solution. Dissolve 4 g of sodium nitrate in 5 ml of deionized water and add dropwise to the above iridium-ruthenium mixed salt solution to form a mixed solution, which is placed in a crucible.

[0070] (2) The crucible was placed in an oven for drying, and the program was set as follows: temperature 80°C, time 640 min. After the oven cooled to room temperature, it was taken out to obtain amorphous iridium ruthenium nanoparticle-modified nanowire titanium oxide, which was then placed in a muffle furnace for calcination, and the program was set as follows: temperature 450°C, time 120 min. After the muffle furnace cooled to room temperature, the crude product powder was collected and washed with deionized water three times to obtain an iridium ruthenium oxide nanoparticle acidic electrolysis water catalyst.

[0071] Comparative Example 2

[0072] The sample catalyst of this comparative example was prepared by a method comprising the following steps:

[0073] (1) 1.1 g of 60-mesh nano-titanium powder was evenly dispersed in 360 mL of deionized water, 40 mL of 2 mol / L NaOH solution was added, and the pH was adjusted to 11 with 0.5 mol / L dilute hydrochloric acid. The solution was evenly dispersed in a polytetrafluoroethylene liner after stirring and mixing, and then placed in a stainless steel reactor, tightened, and placed in an oven. The program was set as follows: temperature 80 ° C, time 360 min, temperature 220 ° C, time 480 min, and the oven was taken out after cooling to room temperature to obtain the primary product sodium titanate precursor.

[0074] (2) 3.2 g of sodium titanate precursor in (1) was added to deionized water, and the supernatant was removed. This operation was repeated three times. While stirring at a constant temperature, 0.5 mol / L dilute hydrochloric acid solution was added dropwise at a rate of 5 ml / min for ion exchange (PH = 1.2). The ion exchange time was 6 h. After washing with deionized water three times, the product was placed in a vacuum drying oven and dried for 8 hours to obtain a titanate precursor.

[0075] (3) Dissolve 100 mg of titanate precursor, 100 mg of anhydrous ruthenium chloride and 223 μL of iridium chloride solution in 80 mL of 0.1 mol / L NaOH solution. Disperse the mixed solution into a polytetrafluoroethylene liner, place it into a stainless steel reactor, tighten it, and put it into an oven. Set the program: temperature 80 ° C, time 640 min. After the oven cools to room temperature, take it out, remove the supernatant, wash it three times, dry it, and place it in a crucible.

[0076] (4) Place the crucible into a muffle furnace for calcination. Set the program as follows: temperature 450°C, time 120 min. After the muffle furnace cools to room temperature, the crude product powder is collected and washed three times with deionized water to obtain a sample catalyst.

[0077] Comparative Example 3

[0078] The preparation scheme of the acidic water electrolysis catalyst in this comparative example does not add chloroiridic acid solution.

[0079] Comparative Example 4

[0080] The preparation scheme of the acidic water electrolysis catalyst in this comparative example does not add ruthenium chloride solution and increases the mass of chloroiridic acid by twenty times.

[0081] Comparative Example 5

[0082] The ultrafine nanowire titanium oxide acidic water electrolysis catalyst of this comparative example is prepared by a method comprising the following steps:

[0083] (1) 1.1 g of 60-mesh nano-titanium powder was evenly dispersed in 360 mL of deionized water, 40 mL of 2 mol / L NaOH solution was added, and the pH was adjusted to 11 with 0.5 mol / L dilute hydrochloric acid. The solution was evenly dispersed in a polytetrafluoroethylene liner after stirring and mixing, and then placed in a stainless steel reactor, tightened, and placed in an oven. The program was set as follows: temperature 80 ° C, time 360 min, temperature 220 ° C, time 480 min, and the oven was taken out after cooling to room temperature to obtain the primary product sodium titanate precursor.

[0084] (2) 3.2 g of sodium titanate precursor in (1) was added to deionized water, and the supernatant was removed. This operation was repeated three times. While stirring at a constant temperature, 0.5 mol / L dilute hydrochloric acid solution was added dropwise at a rate of 5 ml / min for ion exchange (PH = 1.2). The ion exchange time was 6 h. After washing with deionized water three times, the product was placed in a vacuum drying oven and dried for 8 hours to obtain a titanate precursor, which was placed in a crucible.

[0085] (3) The crucible was placed in a muffle furnace for calcination. The program was set as follows: temperature 450 °C, time 120 min. After the muffle furnace was cooled to room temperature, the crude product powder was collected and washed with deionized water three times to obtain a titanium oxide water electrolysis catalyst.

[0086] Comparative Example 6

[0087] The preparation method of this comparative example is basically the same as that of Example 1, except that the second stage hydrothermal reaction is omitted. Specifically,

[0088] Set the program: temperature 80℃, time 360min.

[0089] Comparative Example 7

[0090] The preparation method of this comparative example is basically the same as that of Example 1, except that the first stage hydrothermal reaction is omitted. Specifically,

[0091] Set the program: temperature 220℃, time 480min.

[0092] Performance Testing

[0093] (1) SEM analysis

[0094] The titanate precursor prepared in Example 1 was subjected to SEM analysis, and the results were as follows: Figure 1 shown.

[0095] from Figure 1 It can be seen that the titanate precursor prepared in the present invention is a nanowire.

[0096] The nanocatalyst prepared in Example 1 was subjected to SEM analysis, and the results were as follows: Figure 2 shown.

[0097] from Figure 2 It can be seen that the nanocatalyst prepared in the present invention is iridium ruthenium nanoparticles uniformly modified on titanium oxide nanowires.

[0098] (2) XRD analysis

[0099] Take the catalyst of embodiment and carry out XRD analysis, the result is as follows Figure 3 shown.

[0100] from Figure 3 It can be seen that the peak position corresponding to the acidic water electrolysis catalyst of ultrafine nanowire titanium oxide modified by iridium ruthenium nanoparticles prepared by the present invention indicates that nano-iridium ruthenium oxide is successfully modified on ultrafine nanowire titanium oxide.

[0101] (3) OER testing

[0102] The catalyst prepared in Example 1 was tested for OER. The results were as follows: Figure 4 、 5 , as shown in 6.

[0103] from Figure 4 It can be seen that the catalyst prepared by the present invention ( Figure 4 IrRuO x / TiO2) at 10 mA cm -2 The overpotential at the current density is 167mV compared with the comparative example 1 ( Figure 4 IrRuO x ), Comparative Example 3 ( Figure 4 RuO2 in), Comparative Example 4 ( Figure 4IrO2 in), Comparative Example 5 ( Figure 4 The overpotential of TiO2 in the catalyst is lower under the same test conditions, indicating that the catalyst prepared by the present invention has good performance.

[0104] from Figure 5 It can be seen that the catalyst of Comparative Example 2 has a -2 The overpotential at a current density of 226 mV is lower than the overpotential in Example 1, indicating that the catalyst prepared by the present invention has good performance.

[0105] from Figure 6 It can be seen that in 2%-Ir Example 1, compared with Example 3, the catalytic activity first increases and then decreases with the increase of the iridium content, and the 2% iridium content achieves the greatest catalytic effect.

[0106] from Figure 7 It can be seen that Example 1 and Comparative Examples 6 and 7 show that the catalytic performance of the single process hydrothermal conditions is lower than that of the catalyst obtained by the distributed hydrothermal activation method.

[0107] (4) Stability test

[0108] The catalysts prepared in Example 1 and Comparative Example 2 were tested for stability. Figure 8 shown.

[0109] from Figure 8 It can be seen that the catalyst prepared by the present invention has a high conductivity at 100 mA cm -2 At a current density of 100,000,000, the long-term durability test was conducted for 100 hours, while the stability of Comparative Example 2, which did not undergo molten salt mediation, was difficult to maintain long-term stability. As can be seen from the figure, the potential change of the electrode is negligible, indicating that Experimental Example 1 has good stability.

[0110] (5) EPR test

[0111] The catalyst prepared in Example 1 was subjected to EPR testing, and the results were as follows: Figure 9 shown.

[0112] from Figure 9 As shown in the electron paramagnetic resonance (EPR) spectrum, a signal is detected at 2.0035 in Example 1, which indicates the presence of oxygen vacancies in the material.

[0113] The above experimental results show that the iridium ruthenium nanoparticle modified ultrafine nanowire titanium oxide prepared by the present invention has high stability and catalytic activity, especially when the preferred nano titanium powder obtains the best morphology, and the optimal electrochemical oxygen evolution reaction performance is obtained under the preferred molar mass ruthenium to titanium ratio.

[0114] This invention uses a step-by-step hydrothermal activation method to prepare a titanium-based oxide precursor, and combined with a molten salt treatment process, successfully developed an oxygen evolution reaction (OER) catalyst with excellent acidic catalytic activity. By precisely controlling the molar ratio of the three metal elements iridium, ruthenium, and titanium, a significant improvement in the intrinsic activity of the catalyst is achieved. The prepared catalyst exhibits excellent catalytic performance in a water electrolysis hydrogen production system. Its low overpotential characteristics combined with high stability show important industrial application value in the field of clean energy conversion technology.

[0115] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing an iridium ruthenium nanoparticle-modified ultrafine nanowire titanium oxide acidic water electrolysis catalyst, characterized in that: The following steps are involved: S1. Mix and dissolve a titanium source and sodium hydroxide, and then perform a hydrothermal reaction to obtain a sodium titanate precursor; S2. After dissolving the sodium titanate precursor, performing ion exchange under acidic conditions, and obtaining a titanate precursor after washing and drying; S3, dissolving the iridium source and the ruthenium source, and then adding molten salt to obtain a mixed solution; S4, dissolving the titanate precursor in step S2, and then adding the mixed solution in step S3 dropwise to obtain an iridium ruthenium titanium precursor solution; S5. Dry the iridium ruthenium titanium precursor solution in S4 and then calcine it to obtain.

2. The preparation method according to claim 1, characterized in that In step S1, the titanium source includes at least one of titanium powder, titanium dioxide, and titanium trioxide; and the titanium powder includes at least one of 300-mesh titanium powder and 60-mesh nano titanium powder.

3. The preparation method according to claim 1, characterized in that In step S1, the concentration of sodium hydroxide is 1 to 3 mol / L; the molar ratio of the titanium source to sodium hydroxide is 1 to 3:1; The hydrothermal reaction is carried out under alkaline conditions, and the alkaline conditions are adjusted by inorganic acid; The hydrothermal reaction includes a first-stage hydrothermal reaction and a second-stage hydrothermal reaction; wherein, the temperature of the first-stage hydrothermal reaction is 80°C to 120°C and the time is 4 to 8 hours; the temperature of the second-stage hydrothermal reaction is 160°C to 220°C and the time is 6 to 12 hours.

4. The preparation method according to claim 1, characterized in that In step S2, the acidic condition is adjusted by dropwise adding an inorganic acid; the inorganic acid includes hydrochloric acid; The dropping speed is 2-20 ml / min; The ion exchange time is 6 to 12 hours.

5. The preparation method according to claim 1, characterized in that In step S3, the iridium source includes one or more of chloroiridic acid, iridium acetate, iridium bromide, and iridium acetylacetonate; the ruthenium source includes one or more of ruthenium trichloride, ammonium chlororuthenate, potassium chlororuthenate, and ruthenium acetylacetonate; The ratio of the amount of metal elements in the iridium source to that in the ruthenium source is 0.01 to 0.2:

1.

6. The preparation method according to claim 1, characterized in that In step S3, the molten salt includes one or more of chloride, nitrate, phosphate, carbonate, and silicate; The mass ratio of the molten salt to the sum of the mass of the iridium source, the ruthenium source and the titanate precursor is 10 to 30:

1.

7. The preparation method according to claim 1, characterized in that In step S4, the ratio of the amount of metal elements in the ruthenium source to that in the titanium source is 0.11-0.55:

1.

8. The preparation method according to claim 1, characterized in that In step S5, the drying temperature is 60°C to 100°C and the drying time is 6 to 12 hours; The calcination temperature is 400° C. to 500° C., and the calcination time is 0.5 to 2.5 hours.

9. An acidic water electrolysis catalyst for titanium oxide modified with iridium and ruthenium nanoparticles obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the iridium ruthenium nanoparticle-modified ultrafine nanowire titanium oxide acidic water electrolysis catalyst as claimed in claim 9 in hydrogen production by water electrolysis.

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