Strontium titanate loaded with iridium clusters, and preparation method and application thereof

Abstract

The application belongs to the technical field of electrocatalysis, and particularly relates to a strontium titanate loaded with iridium clusters and a preparation method and application thereof. The strontium titanate loaded with iridium clusters provided by the application comprises: strontium titanate and iridium clusters loaded on the surface of the strontium titanate; components of the iridium clusters comprise iridium single substance and iridium oxide wrapped on the surface of the iridium single substance; the chemical composition of the strontium titanate is SrTiO 3‑x , 0 < x < 0.5; the chemical composition of the iridium oxide is IrO 2‑y , 0 < y < 2; and the strontium carbonate is a cubic octahedral structure. The strontium titanate loaded with iridium clusters not only has excellent electrocatalytic activity, but also has long-term stability, and can be efficiently and stably operated for a long time under the working conditions of PEMWE.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrocatalysis, and particularly relates to a strontium titanate loaded with iridium clusters as well as a preparation method and application thereof. BACKGROUND

[0002] Proton exchange membrane water electrolyzer (PEMWE) has advantages of high working current density, high hydrogen purity and low resistance loss, making it the preferred technology for high efficiency and small footprint. However, the strong acid and oxidizing environment under the working condition of PEMWE brings great challenges to the activity and stability of the catalyst. Due to the high overpotential of the oxygen evolution reaction (OER), PEMWE requires high-performance anode electrocatalysts. So far, the most widely used OER catalyst in PEMWE technology is iridium-based oxide. However, iridium-based oxide not only has the problem of high cost due to the high load of noble metal iridium, but also cannot balance the electrocatalytic activity and stability, so that the PEMWE equipment relying on iridium-based oxide does not have market competitiveness. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a strontium titanate loaded with iridium clusters as well as a preparation method and application thereof. The strontium titanate loaded with iridium clusters not only has excellent electrocatalytic activity, but also has long-term stability, and can be efficiently and stably operated under the working condition of PEMWE.

[0004] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0005] The present application provides a strontium titanate loaded with iridium clusters, comprising: strontium titanate and iridium clusters loaded on the surface of the strontium titanate; the components of the iridium clusters include iridium single element and iridium oxide wrapped on the surface of the iridium single element; the chemical composition of the strontium titanate is SrTiO 3-x , 0 < x < 0.5; the chemical composition of the iridium oxide is IrO 2-y , 0 < y < 2; and the strontium titanate has a cubic octahedral structure.

[0006] Preferably, the diameter of the strontium titanate loaded with iridium clusters is 150-300 nm.

[0007] Preferably, the mass percentage of iridium in the strontium titanate loaded with iridium clusters is 1-60%.

[0008] The present application also provides a preparation method of the strontium titanate loaded with iridium clusters as described in the above technical solutions, comprising the following steps:

[0009] Mixing cubic octahedral strontium titanate, a compound containing iridium ions, an alkali source, a reducing alcohol and water to perform hydrothermal reaction to obtain the strontium titanate loaded with iridium clusters.

[0010] Preferably, the iridium ion-containing compound comprises one or more of iridium chloric acid, iridium tetrachloride and potassium hexachloroiridate(IV).

[0011] Preferably, the alkali source is an alkali metal hydroxide; the alkali metal hydroxide comprises one or more of potassium hydroxide, lithium hydroxide, cesium hydroxide and sodium hydroxide.

[0012] Preferably, the reducing alcohol comprises ethylene glycol and / or glycerol.

[0013] Preferably, the temperature of the hydrothermal reaction is 160-220℃; the time of the hydrothermal reaction is 12-36h.

[0014] The application also provides an application of the iridium cluster-loaded strontium titanate as an anode electrocatalyst in a proton exchange membrane water electrolyzer.

[0015] The application also provides an anode of a proton exchange membrane water electrolyzer, comprising an anode substrate and an anode electrocatalyst coated on the surface of the anode substrate.

[0016] The anode electrocatalyst is the iridium cluster-loaded strontium titanate as described in the above technical solution or the iridium cluster-loaded strontium titanate prepared by the preparation method as described in the above technical solution.

[0017] The application provides an iridium cluster-loaded strontium titanate, comprising: strontium titanate and iridium clusters loaded on the surface of the strontium titanate; the components of the iridium clusters comprise iridium single substance and iridium oxide wrapped on the surface of the iridium single substance; the chemical composition of the strontium titanate is SrTiO 3-x , 0 2-y, 0 < y < 2; the strontium titanate is a cubic octahedron structure. In the electrocatalytic oxygen evolution reaction, after the voltage is applied, the iridium cluster loaded strontium titanate provided by the application can generate in-situ reconstructed Ti-O-Ir interface through bias-induced Ti leaching, the strontium titanate with a cubic octahedron structure is more likely to expose the 110 crystal surface to form a Ti-O-Ir interface with the iridium cluster, such a Ti-O-Ir interface can stabilize the structure of the iridium cluster loaded strontium titanate, and can significantly reduce the energy barrier of the oxygen evolution reaction, reduce the overpotential, greatly improve the oxygen evolution reaction activity, and significantly improve the electrocatalytic activity and cycle stability of the iridium cluster loaded strontium titanate; moreover, the strontium titanate carrier induces Sr leaching to cause carrier lattice oxygen-mediated OH formation when the voltage is applied, which leads to enrichment of OH at the Ti-O-Ir interface, which is conducive to OH overflow. This reverse OH lattice overflow assisted AEM (when the electronic state near the Fermi level is metal, the adsorption oxidation mechanism of metal as the redox center) reaction pathway can avoid the traditional linear scaling relationship, thereby reducing the reaction energy barrier and improving the electrocatalytic activity of the iridium cluster loaded strontium titanate. In addition, the Ti-O-Ir interface also effectively maintains the Ir site in a lower redox state, ensuring the stability of iridium oxide even at challenging high potentials. The iridium cluster loaded strontium titanate provided by the application as a catalyst can be efficiently and stably operated for more than 800 h under the working conditions of a proton exchange membrane water electrolyzer (PEMWE), far exceeding the performance and longest running time of commercial catalysts.

[0018] In addition, the iridium cluster loaded strontium titanate provided by the application can significantly reduce the content of noble metal Ir in the catalyst, greatly reducing the cost. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 XRD characterization diagram of the iridium cluster loaded strontium titanate prepared for Example 2;

[0020] Figure 2 OER polarization curve diagram of the iridium cluster loaded strontium titanate prepared for Examples 2-6, the strontium titanate material (SrTiO 3-x ) prepared for Comparative Example 1, and the commercial catalyst IrO2 (C-IrO2) in Comparative Example 2;

[0021] Figure 3 OER polarization curve diagram of the iridium cluster loaded strontium titanate prepared for Example 2 and the strontium titanate material (SrTiO 3-x ) prepared for Comparative Example 1;

[0022] Figure 4 Polarization curve diagram of a proton exchange membrane water electrolyzer (PEMWE) using the commercial catalyst IrO2 (Com-IrO2) in Comparative Example 2 as an anode electrocatalyst;

[0023] Figure 5 Polarization curve of a proton exchange membrane water electrolyzer (PEMWE) using the iridium cluster loaded strontium titanate prepared in Example 2 as an anode electrocatalyst;

[0024] Figure 6 The iridium cluster loaded strontium titanate prepared in Example 2 has a diameter of 150-300 nm, and the mass percentage of iridium element in the iridium cluster loaded strontium titanate is 1-60%, specifically 30-41.83%. -2 and the constant current test result graph at 80℃. DETAILED DESCRIPTION

[0025] The iridium cluster loaded strontium titanate provided by the application comprises: strontium titanate and an iridium cluster loaded on the surface of the strontium titanate; the component of the iridium cluster comprises iridium element and iridium oxide wrapped on the surface of the iridium element; the chemical composition of the strontium titanate is SrTiO 3-x , 0 2-y < y < 2; and the strontium titanate has a cubic octahedral structure.

[0026] Unless otherwise specified, the application does not have special requirements for the source of the raw materials used, and commercially available products known to those skilled in the art can be used.

[0027] The iridium cluster loaded strontium titanate provided by the application comprises: strontium titanate; and the chemical composition of the strontium titanate is SrTiO 3-x , 0 2.72 < y < 2.

[0028] As an embodiment, 0 2.72 ; and the strontium titanate has a cubic octahedral structure.

[0029] The iridium cluster loaded strontium titanate provided by the application comprises: an iridium cluster loaded on the surface of the strontium titanate; the component of the iridium cluster comprises iridium element and iridium oxide wrapped on the surface of the iridium element; and the chemical composition of the iridium oxide is IrO 2-y , 0< y < 2.

[0030] As an embodiment, the diameter of the iridium cluster loaded strontium titanate is 150-300 nm, and specifically 200-250 nm; and the mass percentage of iridium element in the iridium cluster loaded strontium titanate is 1-60%, and specifically 30-41.83%.

[0031] In the electrocatalytic oxygen evolution reaction, after the voltage is applied, the iridium cluster loaded strontium titanate provided by the application can generate an in-situ reconstructed Ti-O-Ir interface through bias-induced Ti leaching. The strontium titanate with a cubic octahedral structure is more likely to expose the 110 crystal surface to form a Ti-O-Ir interface with the iridium cluster. Such a Ti-O-Ir interface can stabilize the structure of the iridium cluster loaded strontium titanate, significantly reduce the energy barrier of the oxygen evolution reaction, reduce the overpotential, greatly improve the activity of the oxygen evolution reaction, and significantly improve the electrocatalytic activity and cycle stability of the iridium cluster loaded strontium titanate. Moreover, the strontium titanate carrier induces Sr leaching to initiate carrier lattice oxygen-mediated OH formation when the voltage is applied, resulting in enrichment of OH at the Ti-O-Ir interface, which is conducive to the overflow of OH. This reverse OH lattice overflow assisted AEM (adsorbed oxygen oxidation mechanism with metal as the redox center when the electronic state near the Fermi level is metal) reaction pathway can avoid the traditional linear scaling relationship, thereby reducing the reaction energy barrier and improving the electrocatalytic activity of the iridium cluster loaded strontium titanate. In addition, the Ti-O-Ir interface effectively maintains the Ir site in a lower redox state, ensuring the stability of the iridium oxide even at challenging high potentials. The iridium cluster loaded strontium titanate provided by the application can be used as a catalyst for efficient and long-term stable operation of more than 800 h under the working conditions of a proton exchange membrane water electrolyzer (PEMWE), which is far superior to the performance and longest running time of commercial catalysts.

[0032] The application further provides a preparation method of the iridium cluster loaded strontium titanate.

[0033] The cubic octahedral strontium titanate, the iridium ion containing compound, the alkali source, the reducing alcohol, and water are mixed to perform a hydrothermal reaction, so as to obtain the iridium cluster loaded strontium titanate.

[0034] As an implementation form, the preparation method of the cubic octahedral strontium titanate comprises the following steps.

[0035] The titanium-containing compound, the first alkali source, the first reducing alcohol, the first strontium salt, and water are mixed to perform a first hydrothermal reaction, so as to obtain a strontium titanate precursor.

[0036] The strontium titanate precursor, an aluminum salt, and water are mixed, and the obtained mixture is dried and then mixed with a second strontium salt to perform calcination, so as to obtain the cubic octahedral strontium titanate.

[0037] The titanium-containing compound, the first alkali source, the first reducing alcohol, the first strontium salt, and water are mixed to perform a first hydrothermal reaction, so as to obtain a strontium titanate precursor.

[0038] As an implementation form, the titanium-containing compound includes titanium trichloride and / or titanium dioxide, and in particular embodiments, titanium trichloride. In embodiments of the present application, the titanium-containing compound is a TiCl3 solution; the TiCl3 solution is prepared by dissolving TiCl3 in 30 wt% HCl, and the mass concentration of TiCl3 in the TiCl3 solution is 15-20%, and in particular embodiments, 20%.

[0039] As an implementation form, the first alkali source is an alkali metal hydroxide; the alkali metal hydroxide includes one or more of potassium hydroxide, lithium hydroxide, cesium hydroxide, and sodium hydroxide, and in particular embodiments, potassium hydroxide, lithium hydroxide, cesium hydroxide, or sodium hydroxide; the mass ratio of the titanium-containing compound to the first alkali source is 0.01-2:1, and in particular embodiments, 0.05:1.

[0040] As an implementation form, the first reducing alcohol includes ethylene glycol and / or glycerol, and in particular embodiments, ethylene glycol; the water is ultrapure water; the mass ratio of the water to the first reducing alcohol is 20-100:1, and in particular embodiments, 55:1.

[0041] As an implementation form, the first strontium salt is strontium chloride, and in particular embodiments, strontium chloride hexahydrate; the mass ratio of the water to the first strontium salt is 20-100:1, and in particular embodiments, 55:0.74.

[0042] As an implementation form, the mass ratio of the first alkali source to the water is 1:10-100, and in particular embodiments, 4:55.

[0043] As an implementation form, the titanium-containing compound, the first alkali source, the first reducing alcohol, the first strontium salt, and the water are mixed by: adding the titanium-containing compound to the water containing the first reducing alcohol, performing first stirring, then adding an aqueous solution of the first alkali source, performing second stirring, and finally adding the strontium salt, performing third stirring; the stirring rate of the first stirring, the second stirring, and the third stirring is independently 1000 rpm; the stirring time of the first stirring, the second stirring, and the third stirring is independently 5-20 min, and in particular embodiments, 5-15 min. The present application does not have special limitations on the stirring rate of the first stirring, the second stirring, and the third stirring, and uniform stirring is sufficient.

[0044] As an implementation form, the temperature of the first hydrothermal reaction is 160-220°C, and in particular embodiments, 180-200°C; the time of the first hydrothermal reaction is 1-48 h, and in particular embodiments, 2-24 h; the equipment used for the first hydrothermal reaction is a stainless steel autoclave lined with polytetrafluoroethylene.

[0045] As an implementation form, after the first hydrothermal reaction, the product of the first hydrothermal reaction is cooled, and then solid-liquid separation is performed to obtain a solid, which is washed and dried to obtain a strontium titanate precursor.

[0046] As an implementation form, the cooling is cooling in ice water; the cooling is to room temperature; the solid-liquid separation is centrifugation; the centrifugation is performed at a speed of 5000-11000 rpm, and in a specific embodiment, the centrifugation is performed at a speed of 8000-10000 rpm for 3-10 min, and in a specific embodiment, the centrifugation is performed at a speed of 8000-10000 rpm for 5 min; the washing is water washing and alcohol washing in sequence; the reagent used in the water washing is ultrapure water; the reagent used in the alcohol washing is ethanol; the washing is performed until the supernatant is clear; the drying is performed at a temperature of 60-80℃, and in a specific embodiment, the drying is performed at a temperature of 60-70℃; the drying is vacuum drying; the vacuum degree of the vacuum drying is -0.1 MPa. The present application does not have a specific requirement for the time of the drying, and the drying is completed.

[0047] After obtaining the strontium titanate precursor, the present application mixes the strontium titanate precursor, an aluminum salt and water, and then performs drying to obtain a mixture, and then the mixture is mixed with a second strontium salt to perform calcination to obtain a cubic octahedral strontium titanate.

[0048] As an implementation form, the aluminum salt is aluminum chloride, and in a specific embodiment, the aluminum salt is AlCl3·6H2O; the molar ratio of Ti in the strontium titanate precursor to Al in the aluminum salt is 1:0.004-0.02, and in a specific embodiment, the molar ratio is 1:0.004. The aluminum salt acts as a template agent, and can accurately and controllably adjust the percentage of the {110} surface of the crystal.

[0049] As an implementation form, the second strontium salt is strontium chloride, and in a specific embodiment, the second strontium salt is strontium chloride hexahydrate; the molar ratio of Sr in the strontium titanate precursor to Sr in the second strontium salt is 1:8-10, and in a specific embodiment, the molar ratio is 1:10.

[0050] As an implementation form, the mixing of the strontium titanate precursor, the aluminum salt and water is: dispersing the strontium titanate precursor and the aluminum salt in water; the dispersing is performed under stirring; the stirring rate is 1000 rpm; the present application does not have a specific requirement for the stirring rate and time, and the stirring is uniformly performed.

[0051] As an implementation form, the ratio of the total mass of the strontium titanate precursor and the aluminum salt to the mass of water is 0.04-0.25:1, and in a specific embodiment, the ratio is 0.16:1.

[0052] As an embodiment, the drying temperature is 80-150℃, and in particular embodiments, 100-120℃; the drying is performed under stirring. The present application does not have special limitations on the stirring rate and drying time, and complete drying is sufficient. In embodiments of the present application, the stirring rate is 1000 rpm.

[0053] As an embodiment, the calcination temperature is 750-1250℃, and in particular embodiments, 1000-1150℃; the calcination holding time is 8-12h, and in particular embodiments, 9-10h; the temperature rising rate from room temperature to the calcination temperature is 3-5℃ / min, and in particular embodiments, 4℃ / min; the calcination is performed in air.

[0054] As an embodiment, after the calcination, the product of the calcination is cooled from the calcination temperature to room temperature, and then sequentially subjected to washing and drying; the cooling rate is 2-3℃ / min, and in particular embodiments, 2.5℃ / min; the washing reagent is water, and in particular embodiments, ultrapure water; the washing times are 2-5 times, and in particular embodiments, 3-4 times; the washing is centrifugal washing; the centrifugal washing speed is 5000-10000 rpm, and in particular embodiments, 8000-10000 rpm; the centrifugal washing time is 3-10 min, and in particular embodiments, 5 min; the drying temperature is 60-80℃, and in particular embodiments, 60℃; the present application does not have special requirements on the drying time, and complete drying is sufficient; the drying is vacuum drying; the vacuum degree of the vacuum drying is -0.1 MPa. In embodiments of the present application, the drying time is 12h.

[0055] As an embodiment, the compound containing iridium ions includes one or more of iridium chloric acid, iridium tetrachloride and potassium hexachloroiridate (IV), and in particular embodiments, iridium chloric acid; the molar ratio of Ir in the compound containing iridium ions to Sr in cubic octahedral strontium titanate is 1-2:1-8, and in particular embodiments, 2:1, 1:1, 1:2, 1:4 or 1:8.

[0056] As an embodiment, the alkali source is an alkali metal hydroxide; the alkali metal hydroxide includes one or more of potassium hydroxide, lithium hydroxide, cesium hydroxide and sodium hydroxide, and in particular embodiments, potassium hydroxide; the mass ratio of the compound containing iridium ions to the alkali source is 1.5-20:1, and in particular embodiments, 2-16:1.

[0057] As an implementation form, the reducing alcohol includes ethylene glycol and / or glycerol, and in particular embodiments, ethanol; the mass ratio of the compound containing iridium ions and the reducing alcohol is 0.00047-0.03:1, and in particular embodiments, 0.0034-0.029:1.

[0058] As an implementation form, the mass ratio of the compound containing iridium ions and water is 1:50-650, and in particular embodiments, 1:75-625.

[0059] As an implementation form, the cubic octahedral strontium titanate, the compound containing iridium ions, the alkali source, the reducing alcohol and water are mixed as follows: the cubic octahedral strontium titanate and the compound containing iridium ions are dispersed in water, and then the alkali source is added to the obtained dispersion liquid to perform first stirring, and then the reducing alcohol is added to perform second stirring; the stirring rate of the first stirring and the second stirring is not specifically required, and the stirring is uniform; the time of the first stirring and the second stirring is independently 5-40 min, and in particular embodiments, 5-30 min. In the embodiments of the present application, the stirring rate of the first stirring and the second stirring is 1000 rpm.

[0060] As an implementation form, the temperature of the hydrothermal reaction is 160-220℃, and in particular embodiments, 180-200℃; the time of the hydrothermal reaction is 12-36 h, and in particular embodiments, 18-24 h; the equipment used for the hydrothermal reaction is a stainless steel autoclave lined with polytetrafluoroethylene.

[0061] As an implementation form, after the hydrothermal reaction, the method further comprises: after the product of the hydrothermal reaction is cooled to room temperature, washing is performed; the washing is sequentially performed by water washing and alcohol washing; the number of times of the water washing is 2-5 times, and in particular embodiments, 2-4 times; the number of times of the alcohol washing is 2-5 times, and in particular embodiments, 2-4 times; the reagent used for the water washing is ultrapure water; the reagent used for the alcohol washing is ethanol; the washing is centrifugal washing; the rotation speed of each centrifugal washing is 5000-11000 rpm, and in particular embodiments, 8000-10000 rpm; the time of each centrifugal washing is 3-10 min, and in particular embodiments, 5-8 min.

[0062] The present application also provides an application of the iridium cluster loaded strontium titanate or the iridium cluster loaded strontium titanate prepared by the preparation method as an anode electrocatalyst in a proton exchange membrane water electrolyzer.

[0063] As an implementation form, the application is: electrolysis of water to produce hydrogen.

[0064] The present application also provides an anode of a proton exchange membrane water electrolyzer, which comprises an anode substrate and an anode electrocatalyst covering the surface of the anode substrate.

[0065] The anode electrocatalyst is the iridium cluster loaded strontium titanate in the technical solution or prepared by the preparation method.

[0066] As an embodiment, the preparation method of the anode of the proton exchange membrane water electrolyzer comprises the following steps: coating the iridium cluster loaded strontium titanate on the surface of the anode substrate; the anode substrate is Nafion 115 proton exchange membrane; the coating is spraying; the thickness of the coating is not specially limited in the application, and uniform spraying is enough.

[0067] The iridium cluster loaded strontium titanate provided by the application can be used as a catalyst for the proton exchange membrane water electrolyzer (PEMWE) to operate efficiently and stably for more than 800 hours under the working conditions, which is far more than the performance and the longest operation time of commercial catalysts.

[0068] The technical solutions in the application will be clearly and completely described below in combination with the embodiments in the application, but they should not be understood as limitations to the protection scope of the application.

[0069] All the chemicals are obtained from commercial suppliers in analytical grade and used as received without further purification. Iridium chloric acid (H2IrCl6), ethylene glycol (EG), potassium hydroxide (KOH), titanium chloride solution (TiCl3), strontium chloride hexahydrate (SrCl2·6H2O), aluminum chloride hexahydrate (AlCl3·6H2O), lithium hydroxide monohydrate (LiOH·H2O) are purchased from Aladdin. Embodiments

[0070] (1) Synthesis of strontium titanate precursor: 0.8 mL of 20wt% TiCl3 solution (TiCl3 dissolved in 30wt% HCl) was added to 25 mL of ultrapure water containing 0.9 mL of ethylene glycol cooled in an ice bath and stirred at 1000 rpm for 5 min, then 30 mL of LiOH aqueous solution containing 4.0 g of LiOH·H2O was added, stirred at 1000 rpm for 15 min, then 0.74 g of SrCl2·6H2O was added and stirred at 1000 rpm for 10 min, then the mixed raw materials were transferred to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene, and a first hydrothermal reaction was carried out at 180℃ for 2h, after the reaction was completed, the autoclave was directly immersed in ice water to cool quickly to room temperature, and the precipitate was recovered by centrifugation at 10000 rpm for 5 min, then washed with ultrapure water and ethanol until the supernatant was clear, then vacuum dried at 60℃ under a vacuum degree of-0.1 MPa for 12h to obtain the strontium titanate precursor;

[0071] (2) Synthesis of cubic octahedral strontium titanate in SrCl2·6H2O molten salt: The above strontium titanate precursor and AlCl3·6H2O were mixed at a molar ratio of 1:0.004 (Ti / Al molar ratio), dispersed in 20 mL of ultrapure water with stirring at 1000 rpm, and evaporated to complete dryness in an evaporating dish at 120°C with continuous stirring at 1000 rpm. The resulting mixture was collected and mixed with SrCl2·6H2O at a molar ratio of 1:10 of Sr in the strontium titanate precursor to Sr in the SrCl2·6H2O. Then, the mixture was calcined in an alumina crucible in air at a temperature rising rate of 4°C / min from room temperature to 1150°C for 10 h, and then cooled at a rate of 2.5°C / min to room temperature. The product was washed by centrifugation three times with ultrapure water at a speed of 10000 rpm for 5 min each time, and then dried in a vacuum drying chamber at a vacuum degree of -0.1 MPa at 60°C for 12 h to obtain cubic octahedral strontium titanate. Example

[0072] First, 80.06 mg of H2IrCl6 and 18.04 mg of cubic octahedral strontium titanate prepared in Example 1 were dispersed in 25 mL of water at a molar ratio of 2:1 of Ir in the H2IrCl6 to Sr in the cubic octahedral strontium titanate. Then, 20 mg of KOH was added to the dispersion, stirred at 1000 rpm for 5 min, and then 10 mL of ethylene glycol (1.1135 g / cm 3 at 20°C) was added, and stirred at 1000 rpm for 30 min. The resulting mixture was transferred to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene, and subjected to hydrothermal reaction at 180°C for 24 h. After cooling to room temperature, the product was washed by centrifugation twice with water and ethanol, respectively, at a speed of 10000 rpm for 5 min each time to obtain iridium cluster-loaded strontium titanate (IrO2-y@SrTiO3-x (2:1), where SrTiO2.72, 0 < y < 2, and the diameter was 200 nm, and the iridium element accounted for 41.83%). Example

[0073] The difference from Example 2 is that the molar ratio of Ir in the H2IrCl6 to Sr in the cubic octahedral strontium titanate was 1:1, and iridium cluster-loaded strontium titanate (IrO 2-y @SrTiO 3-x (1:1)) was obtained. Example

[0074] The difference from Example 2 is that the molar ratio of Ir in the H2IrCl6 to Sr in the cubic octahedral strontium titanate was 1:2, and iridium cluster-loaded strontium titanate (IrO 2-y @SrTiO 3-x (1:2)) was obtained. Example

[0075] The difference from Example 2 is that the molar ratio of Ir in H2IrCl6 and Sr in cubic octahedral strontium titanate is 1:4, to obtain the iridium cluster loaded strontium titanate (IrO 2-y @SrTiO 3-x (1:4) ). Example

[0076] The difference from Example 2 is that the molar ratio of Ir in H2IrCl6 and Sr in cubic octahedral strontium titanate is 1:8, to obtain the iridium cluster loaded strontium titanate (IrO 2-y @SrTiO 3-x (1:8) ).

[0077] The difference from Example 2 is that H2IrCl6 is removed in the process of synthesizing IrO 2-y @SrTiO 3-x in Example 2, and a hydrothermal reaction is carried out to obtain a strontium titanate material (SrTiO 3-x ).

[0078] A commercial catalyst IrO2 (C-IrO2) is used as a comparative example.

[0079] The iridium cluster loaded strontium titanate prepared in Example 2 is sprayed on the surface of an anode substrate (Nafion 115 proton exchange membrane) of a proton exchange membrane water electrolyzer to electrolyze water to produce hydrogen.

[0080] The difference from Application Example 1 is that the iridium cluster loaded strontium titanate prepared in Example 2 is replaced by the iridium cluster loaded strontium titanate prepared in Examples 3-6, respectively.

[0081] The difference from Application Example 1 is that the iridium cluster loaded strontium titanate prepared in Example 2 is replaced by the strontium titanate material (SrTiO 3-x ) prepared in Comparative Example 1.

[0082] The difference from Application Example 1 is that the iridium cluster loaded strontium titanate prepared in Example 2 is replaced by the commercial catalyst IrO2 (C-IrO2) of Comparative Example 2.

[0083] (1) Figure 1 is an XRD characterization diagram of the iridium cluster loaded strontium titanate prepared in Example 2.

[0084] As can be seen from Figure 1 , the iridium cluster is loaded on the strontium titanate carrier, and the iridium cluster loaded strontium titanate prepared by the application is consistent with the SrTiO 2.72 peak in XRD characterization.

[0085] (2) Figure 2SrTiO 3-x ) and the OER polarization curve of commercial catalyst IrO2(C-IrO2) in Comparative Example 2.

[0086] As can be seen from Figure 2 , IrO 2-y @SrTiO 3-x (2:1) has the best performance, showing only 202 mV overpotential at a current density of 10 mA·cm -2 , and has a great advantage compared with the commercial catalyst.

[0087] (3) Figure 3 The OER polarization curve of iridium cluster loaded strontium titanate prepared in Example 2 and the strontium titanate material (SrTiO 3-x ) prepared in Comparative Example 1.

[0088] As can be seen from Figure 3 , the pure SrTiO 3-x carrier has no OER activity.

[0089] (4) Figure 4 The polarization curve of the proton exchange membrane water electrolyzer (PEMWE) using the commercial catalyst IrO2(Com-IrO2) in Comparative Example 2 as the anode electrocatalyst.

[0090] As can be seen from Figure 4 , under the working conditions of PEMWE (80℃), the commercial catalyst IrO2(Com-IrO2) reaches 2 A·cm -2 current density requires 1.97 V, reaches 1 A·cm -2 current density requires 1.77 V.

[0091] (5) Figure 5 The polarization curve of the proton exchange membrane water electrolyzer (PEMWE) using the iridium cluster loaded strontium titanate prepared in Example 2 as the anode electrocatalyst.

[0092] As can be seen from Figure 5 , under the working conditions of PEMWE (80℃), the iridium cluster loaded strontium titanate reaches 2 A·cm -2 current density only requires 1.854 V, reaches 1 A·cm -2 current density only requires 1.662 V. The iridium cluster loaded strontium titanate has a great advantage compared with the commercial catalyst IrO2(Com-IrO2).

[0093] (6) Figure 6 The polarization curve of the proton exchange membrane water electrolyzer (PEMWE) using the iridium cluster loaded strontium titanate prepared in Example 2 as the anode electrocatalyst. -2and the constant current test result graph at 80℃.

[0094] From Figure 6 It can be seen that the iridium cluster loaded strontium titanate can be stably operated at 1A·cm -2 under the working condition of PEMWE (80℃) without obvious performance decline for 800h, which exceeds the catalysts in most current researches. It shows that the iridium cluster loaded strontium titanate prepared by the present application has stable active metal Ir.

[0095] Although the above embodiment has made a detailed description of the present application, it is only a part of the embodiments of the present application but not all the embodiments. Other embodiments can be obtained according to the present embodiment without creativity, which all belong to the protection scope of the present application.

Claims

1. A strontium titanate supported on iridium clusters, characterized in that, include: Strontium titanate and iridium clusters supported on the surface of the strontium titanate; the iridium clusters consist of elemental iridium and iridium oxides coated on the surface of the elemental iridium; the chemical composition of the strontium titanate is SrTiO₂. 3-x , 0 < x < 0.5; the chemical composition of the iridium oxide is IrO. 2-y , 0 < y < 2; the strontium titanate has a cubic octahedral structure; The method for preparing the strontium titanate loaded with iridium clusters includes the following steps: Strontium titanate with cubic octahedral structure, iridium-containing compound, base source, reducing alcohol and water are mixed and subjected to hydrothermal reaction to obtain iridium-supported strontium titanate. The method for preparing the cubic octahedral strontium titanate includes the following steps: A titanium-containing compound, a first alkali source, a first reducing alcohol, a first strontium salt, and water are mixed and subjected to a first hydrothermal reaction to obtain a strontium titanate precursor. The strontium titanate precursor, aluminum salt, and water are mixed and dried. The resulting mixture is then calcined with a second strontium salt to obtain cubic octahedral strontium titanate.

2. The strontium titanate supported on iridium clusters according to claim 1, characterized in that, The diameter of the strontium titanate loaded with iridium clusters is 150~300 nm.

3. The strontium titanate supported on iridium clusters according to claim 1 or 2, characterized in that, The iridium content in the strontium titanate loaded with iridium clusters is 1-60% by mass.

4. The method for preparing strontium titanate loaded with iridium clusters as described in any one of claims 1 to 3, characterized in that, Includes the following steps: Strontium titanate with cubic octahedral structure, iridium-containing compound, base source, reducing alcohol and water are mixed and subjected to hydrothermal reaction to obtain iridium-supported strontium titanate. The method for preparing the cubic octahedral strontium titanate includes the following steps: A titanium-containing compound, a first alkali source, a first reducing alcohol, a first strontium salt, and water are mixed and subjected to a first hydrothermal reaction to obtain a strontium titanate precursor. The strontium titanate precursor, aluminum salt, and water are mixed and dried. The resulting mixture is then calcined with a second strontium salt to obtain cubic octahedral strontium titanate.

5. The preparation method according to claim 4, characterized in that, The iridium-containing compounds include one or more of iridium chloride, iridium tetrachloride, and potassium hexachloroiridium(IV)ate.

6. The preparation method according to claim 4, characterized in that, In the step of obtaining strontium titanate loaded with iridium clusters, the alkali source is an alkali metal hydroxide; the alkali metal hydroxide includes one or more of potassium hydroxide, lithium hydroxide, cesium hydroxide, and sodium hydroxide.

7. The preparation method according to claim 4, characterized in that, In the step of obtaining strontium titanate loaded with iridium clusters, the reducing alcohols include ethylene glycol and / or glycerol.

8. The preparation method according to claim 4, characterized in that, In the step of obtaining strontium titanate loaded with iridium clusters, the hydrothermal reaction temperature is 160~220℃ and the time is 12~36h.

9. The application of strontium titanate with iridium clusters as described in any one of claims 1 to 3 or strontium titanate with iridium clusters prepared by the preparation method described in any one of claims 4 to 8 as an anode electrocatalyst in a proton exchange membrane water electrolyzer.

10. An anode for a proton exchange membrane water electrolyzer, characterized in that, Includes an anode substrate and an anode electrocatalyst coated on the surface of the anode substrate; The anodic electrocatalyst is strontium titanate with iridium clusters as described in any one of claims 1 to 3, or strontium titanate with iridium clusters prepared by the preparation method described in any one of claims 4 to 8.

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