Oxide-loaded noble metal catalyst as well as preparation method and application thereof

Abstract

The invention relates to an oxide-loaded noble metal catalyst as well as a preparation method and application thereof, and belongs to the technical field of electro-catalytic materials. The preparation method of the oxide-loaded noble metal catalyst comprises the following steps: S1, dissolving a noble metal source and an oxide carrier in an organic solvent, and performing uniform stirring and ultrasonic treatment to obtain a mixed solution; s2, adding a certain amount of nitrate into the mixed solution, and stirring to obtain a precursor mixture; and S3, calcining the precursor mixture to obtain a solid product, carrying out suction filtration and washing, and drying to obtain the oxide-loaded noble metal catalyst. The oxide-loaded noble metal catalyst disclosed by the invention shows relatively excellent electrochemical performance in electrolyzed water; the catalyst provided by the invention has good application prospects in the fields of electrocatalysis, photocatalysis, organic catalysis, biological diagnosis and treatment and the like, and especially has important research significance in promoting the industrialization process of the catalyst taking an oxide as a carrier in electrolyzed water.

Description

Technical Field

[0001] The present application relates to the technical field of electrocatalytic materials, and in particular to an oxide-supported noble metal catalyst and a preparation method and application thereof. Background Art

[0002] As global energy structure and environmental pollution issues become increasingly severe, building a clean and sustainable energy system has become the key to meeting these challenges. Hydrogen energy has been valued and supported by governments of many countries due to its high energy density and zero emissions.

[0003] The process of electrolyzing water using renewable energy is considered to be a promising and sustainable way to produce clean hydrogen. Water electrolysis is a process that uses electrical energy to decompose water into hydrogen and oxygen. It mainly relies on electrolysis reactions and is usually achieved through electrolyzers or electrolytic cells. At present, water electrolysis technologies mainly include two main types: alkaline water electrolysis and proton exchange membrane (PEM) water electrolysis. Although alkaline water electrolysis technology is mature and low-cost, its widespread use in certain high-demand applications is limited by problems such as low energy efficiency, slow reaction rate, catalyst corrosion, and hydrogen purity. In contrast, proton exchange membrane water electrolysis has high hydrogen production capacity, high-purity hydrogen, low operating temperature, non-corrosiveness, and good compatibility with renewable energy. Due to its high system efficiency, flexibility, and environmental friendliness, PEM water electrolysis is considered to be a key technology for future green hydrogen production, especially suitable for combining with renewable energy to promote energy transformation and sustainable development.

[0004] However, the life and cost of anode catalysts are the main obstacles to the large-scale application of PEM water electrolyzers, which directly affect the economy and long-term stability of the system. Improving catalyst performance, reducing costs and extending life are the keys to promoting the widespread application of PEMWE technology. Due to the harsh environment of acidic media, iridium-based precious metal catalysts are often used for OER, but their high cost and relatively low activity limit the popularity of industrial applications. Therefore, it is urgent to develop iridium-based acidic OER catalysts with good durability and low cost, which is of great significance to promote the commercialization of PEM electrolyzers. Summary of the invention

[0005] In view of this, the present application provides an oxide-loaded precious metal catalyst and a preparation method and application thereof, which reduces the precious metal loading and improves the activity of the catalyst, reduces the cost of the acidic OER catalyst, is of great significance to promoting the commercialization process of proton exchange membrane water electrolyzer (PEMWE), and can effectively overcome the defects of the above-mentioned prior art.

[0006] The first aspect of the present application provides a method for preparing an oxide-supported noble metal catalyst, comprising the following steps:

[0007] S1, dissolving the noble metal source and the oxide carrier in an organic solvent, stirring and ultrasonically uniformly obtaining a mixed solution;

[0008] S2, adding a certain amount of nitrate to the mixed solution, stirring to obtain a precursor mixture;

[0009] S3, calcining the precursor mixture to obtain a solid product, filtering and washing the solid product, and drying the solid product to obtain an oxide-supported noble metal catalyst.

[0010] Preferably, in step S3, the specific conditions for calcination are: placing the precursor mixture in a muffle furnace, heating it from room temperature to 360-410°C at a heating rate of 2-10°C / min in an air atmosphere, and keeping it at this temperature for 15min-2h.

[0011] Preferably, in step S3, the specific conditions of the filtration and washing are: the solvents for filtration and washing are ultrapure water, and the number of washings is 4 times, 100-125 ml of ultrapure water is used for each washing, and the total volume of ultrapure water used is 400-500 ml; or

[0012] In step S3, the specific conditions of drying are: placing in a blast drying oven, drying temperature is 60-80°C, and drying time is 6-12h; or

[0013] In step S3, the drying is performed by vacuum drying, the vacuum drying temperature is 60-80° C., and the vacuum drying time is 6-12 hours.

[0014] Preferably, in step S2, the nitrate is potassium nitrate and / or sodium nitrate; or

[0015] In step S2, the specific conditions of the stirring are: stirring time is more than 6 hours at a temperature below 20°C.

[0016] Preferably, in step S1, the specific conditions of the stirring ultrasound are: ultrasonic stirring is performed alternately 3-5 times at a temperature below 20°C, and the ultrasonic time is 30 minutes and the stirring time is 15 minutes.

[0017] Preferably, in step S1, the noble metal is an iridium source, and the iridium source is K 3 IrCl 6 、IrCl 3 .XH 2 O.K 2 IrCl 6 、Na 2 IrCl 6 At least one of; the oxide carrier is a zirconium oxide carrier; the organic solvent is isopropanol; or

[0018] The iridium source is K 3 IrCl 6 , the K 3 IrCl 6 The dosage ratio of zirconium oxide carrier, isopropanol and nitrate is (1-20 mg): 20 mg: 1.5 ml: 2 g.

[0019] Specifically, a method for preparing a zirconium oxide-supported noble metal iridium dioxide catalyst comprises the following steps:

[0020] The iridium source and the zirconium oxide carrier are dissolved in isopropanol, and ultrasonic treatment is performed for 30 minutes and stirring is performed for 15 minutes at a temperature below 20°C for four times to obtain a mixed solution of the iridium source carrier; a certain amount of nitrate is weighed and added to the mixed solution of the iridium source carrier, and stirring is performed at a temperature below 20°C for more than 6 hours, so that the iridium source carrier is uniformly loaded on the nitrate, and the isopropanol is volatilized to obtain a precursor mixture; the precursor mixture is then placed in a muffle furnace, and the temperature is increased from room temperature to 360-410°C at a heating rate of 2-10°C / min in an air atmosphere, and the temperature is kept at this temperature for 15 minutes to 2 hours to obtain a mixture of a zirconium oxide-loaded noble metal iridium dioxide catalyst and a certain amount of residual salt; the mixture of the zirconium oxide-loaded noble metal iridium dioxide catalyst and a certain amount of residual salt is filtered, washed, and dried to remove the residual salt to obtain the zirconium oxide-loaded noble metal iridium dioxide catalyst.

[0021] The second aspect of the present application also provides an oxide-supported precious metal catalyst prepared according to the above-mentioned method for preparing an oxide-supported precious metal catalyst, wherein the oxide-supported precious metal catalyst uses an oxide as a carrier, and the precious metal is supported on the carrier in a molecularly dispersed form.

[0022] The third aspect of the present application also provides an application of the above-mentioned oxide-supported precious metal catalyst as an anode catalyst in the electrolysis of water to produce hydrogen.

[0023] The fourth aspect of the present application also provides a proton exchange membrane water electrolysis device, comprising a proton exchange membrane, a cathode catalyst layer, an anode catalyst layer, a cathode diffusion layer and an anode diffusion layer, wherein the anode catalyst layer is the above-mentioned oxide-loaded precious metal catalyst.

[0024] The fifth aspect of the present application also provides a method for producing hydrogen by electrolyzing water, using the above-mentioned oxide-loaded precious metal catalyst, or using the above-mentioned proton exchange membrane water electrolysis device.

[0025] Compared with the prior art, this application has the following beneficial effects:

[0026] (1) The oxide-supported precious metal catalyst in the present application, on the one hand, applies a semiconductor material that is resistant to acid corrosion and oxidative decomposition to electrolyzed water; on the other hand, it fully exposes the active sites of the iridium-based catalyst, increases the utilization rate of iridium, and improves the quality activity of the catalyst.

[0027] (2) The preparation method in this application can be easily extended to the preparation of other oxide-loaded other precious metal catalysts. It is a universal method with universal applicability.

[0028] (3) The oxide-supported precious metal catalysts in the present application exhibit relatively excellent electrochemical properties in water electrolysis, providing a new research scheme for the industrial application of water electrolysis; the oxide-supported precious metal catalysts obtained by the preparation method of the present application have good application prospects in the fields of electrocatalysis, photocatalysis, organic catalysis, biodiagnosis and treatment, and are particularly important in promoting the industrialization of catalysts with oxides as carriers in water electrolysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present application or the prior art, the drawings required for use in the description of the present application or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 IrO in Example 1 of this application 2 / ZrO 2 A schematic diagram of the preparation method of

[0031] Figure 2 The ZrO in Example 1 of the present application 2 XRD pattern of

[0032] Figure 3 IrO in Example 1 of this application 2 / ZrO 2 XRD pattern of

[0033] Figure 4 The ZrO in Example 1 of the present application 2 SEM images of

[0034] Figure 5 IrO in Example 1 of this application 2 / ZrO 2 SEM images of

[0035] Figure 6 IrO in Example 1 of this application 2 / ZrO 2and commercial IrO 2 Performance graph of the PEM. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0037] Unless otherwise specified, the experimental methods used in the examples of this application are all conventional methods.

[0038] In the following examples and comparative examples, unless otherwise specified, all raw materials can be obtained by commercial purchase or conventional methods.

[0039] Currently in the field of electrochemical water splitting, the development of high-performance acidic OER electrocatalysts with excellent activity and durability is a key issue in promoting the large-scale application of PEM electrolyzers in large-scale hydrogen production.

[0040] High-efficiency electrocatalysts should have excellent catalytic activity and a reasonable cost structure to meet the needs of practical applications. In view of the harsh chemical environment in acidic media, only a few materials can be used as PEM anode catalysts, and the current mainstream catalysts are iridium-based precious metals. However, the high cost of iridium significantly restricts its popularity in large-scale commercial applications. Therefore, the development of iridium-based acidic OER catalysts with both excellent performance and economic advantages is of vital importance to promote the industrialization and widespread application of proton exchange membrane water electrolyzer (PEMWE) technology.

[0041] Example 1

[0042] like Figure 1 As shown, the preparation method of the zirconium oxide supported noble metal iridium dioxide catalyst in this embodiment specifically comprises the following steps:

[0043] Weigh 20 mg ZrO 2 Carrier and 20m g K 3 IrCl 6Dispersed in 1.5 ml isopropanol solution and placed in a 20 ml glass bottle, ultrasonicated for 30 min and stirred for 15 min at below 16 ° C for 3 times to obtain a uniform mixed solution; then 2 g of sodium nitrate was added to the mixed solution, and continued to stir for 6 h at below 16 ° C to obtain a yellow solid salt powder (i.e., precursor); the powder (i.e., precursor) was placed in a muffle furnace, heated to 360 ° C at a heating rate of 2 ° C / min in an air atmosphere, and kept warm for 2 h for sintering to obtain black IrO 2 / ZrO 2 The catalyst and part of the salt crystals were filtered and washed with a large amount of ultrapure water for 4 times, with 125 ml of ultrapure water used for each washing, and the total volume of ultrapure water used was 500 ml. Then, the mixture was placed in a blast drying oven at a drying temperature of 70 ° C and a drying time of 10 h to obtain pure IrO 2 / ZrO 2 Catalyst (i.e., prepared successfully).

[0044] Figure 2 X-ray diffraction phase analysis (XRD) revealed that ZrO 2 It matches well with the standard card PDF-86-1449 of zirconium oxide, proving that the type of carrier has been successfully prepared.

[0045] Figure 3 X-ray diffraction phase analysis (XRD) revealed that IrO 2 / ZrO 2 It matches well with the standard card PDF-86-1449 of zirconium oxide and the standard card PDF-86-0330 of iridium dioxide, proving the successful preparation of the zirconium oxide-loaded noble metal iridium dioxide catalyst.

[0046] Figure 4 The ZrO 2 For very small nanoparticles, Figure 5 Scanning electron microscopy (SEM) was used to observe the IrO 2 / ZrO 2 The morphology is IrO 2 Loading to ZrO 2 On the surface.

[0047] Figure 6 Tested IrO 2 / TiO 2 -TiO 2 The performance graph of PEM demonstrates its superior performance.

[0048] Example 2

[0049] The preparation method of the zirconium oxide-supported noble metal iridium dioxide catalyst provided in this embodiment can refer to Example 1, except that the calcination temperature is 410° C. and the calcination time is 15 min.

[0050] Example 3

[0051] The preparation method of the zirconium oxide-supported noble metal iridium dioxide catalyst provided in this embodiment can refer to Example 1, except that the calcination temperature is 380° C. and the calcination time is 1 hour.

[0052] Comparative Example 1

[0053] Commercial IrO 2 Catalyst. Iridium dioxide Molecular formula: IrO 2 ; CAS number: 12030-49-8; MDL number: MFCD00011065.

[0054] Anode oxygen evolution performance test example

[0055] A linear scan test was performed using a PEM membrane electrode at a scan rate of 10 mV / s. Figure 6 The IrO prepared in Example 1 is shown. 2 / ZrO 2 Catalyst, commercial IrO in Comparative Example 1 2 The OER polarization curve of the catalyst in PEM is based on Figure 6 The polarization curve shows that the catalyst prepared in Example 1 performs better than the commercial IrO catalyst with a low loading. 2 The catalyst prepared in Example 1 exhibits oxygen evolution performance superior to that of .

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing an oxide-supported noble metal catalyst, characterized in that: The following steps are involved: S1, dissolving the noble metal source and the oxide carrier in an organic solvent, stirring and ultrasonically uniformly obtaining a mixed solution; S2, adding a certain amount of nitrate to the mixed solution, stirring to obtain a precursor mixture; S3, calcining the precursor mixture to obtain a solid product, filtering and washing the solid product, and drying the solid product to obtain an oxide-supported noble metal catalyst.

2. The method for preparing an oxide-supported noble metal catalyst according to claim 1, characterized in that: In step S3, the specific conditions of the calcination are: placing the precursor mixture in a muffle furnace, heating it from room temperature to 360-410°C at a heating rate of 2-10°C / min in an air atmosphere, and keeping it at this temperature for 15min-2h.

3. The method for preparing an oxide-supported noble metal catalyst according to claim 1, characterized in that: In step S3, the specific conditions of the filtration and washing are: the solvents for filtration and washing are ultrapure water, and the number of washings is 4 times, 100-125 ml of ultrapure water is used for each washing, and the total volume of ultrapure water used is 400-500 ml; or In step S3, the specific conditions of drying are: placing in a blast drying oven, drying temperature is 60-80°C, and drying time is 6-12h; or In step S3, the drying is performed by vacuum drying, the vacuum drying temperature is 60-80° C., and the vacuum drying time is 6-12 h.

4. The method for preparing an oxide-supported noble metal catalyst according to claim 1, characterized in that: In step S2, the nitrate is potassium nitrate and / or sodium nitrate; or In step S2, the specific conditions of the stirring are: stirring time is more than 6 hours at a temperature below 20°C.

5. The method for preparing an oxide-supported noble metal catalyst according to claim 1, characterized in that: In step S1, the specific conditions of the stirring ultrasound are: ultrasonic stirring is performed alternately 3-5 times at a temperature below 20°C, and the ultrasonic time is 30 minutes and the stirring time is 15 minutes.

6. The method for preparing an oxide-supported noble metal catalyst according to claim 1, characterized in that: In step S1, the noble metal is an iridium source, and the iridium source is at least one of K3IrCl6, IrCl3.XH2O, K2IrCl6, and Na2IrCl6; the oxide carrier is a zirconium oxide carrier; and the organic solvent is isopropanol; or The iridium source is K3IrCl6, and the dosage ratio of K3IrCl6, zirconium oxide carrier, isopropanol and nitrate is (1-20 mg): 20 mg: 1.5 ml: 2 g.

7. The oxide-supported noble metal catalyst prepared by the method for preparing an oxide-supported noble metal catalyst according to any one of claims 1 to 6, characterized in that: The oxide-supported noble metal catalyst uses oxide as a carrier, and the noble metal is supported on the carrier in a molecularly dispersed form.

8. Use of the oxide-supported noble metal catalyst as claimed in claim 7 as an anode catalyst in the electrolysis of water to produce hydrogen.

9. A proton exchange membrane water electrolysis device, comprising a proton exchange membrane, a cathode catalyst layer, an anode catalyst layer, a cathode diffusion layer and an anode diffusion layer, characterized in that: The anode catalyst layer is the oxide-supported noble metal catalyst as described in claim 7.

10. A method for producing hydrogen by electrolyzing water, characterized in that: Use the oxide-supported noble metal catalyst described in claim 7, or use the proton exchange membrane water electrolysis device described in claim 9.

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