A nanorod-like K2Ti8O2 surface loaded with IrO2 nanoparticles 17 Catalyst, process for its preparation and use

Abstract

The application discloses a kind of nanorod-shaped K2Ti8O 17 Catalyst and its preparation method and application, comprising the following steps: K2Ti8O 17 Nanowire is broken to obtain nanorod-shaped K2Ti8O 17 Mixed with IrCl3·3H2O and solvent to obtain dispersion suspension, after adding reducing agent reaction, nanorod-shaped K2Ti88 loaded with Ir is obtained 17 Intermediate material is placed in the oxygen environment of 250-550 DEG C and is reacted to obtain nanorod-shaped K2Ti8O 17 Catalyst loaded with IrO2 nanoparticles on the surface of nanorod-shaped K2Ti8O 17 The uniformity of the catalyst loaded on the carrier is high, the particle size is small, there is no agglomeration phenomenon, the catalyst morphology is regular, and the catalyst has good acidic OER catalytic performance; the preparation method is simple, the cost is low, the controllability is good, the result repeatability is high, and industrial production is easy to realize.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to a nanorod-shaped K2Ti8O with IrO2 nanoparticles supported on its surface. 17 Catalysts, their preparation methods, and applications. Background Technology

[0002] Proton exchange membrane acidic water electrolysis for hydrogen production is currently widely recognized as the most promising green hydrogen production technology. It boasts advantages such as high hydrogen purity, compact structure, low operating costs, and rapid response to load changes, making it significant for addressing environmental and energy shortage issues. However, the high cost of this technology currently hinders its widespread application and urgently needs optimization, most notably the anolyte OER (oxygen evolution reaction) catalyst.

[0003] Oxygen evolution reaction (OER) is a four-electron process characterized by high reaction barriers and slow kinetics. Furthermore, since it involves oxygen evolution, the anode catalyst operates in a strongly oxidizing and acidic environment, placing high demands on its stability. Regarding the selection of anode catalyst materials, considering the poor stability of common noble metals under acidic oxidation conditions, only Ir and its oxides have achieved relatively mature commercial applications. However, Ir reserves are low and costs are high, necessitating modification and optimization to reduce costs and increase efficiency. Among current catalyst modification strategies, introducing a support is a highly effective approach, significantly reducing the loading of noble metals while maintaining catalyst activity, and has become a research focus in recent years.

[0004] Currently, researchers have developed and designed a series of unique supported catalysts, achieving both reduced Ir loading and enhanced catalytic activity, demonstrating the enormous potential of supported catalysts, as exemplified by patents CN114990615A and CN115369422A. However, existing supported catalysts still face challenges such as uneven distribution of defects on the support surface, low density leading to unsatisfactory Ir loading distribution, and large support size resulting in Ir waste.

[0005] Meanwhile, in the loading process of Ir, the currently widely used mixed salt oxidation method also has problems such as low loading density, excessively large loading particle size, and even Ir agglomeration, which seriously hinder the manifestation of the carrier's advantages, such as patents CN116329561A and CN116377481A. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a nanorod-shaped K2Ti8O nanoparticle-supported surface-mounted IrO2 nanoparticle-supported structure. 17 Catalysts, their preparation methods and applications, using nanorod-shaped K2Ti8O 17Using IrCl3·3H2O as the reaction raw material, nanorod-shaped K2Ti8O nanoparticles with surface-loaded IrO2 nanoparticles were prepared by a simple room-temperature reduction and thermal oxidation method. 17 Catalyst, IrO2 nanoparticles in nanorod-shaped K2Ti8O 17 The catalyst exhibits high uniformity of loading on the support, small particle size, no agglomeration, regular catalyst morphology, and excellent acidic OER catalytic performance. The preparation method is simple, controllable, and yields highly reproducible results.

[0007] To address the aforementioned technical problems, this invention provides, in one aspect, a nanorod-shaped K2Ti8O nanoparticle-loaded on its surface. 17 The catalyst preparation method includes the following steps:

[0008] S1, K2Ti8O 17 Nanowires were broken down to obtain nanorod-shaped K2Ti8O. 17 ;

[0009] S2, the nanorod-shaped K2Ti8O 17 The mixture was mixed with IrCl3·3H2O and a solvent to obtain a dispersion suspension;

[0010] S3. Add a reducing agent to the dispersion suspension, and after the reaction, obtain nanorod-shaped K2Ti8O with Ir surface loaded. 17 intermediate materials;

[0011] S4. The intermediate material is placed in an aerobic environment at 250-550℃, and after reaction, nanorod-shaped K2Ti8O with IrO2 nanoparticles loaded on the surface is obtained. 17 catalyst.

[0012] This invention employs a hydrothermal method to synthesize nanowire-like K2Ti8O with multiple surface defects. 17 The K2Ti8O nanorods were obtained by crushing and adjusting their size. 17 The carrier was mixed with IrCl3·3H2O and a solvent to obtain a dispersion suspension. The solvent was heated to dissolve the IrCl3·3H2O, and the reaction process did not require heating. Under the action of a reducing agent, Ir was loaded onto the surface of the multi-defect nanorod-shaped carrier. After a thermal oxidation reaction, nanorod-shaped K2Ti8O nanoparticles with surface-loaded IrO2 nanoparticles were obtained. 17 Catalyst. Nanorod-shaped K₂Ti₈O 17 The IrO2 nanoparticles loaded on the support surface have high uniformity and small particle size, with particle size as small as a few nanometers. They do not exhibit agglomeration and have a regular catalyst shape. They have excellent acidic OER catalytic performance and can be widely used in the oxygen evolution reaction of acidic water electrolysis to produce hydrogen. The preparation method is simple, controllable, and has high reproducibility.

[0013] The K2Ti8O with multiple surface defects in this invention 17 The microstructure of the carrier determines its excellent charge transfer capability, and the K2Ti8O after crushing treatment... 17 The surface of the carrier has a high density of defects and active sites, which enables more uniform loading of IrO2 nanoparticles.

[0014] Furthermore, the solvent is deionized water, which can be partially mixed with K2Ti8O. 17 Mixing, partially mixing with IrCl3·3H2O, or any other combination of the three to form a dispersion suspension.

[0015] Furthermore, the nanorod-shaped K2Ti8O 17 The diameter is 20-200nm, such as 20nm, 30nm, 50nm, 75nm, 100nm, 200nm, etc., and including but not limited to these, and the length is less than 1μm, such as 50nm, 100nm, 200nm, 500nm, 600nm, 800nm, etc., and including but not limited to these.

[0016] Furthermore, the particle size of the IrO2 nanoparticles is 1-100nm, such as 1nm, 5nm, 10nm, 20nm, 50nm, 75nm, 100nm, etc., including but not limited to these. The size of the IrO2 nanoparticles is affected by the concentration of IrCl3·3H2O in the dispersion suspension. Adjusting the concentration of IrCl3·3H2O in the dispersion suspension can adjust the size of the IrO2 nanoparticles.

[0017] Furthermore, the K2Ti8O 17 The mass ratio of IrCl3·3H2O to IrCl3·3H2O is (1-5):(1-5).

[0018] Furthermore, the reducing agent is one or more of ammonia, sodium borohydride, and citric acid.

[0019] Furthermore, the amount of the reducing agent is greater than or equal to the amount of IrCl3·3H2O.

[0020] Furthermore, the crushing process is one or more of ultrasonication, grinding, and ball milling.

[0021] Furthermore, in S3, the reaction time is 2-20 hours;

[0022] And / or, the reaction may further include a step of washing the precipitate with deionized water and drying it, wherein the drying temperature is 50-80℃.

[0023] Furthermore, in S4, the reaction time is 0.5-5 hours.

[0024] The second aspect of this invention provides nanorod-shaped K2Ti8O nanoparticles with surface-loaded IrO2 nanoparticles prepared by the preparation method described in the first aspect. 17 catalyst.

[0025] A third aspect of the present invention provides nanorod-shaped K2Ti8O with surface-loaded IrO2 nanoparticles as described in the second aspect. 17 Application of catalysts as oxygen evolution reaction catalysts in acidic water electrolysis for hydrogen production.

[0026] The beneficial effects of this invention are:

[0027] This invention uses crushed nanorod-shaped K2Ti8O 17 Using IrCl3·3H2O as the reaction raw material, nanorod-shaped K2Ti8O with surface-loaded IrO2 nanoparticles was prepared by room temperature reduction and thermal oxidation. 17 Catalyst, IrO2 nanoparticles in nanorod-shaped K2Ti8O 17 The catalyst exhibits high uniformity of loading on the support, small particle size, no agglomeration, and regular catalyst morphology.

[0028] The supported catalyst prepared by the method of this invention has excellent acidic OER catalytic performance and can be widely used in fields such as acidic water electrolysis for hydrogen production.

[0029] The preparation method of this invention is simple, low-cost, highly controllable, and has high reproducibility, making it easy to achieve industrial production. Attached Figure Description

[0030] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This refers to the nanorod-shaped K2Ti8O nanoparticles with surface-loaded IrO2 nanoparticles prepared in Example 1 of the present invention. 17 Transmission electron microscope image of the catalyst;

[0032] Figure 2 This is a scanning electron microscope image of the TiO2 particle catalyst supported on IrO2 prepared in Comparative Example 1 of the present invention.

[0033] Figure 3 The surface-loaded IrO2 nanorod-shaped K2Ti8O prepared in Comparative Example 2 of this invention 17 Scanning electron microscope image of the catalyst;

[0034] Figure 4These are the linear polarization curves of the catalysts prepared in the embodiments and comparative examples of this invention. Detailed Implementation

[0035] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] This embodiment provides a nanorod-shaped K2Ti8O with IrO2 nanoparticles loaded on its surface. 17 The catalyst preparation method includes the following steps:

[0037] S1, K2Ti8O 17 Nanowires were broken down to obtain nanorod-shaped K2Ti8O. 17 ;

[0038] The solvent is deionized water, which can be partially mixed with K2Ti8O. 17 Mixing, partially mixing with IrCl3·3H2O, or any other combination of the three to form a dispersion suspension;

[0039] S2, the nanorod-shaped K2Ti8O 17 The mixture was mixed with IrCl3·3H2O and a solvent to obtain a dispersion suspension;

[0040] Among them, the K2Ti8O 17 The mass ratio of IrCl3·3H2O to IrCl3·3H2O is (1-5):(1-5).

[0041] S3. Add a reducing agent to the dispersion suspension, and after the reaction, obtain nanorod-shaped K2Ti8O with Ir surface loaded. 17 intermediate materials;

[0042] The reaction time is 2-20 hours, and the reaction includes steps of washing the precipitate with deionized water and drying it, with the drying temperature being 50-80℃.

[0043] S4. The intermediate material is placed in an aerobic environment at 250-550℃ and reacted for 0.5-5 hours to obtain the nanorod-shaped K2Ti8O with surface-loaded IrO2 nanoparticles. 17 catalyst.

[0044] As a specific example, the nanorod-shaped K2Ti8O 17The diameter of the IrO2 nanoparticles is 20-200 nm, such as 20 nm, 30 nm, 50 nm, 75 nm, 100 nm, 200 nm, etc., and is not limited to these. The length is less than 1 μm, such as 50 nm, 100 nm, 200 nm, 500 nm, 600 nm, 800 nm, etc., and is not limited to these. The particle size of the IrO2 nanoparticles is 1-100 nm, such as 1 nm, 5 nm, 10 nm, 20 nm, 50 nm, 75 nm, 100 nm, etc., and is not limited to these. The size of the IrO2 nanoparticles is affected by the concentration of IrCl3·3H2O in the dispersion suspension. Adjusting the concentration of IrCl3·3H2O in the dispersion suspension can adjust the size of the IrO2 nanoparticles.

[0045] As a specific example, the reducing agent is one or more of ammonia, sodium borohydride, and citric acid, and the amount of the reducing agent is greater than or equal to the amount of IrCl3·3H2O.

[0046] As a specific example, the crushing process is one or more of ultrasonication, grinding, and ball milling.

[0047] This embodiment uses a hydrothermal method to synthesize nanowire-like K2Ti8O with multiple surface defects. 17 The K2Ti8O nanorods were obtained by crushing and adjusting their size. 17 The carrier was mixed with IrCl3·3H2O and a solvent to obtain a dispersion suspension. The solvent was heated to dissolve the IrCl3·3H2O, and the reaction process did not require heating. Under the action of a reducing agent, Ir was loaded onto the surface of the multi-defect nanorod-shaped carrier. After a thermal oxidation reaction, nanorod-shaped K2Ti8O nanoparticles with surface-loaded IrO2 nanoparticles were obtained. 17 catalyst.

[0048] K2Ti8O with multiple surface defects 17 The microstructure of the carrier determines its excellent charge transfer capability, and the K2Ti8O after crushing treatment... 17 The surface of the carrier has a high density of defects and active sites, which enables more uniform loading of IrO2 nanoparticles.

[0049] This embodiment features nanorod-shaped K2Ti8O 17 The IrO2 nanoparticles loaded on the support surface have high uniformity and small particle size, with particle size as small as a few nanometers. They do not exhibit agglomeration and have a regular catalyst shape. They have excellent acidic OER catalytic performance and can be widely used in the oxygen evolution reaction of acidic water electrolysis to produce hydrogen. The preparation method is simple, controllable, and has high reproducibility.

[0050] Another embodiment provides nanorod-shaped K2Ti8O with surface-loaded IrO2 nanoparticles prepared by the preparation method described in the above embodiments. 17 catalyst.

[0051] Another embodiment provides nanorod-shaped K2Ti8O with surface-loaded IrO2 nanoparticles as described in the above embodiments. 17 Application of catalysts as oxygen evolution reaction catalysts in acidic water electrolysis for hydrogen production.

[0052] The following are specific examples.

[0053] Example 1

[0054] This embodiment relates to a nanorod-shaped K2Ti8O with surface-loaded IrO2 nanoparticles. 17 The catalyst preparation method includes the following steps:

[0055] 1) Add 0.03g of K2Ti8O to a 50mL beaker. 17 Nanowires and 25 mL of water were ultrasonically treated for 30 min with stirring to treat K2Ti8O 17 The nanowires are broken down.

[0056] 2) Add 0.02g of IrCl3·3H2O and 25mL of water at 50℃, stir well to obtain a dispersion suspension;

[0057] 3) Keep the dispersion suspension stirred and add 0.06 g of sodium borohydride to it, and react overnight;

[0058] 4) Wash the precipitate with deionized water and dry the resulting precipitate in an oven at 60°C;

[0059] 5) The dried sample was heated to 350℃ in a muffle furnace and held for 2 hours. After cooling to room temperature, it was removed to obtain nanorod-shaped K2Ti8O with IrO2 nanoparticles loaded on the surface. 17 Supported catalysts.

[0060] The catalyst prepared in this example was analyzed by transmission electron microscopy, with reference to... Figure 1 From points a and b, it can be seen that the diameter of IrO2 nanoparticles is around 3.5 nm, while the diameter of nanorods is around 55 nm. The IrO2 nanoparticles are in the nanorod shape of K2Ti8O. 17 Uniformly distributed on the carrier.

[0061] Comparative Example 1

[0062] This comparative example relates to a method for preparing a TiO2 particle catalyst supported on IrO2, comprising the following steps:

[0063] 1) Add 0.03g of TiO2 and 25mL of water to a 50mL beaker, sonicate for 30min and stir;

[0064] 2) Add 0.02g of IrCl3·3H2O and 25mL of water at 50℃, stir well to obtain a dispersion suspension;

[0065] 3) Keep the dispersion suspension stirred and add 0.06 g of sodium borohydride to it, and react overnight;

[0066] 4) Wash the precipitate with deionized water and dry the resulting precipitate in an oven at 60°C;

[0067] 5) The dried sample was heated to 350°C in a muffle furnace, kept at that temperature for 2 hours, cooled to room temperature and then removed to obtain the TiO2 particle catalyst supported on IrO2.

[0068] The catalyst prepared in the comparative example was analyzed by scanning electron microscopy, with reference to... Figure 2 As shown in a and b, TiO2 particles loaded with IrO2 were formed. In addition to the surface-loaded particles, there are also many independent small-sized IrO2 clusters. These clusters are composed of particles with a diameter of about 20 nm, and the overall size of the clusters varies between 50 and 500 nm.

[0069] Comparative Example 2

[0070] This comparative example involves a nanorod-shaped K2Ti8O supported on IrO2. 17 The catalyst preparation method includes the following steps;

[0071] 1) Add 0.03g of K2Ti8O 17 Nanowires and 0.02 g of IrCl3·3H2O were ground and mixed to obtain a reaction mixture;

[0072] 2) The reaction mixture was transferred to a ceramic boat, heated to 350°C in a muffle furnace, held at that temperature for 2 hours, cooled to room temperature, and then removed to obtain IrO2-loaded nanorod-shaped K2Ti8O. 17 catalyst.

[0073] The catalyst prepared in the comparative example was analyzed by scanning electron microscopy, with reference to... Figure 3 In a and b, it can be seen that the nanorod-shaped K2Ti8O 17 The support is loaded with IrO2 nanoparticles, and also contains a number of independent IrO2 clusters, including K2Ti8O. 17 The length of the carrier varies between 200 and 850 nm, and the size of the IrO2 nanoparticles it supports is about 15 nm in diameter.

[0074] In summary, the nanorod-shaped K2Ti8O prepared in the embodiments of the present invention... 17 The IrO2 nanoparticles loaded on the support surface exhibit high uniformity and small particle size, with particle sizes as small as 3 nanometers, and show no agglomeration. The catalyst has a regular shape, which is due to the K2Ti8O surface with many defects. 17 The microstructure of the carrier determines its excellent charge transfer capability, and the K2Ti8O after crushing treatment... 17 The surface of the carrier has a high density of defects and active sites, which enables more uniform loading of IrO2 nanoparticles.

[0075] Application examples

[0076] The catalytic performance of the catalysts from Examples 1 and Comparative Examples 1-2 was tested. The prepared catalysts from Examples 1 and 1-2 were coated onto the surface of the working electrode (glassy carbon electrode), respectively. The counter electrode was a platinum sheet, the reference electrode was a standard hydrogen electrode, and the electrolyte was a 0.5M sulfuric acid solution. The linear polarization curves of the three are shown below. Figure 4 As shown. Among them, the catalysts prepared in Example 1 and Comparative Examples 1-2 were tested at 10 mA cm⁻¹. -2 The overpotentials at the current densities were 254 mV, 590 mV, and 388 mV, respectively, indicating that the catalyst prepared in Example 1 of this invention has superior catalytic performance.

[0077] It is evident that the catalyst prepared in the embodiments of the present invention exhibits superior acidic OER catalytic performance because the catalyst prepared in the embodiments of the present invention contains nanorod-shaped K2Ti8O 17 The IrO2 nanoparticles loaded on the support surface have high uniformity and small particle size, with a particle size as small as 3 nanometers. They do not exhibit agglomeration and have a regular catalyst shape, thus exhibiting superior catalytic performance. The catalyst prepared in the embodiments of this invention can be widely used in the oxygen evolution reaction of acidic water electrolysis to produce hydrogen.

[0078] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A nanorod-like K2Ti8O17 nanomaterial surface loaded with IrO2 nanoparticles. 17 A method for producing a catalyst, characterized by, The method comprises the following steps: S1, K2Ti8O 17 The nanowires are subjected to a breaking treatment to obtain nanorod-shaped K2Ti8O 17 ; S2, the nanorod-like K2Ti8O 17 mixed with IrCl3-3H2O and a solvent to obtain a dispersed suspension; S3, adding a reducing agent to the dispersion suspension, and obtaining nanorod-like K2Ti8O 17 Intermediate material; S4, placing the intermediate material in an oxygen-containing environment at 250-550 °C, after reaction obtaining the K2Ti8O 17 catalyst.

2. The surface loaded IrO2 nanoparticulate nanorod-like K2Ti8O 17 A method for producing a catalyst, characterized by, The nanorod-like K2Ti8O 17 has a diameter of 20-200 nm and a length of less than 1 μm.

3. The nanorod-like K2Ti80i8 surface loaded with IrO2 nanoparticles as claimed in claim 1 17 A method for producing a catalyst, characterized by, K2Ti8O 17 in a mass ratio of (1-5):(1-5) to IrCl3-3H2O.

4. The surface loaded IrO2 nanoparticulate nanorod-like K2Ti8O 17 A method for producing a catalyst, characterized by, The reducing agent is one or more of ammonia, sodium borohydride and citric acid.

5. The surface loaded IrO2 nanoparticulate nanorod-like K2Ti8O 17 A method for producing a catalyst, characterized by, The amount of the reducing agent is equal to or greater than the amount of IrCl3·3H2O.

6. The surface loaded IrO2 nanoparticulate nanorod-like K2Ti8O 17 A method for producing a catalyst, characterized by, The breaking treatment is one or more of ultrasonic, grinding and ball milling.

7. The surface loaded IrO2 nanoparticulate nanorod-like K2Ti8O 17 A method for producing a catalyst, characterized by, In S3, the reaction time is 2-20 h. After the reaction, the method further comprises the steps of washing the precipitate with deionized water and drying, and the drying temperature is 50-80 ℃.

8. The surface loaded IrO2 nanoparticulate nanorod K2Ti8O 17 A method for producing a catalyst, characterized by, In S4, the reaction time is 0.5-5 h.

9. Nanorod-like K2Ti80i8 loaded with IrO2 nanoparticles obtained by the preparation process according to any one of claims 1 to 8. 17 catalyst.

10. The nanorod-like K2Ti80i8 surface loaded with Ir02 nanoparticles of claim 9. 17 Application of catalyst as oxygen evolution reaction catalyst in hydrogen production by acidic electrolysis of water.

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