A supported ir / tab2 catalyst, its preparation method and application

Abstract

The application relates to a supported Ir / TaB2 catalyst and a preparation method and application thereof. The application is characterized in that: the preparation method comprises the following steps: dissolving tantalum diboride and urea in deionized water, adding iridium tetrachloride into the deionized water under ultrasonic treatment at room temperature, carrying out ultrasonic treatment again, carrying out hydrothermal reaction on the obtained reaction mixture, cooling the reaction product to room temperature after the reaction is completed, and carrying out vacuum drying; carrying out calcination on the dried reaction product, obtaining a black product, carrying out centrifugal washing on the black product, and air-drying at room temperature to obtain the supported Ir / TaB2 catalyst. The synthesis method is simple, the operation steps are few, the time consumption is short, the cost is low, high instruments and equipment are not needed, raw materials are easy to obtain, the method is economic and environment-friendly, and the method is easy to realize large-scale production. The prepared Ir / TaB2 catalyst is used as an anode catalyst for PEM electrocatalytic water splitting to produce hydrogen, can significantly reduce the anode oxygen evolution overpotential, increase the current, and has high activity and good use stability.

Description

Technical Field

[0001] This invention belongs to the field of proton exchange membrane (PEM) electrocatalytic water splitting for hydrogen production technology, and relates to an anode catalyst for PEM electrocatalytic water splitting for hydrogen production and its preparation method, especially a supported Ir / TaB2 catalyst, its preparation method and application. Background Technology

[0002] Electrolysis of water using renewable energy sources such as wind, solar, and geothermal energy is a green hydrogen production technology. Compared with traditional alkaline electrolyzers, proton exchange membrane (PEM) electrolyzers offer advantages such as faster response speed, higher power density, higher efficiency, and higher gas purity, and are considered the next-generation hydrogen production technology. Water electrolysis mainly involves two half-reaction processes: hydrogen evolution reaction (HER) at the cathode and oxygen evolution reaction (OER) at the anode. The slower kinetics, higher overpotential, and strong acid and oxidizing environment of the OER at the anode make the development of OER catalysts a crucial direction for the large-scale application of PEM electrocatalytic water splitting hydrogen production technology.

[0003] To date, iridium, ruthenium-based noble metals, and their derivatives are widely considered excellent anode catalysts for OER (Optical Emission Reactor). Ruthenium oxide exhibits excellent activity under acidic conditions, but it is more susceptible to oxidation, leading to catalyst structural collapse, dissolution, and reduced catalytic activity. Iridium oxide maintains good catalytic activity while possessing good stability, but its low reserves, limited production capacity, and high price increase the cost of PEM (Potentially Activated Metal) water electrolysis. Supporting noble metals or other active phases on suitable supports can improve the utilization rate, activity, and stability of active components, while reducing catalyst production costs, which is of great significance for the large-scale application of PEM water electrolysis.

[0004] Patent CN117626329A discloses a PEM electrolysis water-supported Ir / MnO2 catalyst and its preparation method, which first utilizes high-valence Nb +5 A Nb-MnO2 support is formed by doping MnO2, and then Ir nanoparticles are uniformly loaded onto the Nb-MnO2 via cation exchange to form an Ir / Nb-MnO2 supported catalyst. This patent can reduce the amount of precious metals used, but the niobium pentachloride used does not conform to the concept of environmentally friendly chemistry, and the process is complex and time-consuming.

[0005] Patent CN114657577B discloses a method for preparing a supported catalyst for PEM water electrolysis, comprising the following steps: first, conductive polymer nanofibers of various sizes are spun using an electrospinning machine; then, using these conductive polymer nanofibers as templates, the nanofibers are immersed in a chloroiridium acid solution; excess sodium borohydride is added to reduce the chloroiridium acid to iridium nanoparticles, which are then loaded onto the surface of the nanofibers; finally, the iridium / conductive polymer nanofibers are calcined to obtain the finished catalyst. However, the size of the support prepared by this patent using electrospinning technology is much larger than that of the metal oxide support, which is not conducive to the uniform dispersion of the active material and the improvement of catalyst activity.

[0006] Patent CN118390091A discloses a method for preparing a highly active supported iridium-based catalyst. The catalyst support is anatase TiO2: iridium salt is dissolved in ethylene glycol to prepare solution A; an alkaline substance is dissolved in ethylene glycol to prepare solution B; the pH of solution A is adjusted to alkaline using solution B to obtain precursor solution C; titanium salt is dissolved in the ethylene glycol solution, and then water is added to prepare solution D, followed by a solvothermal reaction to obtain titanium oxide support; the titanium oxide support is uniformly dispersed in ethylene glycol to prepare dispersion E; precursor solution C is slowly added dropwise to dispersion E to prepare dispersion F with a certain iridium loading, then heated to a certain temperature and held for a certain time, cooled to a certain temperature, separated, washed, and dried to obtain the supported iridium-based catalyst. This supported iridium-based catalyst synthesis process is complex and time-consuming.

[0007] In summary, the current synthesis process of supported iridium-based catalysts is complex, environmentally unfriendly, and time-consuming, and the synthesized catalysts have poor catalytic activity and stability. Therefore, there is an urgent need to provide a new supported iridium-based catalyst with both high activity and stability, as well as its preparation method. Summary of the Invention

[0008] The purpose of this invention is to provide a supported Ir / TaB2 catalyst, its preparation method, and its application, aiming to solve the problems of complex operation, environmental unfriendliness, long time consumption, and low catalyst activity and stability in existing supported iridium-based catalyst synthesis methods.

[0009] This invention is specifically achieved through the following technical solution: A method for preparing a supported Ir / TaB2 catalyst according to this invention includes the following steps: Tantalum diboride and urea are dissolved in deionized water and sonicated at room temperature for 30-60 min. Then, iridium tetrachloride is added, and the mixture is sonicated again at room temperature for 30-60 min. The resulting reaction mixture is transferred to the lining of a high-pressure reactor for hydrothermal reaction. After the reaction is completed, the reaction product is cooled to room temperature and then vacuum dried. The dried reaction product is transferred to a ceramic boat, which is placed in a tube furnace and calcined under an Ar / H2 atmosphere to obtain a black product. The black product is centrifuged, washed, and dried at room temperature to obtain the supported Ir / TaB2 catalyst.

[0010] In the aforementioned method for preparing the supported Ir / TaB2 catalyst, the molar ratio of tantalum diboride to iridium is 1:(1~2).

[0011] In the aforementioned method for preparing the supported Ir / TaB2 catalyst, the molar ratio of urea to iridium is (1~4):1.

[0012] In the aforementioned method for preparing the supported Ir / TaB2 catalyst, the hydrothermal reaction temperature is 90~120℃ and the hydrothermal reaction time is 3~5 h.

[0013] In the aforementioned method for preparing the supported Ir / TaB2 catalyst, the vacuum drying temperature is 70°C and the vacuum drying time is 10-12 h.

[0014] In the aforementioned method for preparing the supported Ir / TaB2 catalyst, the calcination temperature is 450℃ and the calcination time is 4~6 h.

[0015] In the aforementioned method for preparing the supported Ir / TaB2 catalyst, the black product is first washed 2-3 times with anhydrous ethanol by centrifugation, and then washed 6-10 times with deionized water by centrifugation.

[0016] The aforementioned method for preparing supported Ir / TaB2 catalysts produces supported Ir / TaB2 catalysts with a particle size of 3-4 nm, and their XRD patterns show characteristic peaks of elemental iridium and tantalum diboride.

[0017] The present invention also provides an application of the supported Ir / TaB2 catalyst obtained according to the aforementioned preparation method as an anode catalyst in PEM water electrolysis.

[0018] Compared with existing technologies, this invention has significant advantages and beneficial effects. Through the above technical solution, this invention achieves considerable technological advancement and practicality, and has broad application value, possessing at least the following advantages:

[0019] This invention uses tantalum diboride as a support, iridium tetrachloride as the iridium source, and urea as a ligand. Through hydrothermal reaction and high-temperature calcination under an Ar / H2 atmosphere, iridium tetrachloride is reduced to iridium. Iridium is then supported on the tantalum diboride support as the active component, resulting in a supported Ir / TaB2 catalyst with small size and uniform particle distribution. This supported Ir / TaB2 catalyst has a uniform particle size of approximately 3-4 nm. Its XRD pattern shows characteristic peaks for elemental iridium and tantalum diboride, indicating that elemental iridium is uniformly supported on the tantalum diboride support. Its LSV curve shows that at a current density of 10 mA cm⁻¹... -2 At the specified time, the supported Ir / TaB2 catalyst exhibits a smaller overpotential than the commercial iridium black catalyst, indicating that the supported Ir / TaB2 catalyst prepared in this invention possesses superior acid oxygen evolution reaction activity compared to the commercial iridium black catalyst. Catalyst stability test results show that after 30,000 CV cycles, at a current density of 10 mA cm⁻¹, the catalyst exhibits a lower overpotential. -2 When the overpotential of the Ir / TaB2 catalyst increased by only 22 mV, while under the same conditions, the overpotential of the commercial iridium-based catalyst increased by 33~40 mV, indicating that the supported Ir / TaB2 catalyst prepared in this invention has excellent cycle stability.

[0020] The synthesis method of the supported Ir / TaB2 catalyst provided by this invention is simple, involves few steps, is time-efficient, and low-cost. It requires no expensive equipment, uses readily available raw materials, is economical and environmentally friendly, and is easy to scale up for production. The prepared Ir / TaB2 catalyst, when used as an anode catalyst in PEM electrocatalytic water splitting for hydrogen production, can significantly reduce the anode oxygen evolution overpotential, increase the current, and exhibit excellent catalytic performance, combining high activity with good stability in use. Attached Figure Description

[0021] Figure 1 This is the XRD pattern of the supported Ir / TaB2 catalyst prepared in Example 1.

[0022] Figure 2 This is a TEM image of the supported Ir / TaB2 catalyst prepared in Example 1.

[0023] Figure 3 This is a comparison of the LSV curves of the supported Ir / TaB2 catalyst prepared in Example 1 and the commercial iridium black catalyst in Comparative Example 1 under acidic conditions for the oxygen evolution reaction.

[0024] Figure 4 This is a graph showing the stability test results of the supported Ir / TaB2 catalyst prepared in Example 1. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0026] The present invention will be described in detail below with reference to specific embodiments. Unless otherwise specified, all conditions in the following embodiments were performed under conventional conditions or conditions recommended by the manufacturer. Raw materials and reagents whose manufacturers are not specified are all commercially available products. Iridium tetrachloride used in the following embodiments was purchased from Beijing Innocare Technology Co., Ltd., catalog number 207399-11-9, with a molecular weight of 334.03.

[0027] Example 1

[0028] First, 365 mg of tantalum diboride and 108 mg of urea were dissolved in 30 mL of deionized water and sonicated for 30 min at room temperature. Then, 601 mg of iridium tetrachloride was added, and the mixture was sonicated again for 30 min at room temperature. The resulting reaction mixture was transferred to the lining of a high-pressure reactor and hydrothermally reacted at 110 °C for 3 h. After the reaction was complete, the reaction product was cooled to room temperature and then dried in a vacuum drying oven at 70 °C for 10 h. The dried reaction product was then transferred to a ceramic boat and placed in a tube furnace. Under an Ar / H2 atmosphere, the mixture was heated at 5 °C for 1 min. -1 The temperature was increased to 450℃ and calcined for 5 h to obtain a black product. The black product was first washed three times with anhydrous ethanol by centrifugation, then washed eight times with deionized water by centrifugation, and then dried at room temperature to obtain the supported Ir / TaB2 catalyst.

[0029] Example 2

[0030] First, 182.5 mg of tantalum diboride and 108 mg of urea were dissolved in 30 mL of deionized water and sonicated for 30 min at room temperature. Then, 601 mg of iridium tetrachloride was added, and the mixture was sonicated again for 30 min at room temperature. The resulting reaction mixture was transferred to the lining of a high-pressure reactor and hydrothermally reacted at 110 °C for 3 h. After the reaction was complete, the reaction product was cooled to room temperature and then dried in a vacuum drying oven at 70 °C for 10 h. The dried reaction product was then transferred to a ceramic boat and placed in a tube furnace. Under an Ar / H2 atmosphere, the mixture was heated at 5 °C for 1 min. -1The temperature was increased to 450℃ and calcined for 5 h to obtain a black product. The black product was first washed three times with anhydrous ethanol by centrifugation, then washed seven times with deionized water by centrifugation, and then dried at room temperature to obtain the supported Ir / TaB2 catalyst.

[0031] Example 3

[0032] First, 365 mg of tantalum diboride and 216 mg of urea were dissolved in 30 mL of deionized water and sonicated for 30 min at room temperature. Then, 601 mg of iridium tetrachloride was added, and the mixture was sonicated again for 30 min at room temperature. The resulting reaction mixture was transferred to the lining of a high-pressure reactor and hydrothermally reacted at 110 °C for 3 h. After the reaction was complete, the reaction product was cooled to room temperature and then dried in a vacuum drying oven at 70 °C for 10 h. The dried reaction product was then transferred to a ceramic boat and placed in a tube furnace. Under an Ar / H2 atmosphere, the mixture was heated at 5 °C for 1 min. -1 The temperature was increased to 450℃ and calcined for 5 h to obtain a black product. The black product was first washed three times with anhydrous ethanol by centrifugation, then washed eight times with deionized water by centrifugation, and then dried at room temperature to obtain the supported Ir / TaB2 catalyst.

[0033] Example 4

[0034] First, 365 mg of tantalum diboride and 108 mg of urea were dissolved in 30 mL of deionized water and sonicated for 30 min at room temperature. Then, 601 mg of iridium tetrachloride was added, and the mixture was sonicated again for 30 min at room temperature. The resulting reaction mixture was transferred to the lining of a high-pressure reactor and hydrothermally reacted at 90 °C for 3 h. After the reaction was complete, the reaction product was cooled to room temperature and then dried in a vacuum drying oven at 70 °C for 10 h. The dried reaction product was then transferred to a ceramic boat and placed in a tube furnace. Under an Ar / H2 atmosphere, the mixture was heated at 5 °C for 1 min. -1 The temperature was increased to 450℃ and calcined for 5 h to obtain a black product. The black product was first washed three times with anhydrous ethanol by centrifugation, then washed seven times with deionized water by centrifugation, and then dried at room temperature to obtain the supported Ir / TaB2 catalyst.

[0035] Example 5

[0036] First, 365 mg of tantalum diboride and 108 mg of urea were dissolved in 30 mL of deionized water and sonicated for 30 min at room temperature. Then, 601 mg of iridium tetrachloride was added, and the mixture was sonicated again for 30 min at room temperature. The resulting reaction mixture was transferred to the lining of a high-pressure reactor and hydrothermally reacted at 110 °C for 3 h. After the reaction was complete, the reaction product was cooled to room temperature and then dried in a vacuum drying oven at 70 °C for 10 h. The dried reaction product was then transferred to a ceramic boat and placed in a tube furnace. Under an Ar / H2 atmosphere, the mixture was heated at 5 °C for 1 min. -1 The temperature was increased to 450℃ and calcined for 8 h to obtain a black product. The black product was first washed three times with anhydrous ethanol by centrifugation, then washed eight times with deionized water by centrifugation, and then air-dried at room temperature to obtain the supported Ir / TaB2 catalyst.

[0037] Comparative Example 1

[0038] A commercial iridium black catalyst was used, purchased from Alfa, product number: 010746.

[0039] Comparative Example 2

[0040] A commercial iridium oxide catalyst was used, purchased from Sigma Aldrich, product number 206237.

[0041] The supported Ir / TaB2 catalyst prepared in Example 1 was characterized. XRD analysis was performed using a Rigaku SmartLab 9 kW Cu-Kα diffraction instrument (1.54184 Å). TEM mapping was performed using a JEOL JEM-ARM200F Cs-corrected S / TEM with HAADF-STEM tomography. Its XRD pattern is shown below. Figure 1 As shown, Figure 1 The presence of characteristic peaks for elemental iridium and tantalum diboride in the XRD pattern indicates that elemental iridium has been uniformly loaded onto the tantalum diboride support.

[0042] Figure 2 This is a TEM image of the supported Ir / TaB2 catalyst prepared in Example 1. The particle size of the supported Ir / TaB2 catalyst is approximately 3-4 nm, and the particles are uniformly distributed.

[0043] The prepared supported Ir / TaB2 catalyst was used as the anode catalyst for PEM water electrolysis. The specific application method was as follows: 10 mg of the supported Ir / TaB2 catalyst prepared in Examples 1-5, 10 mg of the commercial iridium black catalyst of Comparative Example 1, and 10 mg of the commercial iridium oxide catalyst of Comparative Example 2 were weighed respectively. 109 μL of 5% Nafion solution, 545 μL of ultrapure water, and 1345 μL of isopropanol were added to each catalyst sample to prepare a catalyst mixture. The catalyst mixture was ultrasonicated for at least 2 h to ensure homogeneity, resulting in a catalyst dispersion. 15 μL of the catalyst dispersion was taken with a pipette and evenly drop-coated onto the surface of a glassy carbon electrode in three portions. The electrode was then dried with an infrared lamp and used as the working electrode in a three-cell system. A saturated calomel electrode was used as the reference electrode, and a platinum sheet was used as the auxiliary electrode. The electrolyte was a 0.5 M H2SO4 solution. The OER performance of the working electrodes with different catalyst dispersions was tested at room temperature. Before the electrochemical OER test, the electrode was activated by 20 CV cycles. LSV curves were obtained at a scanning rate of 5 mV / s at a rotation speed of 2500 rpm within a voltage range of 1.06~1.55 V (relative to the reversible hydrogen electrode). All data were acquired after the scanning current stabilized.

[0044] Figure 3 This is a comparison of the LSV curves of the supported Ir / TaB2 catalyst prepared in Example 1 and the commercial iridium black catalyst in Comparative Example 1 under acidic conditions for the oxygen evolution reaction. It can be seen that at a current density of 10 mAcm⁻¹, the LSV curves show a significant difference between the two catalysts. -2 When the supported Ir / TaB2 catalyst prepared in Example 1 has a smaller overpotential than the commercial iridium black catalyst in Comparative Example 1, it indicates that the supported Ir / TaB2 catalyst prepared in this invention has superior acid oxygen evolution reaction activity compared to commercial iridium-based catalysts.

[0045] Figure 4 This is a stability test result of the supported Ir / TaB2 catalyst prepared in Example 1. After 30,000 CV cycles, at a current density of 10 mA cm⁻¹, the stability was achieved. -2 At that time, the overpotential increased by only 22 mV.

[0046] Table 1 shows the supported Ir / TaB2 catalysts prepared in Examples 1-5, the commercial iridium black catalyst of Comparative Example 1, and the commercial iridium oxide catalyst of Comparative Example 2 at a current density of 10 mA cm⁻¹. -2Table 1 shows the initial overpotential and the final overpotential after 30,000 cycles. As can be seen, the initial overpotentials of the supported Ir / TaB2 catalysts prepared in Examples 1-5 are superior to those of the commercial iridium black catalyst (Comparative Example 1) and the commercial iridium oxide catalyst (Comparative Example 2). After stability testing, the increase in the final overpotential of the supported Ir / TaB2 catalysts prepared in Examples 1-5 compared to the initial overpotential is significantly lower than that of the commercial iridium black catalyst (Comparative Example 1) and the commercial iridium oxide catalyst (Comparative Example 2).

[0047] Table 1. Initial overpotential and final overpotential after 30,000 cycles for different catalysts

[0048]

[0049] As can be seen from the above, the supported Ir / TaB2 catalyst provided by this invention has a small particle size, approximately 3-4 nm, and a uniform structure. The supported Ir / TaB2 catalysts prepared in all embodiments have achieved significant results in OER reactions, with current densities reaching 10 mA cm⁻¹. -2 The initial overpotentials were all less than 260 mV; in particular, the supported Ir / TaB2 catalyst prepared in Example 1 had an overpotential of only 220 mV, which is far superior to commercial iridium-based catalysts. The supported Ir / TaB2 catalyst provided by this invention also has excellent stability. After 30,000 CV cycles, the overpotential increased by only 22-26 mV compared to the initial overpotential, while under the same conditions, the overpotential increase of commercial iridium black catalyst (Comparative Example 1) and commercial iridium oxide catalyst (Comparative Example 2) was 33-40 mV, indicating that the catalyst of this invention has both high activity and high stability.

[0050] The above description is merely an embodiment of the present invention and is not intended to limit the present invention in any way. The present invention can also have other embodiments based on the above structure and function, which will not be listed hereafter. Therefore, any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a supported Ir / TaB2 catalyst, characterized by, The method comprises the following steps: The tantalum diboride and urea are dissolved in deionized water, and ultrasonic treatment is performed at room temperature for 30-60 min; then, iridium tetrachloride is added, and ultrasonic treatment is performed again at room temperature for 30-60 min; the obtained reaction mixture is transferred into an inner liner of a high-pressure reaction kettle for hydrothermal reaction; after the reaction is completed, the reaction product is cooled to room temperature, and then vacuum drying is performed; the dried reaction product is transferred into a porcelain boat, and the porcelain boat is placed in a tube furnace for calcination under Ar / H2 atmosphere to obtain a black product; the black product is centrifuged and washed, and then air-dried at room temperature to obtain the supported Ir / TaB2 catalyst.

2. The method for preparing a supported Ir / TaB2 catalyst according to claim 1, characterized by, The molar ratio of tantalum diboride to iridium is 1: (1-2).

3. The preparation method of the supported Ir / TaB2 catalyst according to claim 1 or 2, characterized in that, The molar ratio of urea to iridium is (1-4):

1.

4. The method for preparing a supported Ir / TaB2 catalyst according to claim 1, wherein the TaB2 powder is prepared by the method according to any one of claims 2 to 4. The temperature of the hydrothermal reaction is 90-120 ℃, and the time of the hydrothermal reaction is 3-5 h.

5. The method for preparing a supported Ir / TaB2 catalyst according to claim 1, wherein the TaB2 is prepared by the method according to any one of claims 2 to 4. The temperature of the vacuum drying is 70 ℃, and the time of the vacuum drying is 10-12 h.

6. The preparation method of the supported Ir / TaB2 catalyst according to claim 1 or 4, characterized in that, The temperature of the calcination is 450 ℃, and the time of the calcination is 4-6 h.

7. The method for preparing a supported Ir / TaB2 catalyst according to claim 1, wherein the TaB2 powder is prepared by the method according to any one of claims 2 to 6. The black product is centrifuged and washed with anhydrous ethanol for 2-3 times, and then centrifuged and washed with deionized water for 6-10 times.

8. The method for preparing a supported Ir / TaB2 catalyst according to claim 1, wherein The prepared supported Ir / TaB2 catalyst has a particle size of 3-4 nm, and the XRD pattern thereof contains characteristic peaks of elemental iridium and tantalum diboride.

9. Application of the supported Ir / TaB2 catalyst prepared by the method of claim 1 as an anode catalyst in PEM electrolytic water.

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