Cerium oxide loaded PtPdRhRuNi high-entropy alloy cluster catalyst as well as preparation method and application thereof

Abstract

The invention provides a cerium oxide loaded PtPdRhRuNi high-entropy alloy cluster catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalysts. The catalyst comprises a carrier cerium oxide and a PtPdRhRuNi high-entropy alloy cluster loaded on the carrier. Through testing, the cerium oxide loaded PtPdRhRuNi high-entropy alloy cluster catalyst provided by the invention has relatively good cycling stability; and the catalyst has excellent catalytic performance in the reaction of hydrogen production through hydrolysis of ammonia borane.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst, its preparation method and application, and particularly to the application of this catalyst in the hydrolysis of ammonia borane to produce hydrogen. Background Technology

[0002] Among new energy sources, hydrogen (H2) is considered one of the most promising energy carriers for meeting the growing demand for clean energy due to its high energy density, renewability, and environmental friendliness. Recently, liquid chemical hydrogen storage has emerged as a viable practical application due to its superior safety and great convenience. Ammonia borane (NH3BH3) is a non-toxic chemical hydrogen carrier with a high hydrogen storage density (19.6 wt%), exhibiting good solubility and stability in solvents, making it one of the most promising liquid chemical hydrogen storage materials. Noble metal catalysts (such as Pt, Pd, and Rh) possess high catalytic activity for the hydrolysis of ammonia borane to produce hydrogen, but their application is limited by high cost and the ease with which active sites can be masked.

[0003] High-entropy alloys (HEAs) are composed of five or more metallic elements and possess characteristics such as high configurational entropy, lattice distortion, and slow diffusion. Compared with traditional binary alloys, HEAs exhibit superior catalytic activity, tunable selectivity, and excellent structural stability. Therefore, HEAs, especially supported HEA nanoparticles, have been used as highly efficient catalysts. However, there is a trade-off between the exposure of active sites and the degree of element mixing in HEAs. Excessive pursuit of element mixing may lead to the dilution or burial of active sites; while insufficient mixing will prevent the full utilization of the synergistic advantages of the high-entropy system. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst, its preparation method, and its application. The catalyst provided by this invention exhibits excellent catalytic activity and cycling stability.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst, comprising a cerium oxide support and a PtPdRhRuNi high-entropy alloy cluster supported on the support.

[0007] Preferably, the size of the cerium oxide is 20~50 nm.

[0008] Preferably, the particle size of the high-entropy alloy cluster is 1.2 ± 0.3 nm.

[0009] Preferably, the mass ratio of cerium oxide to high-entropy alloy clusters is 100:(0.5~5).

[0010] Secondly, the present invention provides a method for preparing the above-mentioned cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst, comprising the following steps:

[0011] S1: Pt, Pd, Rh, Ru, Ni precursor salts and solvents are mixed to obtain a first mixture; cerium oxide is mixed with the first mixture to obtain a second mixture;

[0012] S2: Remove the solvent from the second mixture to obtain a mixed solid, and then perform calcination and reduction treatment to obtain a cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst.

[0013] Preferably, the mass ratio of cerium oxide, element Pt, element Pd, element Rh, element Ru, element Ni and solvent is 100:(0.5~0.6):(0.2~0.3):(0.2~0.3):(0.2~0.3):(0.1~0.2):(2500~25000).

[0014] Preferably, the precursor salt of Pt is selected from any one or more of H2PtCl6·6H2O, K2PtCl4, or Na2PtCl4.

[0015] Preferably, the precursor salt of Pd is selected from any one or more of PdCl2, Pd(NO3)2 or K2PdCl4.

[0016] Preferably, the precursor salt of Rh is selected from any one or more of RhCl3 hydrate or Rh(NO3)3.

[0017] Preferably, the precursor salt of Ru is selected from one or more of RuCl3 hydrate or (NH4)2RuCl6.

[0018] Preferably, the precursor salt of Ni is selected from NiCl2·6H2O or any one or more of Ni(NO3)2 and NiSO4.

[0019] Preferably, the solvent is selected from water, and the water is deionized water.

[0020] Preferably, the cerium oxide and the first mixture are mixed under stirring conditions, and the mixing time is 0.5 to 1 h.

[0021] Preferably, the solvent removal is carried out by rotary evaporation at a temperature of 50-55°C.

[0022] Preferably, the calcination treatment is carried out at 5~10℃ min. -1 The temperature is increased to 500~550℃ at a rate of 1~1.5h.

[0023] Preferably, the reduction treatment is carried out in an atmosphere containing hydrogen, and the temperature of the reduction treatment is 5~10℃ / min. -1 The temperature is increased to 300~500℃ at a rate of 2~2.5 h.

[0024] Thirdly, the present invention provides an application of the above-mentioned cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst in the catalytic hydrolysis of ammonia borane to produce hydrogen.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] This invention provides a cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst, comprising a cerium oxide support and PtPdRhRuNi high-entropy alloy clusters supported on the support. The strong interaction between cerium oxide and metal species generates small metal clusters, while the high-entropy alloy clusters provide active sites.

[0027] Tests have shown that the cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst provided by this invention exhibits high hydrogen production rate and cycle stability in the hydrolysis reaction of ammonia borane. Attached Figure Description

[0028] Figure 1 Aberration-corrected high-angle annular dark-field scanning transmission electron microscope image and elemental distribution map of the cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst (i.e., PtPdRhRuNi / CeO2 catalyst) prepared in Example 1.

[0029] in, Figure 1 a corresponds to a transmission electron microscope image. Figure 1 b corresponds to the distribution mapping of different elements;

[0030] Figure 2 Aberration-corrected high-angle annular dark-field scanning transmission electron microscope image and particle size distribution statistics of the cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst prepared in Example 1.

[0031] in, Figure 2 a corresponds to a transmission electron microscope image. Figure 2 b corresponds to the particle size distribution statistics;

[0032] Figure 3A comparison of the volume of H2 generated in the hydrolysis reaction of ammonia borane by the catalysts prepared in Example 1 and Comparative Examples 1-8, and a graph showing the relationship between the rate of hydrogen generation and time.

[0033] in, Figure 3 a~c correspond to a comparison of the volume of H2 generated in the hydrolysis reaction of ammonia borane using different catalysts. Figure 3 d represents the Arrhenius diagram and the corresponding activation energies for different catalysts;

[0034] Figure 4 This is a comparison graph showing the cyclic stability of the catalysts prepared in Example 1 and Comparative Example 8;

[0035] in, Figure 4 a corresponds to Example 1. Figure 4 b corresponds to a response rate of 8;

[0036] Figure 5 Aberration-corrected high-angle annular dark-field scanning transmission electron microscope image and elemental distribution map of the PtPdRhRuNi / CeO2 catalyst prepared in Example 1 after the hydrolysis reaction of ammonia borane;

[0037] in, Figure 5 a corresponds to a transmission electron microscope image. Figure 5 b corresponds to the distribution mapping of different elements. Detailed Implementation

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] To address the problems of existing high-entropy alloys, this invention provides a cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst, comprising a cerium oxide support and PtPdRhRuNi high-entropy alloy clusters supported on the support. In some embodiments of this invention, the mass ratio of cerium oxide to high-entropy alloy clusters is 100:(0.5~5), such as 100:0.5, 100:0.8, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5, or 100:5. In this invention, the mass ratio of cerium oxide to high-entropy alloy clusters within the above range is for the formation of a high-entropy alloy. If the mass content of the high-entropy alloy clusters is too high, sintering will occur; conversely, if it is too low, single-atom formation will occur.

[0040] In this invention, the cerium oxide serves as a carrier, and its particle size is 20~50 nm, such as 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm or 50 nm, etc.

[0041] In this invention, the PtPdRhRuNi high-entropy alloy cluster catalyst formed on the cerium oxide has an average particle size of 1.2 ± 0.3 nm.

[0042] It should be noted that the PtPdRhRuNi high-entropy alloy cluster catalyst composed of five elements—Pt, Pd, Rh, Ru, and Ni—was obtained after screening. During the experimental investigation phase, the applicant synthesized a series of catalysts, including PtPdRhRuFe / CeO2, PtPdRhRuCo / CeO2, PtPdRhRuCu / CeO2, PtPdRhRu / CeO2, PtPdRh / CeO2, Pt / CeO2, Pd / CeO2, and Rh / CeO2. Comparison revealed that only the PtPdRhRuNi / CeO2 catalyst provided by this invention exhibits excellent catalytic performance in the hydrolysis of ammonia borane to produce hydrogen, and demonstrates excellent cycle stability under harsh reaction conditions. Therefore, the PtPdRhRuNi / CeO2 catalyst provided by this invention effectively solves the problems existing in high-entropy alloys in the prior art.

[0043] This invention also provides a method for preparing the above-mentioned cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst, comprising the following steps:

[0044] S1: Pt, Pd, Rh, Ru, Ni precursor salts and solvents are mixed to obtain a first mixture; cerium oxide is mixed with the first mixture to obtain a second mixture;

[0045] S2: Remove the solvent from the second mixture to obtain a mixed solid, and then perform calcination and reduction treatment to obtain a cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst.

[0046] According to the present invention, a first mixture is prepared by mixing a precursor salt of Pt, Pd, Rh, Ru, or Ni with a solvent to obtain a first mixture. The precursor salt of Pt is selected from any one or more of H₂PtCl₆·6H₂O, K₂PtCl₄, or Na₂PtCl₄; the precursor salt of Pd is selected from any one or more of PdCl₂, Pd(NO₃)₂, or K₂PdCl₄; the precursor salt of Rh is selected from any one or more of RhCl₃ hydrate or Rh(NO₃)₃; the precursor salt of Ru is selected from any one or more of RuCl₃ hydrate or (NH₄)₂RuCl₆; the precursor salt of Ni is selected from any one or more of NiCl₂·6H₂O, Ni(NO₃)₂, or NiSO₄; and the solvent is selected from water, preferably deionized water.

[0047] Then, according to the present invention, cerium oxide and the first mixture are mixed to obtain a second mixture. In the present invention, the mass ratio of cerium oxide, element Pt, element Pd, element Rh, element Ru, element Ni and solvent is 100:(0.5~0.6):(0.2~0.3):(0.2~0.3):(0.2~0.3):(0.1~0.2):(2500~25000), preferably 100:(0.5~0.55):(0.25~0.3):(0.25~0.3):(0.25~0.3):(0.15~0.2):(2500~25000), more preferably 100:0.52:0.284:0.274:0.269:0.157:2500.

[0048] In some embodiments of the present invention, the mixing of cerium oxide and the first mixture is carried out under stirring conditions, and the mixing time is 0.5 to 1 h, such as 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, or 1 h, preferably 1 h. Specifically, in some embodiments of the present invention, the first mixture is preferably added to the CeO2 support and stirred at room temperature for 0.5 to 5 h to ensure thorough mixing, thereby obtaining the second mixture.

[0049] Then, according to the present invention, the solvent is removed from the second mixture to obtain a mixed solid.

[0050] In some embodiments of the present invention, the solvent removal is carried out by rotary evaporation, and the temperature of the rotary evaporation is 50~55°C, such as 50°C, 51°C, 52°C, 53°C, 54°C or 55°C.

[0051] After obtaining the mixed solid, according to the present invention, the mixed solid is preferentially subjected to calcination treatment to ensure that the precursor salts of each metal element can be better loaded on the CeO2 support surface. In the present invention, the calcination treatment is preferably performed at 5~10℃ for 1 minute. -1 The temperature is increased to 500~550℃ (preferably 500~520℃) at a rate of 1~1.5 h, preferably 1.2~1.3 h.

[0052] In this invention, the calcination treatment is preferably carried out in a muffle furnace.

[0053] After the calcination process is completed, according to the present invention, it is preferable to perform a reduction treatment on the product obtained after cooling the calcination process, so that the oxide produced by the calcination process is reduced to a high-entropy alloy cluster.

[0054] In this invention, the reduction process is carried out in an atmosphere containing hydrogen, such as pure hydrogen or a mixture of hydrogen and other inert gases. The reduction process is preferably performed at a temperature of 5-10°C per minute. -1 The temperature is increased to 300-500℃ at a rate of [temperature value missing], and the holding time is 2-2.5 h, preferably 2.2-2.3 h. This invention can effectively control the cluster structure of high-entropy alloys by regulating the temperature of the reduction treatment.

[0055] In this invention, the reduction process is preferably carried out in a tube furnace.

[0056] After the above reduction treatment is completed, the PtPdRhRuNi / CeO2 catalyst can be obtained by naturally cooling to room temperature.

[0057] This invention demonstrates the formation of the PtPdRhRuNi / CeO2 catalyst through aberration-corrected high-angle annular dark-field scanning transmission electron microscopy characterization.

[0058] Finally, the present invention also provides an application of the above-mentioned PtPdRhRuNi / CeO2 catalyst in the catalytic hydrolysis of ammonia borane to produce hydrogen.

[0059] Tests showed that the morphology of the above-mentioned PtPdRhRuNi / CeO2 catalyst did not change significantly after being used multiple times as a catalyst for the hydrolysis of ammonia borane to produce hydrogen, proving its good cycle stability.

[0060] To further illustrate the present invention, the following examples provide a detailed description. All experimental materials used in the following examples are commercially available products. Specifically, RhCl3·xH2O was purchased from Bid Pharmaceutical Co., Ltd., model number BD150383; RuCl3·xH2O was purchased from Sinopharm Chemical Reagent Co., Ltd., model number 51022061.

[0061] Example 1

[0062] Weigh 500 mg of commercial CeO2 support (particle size 20–50 nm) and place it in a beaker. Weigh 13 μmol each of H2PtCl6·6H2O, PdCl2, RhCl3·xH2O, RuCl3·xH2O, and NiCl2·6H2O, and dissolve them in 25 mL of deionized water to prepare a mixed metal salt solution. Add the above solution to the CeO2 support and stir at room temperature for 1 h to ensure thorough mixing. Then, rotary evaporate the mixed solution at 50 °C to remove the solvent. The resulting solid powder is calcined in a muffle furnace at 500 °C for 1 h (heating rate 5 °C / min). -1 The calcined powder was cooled to room temperature. The powder was then placed in a tube furnace under a H2 atmosphere (flow rate 100 mL / min). -1 The PtPdRhRuNi / CeO2 catalyst was obtained by reduction at 400℃ for 2 h and then naturally cooled to room temperature. The aberration-corrected high-angle annular dark-field scanning transmission electron microscope image and elemental distribution map of this catalyst are shown below. Figure 1 As shown (where, Figure 1 a corresponds to a transmission electron microscope image. Figure 1 (b corresponds to the distribution mapping of different elements), which proves that a cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst has been obtained. Furthermore, the scanning transmission electron microscopy image of this catalyst shows... Figure 2 The average particle size of the PtPdRhRuNi high-entropy alloy clusters is approximately 1.2 nm. (See...) Figure 2 b.

[0063] Example 2

[0064] Weigh 500 mg of commercial CeO2 support (particle size 20-50 nm) and place it in a beaker. Weigh 15 μmol each of H2PtCl6·6H2O, PdCl2, RhCl3·xH2O, RuCl3·xH2O, and NiCl2·6H2O, and dissolve them in 25 mL of deionized water to prepare a mixed metal salt solution. Add the above solution to the CeO2 support and stir at room temperature for 1 h to ensure thorough mixing. Then, rotary evaporate the mixed solution at 50 °C to remove the solvent. The resulting solid powder is calcined in a muffle furnace at 500 °C for 1 h (heating rate 5 °C / min). -1 The calcined powder was cooled to room temperature. The powder was then placed in a tube furnace under a H2 atmosphere (flow rate 100 mL / min). -1 The catalyst was reduced at 300℃ for 2 h and then naturally cooled to room temperature to obtain the PtPdRhRuNi / CeO2 catalyst.

[0065] Example 3

[0066] Weigh 500 mg of commercial CeO2 support (particle size 20-50 nm) and place it in a beaker. Weigh 9 μmol each of H2PtCl6·6H2O, PdCl2, RhCl3·xH2O, RuCl3·xH2O, and NiCl2·6H2O, and dissolve them in 25 mL of deionized water to prepare a mixed metal salt solution. Add the above solution to the CeO2 support and stir at room temperature for 1 h to ensure thorough mixing. Then, rotary evaporate the mixed solution at 50 °C to remove the solvent. The resulting solid powder is calcined in a muffle furnace at 500 °C for 1 h (heating rate 5 °C / min). -1 The calcined powder was cooled to room temperature. The powder was then placed in a tube furnace under a H2 atmosphere (flow rate 100 mL / min). -1 The catalyst was reduced at 500℃ for 2 h and then naturally cooled to room temperature to obtain the PtPdRhRuNi / CeO2 catalyst.

[0067] Comparative Example 1

[0068] Weigh 500 mg of commercial CeO2 support (particle size 20–50 nm) and place it in a beaker. Weigh 13 μmol each of H2PtCl6·6H2O, PdCl2, RhCl3·xH2O, RuCl3·xH2O, and FeCl3, and dissolve them in 25 mL of deionized water to prepare a mixed metal salt solution. Add the above solution to the CeO2 support and stir at room temperature for 1 h to ensure thorough mixing. Then, rotary evaporate the mixed solution at 50 °C to remove the solvent. The resulting solid powder is calcined in a muffle furnace at 500 °C for 1 h (heating rate 5 °C / min). -1 The calcined powder was cooled to room temperature. The calcined powder was then placed in a tube furnace under a H2 atmosphere (flow rate 100 mL / min). -1 The catalyst was reduced at 400℃ for 2 h and then naturally cooled to room temperature to obtain the PtPdRhRuFe / CeO2 catalyst.

[0069] Comparative Example 2

[0070] Weigh 500 mg of commercial CeO2 support (particle size 20–50 nm) and place it in a beaker. Weigh 13 μmol each of H2PtCl6·6H2O, PdCl2, RhCl3·xH2O, RuCl3·xH2O, and CoCl2·6H2O, and dissolve them in 25 mL of deionized water to prepare a mixed metal salt solution. Add the above solution to the CeO2 support and stir at room temperature for 1 h to ensure thorough mixing. Then, rotary evaporate the mixed solution at 50 °C to remove the solvent. The resulting solid powder is calcined in a muffle furnace at 500 °C for 1 h (heating rate 5 °C / min). -1The calcined powder was cooled to room temperature. The powder was then placed in a tube furnace under a H2 atmosphere (flow rate 100 mL / min). -1 The catalyst was reduced at 400 °C for 2 h and then naturally cooled to room temperature to obtain the PtPdRhRuCo / CeO2 catalyst.

[0071] Comparative Example 3

[0072] Weigh 500 mg of commercial CeO2 support (particle size 20–50 nm) and place it in a beaker. Weigh 13 μmol each of H2PtCl6·6H2O, PdCl2, RhCl3·xH2O, RuCl3·xH2O, and CuCl2·2H2O, and dissolve them in 25 mL of deionized water to prepare a mixed metal salt solution. Add the above solution to the CeO2 support and stir at room temperature for 1 h to ensure thorough mixing. Then, rotary evaporate the mixed solution at 50 °C to remove the solvent. The resulting solid powder is calcined in a muffle furnace at 500 °C for 1 h (heating rate 5 °C / min). -1 The calcined powder was cooled to room temperature. The powder was then placed in a tube furnace under a H2 atmosphere (flow rate 100 mL / min). -1 The catalyst was reduced at 400℃ for 2 h and then naturally cooled to room temperature to obtain the PtPdRhRuCu / CeO2 catalyst.

[0073] Comparative Example 4

[0074] Weigh 500 mg of commercial CeO2 support (particle size 20-50 nm) and place it in a beaker. Weigh 13 μmol each of H2PtCl6·6H2O, PdCl2, RhCl3·xH2O, and RuCl3·xH2O, and dissolve them in 25 mL of deionized water to prepare a mixed metal salt solution. Add the above solution to the CeO2 support and stir at room temperature for 1 h to ensure thorough mixing. Then, rotary evaporate the mixed solution at 50 °C to remove the solvent. The resulting solid powder is calcined in a muffle furnace at 500 °C for 1 h (heating rate 5 °C / min). -1 The calcined powder was cooled to room temperature. The calcined powder was then placed in a tube furnace under a H2 atmosphere (flow rate 100 mL / min). -1 The catalyst was reduced at 400℃ for 2 h and then naturally cooled to room temperature to obtain the PtPdRhRu / CeO2 catalyst.

[0075] Comparative Example 5

[0076] Weigh 500 mg of commercial CeO2 support (particle size 20-50 nm) and place it in a beaker. Weigh 13 μmol each of H2PtCl6·6H2O, PdCl2, and RhCl3·xH2O, and dissolve them in 25 mL of deionized water to prepare a mixed metal salt solution. Add the above solution to the CeO2 support and stir at room temperature for 1 h to ensure thorough mixing. Then, rotary evaporate the mixed solution at 50 °C to remove the solvent. The resulting solid powder is calcined in a muffle furnace at 500 °C for 1 h (heating rate 5 °C / min). -1 The calcined powder was cooled to room temperature. The calcined powder was then placed in a tube furnace under a H2 atmosphere (flow rate 100 mL / min). -1 The catalyst was reduced at 400℃ for 2 h and then naturally cooled to room temperature to obtain the PtPdRh / CeO2 catalyst.

[0077] Comparative Example 6

[0078] Weigh 500 mg of commercial CeO2 support (particle size 20–50 nm) and 67 μmol of H2PtCl6·6H2O into a beaker, dissolve in 25 mL of deionized water to prepare a metal salt solution. Add the above solution to the CeO2 support and stir at room temperature for 1 h to ensure thorough mixing. Then, rotary evaporate the mixture at 50 °C to remove the solvent. The resulting solid powder is calcined in a muffle furnace at 500 °C for 1 h (heating rate 5 °C / min). -1 The calcined powder was cooled to room temperature. The calcined powder was then placed in a tube furnace under a H2 atmosphere (flow rate 100 mL / min). -1 The catalyst was reduced at 400℃ for 2 h and then naturally cooled to room temperature to obtain the Pt / CeO2 catalyst.

[0079] Comparative Example 7

[0080] Weigh 500 mg of commercial CeO2 support (particle size 20–50 nm) and place it in a beaker. Weigh 67 μmol of PdCl2 and dissolve it in 25 mL of deionized water to prepare a metal salt solution. Add this solution to the CeO2 support and stir at room temperature for 1 h to ensure thorough mixing. Then, remove the solvent by rotary evaporation at 50 °C. The resulting solid powder is calcined in a muffle furnace at 500 °C for 1 h (heating rate 5 °C / min). -1 The calcined powder was cooled to room temperature. The calcined powder was then placed in a tube furnace under a H2 atmosphere (flow rate 100 mL / min). -1 The catalyst was reduced at 400℃ for 2 h and then naturally cooled to room temperature to obtain the Pd / CeO2 catalyst.

[0081] Comparative Example 8

[0082] Weigh 500 mg of commercial CeO2 support (particle size 20–50 nm) and place it in a beaker. Weigh 67 μmol of RhCl3·xH2O and dissolve it in 25 mL of deionized water to prepare a metal salt solution. Add the above solution to the CeO2 support and stir at room temperature for 1 h to ensure thorough mixing. Then, remove the solvent by rotary evaporation at 50 °C. The resulting solid powder is calcined in a muffle furnace at 500 °C for 1 h (heating rate 5 °C / min). -1 The calcined powder was cooled to room temperature. The calcined powder was then placed in a tube furnace under a H2 atmosphere (flow rate 100 mL / min). -1 The catalyst was reduced at 400℃ for 2 h and then naturally cooled to room temperature to obtain the Rh / CeO2 catalyst.

[0083] Application Example 1

[0084] The hydrolysis of ammonia borane was carried out in a 50 mL three-necked round-bottom flask under normal pressure at 25 °C. 10 mg of the catalyst prepared in Example 1 and Comparative Examples 1-8 and 0.5 mL of water were added to the reaction flask, and the mixture was ultrasonically dispersed for 1 minute. 10 mL of 0.1 mol L⁻¹ catalyst, kept in a water bath at 25 °C, was added through a constant-pressure dropping funnel. -1 An aqueous solution of NH3BH3 was prepared, and the reaction was started and timed. The produced hydrogen gas was collected by water displacement, and the volume change of hydrogen gas over time was recorded. The results are as follows: Figure 3 As shown, a~c correspond to different comparative examples and Example 1; d is the Arrhenius diagram and the corresponding activation energy of different catalysts. It can be seen that the PtPdRhRuNi / CeO2 catalyst provided by this invention has the highest activity.

[0085] Application Example 2

[0086] Cyclic stability tests were conducted on the PtPdRhRuNi / CeO2 catalyst from Example 1 and the catalyst obtained in Comparative Example 8. After each reaction cycle, the catalyst was recovered by vacuum filtration, washed three times with deionized water, dried overnight at 80°C, and then used for the next reaction cycle. Figure 4 As shown in Figure a, the PtPdRhRuNi / CeO2 catalyst retains over 90% of its initial activity after the third cycle, while the Rh / CeO2 catalyst (in contrast) Figure 4 b) The activity decreased to less than 60% of the initial value after the third cycle, indicating that the high-entropy alloy cluster catalyst prepared in this invention has excellent cycle stability.

[0087] Aberration-corrected high-angle annular dark-field scanning transmission electron microscope image and elemental distribution mapping of the high-entropy alloy cluster catalyst after the reaction are shown below. Figure 5 As shown. From Figure 5As can be seen, the high-entropy alloy clusters remain uniformly dispersed on the CeO2 support after the reaction, with no significant change in average particle size, and no elemental segregation or phase separation was observed. The five metal elements remain uniformly distributed within the clusters. This result directly demonstrates that the high-entropy alloy cluster catalyst of this invention exhibits excellent cycle stability under harsh reaction conditions.

[0088] As can be seen from the above embodiments, the cerium oxide-supported high-entropy alloy cluster catalyst provided by the present invention has good cycle stability; and the PtPdRhRuNi / CeO2 catalyst has excellent catalytic performance in the hydrolysis of ammonia borane to produce hydrogen.

[0089] In summary, this invention provides a cerium oxide-supported high-entropy alloy cluster catalyst, its preparation method, and its application. The catalyst comprises: cerium oxide particles with a size of 20-50 nm; and high-entropy alloy clusters supported on the cerium oxide surface with an average size of approximately 1.2 nm. The high-entropy alloy clusters are composed of five elements: Pt, Pd, Rh, Ru, and Ni. In this invention, cerium oxide is dispersed in water, and a corresponding metal precursor salt is added and stirred. The mixed solution is then evaporated under vacuum to obtain a solid powder. The solid powder is calcined and then subjected to reduction treatment. This method successfully synthesizes PtPdRhRuNi high-entropy alloy clusters on cerium oxide. By controlling the reduction temperature, the structure of the high-entropy alloy clusters can be effectively regulated, exhibiting high hydrogen production rates and cycle stability in the hydrolysis reaction of ammonia borane.

[0090] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst, characterized in that, It includes cerium oxide support and PtPdRhRuNi high-entropy alloy clusters supported on the support.

2. The cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst according to claim 1, characterized in that, The size of the cerium oxide is 20~50 nm; The average particle size of the high-entropy alloy clusters is 1.2 ± 0.3 nm.

3. The cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst according to claim 1 or 2, characterized in that, The mass ratio of cerium oxide to high-entropy alloy clusters is 100:(0.5~5).

4. A method for preparing a cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S1: Pt, Pd, Rh, Ru, Ni precursor salts and solvents are mixed to obtain a first mixture; cerium oxide is mixed with the first mixture to obtain a second mixture; S2: Remove the solvent from the second mixture to obtain a mixed solid, and then perform calcination and reduction treatment to obtain a cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst.

5. The preparation method according to claim 4, characterized in that, The mass ratio of cerium oxide, element Pt, element Pd, element Rh, element Ru, element Ni and solvent is 100:(0.5~0.6):(0.2~0.3):(0.2~0.3):(0.2~0.3):(0.1~0.2):(2500~25000).

6. The preparation method according to claim 4 or 5, characterized in that, The precursor salt of Pt is selected from any one or more of H2PtCl6·6H2O, K2PtCl4 or Na2PtCl4; The precursor salt of Pd is selected from any one or more of PdCl2, Pd(NO3)2 or K2PdCl4; Rh precursor salts are selected from any one or more of RhCl3 hydrate or Rh(NO3)3; The precursor salt of Ru is selected from one or more of RuCl3 hydrate or (NH4)2RuCl6; Ni precursor salts are selected from any one or more of NiCl2·6H2O or Ni(NO3)2 and NiSO4; The solvent is selected from water, and the water is deionized water.

7. The preparation method according to any one of claims 4 to 6, characterized in that, The mixing of cerium oxide and the first mixture is carried out under stirring conditions, and the mixing time is 0.5~1 h; The solvent removal is carried out by rotary evaporation at a temperature of 50-55°C.

8. The preparation method according to any one of claims 4 to 7, characterized in that, The calcination treatment is carried out at 5~10℃ for min. -1 The temperature is increased to 500~550℃ at a rate of 1~1.5 h.

9. The preparation method according to any one of claims 4 to 8, characterized in that, The reduction process is carried out in an atmosphere containing hydrogen, and the temperature of the reduction process is 5~10℃ min. -1 The temperature is increased to 300~500℃ at a rate of 2~2.5 h.

10. The application of the cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst according to any one of claims 1 to 3, or the cerium oxide-supported PtPdRhRuNi high-entropy alloy cluster catalyst prepared by the preparation method according to any one of claims 4 to 9, in the catalytic hydrolysis of ammonia borane to produce hydrogen.

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