A trimetallic PdNiRu ultrathin nanosheet, its preparation method and application

Abstract

This invention discloses a trimetallic PdNiRu ultrathin nanosheet, its preparation method, and its applications. The nanosheet possesses ultrathin nanoscale dimensions, a two-dimensional sheet structure, and a multi-metallic composition. Using palladium(II), ruthenium(III), and nickel(II) acetylacetone as metal precursors, oleylamine and oleic acid as solvents, and carbon monoxide generated from the decomposition of the carbonyl compound Mo(CO)6 as a structure directing agent, the trimetallic PdNiRu nanosheet was synthesized via a one-step solvothermal method at 180°C for 3 hours. The highly curved ultrathin nanosheet structure and the ternary metal effect can synergistically regulate the surface electronic structure, helping to optimize the adsorption intensity of oxygen-containing species. It possesses advantages such as ultrathinness (~3.5 nm), good conductivity, high electrochemical activity, and good electrochemical stability. It can be used as an ethylene glycol oxidation anode catalyst and an oxygen reduction cathode catalyst, exhibiting high catalytic activity and stability in both applications.

Description

TECHNICAL FIELD

[0001] The present application relates to a catalyst for electrocatalytic reaction technology, in particular to a three-metal PdNiRu ultrathin nanosheet and a preparation method and application thereof. BACKGROUND

[0002] The increasing energy consumption and environmental pollution have prompted researchers to find economic and environmentally friendly energy generation, storage and conversion devices. Fuel cells have become the preferred energy device for automobiles and portable electronic devices due to their high efficiency, environmental protection and abundant fuel sources (such as hydrogen, formic acid, methanol, ethanol and ethylene glycol, etc.). Traditionally, Pt and Pt-based alloys are considered to be the most advanced catalysts for anodic oxidation reactions and cathodic oxygen reduction reactions (ORR), however, the wide application of these catalysts is limited by their high cost, scarcity and electrochemical instability in the oxygen reduction process, and it is necessary to develop high-performance renewable energy technologies and design the most advanced electrocatalysts. Pd has a similar electronic configuration to Pt (with an electron difference of only 0.77%), and also exhibits similar chemical properties. However, compared with Pt, the stronger binding ability of Pd to oxygen molecules leads to relatively weak oxygen reduction activity, but the alloying of Pd with transition metals can solve this problem due to the ensemble effect, lattice strain and ligand effect, which promotes the activation of O2 and H2O, while weakening the adsorption strength of oxygen-containing intermediates, thereby improving the catalytic activity and the ability to oxidize small organic molecules, such as Pd-Fe, Pd-Co, Pd-Ni, Pd-Ag, Pd-Cu, have been explored as candidate catalysts for ORR, EOR and EGOR, most of the reported Pd-based nano-alloys are mainly focused on 0D, 1D or twinned nanostructures, but there are still some shortcomings (such as complicated synthesis method, poor stability and low mass activity).

[0003] As an important class of functional materials, ultrathin two-dimensional nanostructures have attracted much attention due to their inherent advantages, such as high surface metal atom volume ratio, abundant low-coordinated atoms (such as the topmost surface atoms and edge atoms), unique electronic and photonic properties, and surface interface effects, and have great application prospects in photothermal therapy, sensing and electrocatalysis. For electrocatalytic applications, electrocatalytic processes only occur on or near the surface of the catalyst. Therefore, ultrathin Pd nanosheets can provide higher atom utilization and have larger specific surface area; therefore, the synthesis of ultrathin Pd nanosheets is a hot issue in electrocatalysis research. SUMMARY

[0004] In view of the existing technical problems, the present application provides a kind of three-metal PdNiRu ultra-thin nanosheet and its preparation method and application, three-metal PdNiRu ultra-thin nanosheet is prepared by one-pot solvothermal method, the PdNiRu nanosheet obtained has ultra-thin and highly curved fold structure, which not only improves the catalytic activity of Pd in the catalyst but also effectively improves the stability of the catalyst, and can be applied in anodic ethylene glycol oxidation and cathodic oxygen reduction electrocatalysis.

[0005] To solve the problems in the prior art, the technical solution adopted by the present application is:

[0006] A preparation method of a three-metal PdNiRu ultra-thin nanosheet, an oil amine and an oleic acid mixed solution are used as a solvent, Pd(acac)2, Ru(acac)3 and Ni(acac)2 are added as metal precursor reactants, Mo(CO)6 is used as a structure directing agent, the substances are mixed and magnetically stirred uniformly, a high-pressure reaction kettle is sealed and transferred to an oven, heated to 180°C, and kept at 180°C for 3 hours, after they are naturally cooled to room temperature, the black product is collected by centrifugation and washed several times with an ethanol / cyclohexane mixture, and dried to obtain PdNiRu nanosheets, wherein the carbon monoxide generated by the decomposition of the Mo(CO)6 carbonyl compound serves as a structure directing agent to produce nanosheets with an ultra-thin thickness.

[0007] As an improvement, the preparation method of the above-mentioned three-metal PdNiRu ultra-thin nanosheet specifically includes the following steps:

[0008] 1) Preparation of a metal precursor solution: weigh Pd(acac)2, Ru(acac)3, Ni(acac)2 and Mo(CO)6, add oil amine and oleic acid as a mixed solvent, stir to mix thoroughly to obtain a metal precursor solution;

[0009] 2) Preparation of three-metal PdNiRu ultra-thin nanosheet: seal the metal precursor solution in a high-pressure kettle and transfer it to an oven, heat to 180°C, and keep for 3 hours, then cool to room temperature, wash and dry to obtain PdNiRu nanosheets.

[0010] Preferably, the volume ratio of oil amine to oleic acid in the mixed solvent in step 1) is 4:1.

[0011] Preferably, the three metal acetylacetone palladium (II), acetylacetone nickel (II) and acetylacetone ruthenium (III) in the metal precursor solution have the same proportion, i.e. Pd:Ni:Ru=1:1:1, wherein (II) and (III) represent the valence state of the corresponding metal elements in the compound).

[0012] Preferably, the drying in step 2) is drying overnight in a vacuum oven at 60°C.

[0013] The trimetallic PdNiRu ultrathin nanosheets prepared by any of the above methods are two-dimensional ultrathin nanosheet structures with a thickness of 3.5 nm.

[0014] The application of trimetallic PdNiRu ultrathin nanosheets prepared by any of the above methods as fuel cell catalysts.

[0015] The excellent electrocatalytic performance of the trimetallic PdNiRu ultrathin nanosheets prepared in this invention is mainly attributed to the following reasons: (1) The highly curved and ultrathin structural features of PdNiRu nanosheets can provide defects and surface strain; (2) The synergistic effect between Pd, Ni and Ru elements exists in the top atomic layer and is beneficial to the removal of poisoning intermediates generated in the electrocatalytic reaction (such as CO adsorption (CO-ads) and OH adsorption (OH-ads)). In addition, it has been found that metals Ni and Ru can constitute sites for active oxygen, water or small organic molecules and improve the activity and durability of fuel cells; (3) The alloying of Pd with Ni and Ru changes the surface electronic structure and d-band center of Pd, which can regulate the adsorption / desorption capacity of activated reactant molecules or intermediates and improve catalytic performance.

[0016] Beneficial effects:

[0017] Compared with existing technologies, this invention provides a trimetallic PdNiRu ultrathin nanosheet, its preparation method, and its application. The resulting material has an ultrathin nanosheet structure, with Pd, Ni, and Ru uniformly distributed within the nanosheet. This material can be used as a fuel cell catalyst, exhibiting excellent electrocatalytic performance and stability in ethylene glycol oxidation and oxygen reduction. It has the following advantages:

[0018] 1. This invention synthesizes ultrathin PdNiRu nanosheets via a simple one-pot method by systematically designing electronic structures and material morphologies. The PdNiRu nanosheets are predominantly graphene-like two-dimensional nanosheets with an average lateral dimension of 400 nm and a thickness of approximately 3.5 nm. High-resolution TEM (HRTEM) images and corresponding Fast Fourier Transform (FFT) modes demonstrate the coexistence of amorphous and crystalline phases. The ultrathin and highly flexible structure induces interwoven geometries between the nanosheets. The structural features of the PdNiRu nanosheets provide abundant active sites and enhance the catalytic performance of the catalyst in catalytic reactions.

[0019] 2. This invention prepares trimetallic PdNiRu ultrathin nanosheets via a simple, safe, efficient, and scalable one-pot solvothermal method, and the resulting catalyst is a novel bifunctional catalyst for anodic ethylene glycol oxidation (EGOR) and cathodic oxygen reduction (ORR).

[0020] 3. This invention presents a high-performance non-Pt nanocatalyst. Current-time curves, cycle stability, and CO stripping tests demonstrate that PdNiRu nanosheets exhibit better stability and CO tolerance than commercially available Pd / C. This method represents a novel approach to preparing a bifunctional non-platinum catalyst. The selected Pd-based metal precursor is relatively inexpensive and abundant compared to Pt. Compared to other traditional methods for preparing Pd-based catalysts, this method is simple, easy to implement, requires minimal equipment, and is safe and efficient. The resulting nanosheets possess an ultrathin, curved, wrinkled structure, with Pd, Ni, and Ru uniformly distributed throughout. The prepared catalyst exhibits numerous active sites, high electrocatalytic activity, and high stability. Compared to conventional Pd-based catalysts, the prepared trimetallic PdNiRu ultrathin nanosheets demonstrate superior electrocatalytic performance and stability in ethylene glycol oxidation and oxygen reduction, making them a highly promising fuel cell catalyst with broad application prospects in the future energy industry. Attached Figure Description

[0021] Figure 1 SEM images of the trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention;

[0022] Figure 2 TEM images of trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention at different scales;

[0023] Figure 3 AFM spectrum of trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention;

[0024] Figure 4 HRTEM images and corresponding FFT spectra of trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention;

[0025] Figure 5 High-magnification HAADF-STEM images and elemental mapping spectra of trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention;

[0026] Figure 6 XRD pattern of trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention;

[0027] Figure 7 The corresponding SEM, TEM, and XRD patterns of the dimetallic PdNi ultrathin nanosheets prepared by the method of this invention;

[0028] Figure 8 The corresponding SEM, TEM, and XRD patterns of the dimetallic PdRu ultrathin nanosheets prepared by the method of this invention;

[0029] Figure 9The SEM, TEM, and XRD patterns of the pure Pd ultrathin nanosheets prepared by the method of this invention are shown below.

[0030] Figure 10 XPS full spectrum of trimetallic PdNiRu ultrathin nanosheets prepared by the method of the present invention;

[0031] Figure 11 Fine spectra of Pd3d, Ni2p, and Ru3d of trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention, and comparison with fine spectra of Pd3d of pure Pd and dimetallic PdNi nanosheets;

[0032] Figure 12 A represents the ORR polarization curves of the trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention and the control sample. Figure 12 B represents the initial potential and half-wave potential of the trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention and the control sample.

[0033] Figure 12 C represents the Tafel curves of the trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention and the control sample.

[0034] Figure 12 D represents a comparison of the specific activity and mass activity (vs. RHE) of the trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention with the control sample at 0.90 V;

[0035] Figure 13 The corresponding oxygen reduction (ORR) electrocatalytic performance test diagrams of the trimetallic PdNiRu ultrathin nanosheets prepared by the method of the present invention are shown.

[0036] Figure 14 The corresponding oxygen reduction (ORR) electrocatalytic stability test diagrams of the trimetallic PdNiRu ultrathin nanosheets prepared by the method of the present invention are shown.

[0037] Figure 15 The graph shows the electrocatalytic performance test results of the trimetallic PdNiRu ultrathin nanosheets prepared by the method of this invention for ethylene glycol oxidation (EGOR).

[0038] Figure 16 The graph shows the CO tolerance and stability test results of the trimetallic PdNiRu ultrathin nanosheets prepared by the method of the invention in the corresponding ethylene glycol oxidation (EGOR). Detailed Implementation

[0039] The technical solution of the present invention will be further described in detail below through specific embodiments. However, it should be noted that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the scope of protection of the present invention.

[0040] Example 1

[0041] A method for preparing trimetallic PdNiRu ultrathin nanosheets includes the following steps:

[0042] 1) Preparation of metal precursor solution: At 25℃, 0.04 mmol Pd(acac)2, 0.04 mmol Ru(acac)3, 0.04 mmol Ni(acac)2, 32 mg Mo(CO)6, 8 mL oleic acid and 2 mL oleic acid were added sequentially to a polytetrafluoroethylene reactor and magnetically stirred to mix thoroughly to obtain the metal precursor solution;

[0043] 2) Preparation of trimetallic PdNiRu ultrathin nanosheets: The metal precursor solution obtained in step 1) is sealed in an autoclave and transferred to an oven, heated to 180°C and held at that temperature for 3 hours, and then cooled to room temperature. After washing and drying, the final product can be obtained.

[0044] Comparative Example 1

[0045] 1) Preparation of metal precursor solution: At room temperature (25℃), 0.04 mmol Pd(acac)2, 0.04 mmol Ru(acac)3, 0.04 mmol Ni(acac)2, 32 mg Mo(CO)6, 8 mL oleic acid and 2 mL oleic acid were added sequentially to a polytetrafluoroethylene reactor and magnetically stirred to ensure thorough mixing, thus obtaining the metal precursor solution;

[0046] 2) Preparation of trimetallic PdNiRu ultrathin nanosheets: The metal precursor solution obtained in step 1) is sealed in an autoclave and transferred to an oven. The oven is heated from room temperature to 180°C and maintained at that temperature for 1.5 h. Then, it is cooled to room temperature, washed and dried to obtain the final product.

[0047] Comparative Example 2

[0048] 1) Preparation of metal precursor solution: At 25℃, 0.04 mmol Pd(acac)2, 0.04 mmol Ru(acac)3, 0.04 mmol Ni(acac)2, 32 mg Mo(CO)6, 8 mL oleic acid and 2 mL oleic acid were added sequentially to a polytetrafluoroethylene reactor and magnetically stirred to mix thoroughly to obtain the metal precursor solution;

[0049] 2) Preparation of trimetallic PdNiRu ultrathin nanosheets: The metal precursor solution obtained in step 1) is sealed in an autoclave and transferred to an oven to be heated to 180°C and kept at that temperature for 6 hours. Then, it is cooled to room temperature, washed and dried to obtain the final product.

[0050] Comparative Example 3

[0051] 1) Preparation of metal precursor solution: At 25℃, 0.04 mmol Pd(acac)2, 0.04 mmol Ru(acac)3, 0.04 mmol Ni(acac)2, 32 mg Mo(CO)6, 8 mL oleic acid and 2 mL oleic acid were added sequentially to a polytetrafluoroethylene reactor and magnetically stirred to mix thoroughly to obtain the metal precursor solution;

[0052] 2) Preparation of trimetallic PdNiRu ultrathin nanosheets: The metal precursor solution obtained in step 1) is sealed in an autoclave and transferred to an oven, heated to 150°C and held at that temperature for 3 hours, then cooled to room temperature and washed and dried to obtain the final product.

[0053] Comparative Example 4

[0054] 1) Preparation of metal precursor solution: At 25℃, 0.04 mmol Pd(acac)2, 0.04 mmol Ru(acac)3, 0.04 mmol Ni(acac)2, 32 mg Mo(CO)6, 8 mL oleic acid and 2 mL oleic acid were added sequentially to a polytetrafluoroethylene reactor and magnetically stirred to mix thoroughly to obtain the metal precursor solution;

[0055] 2) Preparation of trimetallic PdNiRu ultrathin nanosheets: The metal precursor solution obtained in step 1) is sealed in an autoclave and transferred to an oven, heated to 210°C and held at that temperature for 3 hours, and then cooled to room temperature. After washing and drying, the final product can be obtained.

[0056] Comparative Example 5

[0057] A method for preparing dimetallic PdNi ultrathin nanosheets includes the following steps:

[0058] 1) Preparation of metal precursor solution: At 25℃, 0.04 mmol Pd(acac)2, 0.04 mmol Ni(acac)2, 32 mg Mo(CO)6, 8 mL oleic acid and 2 mL oleic acid were added sequentially to a polytetrafluoroethylene reactor and magnetically stirred to mix thoroughly and uniformly to obtain the metal precursor solution;

[0059] 2) Preparation of dimetallic PdNi ultrathin nanosheets: The metal precursor solution obtained in step 1) is sealed in an autoclave and transferred to an oven, heated to 180°C and held at that temperature for 3 hours, and then cooled to room temperature. After washing and drying, the final product can be obtained.

[0060] Comparative Example 6

[0061] A method for preparing dimetallic PdRu ultrathin nanosheets includes the following steps:

[0062] 1) Preparation of metal precursor solution: At 25℃, 0.04 mmol Pd(acac)2, 0.04 mmol Ru(acac)3, 32 mg Mo(CO)6, 8 mL oleic acid and 2 mL oleic acid were added sequentially to a polytetrafluoroethylene reactor and magnetically stirred to mix thoroughly to obtain the metal precursor solution.

[0063] 2) Preparation of dimetallic PdRu ultrathin nanosheets: The metal precursor solution obtained in step 1) is sealed in an autoclave and transferred to an oven, heated to 180°C and held at that temperature for 3 hours, and then cooled to room temperature. After washing and drying, the final product can be obtained.

[0064] Comparative Example 7

[0065] A method for preparing pure Pd ultrathin nanosheets includes the following steps:

[0066] 1) Preparation of metal precursor solution: At 25℃, 0.04 mmol Pd(acac)2, 32 mg Mo(CO)6, 8 mL oleic acid and 2 mL oleic acid were added sequentially to a polytetrafluoroethylene reactor and magnetically stirred to mix thoroughly to obtain the metal precursor solution.

[0067] 2) Preparation of pure Pd ultrathin nanosheets: The metal precursor solution obtained in step 1) is sealed in an autoclave and transferred to an oven, heated to 180°C and held at that temperature for 3 hours, and then cooled to room temperature. After washing and drying, the final product can be obtained.

[0068] Comparative Example 8

[0069] A method for preparing trimetallic PdCoRu ultrathin nanosheets includes the following steps:

[0070] 1) Preparation of metal precursor solution: At 25℃, 0.04 mmol Pd(acac)2, 0.04 mmol Co(acac)3, 0.04 mmol Ru(acac)3, 32 mg Mo(CO)6, 8 mL oleic acid and 2 mL oleic acid were added sequentially to a polytetrafluoroethylene reactor and magnetically stirred to mix thoroughly to obtain the metal precursor solution;

[0071] 2) Preparation of trimetallic PdCoRu ultrathin nanosheets: The metal precursor solution obtained in step 1) is sealed in an autoclave and transferred to an oven, heated to 180°C and held at that temperature for 3 hours, and then cooled to room temperature. After washing and drying, the final product can be obtained.

[0072] Comparative Example 9

[0073] A method for preparing trimetallic PdFeRu ultrathin nanosheets includes the following steps:

[0074] 1) Preparation of metal precursor solution: At 25℃, 0.04 mmol Pd(acac)2, 0.04 mmol Fe(acac)3, 0.04 mmol Ru(acac)3, 32 mg Mo(CO)6, 8 mL oleic acid and 2 mL oleic acid were added sequentially to a polytetrafluoroethylene reactor and magnetically stirred to mix thoroughly to obtain the metal precursor solution;

[0075] 2) Preparation of trimetallic PdFeRu ultrathin nanosheets: The metal precursor solution obtained in step 1) is sealed in an autoclave and transferred to an oven, heated to 180°C and held at that temperature for 3 hours, and then cooled to room temperature. After washing and drying, the final product can be obtained.

[0076] The Pd-based ultrathin nanosheets prepared in the above examples were physically characterized using TEM, SEM, XRD, and AFM. Scanning electron microscopy (SEM) was used to characterize the nanosheets. Figure 1 ) and transmission electron microscopy (TEM) Figure 2 The morphology of the synthesized PdNiRu NSs was measured, indicating that the obtained product is mainly composed of graphene-like two-dimensional nanosheets. The nanosheets are clearly ultrathin and highly flexible, which can induce an interwoven geometry between them. The average lateral dimension of the PdNiRu nanosheets can reach 400 nm. The average thickness was measured using atomic force microscopy (AFM). Figure 3 ), approximately 3.5 nm. High-resolution TEM (HRTEM) images and corresponding Fast Fourier Transform (FFT) modes ( Figure 4 This demonstrates the coexistence of amorphous and crystalline structures, due to rapid nucleation and crystallization resulting from the fast reaction rate. In the crystalline region, HRTEM images show clear lattice fringes with an interplanar spacing of 0.219 nm, very close to the (111) interplanar spacing of face-centered cubic (fcc) Pd. In addition to abundant mesopores, steps, corners, and twins are also clearly visible. Therefore, PdNiRu nanosheets provide abundant active sites and enhance the catalytic performance of trimetallic PdNiRu ultrathin nanosheets in catalytic reactions. Furthermore, HAADF-STEM images and elemental mapping diagrams ( Figure 5The results showed that Pd, Ni, and Ru elements were uniformly dispersed on the nanosheets, and the crystal structure of the PdNiRu nanosheets was confirmed by X-ray diffraction (XRD). Figure 6 As shown, the XRD spectrum reveals a good correspondence between the PdNiRu nanosheet peaks and the Pd peaks (JCPDS No. 46-1043). However, the diffraction pattern of the catalytic powder exhibits relatively broad low-intensity peaks, indicating the formation of an amorphous structure within the metallic phase, which is consistent with the results of the HRTEM images. Figure 7 , 8 9 and 9 represent the SEM, TEM, and XRD values ​​for PdNi nanosheets, PdRu nanosheets, and pure Pd nanosheets, respectively. X-ray photoelectron spectroscopy (XPS) measurements were performed to reveal the near-surface valence states of each element in PdNiRu NSs. PdNiRu NSs XPS full-scan spectrum ( Figure 10 This indicates the presence of Pd, Ni, and Ru elements; C, N, and O originate from air or residual surfactants. (For example...) Figure 11 The fine Pd3d spectrum of the PdNiRu nanosheets shown in Figure A indicates that Pd in ​​the alloy coexists in the forms of Pd(II) and Pd(0). The shift of the Pd3d XPS peak of PdNi-NSs to a higher binding energy relative to the Pd-NSs peak indicates a downward shift of the d-band center, which is consistent with the previously reported properties of noble metal group (PGM) based alloys. Compared with pure Pd-NSs, the XPS spectrum of Pd3d in Pd-NiRu-NSs shows a negative shift, indicating that the electronic structure has changed due to charge transfer between Pd, Ni, and Ru. Figure 11 B) Figure 11 C and 11D are fine spectra of Ni2p and Ru3d in PdNiRu nanosheets, respectively.

[0077] To evaluate the ORR performance of the nanosheets, electrochemical performance characterization was performed in 0.1 M KOH solution. Figure 12 For comparison, pure Pd, PdNi, PdRu nanosheets and commercial Pt / C were selected as control catalysts. PdNiRu nanosheets exhibited the highest onset potential, half-wave potential, and lowest Tafel slope. At a potential of 0.90 V (vs. RHE), the Ji of PdNiRuNSs was the highest. k 5.52mA cm -2 j m 1.13A mgPd -1 These are 4.8 times and 3.4 times that of commercial Pt / C, respectively;

[0078] like Figure 13 As shown, the PdNiRu nanosheet catalyst undergoes a transition from O2 to OH. - The ideal "4e-" direct transfer pathway and the resulting peroxide species (HO)2- The yield is low, and electrochemical impedance spectroscopy (EIS) indicates that it has the lowest electron transfer resistance.

[0079] like Figure 14 As shown, after 5000 CV cycles, the half-wave potential of the ORR polarization curve of the PdNiRu nanosheet catalyst decreased slightly (~11 mV), indicating that the PdNiRu nanosheet catalyst possesses excellent ORR catalytic activity and stability. Furthermore, the electrocatalytic activity of PdNiRu nanosheets for ethylene glycol oxidation under alkaline conditions was also tested. Figure 15 ) and durability ( Figure 16 The electrochemically active surface area (ECSA) of the PdNiRu nanosheets is 62.2 m². 2 g -1 For EGOR, the MA of PdNiRu nanosheets (3.86Amg Pd) -1 ) is a commercial Pd / C (1.51Amg Pd) -1 The current-time curve, cycling stability, and CO stripping test all show that PdNiRu NSs has better stability and CO tolerance than commercial Pd / C. (This is 2.6 times higher than that of Pd / C.)

Claims

1. A method for preparing trimetallic PdNiRu ultrathin nanosheets, characterized in that: Using a mixed solution of oleylamine and oleic acid as a solvent, Pd(acac)₂, Ru(acac)₃, and Ni(acac)₂ were added as metal precursor reactants, and Mo(CO)₆ was used as a structure directing agent. The reactants were mixed and magnetically stirred until homogeneous to obtain a metal precursor solution. This solution was then sealed in a high-pressure reactor and transferred to an oven, heated to 180°C, and maintained at 180°C for 3 hours. After natural cooling to room temperature, the product was collected by centrifugation and washing several times with an ethanol / cyclohexane mixture. The black product was then dried to obtain PdNiRu nanosheets. The preparation of the metal precursor solution specifically includes the following steps: Weigh Pd(acac)2, Ru(acac)3, Ni(acac)2, and Mo(CO)6, add oleylamine and oleic acid in a volume ratio of 4:1 as a mixing solvent, and stir magnetically to mix them thoroughly to obtain a metal precursor solution. The molar ratios of palladium acetylacetone (II), nickel acetylacetone (II), and ruthenium acetylacetone (III) are the same, i.e., Pd:Ni:Ru=1:1:

1.

2. The method for preparing trimetallic PdNiRu ultrathin nanosheets according to claim 1, characterized in that, The drying described in step 2) is to dry overnight in a vacuum oven at 60°C.

3. The trimetallic PdNiRu ultrathin nanosheets prepared by any one of claims 1-2, characterized in that, The trimetallic PdNiRu ultrathin nanosheets are two-dimensional ultrathin nanosheet structures with a thickness of 3.5 nm.

4. The application of trimetallic PdNiRu ultrathin nanosheets prepared by any one of claims 1-2 as fuel cell catalysts.

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