Pt single atom / cluster co-supported on NiCo layered double metal oxide material, preparation method and application thereof

Abstract

This invention provides a Pt single-atom / cluster co-supported NiCo layered bimetallic oxide material, its preparation method, and its application. The preparation method includes: adding cobalt salt and 2-methylimidazole to an anhydrous methanol solution and stirring at room temperature; after the reaction is complete, centrifuging to collect the product, repeatedly washing, and drying to obtain a zeolite-like imidazolium ester framework material, Co-ZIF; adding Co-ZIF, nickel salt, and platinum source to an anhydrous ethanol solution and stirring at room temperature; after the reaction is complete, centrifuging to collect the product, repeatedly washing, and drying to obtain a Pt-supported NiCo layered bimetallic hydroxide material; and calcining the Pt-supported NiCo layered bimetallic hydroxide material to obtain a Pt single-atom / cluster co-supported NiCo layered bimetallic oxide material. The material of this invention exhibits excellent catalytic activity, demonstrating superior activity and stability in the hydrogen evolution reaction in alkaline electrolytes.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation methods and electrocatalysis cross-application, specifically involving a Pt single atom / cluster co-supported NiCo layered bimetallic oxide material, its preparation method and application. Background Technology

[0002] In recent years, renewable energy has received increasing attention as an alternative to fossil fuels, and hydrogen, with its high energy density and eco-friendliness, is considered an ideal energy carrier for achieving sustainable economic development. Alkaline electrocatalytic water splitting is one of the most efficient and environmentally friendly methods for large-scale industrial production of high-purity hydrogen, and efficient and economical electrocatalysts have always been a key industrial goal. Single-atom catalysts, due to their high atomic efficiency, unique electronic structure, and easily tunable coordination environment, exhibit advantages of high activity and low cost, and have received considerable attention in recent years. However, previous studies have reported that these noble metal catalysts exhibit less than ideal electrocatalytic hydrogen evolution performance, sometimes even inferior to traditional nanoparticle catalysts. The main reason is the extremely low noble metal content (<1 wt%), and the tendency of single atoms to aggregate at high current densities. Currently, a common strategy to address this problem is to integrate noble metal single atoms and clusters onto a substrate, which allows for reconfiguration of the electronic structure, thereby improving electrocatalytic activity. Metal oxide supports have strong interactions with active metals; therefore, metal oxides may be an ideal substrate for the coexistence of noble metal single atoms and clusters to improve hydrogen evolution performance. However, research on this topic is currently limited.

[0003] Integrating noble metal single atoms into layered bimetallic oxides is one of the best methods to improve hydrogen evolution performance. However, inserting single atoms into the layers of such layered bimetallic oxide / single-atom electrocatalysts remains a significant challenge. Therefore, the high cost, poor activity, and instability of such catalysts in existing technologies still limit the development and application of electrocatalytic hydrogen production. Summary of the Invention

[0004] This invention is made to solve the above-mentioned problems, and aims to provide a Pt single atom / cluster co-loaded NiCo layered bimetallic oxide material, its preparation method and application.

[0005] This invention provides a method for preparing a NiCo layered bimetallic oxide material with Pt single atoms / clusters co-supported on it, characterized by the following steps:

[0006] Step 1: Cobalt salt and 2-methylimidazole were added to anhydrous methanol solution and stirred at room temperature. After the reaction was completed, the product was collected by centrifugation, washed repeatedly, and dried to obtain the zeolite-like imidazole ester framework material Co-ZIF.

[0007] Step 2: Co-ZIF, nickel salt, and platinum source are added to anhydrous ethanol solution and stirred at room temperature. After the reaction is completed, the product is collected by centrifugation, washed repeatedly, and dried to obtain Pt-supported NiCo layered bimetallic hydroxide material.

[0008] Step 3: The Pt-supported NiCo layered bimetallic hydroxide material is calcined to obtain a Pt single atom / cluster co-supported NiCo layered bimetallic oxide material.

[0009] The preparation method provided by the present invention may also have the following characteristics: wherein the cobalt salt is cobalt nitrate hexahydrate, the nickel salt is nickel nitrate hexahydrate, and the platinum source is hydrated chloroplatinic acid.

[0010] The preparation method provided by the present invention may also have the following characteristics: in step 1, the molar ratio of cobalt salt and 2-methylimidazolium is 1:8-1:4, and the stirring reaction time at room temperature is 4h-6h.

[0011] The preparation method provided by the present invention may also have the following feature: in step 2, the mass ratio of Co-ZIF, nickel salt and platinum source is 0.2g:0.5816g:(0.0153g~0.0921g).

[0012] The preparation method provided by the present invention may also have the following feature: in step 2, the stirring reaction time at room temperature is 8-12 hours.

[0013] The preparation method provided by the present invention may also have the following characteristics: in step 3, the calcination temperature is 250℃-350℃, the heating rate is 1℃ / min~3℃ / min, and the time is 3h.

[0014] The preparation method provided by the present invention may also have the following feature: the calcination atmosphere is air.

[0015] The preparation method provided by the present invention may also have the following features: wherein, in step 2, the process of adding Co-ZIF, nickel salt and platinum source to anhydrous ethanol solution is as follows: Co-ZIF is dissolved in anhydrous ethanol to obtain solution A; nickel salt and platinum source are dissolved in anhydrous ethanol to obtain solution B; solution B is added dropwise to solution A.

[0016] The present invention also provides a Pt single atom / cluster co-supported NiCo layered bimetallic oxide material, characterized in that it is prepared by the above-described preparation method.

[0017] This invention also provides an application of Pt single atoms / clusters co-supported on NiCo layered bimetallic oxide materials, characterized in that Pt single atoms / clusters co-supported on NiCo layered bimetallic oxide materials serve as an electrocatalyst for the electrochemical hydrogen evolution reaction (HER).

[0018] When Pt single atoms / clusters are co-loaded onto NiCo layered bimetallic oxide materials as HER electrocatalysts, the specific method is as follows:

[0019] Pt single atoms / clusters co-supported on NiCo layered bimetallic oxide material were used as the working electrode, Hg / HgO (1 M KOH solution, ~0.924 V vs. NHE) as the reference electrode, and a graphite rod as the counter electrode. The electrolyte was 1.0 M KOH solution. Electrochemical tests were performed using a CHI 760E electrochemical workstation. The preparation process of the working electrode was as follows: 5 μL of ultrasonically mixed catalyst dispersion (dispersion composition: 4 mg catalyst material + 20 μL 5 wt% Nafion solution + 750 μL deionized water + 250 μL anhydrous ethanol) was drop-coated onto an area of ​​0.07 cm². 2 The electrode was placed on a glassy carbon electrode and allowed to air dry before being used as the working electrode. The linear voltammetry (LSV) scan rate was 2 mV / s. -1 Furthermore, all polarization curves undergo iR compensation; the Tafel slope is calculated by fitting a linear scan curve; the electrochemical impedance spectroscopy (EIS) test frequency range is 0.01–10 Hz. 5 Hz, amplitude of 5mV. Furthermore, at 60mAcm... -2 The electrochemical HER stability of the catalyst was investigated by performing a chronovoltammetric test for 105 hours.

[0020] The role and effect of invention

[0021] The beneficial effects obtained by this invention include:

[0022] 1. A precise positioning of Pt single atoms inserted into a NiCo layered bimetallic oxide layer (Pt-NiCo LDO) was achieved through a self-sacrificial template process and subsequent phase transition method. This invention utilizes a green and simple synthesis method that has certain universality for preparing materials with coexistence of single atoms and clusters and precise positioning of single atoms.

[0023] 2. Simple inorganic salts are used as reactants, raw materials are abundant, and industrial costs are low.

[0024] 3. In this invention, due to 1) the unique insertion of Pt single atoms into the LDO layer, effective electronic interaction between Pt and NiCo LDO is promoted; 2) its unique dodecahedral hollow structure and two-dimensional nanosheets are conducive to proton transfer and transport. Therefore, the product prepared according to this method has good electrochemical hydrogen evolution performance and high-quality activity within 105 h (nearly 6 times higher than 20 wt% commercial platinum-carbon catalyst). It can be used as a high-performance electrocatalytic hydrogen evolution material and has a broad development prospect and application space.

[0025] 4. The process of this invention is simple, the preparation conditions are mild, the product has stable morphology and high purity, and the product processing is convenient and simple, making it suitable for medium-scale industrial production.

[0026] 5. The method of the present invention loads Pt single atoms / clusters onto NiCo layered bimetallic oxide, which greatly improves the atom utilization rate and the cycle stability of the composite material, and has important application prospects in green energy fields such as water electrolysis to produce hydrogen. Attached Figure Description

[0027] Figure 1 This is an electron microscope image of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material in Example 1 of the present invention, wherein... Figure 1 Image a is a scanning electron microscope (SEM) image of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material at 250 nm magnification. Figure 1 b is a transmission electron microscope (TEM) image of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material at 100 nm magnification. Figure 1 c is an aberration-corrected high-angle annular dark-field scanning transmission electron microscope (AC-HAADF-STEM) image of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material at a magnification of 2 nm.

[0028] Figure 2 This is the X-ray powder diffraction (XRD) pattern of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material in Example 1 of the present invention. Figure 2 a) and energy-dispersive X-ray spectroscopy (EDS) spectrum ( Figure 2 b).

[0029] Figure 3 This is a high-resolution transmission electron microscope (HRTEM) image of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material in Example 1 of the present invention. Figure 3 a) and selected area electron diffraction (SAED) patterns ( Figure 3 b).

[0030] Figure 4 In Example 1 of this invention, the X-ray absorption spectrum (XAFS) of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material includes near-edge absorption structures (XANES). Figure 4 a) Extended edge absorption structure (EXAFS, Figure 4 b) and wavelet transform analysis results ( Figure 4 c).

[0031] Figure 5 This is an electron microscope image of the NiCo layered bimetallic oxide material co-loaded with Pt single atoms / clusters in Example 2 of the present invention. Figure 5 a is a SEM image of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material at a magnification of 250 nm; Figure 5 b is a TEM image of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material at a magnification of 100 nm.

[0032] Figure 6 This is an electron microscope image of the Pt single atom / cluster co-loaded NiCo layered bimetallic oxide material in Example 3 of the present invention. Figure 6 a is a SEM image of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material at a magnification of 200 nm; Figure 6 b is a TEM image of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material at a magnification of 100 nm.

[0033] Figure 7 This is an electron microscope image of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material (Pt / NiCo LDO) in Example 4 of the present invention. Figure 7 a is a TEM image of Pt / NiCo LDO at a magnification of 50 nm; Figure 7 b is a TEM image of Pt / NiCo LDO at a magnification of 5 nm.

[0034] Figure 8 These are the HER performance diagrams of Pt single atoms / clusters co-loaded in the NiCo layered bimetallic oxide material and the comparative material in the test examples of this invention. Figure 8 a) LSV curve; Figure 8 b) Tafel slope; Figure 8 c) EIS diagram; Figure 8 d) Voltage-time curve. Detailed Implementation

[0035] To facilitate understanding of the technical means, creative features, objectives, and effects of this invention, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate a Pt single-atom / cluster co-loaded NiCo layered bimetallic oxide material, its preparation method, and its applications. The cobalt salt, nickel salt, 2-methylimidazole, platinum source, anhydrous methanol, anhydrous ethanol, etc., used in the following embodiments have a purity no lower than chemical purity.

[0036] <Example 1>

[0037] Example 1 provides a method for preparing a Pt single-atom / cluster co-supported NiCo layered bimetallic oxide material. The preparation method includes the following steps:

[0038] Step 1: 0.873 g Co(NO3)2·6H2O (3 mmol) and 2 g 2-methylimidazole (24 mmol) were dissolved in 50 mL and 150 mL of anhydrous methanol, respectively, and stirred at room temperature for 20 min. Then, the methanol solution of 2-methylimidazole was slowly added to the methanol solution of Co(NO3)2·6H2O while continuously stirring. The mixture was then stirred at room temperature for 4 h, and the purple product was collected by centrifugation. The purple product was washed three times with methanol, dried under vacuum at 60 °C for 12 h, and collected to obtain the zeolite-like imidazole ester framework material (Co-ZIF).

[0039] Step 2: Dissolve 0.2 g of Co-ZIF obtained in Step 1 in 40 mL of anhydrous ethanol and stir for 20 min as solution A. Dissolve 0.5816 g of Ni(NO3)2·6H2O (2 mmol) and 0.0307 g of H2Cl6Pt·xH2O (0.075 mmol of hydrated chloroplatinic acid) in 10 mL of anhydrous ethanol, and label the product as solution B. Add solution B dropwise to solution A and stir continuously at room temperature for 12 h. Wash the resulting yellow-green product three times each with deionized water and ethanol, then dry it under vacuum at 60 °C for 12 h and collect the product to obtain the Pt-supported NiCo layered bimetallic hydroxide material (Pt-NiCo LDH).

[0040] Step 3: Place the Pt-loaded NiCo layered bimetallic hydroxide obtained in Step 2 in a ceramic boat in a tube furnace and calcine it in air at a heating rate of 300℃ and 2℃ / min for 3h to obtain a Pt single atom / cluster co-loaded NiCo layered bimetallic oxide material (Pt-NiCo LDO).

[0041] Figure 1 This is an electron microscope image of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material in Example 1 of the present invention, wherein... Figure 1Image a is a scanning electron microscope (SEM) image of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material at 250 nm magnification. Figure 1 b is a transmission electron microscope (TEM) image of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material at 100 nm magnification. Figure 1 c is an aberration-corrected high-angle annular dark-field scanning transmission electron microscope (AC-HAADF-STEM) image of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material at a magnification of 2 nm.

[0042] from Figure 1 SEM images in a and Figure 1 The TEM image in b shows that, after calcination, the hollow nanostructures of the NiCo layered bimetallic oxide material, co-loaded with Pt single atoms / clusters, have an average size of approximately 300-400 nm, exhibiting a dodecahedral shape and a layered nanosheet morphology. Figure 1 The AC-HAADF-STEM image in c shows that Pt single atoms / clusters are co-loaded in the NiCo layered bimetallic oxide material. Pt single atoms (highlights marked with green circles) and Pt clusters (orange circles) coexist, and the total amount of single atoms is greater than that of clusters.

[0043] Figure 2 This is the X-ray powder diffraction (XRD) pattern of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material in Example 1 of the present invention. Figure 2 a) and energy-dispersive X-ray spectroscopy (EDS) spectrum ( Figure 2 b).

[0044] Figure 2 The XRD pattern of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material shows clear NiO (PDF#47-1049) and Co3O4 (PDF#43-1003) diffraction peaks. The amount of Pt is too small to produce obvious diffraction peaks. Figure 2 EDS characterization in b indicates that the atomic ratio of Pt single atoms / clusters co-loaded in the NiCo layered bimetallic oxide material is 1:20:10:4.

[0045] Figure 3 This is a high-resolution transmission electron microscope (HRTEM) image of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material in Example 1 of the present invention. Figure 3 a) and selected area electron diffraction (SAED) patterns ( Figure 3 b).

[0046] Figure 3The high-resolution transmission electron microscope (HRTEM) image of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material shows that the lattice spacings of the (111), (200) and (222) planes of Pt, NiO and Co3O4 in the material are 0.225, 0.217 and 0.230 nm, respectively. Figure 3 The SAED diagram in b shows that the polycrystalline diffraction rings of the NiCo layered bimetallic oxide material, which are co-loaded with Pt single atoms / clusters, can be labeled as the (111), (220) and (331) planes of NiO, the (311) plane of Pt, and the (400) plane of Co3O4, respectively.

[0047] Figure 4 In Example 1 of this invention, the X-ray absorption spectrum (XAFS) of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material includes near-edge absorption structures (XANES). Figure 4 a) Extended edge absorption structure (EXAFS, Figure 4 b) and wavelet transform analysis results ( Figure 4 c).

[0048] Figure 4 XANES spectroscopy in the model indicates that the white line intensity of Pt in Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide materials and Pt / NiCo LDO is located at the Pt foil (Pt0) and PtO2 (PtO2). 4+ The values ​​between 0 and +4 indicate that Pt single atoms / clusters are co-loaded in NiCo layered bimetallic oxide materials and Pt / NiCo LDOs, respectively. Then, the Fourier transform of the Pt L3 edge EXAFS spectrum is analyzed to determine the chemical coordination environment, and the results are as follows: Figure 4 As shown in b, significant differences can be detected in Pt single-atom / cluster co-loaded NiCo layered bimetallic oxide materials and Pt / NiCo LDO. Pt-O peak and The Pt-Pt peak indicates the coexistence of SA and Pt clusters. Figure 4 Wavelet transform analysis in c also revealed the existence of Pt-O and Pt-Pt pathways in both Pt single-atom / cluster co-loaded NiCo layered bimetallic oxide materials and Pt / NiCo LDOs. Notably, 5 and 5 were detected in the Pt single-atom / cluster co-loaded NiCo layered bimetallic oxide materials. The nearby peaks correspond to Pt-Cl and Pt-M (M = Ni / Co). Therefore, Pt atoms are inserted into the LDO layer and bonded to Ni or Co, rather than simply residing on the layer surface. In contrast, no such peaks were observed in the wavelet transform analysis results of the Pt / NiCo LDO. The nearby peaks clearly rule out the possibility of Pt being inserted into the NiCo LDO layer. Therefore, co-loading of Pt single atoms / clusters into NiCo layered bimetallic oxide materials can greatly promote the interaction between Pt and NiCo LDO.

[0049] <Example 2>

[0050] Example 2 provides a method for preparing a Pt single-atom / cluster co-supported NiCo layered bimetallic oxide material. The preparation method includes the following steps:

[0051] Step 1: 0.873 g Co(NO3)2·6H2O (3 mmol) and 1 g 2-methylimidazole (12 mmol) were dissolved in 50 mL and 150 mL of anhydrous methanol, respectively, and stirred for 20 min. Then, the methanol solution containing 2-methylimidazole was slowly added to the methanol solution of Co(NO3)2·6H2O while continuously stirring. The mixture was then stirred at room temperature for 5 h, and the purple sample was collected by centrifugation. The purple product was washed three times with methanol, dried under vacuum at 60 °C for 8 h, and collected to obtain the zeolite-like imidazole ester framework material (Co-ZIF).

[0052] Step 2: Dissolve 0.2 g of Co-ZIF obtained in Step 1 in 40 mL of anhydrous ethanol, and stir for 20 min as solution A. Then, dissolve 0.5816 g of Ni(NO3)2·6H2O (2 mmol) and 0.0614 g of H2Cl6Pt·xH2O (0.15 mmol of hydrated chloroplatinic acid) in 10 mL of anhydrous ethanol, and label the product as solution B. Add solution B dropwise to solution A and stir continuously for 8 h at room temperature. Wash the resulting yellow-green product three times each with deionized water and ethanol, then vacuum dry at 60 °C for 12 h and collect the product to obtain the Pt-supported NiCo layered bimetallic hydroxide material (Pt-NiCo LDH).

[0053] Step 3: Place the Pt-loaded NiCo layered bimetallic hydroxide obtained in Step 2 in a ceramic boat in a tube furnace and calcine it in air at a heating rate of 300℃ and 2℃ / min for 3h to obtain a Pt single atom / cluster co-loaded NiCo layered bimetallic oxide material (Pt-NiCo LDO).

[0054] Figure 5 This is an electron microscope image of the NiCo layered bimetallic oxide material co-loaded with Pt single atoms / clusters in Example 2 of the present invention. Figure 5 a is a SEM image of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material at a magnification of 250 nm; Figure 5b is a TEM image of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material at a magnification of 100 nm.

[0055] Depend on Figure 5 It can be seen that the Pt single atom / cluster co-loaded on NiCo layered bimetallic oxide prepared in Example 2 still has a hollow dodecahedral nanolayered structure, and the diameter, thickness and other properties have not changed.

[0056] <Example 3>

[0057] Example 3 provides a method for preparing a Pt single-atom / cluster co-supported NiCo layered bimetallic oxide material. The preparation method includes the following steps:

[0058] Step 1: 0.873 g Co(NO3)2·6H2O (3 mmol) and 2 g 2-methylimidazole (24 mmol) were dissolved in 50 mL and 150 mL of anhydrous methanol, respectively, and stirred for 20 min. Then, the methanol solution containing 2-methylimidazole was slowly added to the methanol solution of Co(NO3)2·6H2O while continuously stirring. The mixture was then stirred at room temperature for 4 h, and the purple sample was collected by centrifugation. The purple product was washed three times with methanol, dried under vacuum at 60 °C for 8 h, and collected to obtain the zeolite-like imidazole ester framework material (Co-ZIF).

[0059] Step 2: Dissolve 0.2 g of Co-ZIF obtained in Step 1 in 40 mL of ethanol, and stir for 20 min as solution A. Then, dissolve 0.5816 g of Ni(NO3)2·6H2O (2 mmol) and 0.0153 g of H2Cl6Pt·xH2O (0.0375 mmol of hydrated chloroplatinic acid) in 10 mL of anhydrous ethanol, and label the product as solution B. Add solution B dropwise to solution A and stir continuously for 8 h at room temperature. The resulting yellow-green product is washed three times each with deionized water and ethanol, then dried under vacuum at 60 °C for 12 h and collected to obtain Pt-supported NiCo layered bimetallic hydroxide material (Pt-NiCo LDH).

[0060] Step 3: Place the Pt-loaded NiCo layered bimetallic hydroxide obtained in Step 2 in a ceramic boat in a tube furnace and calcine it in air at a heating rate of 350℃ and 2℃ / min for 3h to obtain a Pt single atom / cluster co-loaded NiCo layered bimetallic oxide material (Pt-NiCo LDO).

[0061] Figure 6 This is an electron microscope image of the Pt single atom / cluster co-loaded NiCo layered bimetallic oxide material in Example 3 of the present invention. Figure 6a is a SEM image of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material at a magnification of 200 nm; Figure 6 b is a TEM image of Pt single atoms / clusters co-loaded in NiCo layered bimetallic oxide material at a magnification of 100 nm.

[0062] Depend on Figure 6 It can be seen that the Pt single atom / cluster co-loaded on NiCo layered bimetallic oxide prepared in Example 3 still has a hollow dodecahedral nanolayered structure, and its diameter, thickness and other properties have not changed.

[0063] <Example 4>

[0064] Example 4 provides a Pt / NiCo LDO material co-loaded with Pt single atoms / clusters and its preparation method. The only difference between this Pt / NiCo LDO preparation method and the preparation method in Example 1 is the timing of the addition of H2Cl6Pt·xH2O in step 2.

[0065] Specifically, the preparation method of Pt / NiCo LDO in Example 4 includes the following steps:

[0066] Step 1: 0.873 g Co(NO3)2·6H2O (3 mmol) and 2 g 2-methylimidazole (24 mmol) were dissolved in 50 mL and 150 mL of anhydrous methanol, respectively, and stirred for 20 min. Then, the methanol solution containing 2-methylimidazole was slowly added to the methanol solution of Co(NO3)2·6H2O while continuously stirring. The mixture was then stirred at room temperature for 4 h, and the purple sample was collected by centrifugation. The purple product was washed three times with methanol, dried under vacuum at 60 °C for 8 h, and collected to obtain the zeolite-like imidazole ester framework material (Co-ZIF).

[0067] Step 2: Dissolve 0.2 g of Co-ZIF obtained in Step 1 in 40 mL of ethanol and stir for 20 min as solution A. Dissolve 0.5816 g of Ni(NO3)2·6H2O (2 mmol) in 10 mL of anhydrous ethanol, and label the product as solution C. Add solution C dropwise to solution A and stir continuously for 8 h at room temperature. Wash the resulting yellow-green product three times each with deionized water and ethanol, then dry it under vacuum at 60 °C for 12 h and collect the product to obtain NiCo layered bimetallic hydroxide material. Then dissolve the NiCo layered bimetallic hydroxide material in 40 mL of ethanol again and stir for 20 min as solution D. Then dissolve 0.0307 g of H2Cl6Pt·xH2O (0.075 mmol) in 10 mL of anhydrous ethanol, and label the product as solution E. Solution E was added dropwise to solution D and stirred continuously for 8 hours at room temperature. The resulting yellow-green product was washed three times each with deionized water and ethanol, and then dried under vacuum at 60°C for 12 hours. The product was collected to obtain Pt-supported NiCo layered bimetallic hydroxide material.

[0068] Step 3: Place the Pt-supported NiCo layered bimetallic hydroxide obtained in Step 2 in a ceramic boat in a tube furnace and calcine it in air at a heating rate of 350℃ and 2℃ / min for 3h to obtain Pt single atoms / clusters co-supported NiCo layered bimetallic oxide (Pt / NiCo LDO).

[0069] Figure 7 This is an electron microscope image of Pt single atoms / clusters co-loaded on NiCo layered bimetallic oxide material (Pt / NiCo LDO) in Example 4 of the present invention. Figure 7 a is a TEM image of Pt / NiCo LDO at a magnification of 50 nm; Figure 7 b is a TEM image of Pt / NiCo LDO at a magnification of 5 nm.

[0070] Depend on Figure 7 It can be seen that the Pt single atom / cluster co-loaded NiCo layered bimetallic oxide material (Pt / NiCo LDO) prepared in Example 4 still has a hollow dodecahedral nanolayered structure, but the structure has collapsed slightly and the particle size has become very large.

[0071] <Test Example>

[0072] This test case evaluated the performance of Pt-NiCo LDO prepared in Example 1, Pt / NiCo LDO prepared in Example 4, Pt-NiCo LDH produced in step 2 of Example 1, and commercially available 20% Pt / C as electrocatalytic hydrogen evolution catalysts.

[0073] The specific testing method is as follows:

[0074] Electrochemical tests were performed using the four catalyst materials mentioned above (Pt-NiCo LDO, Pt / NiCo LDO, Pt-NiCo LDH, and commercial 20% Pt / C) as working electrodes, Hg / HgO (1M KOH solution, ~0.924V vs. NHE) as the reference electrode, graphite rod as the counter electrode, and 1.0M KOH solution as the electrolyte, using a CHI 760E electrochemical workstation.

[0075] The preparation process of the working electrode is as follows: 5 μL of ultrasonically mixed catalyst dispersion (dispersion composition: 4 mg catalyst material, 20 μL 5 wt% Nafion solution, 750 μL deionized water, 250 μL anhydrous ethanol) is drop-coated onto an area of ​​0.07 cm². 2 The electrode was placed on a glassy carbon electrode and allowed to air dry before being used as the working electrode. The linear voltammetry (LSV) scan rate was 2 mV / s. -1 Furthermore, all polarization curves undergo iR compensation; the Tafel slope is calculated by fitting a linear scan curve; the electrochemical impedance spectroscopy (EIS) test frequency range is 0.01–10 Hz. 5 Hz, amplitude of 5mV. Furthermore, at 60mAcm... -2 The electrochemical HER stability of the catalyst was investigated by performing a chronovoltammetric test for 105 hours.

[0076] Figure 8 These are the HER performance diagrams of Pt single atoms / clusters co-loaded in the NiCo layered bimetallic oxide material and the comparative material in the test examples of this invention. Figure 8 a) LSV curve; Figure 8 b) Tafel slope; Figure 8 c) EIS diagram; Figure 8 d) Voltage-time curve.

[0077] Depend on Figure 8 The LSV curve shows that Pt-NiCo LDO operates at 10 mA / cm². -2 It has an overpotential of 92mV, which is much lower than that of Pt / NiCo LDO (231mV) and Pt-NiCo LDH (435mV); Figure 8 b shows the Tafel curve of the material, and the measured Tafel slope of Pt-NiCo LDO is 73 mV dec. -1 Much smaller than Pt / NiCo LDO (177mV dec) -1 ) and Pt-NiCo LDH (144mV dec -1 This value is comparable to 20% commercial Pt / C (60mV dec). -1This is also highly competitive compared to other methods, indicating that the HER of Pt-NiCo LDOs follows the Volmer-Heyrovsky mechanism more closely. Notably, Pt-NiCo LDOs exhibit strong performance at ~100 mA / cm². -2 The Tafel slope below is 199mV dec -1 Far below 20% Pt / C (426mV dec) -1 This confirms its faster HER kinetics at higher current densities. Figure 8 The EIS spectrum of c shows that the electrochemical impedance of Pt-NiCo LDO is 56Ω, which is smaller than that of Pt / NiCo LDO (270Ω) and Pt-NiCo LDH (700Ω), indicating that Pt-NiCo LDO has a faster electron transport rate and higher conductivity in the HER process. Figure 8 Figure d shows the voltage-time curves for evaluating the electrocatalytic stability of the two materials in the HER process. Pt-NiCo LDO exhibits a stable potential with only a 50 mV decay after 105 h, demonstrating its excellent HER stability. In contrast, under the same conditions, the stability of 20% commercial Pt / C decreases sharply. This indicates that Pt single atoms / clusters co-supported in NiCo layered bimetallic oxide materials (Pt-NiCo LDO) possess good electrocatalytic stability for HER.

[0078] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a NiCo layered bimetallic oxide material co-supported with Pt single atoms / clusters, characterized in that, Includes the following steps: Step 1: Cobalt salt and 2-methylimidazole were added to anhydrous methanol solution and stirred at room temperature. After the reaction was completed, the product was collected by centrifugation, washed repeatedly, and dried to obtain the zeolite-like imidazole ester framework material Co-ZIF. Step 2: Add the Co-ZIF, nickel salt, and platinum source to anhydrous ethanol solution and stir at room temperature. After the reaction is complete, centrifuge to collect the product, wash it repeatedly, and dry it to obtain Pt-supported NiCo layered bimetallic hydroxide material. Step 3: The Pt-supported NiCo layered bimetallic hydroxide material is calcined to obtain a Pt single atom / cluster co-supported NiCo layered bimetallic oxide material.

2. The preparation method according to claim 1, characterized in that: in, The cobalt salt is cobalt nitrate hexahydrate, the nickel salt is nickel nitrate hexahydrate, and the platinum source is hydrated chloroplatinic acid.

3. The preparation method according to claim 1 or 2, characterized in that: in, In step 1, the molar ratio of the cobalt salt to 2-methylimidazolium is 1:8 to 1:4, and the stirring reaction at room temperature lasts for 4 to 6 hours.

4. The preparation method according to claim 1 or 2, characterized in that: in, In step 2, the mass ratio of the Co-ZIF, the nickel salt, and the platinum source is 0.2g:0.5816g:(0.0153g~0.0921g).

5. The preparation method according to claim 1, characterized in that: in, In step 2, the stirring reaction at room temperature takes 8-12 hours.

6. The preparation method according to claim 1, characterized in that: in, In step 3, the calcination treatment is carried out at a temperature of 250℃-350℃, a heating rate of 1℃ / min to 3℃ / min, and a time of 3h.

7. The preparation method according to claim 1, characterized in that: in, The atmosphere for the calcination treatment is air.

8. The preparation method according to claim 1, characterized in that: in, In step 2, the process of adding the Co-ZIF, the nickel salt, and the platinum source to the anhydrous ethanol solution is as follows: The Co-ZIF was dissolved in anhydrous ethanol to obtain solution A; The nickel salt and the platinum source were dissolved in anhydrous ethanol to obtain solution B; Add the B solution dropwise into the A solution.

9. A Pt single-atom / cluster co-supported NiCo layered bimetallic oxide material, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.

10. The application of Pt single atoms / clusters co-supported in NiCo layered bimetallic oxide materials as described in claim 9, characterized in that, The Pt single atoms / clusters are co-supported on NiCo layered bimetallic oxide material as an electrocatalyst for the electrochemical hydrogen evolution reaction (HER).

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