A hollow multi-shell nanosphere loaded with a coP / re heterojunction and a preparation method and application thereof

Abstract

The application discloses a hollow multi-shell nanosphere loaded with CoP / Re heterojunction and a preparation method and application thereof. A precursor solution is prepared by dissolving a cobalt salt and ammonium perrhenate in a mixed ethyl alcohol aqueous solution containing polyvinylpyrrolidone (PVP) and nitric acid; the precursor solution is subjected to an electrostatic spraying technology to obtain solid nanoparticles; the solid nanoparticles are pyrolyzed at high temperature in an air atmosphere, and are further subjected to phosphating treatment, and are naturally cooled to obtain the hollow multi-shell nanosphere material loaded with the CoP / Re heterojunction. The preparation method is low in cost and simple in operation; the prepared material has a hollow multi-shell spherical structure, a relatively large effective specific surface area, can provide more active sites, is favorable for gas diffusion, and maintains structural stability. Meanwhile, the establishment of the CoP / Re heterostructure can significantly change the electronic configuration of the active sites, improve the conductivity, and thus improve the electrochemical activity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water electrolysis catalysts, and relates to a hollow multi-shell nanosphere loaded with a CoP / Re heterojunction and a preparation method and application thereof. BACKGROUND

[0002] In order to reduce the use of traditional fossil fuels, researchers are committed to developing new energy storage methods, such as hydrogen production by water electrolysis. Therefore, in order to meet the growing demand for clean and renewable hydrogen energy, it is imperative to develop economic and efficient bifunctional electrocatalysts. So far, commercial PtC has excellent hydrogen evolution reaction (HER) electrocatalytic performance, and IrO2 and RuO2 catalysts have excellent oxygen evolution reaction (OER) electrocatalytic performance, but due to their scarcity and high price, they hinder the widespread commercial application of full water splitting. Therefore, it is urgent to develop efficient and stable and inexpensive bifunctional electrocatalysts to replace noble metal-based catalysts.

[0003] At present, many studies have turned their attention to non-noble metal-based electrocatalysts. Among them, transition metal phosphides have attracted extensive research in the field of electrocatalysis due to their excellent electrochemical performance and adjustable component structure, and are expected to replace noble metals for water electrolysis. However, they also have the common shortcomings of non-noble metal catalysts, which are low electrical conductivity and poor intrinsic activity, and further strategies are needed to improve their catalytic performance. Among them, the use of heterojunction effect to modify the electronic state of active sites is one of the effective strategies to improve the HER and OER electrocatalytic performance. In addition, the construction of hollow structure makes the catalyst have relatively large effective specific surface area, which can provide more active sites, is conducive to gas diffusion, and maintains structural stability. In summary, it is a wise strategy to synthesize hollow structure materials loaded with heterojunction by synergizing the above advantages. However, the preparation process of such materials is usually time-consuming, complex and has low yield, and the process needs to be improved. SUMMARY

[0004] In view of the deficiencies of the prior art, the application provides a hollow multi-shell nanosphere loaded with a CoP / Re heterojunction and a preparation method and application thereof. The preparation method is simple and universal, has low cost, and the hollow multi-shell nanosphere loaded with the CoP / Re heterostructure as a hydrogen evolution and oxygen evolution electrocatalyst material exhibits excellent activity and stability.

[0005] To solve the existing technical problems, the technical scheme adopted by the application is as follows:

[0006] A preparation method of a hollow multi-shell nanosphere material loaded with a CoP / Re heterojunction, comprising the following steps:

[0007] Step 1: Add the cobalt salt and ammonium perrhenate aqueous solution to a mixed ethanol solution containing polyvinylpyrrolidone (PVP) and nitric acid to prepare a precursor solution;

[0008] Step 2: The precursor solution is subjected to electrostatic spraying to obtain solid nanoparticles, and then pyrolyzed at high temperature in air at 500°C to obtain the precursor.

[0009] Step 3: The precursor is further phosphating in an oxygen-free atmosphere by heating to 300-400℃ according to a program. The temperature is maintained to ensure a full reaction, and then the material is naturally cooled to obtain hollow multi-shell nanospheres loaded with CoP / Re heterostructures.

[0010] As an improvement, the cobalt salt mentioned in step 1 is cobalt acetate.

[0011] A further improvement is that the molar ratio of cobalt acetate to ammonium perrhenate is 2:1-8:1, and the molecular weight of PVP(K30) is 40,000.

[0012] As an improvement, the electrostatic spraying conditions in step 2 are: temperature 15-35℃, syringe injection speed 0.5-1.0 mL / h. -1 Voltage 10-30kV.

[0013] As an improvement, the heating rate of high-temperature pyrolysis in step 2 is 1℃ / min.

[0014] As an improvement, the phosphating process described in step 3 is as follows: the precursor and sodium hypophosphite are heated to 300-350°C in an oxygen-free atmosphere using a programmed heating method, with a heating rate of 2°C / min, and held for 80-120 min to perform phosphating. The oxygen-free atmosphere is one or a mixture of nitrogen, argon, or neon.

[0015] The above preparation method yields a hollow multi-shell nanosphere material supported on a CoP / Re heterostructure.

[0016] As an improvement, the aforementioned hollow multi-shell nanosphere material loaded with CoP / Re heterostructure is characterized by a rough sample surface, a hollow multi-shell spherical structure, and mutual support between different shells, with the outer shell protecting the inner shell, thus achieving better structural and catalytic stability. A CoP-Re hetero interface is constructed, and the introduction of Re helps to regulate the electronic structure of the CoP active center, causing a redistribution of charge at the hetero interface, which reduces the rate-determining step energy and facilitates H2O dissociation.

[0017] The hollow multi-shell nanosphere material with CoP / Re heterostructure prepared by the above method is used as an electrocatalyst in alkaline water electrolysis reaction.

[0018] The reaction principle is as follows:

[0019] Using cobalt acetate and ammonium perrhenate as metal sources, PVP as carbon and nitrogen sources, and volatile ethanol and water as solvents, solid nanoparticles were pre-prepared using electrostatic spraying technology. These nanoparticles were then subjected to high-temperature pyrolysis in air, followed by further phosphating reduction in a high-temperature inert atmosphere to prepare hollow multi-shell nanospheres supported by CoP / Re heterojunctions. This material exhibits a rough surface, a hollow multi-shell structure, and mutual support between different shells. The outer shells protect the inner shells, resulting in better structural and catalytic stability. The CoP / Re heterojunction nanoparticles are small in size and uniformly embedded within the nanospheres. Due to the structural and compositional advantages between the hollow multi-shell nanospheres and the active material CoP / Re heterojunctions, the resulting material exhibits high catalytic activity in water electrolysis and excellent stability.

[0020] Beneficial effects:

[0021] Compared with the prior art, the hollow multi-shell nanosphere material supported on CoP / Re heterostructure of the present invention, its preparation method and application, have the following advantages;

[0022] 1) This invention utilizes a simple and scalable electrostatic spraying technique combined with phosphating to prepare hollow multi-shell nanosphere-supported CoP / Re heterojunction electrocatalyst materials. The sample has a rough surface and a hollow multi-shell spherical structure, with different shells supporting each other. The outer shell protects the inner shell, resulting in better structural and catalytic stability. This material constructs a CoP-Re heterojunction interface. The introduction of Re helps to regulate the electronic structure of the CoP active center, causing charge redistribution at the heterojunction interface, lowering the rate-determining step energy, and facilitating H2O dissociation.

[0023] 2) The PVP used in this invention is inexpensive and readily available, and water and ethanol are highly environmentally friendly solvents. Compared with traditional methods for preparing electrolytic water catalysts, this method is simple, cost-effective, easy to operate, green and environmentally friendly, and can achieve large-scale production.

[0024] 3) The CoP / Re heterojunction electrocatalyst material supported by hollow multi-shell nanospheres in this invention has a regular morphology. The CoP / Re heterojunction nanoparticles are uniformly loaded in the multi-shell nanosphere material. The introduction of Re helps to regulate the electronic structure of the CoP active center, causing a redistribution of charge at the heterojunction interface, which lowers the rate-determining step energy and facilitates the dissociation of H2O. At a speed of 10 mA cm⁻¹, the electrocatalyst material exhibits this characteristic. 2It requires only an applied voltage of 1.57V and exhibits excellent water electrolysis activity. After a chronoamperometry test following 12 hours, the catalyst's hydrogen and oxygen evolution performance did not decline, demonstrating excellent stability. Compared to conventional Co-based catalysts, the CoP / Re heterojunction electrocatalyst supported on hollow multi-shell nanospheres in this invention possesses superior structural characteristics and compositional advantages, making it a highly promising water electrolysis catalyst material with broad prospects for future applications in the energy industry. Attached Figure Description

[0025] Figure 1 This is the SEM image of the hollow multi-shell nanospheres loaded with CoP / Re heterostructure prepared in Example 1 of this invention.

[0026] Figure 2 This is a TEM image of the hollow multi-shell nanospheres loaded with CoP / Re heterostructure prepared in Example 1 of this invention.

[0027] Figure 3 This is the HRTEM image of the hollow multi-shell nanospheres loaded with CoP / Re heterostructure prepared in Example 1 of this invention.

[0028] Figure 4 This is the X-ray diffraction (XRD) pattern of the hollow multi-shell nanosphere material with CoP / Re heterostructure prepared in Example 1 of this invention.

[0029] Figure 5 This is the electron paramagnetic resonance (EPR) spectrum of the hollow multi-shell nanosphere material with CoP / Re heterostructure prepared in Example 1 of this invention.

[0030] Figure 6 This is the X-ray photoelectron spectroscopy (XPS) of the hollow multi-shell nanosphere material with CoP / Re heterostructure prepared in Example 1 of this invention.

[0031] Figure 7 The LSV curve is obtained from the hydrogen evolution reaction performance test of hollow multi-shell nanospheres with CoP / Re heterostructure prepared in Example 1 of this invention in 1.0 MkOH solution.

[0032] Figure 8 This is the hydrogen evolution stability test curve of the hollow multi-shell nanosphere material with CoP / Re heterostructure prepared in Example 1 of this invention.

[0033] Figure 9 The LSV curve is obtained from the oxygen evolution reaction performance test of hollow multi-shell nanospheres with CoP / Re heterostructure prepared in Example 1 of this invention in 1.0 MkOH solution.

[0034] Figure 10This is the oxygen evolution stability test curve of the hollow multi-shell nanosphere material with CoP / Re heterostructure prepared in Example 1 of this invention.

[0035] Figure 11 The LSV curves of alkaline water splitting of hollow multi-shell nanospheres with CoP / Re heterostructures prepared in Example 1 of this invention are shown. Detailed Implementation

[0036] The technical solution of the present invention will be further described below with reference to the embodiments.

[0037] Example 1

[0038] Dissolve 1g of Co(CH3COOH)2·4H2O and 0.27g of NH4ReO4 in 4mL of H2O and stir at room temperature for 20min to obtain solution A; weigh 2.4g of PVP and dissolve it in 16mL of LEtOH solution and stir at room temperature for 2h to obtain solution B; add solution A to solution B, stir at room temperature for 10min, add 200μL of HNO3, and stir for 10min to mix evenly to obtain the precursor solution;

[0039] The precursor solution was treated with electrospinning technology (electrospinning conditions: needle size 21, needle-to-receiver plate distance, 12cm receiver, aluminum foil; voltage, 20kV; solution flow rate, 0.08mL / h; electrospinning time, 6h) to obtain solid nanoparticles.

[0040] The precursor was obtained by heating the solid nanoparticles to 500℃ in air at a heating rate of 1℃ / min for 1 hour.

[0041] The precursor was heated to 350°C in an Ar atmosphere at a heating rate of 2°C / min and held at that temperature for 2 hours. Then it was naturally cooled to room temperature to obtain hollow multi-shell nanospheres loaded with CoP / Re heterostructures.

[0042] Example 2

[0043] Dissolve 1g of Co(CH3COOH)2·4H2O and 0.54g of NH4ReO4 in 4mL of H2O and stir at room temperature for 20min to obtain solution A; weigh 2.4g of PVP and dissolve it in 16mL of LEtOH solution and stir at room temperature for 2h to obtain solution B; add solution A to solution B, stir at room temperature for 10min, add 200μL of HNO3, stir for 10min to mix evenly, and obtain the precursor solution;

[0044] The precursor solution was treated with electrospinning technology (electrospinning conditions: needle size 21, needle-to-receiver plate distance, 12cm receiver, aluminum foil; voltage, 20kV; solution flow rate, 0.08mL / h; electrospinning time, 6h) to obtain solid nanoparticles.

[0045] The precursor was obtained by heating the solid nanoparticles to 500℃ in air at a heating rate of 1℃ / min for 1 hour.

[0046] The precursor was heated to 350°C in an Ar atmosphere at a heating rate of 2°C / min and held at that temperature for 2 hours. Then it was naturally cooled to room temperature to obtain hollow multi-shell nanospheres loaded with CoP / Re heterostructures.

[0047] Example 3

[0048] 1 g of Co(CH3COOH)2·4H2O and 0.135 g of NH4ReO4 were dissolved in 4 mL of H2O and stirred at room temperature for 20 min to obtain solution A; 2.4 g of PVP was weighed and dissolved in 16 mL of LEtOH solution and stirred at room temperature for 2 h to obtain solution B; solution A was added to solution B and stirred at room temperature for 10 min, then 200 μL of HNO3 was added and stirred for 10 min to mix evenly to obtain the precursor solution;

[0049] The precursor solution was treated with electrospinning technology (electrospinning conditions: needle size 21, needle-to-receiver plate distance, 12cm receiver, aluminum foil; voltage, 20kV; solution flow rate, 0.08mL / h; electrospinning time, 6h) to obtain solid nanoparticles.

[0050] The precursor was obtained by heating the solid nanoparticles to 500℃ in air at a heating rate of 1℃ / min for 1 hour.

[0051] The precursor was heated to 350°C in an Ar atmosphere at a heating rate of 2°C / min and held at that temperature for 2 hours. Then it was naturally cooled to room temperature to obtain hollow multi-shell nanospheres loaded with CoP / Re heterostructures.

[0052] Example 4

[0053] Dissolve 1g of Co(CH3COOH)2·4H2O and 0.27g of NH4ReO4 in 4mL of H2O and stir at room temperature for 20min to obtain solution A; weigh 2.4g of PVP and dissolve it in 16mL of LEtOH solution and stir at room temperature for 2h to obtain solution B; add solution A to solution B, stir at room temperature for 10min, add 200μL of HNO3, and stir for 10min to mix evenly to obtain the precursor solution;

[0054] The precursor solution was treated with electrospinning technology (electrospinning conditions: needle size 21, needle-to-receiver plate distance, 12cm receiver, aluminum foil; voltage, 20kV; solution flow rate, 0.08mL / h; electrospinning time, 6h) to obtain solid nanoparticles.

[0055] The precursor was obtained by heating the solid nanoparticles to 500℃ in air at a heating rate of 1℃ / min for 1 hour.

[0056] The precursor was heated to 350°C in an Ar atmosphere at a heating rate of 1°C / min and held at that temperature for 2 hours, and then naturally cooled to room temperature to obtain hollow multi-shell nanospheres loaded with CoP / Re heterostructures.

[0057] Example 5

[0058] Dissolve 1g of Co(CH3COOH)2·4H2O and 0.27g of NH4ReO4 in 4mL of H2O and stir at room temperature for 20min to obtain solution A; weigh 2.4g of PVP and dissolve it in 16mL of LEtOH solution and stir at room temperature for 2h to obtain solution B; add solution A to solution B, stir at room temperature for 10min, add 200μL of HNO3, and stir for 10min to mix evenly to obtain the precursor solution;

[0059] The precursor solution was treated with electrospinning technology (electrospinning conditions: needle size 21, needle-to-receiver plate distance, 12cm receiver, aluminum foil; voltage, 20kV; solution flow rate, 0.08mL / h; electrospinning time, 6h) to obtain solid nanoparticles.

[0060] The precursor was obtained by heating the solid nanoparticles to 500℃ in air at a heating rate of 1℃ / min for 1 hour.

[0061] The precursor was heated to 300℃ in an Ar atmosphere at a heating rate of 2℃ / min and held at that temperature for 2h. Then it was naturally cooled to room temperature to obtain hollow multi-shell nanospheres loaded with CoP / Re heterostructures.

[0062] Example 6

[0063] Dissolve 1g of Co(CH3COOH)2·4H2O and 0.27g of NH4ReO4 in 4mL of H2O and stir at room temperature for 20min to obtain solution A; weigh 2.4g of PVP and dissolve it in 16mL of LEtOH solution and stir at room temperature for 2h to obtain solution B; add solution A to solution B, stir at room temperature for 10min, add 200μL of HNO3, and stir for 10min to mix evenly to obtain the precursor solution;

[0064] The precursor solution was treated with electrospinning technology (electrospinning conditions: needle size 21, needle-to-receiver plate distance, 12cm receiver, aluminum foil; voltage, 20kV; solution flow rate, 0.08mL / h; electrospinning time, 6h) to obtain solid nanoparticles.

[0065] The precursor was obtained by heating the solid nanoparticles to 500℃ in air at a heating rate of 1℃ / min for 1 hour.

[0066] The precursor was heated to 400℃ in an Ar atmosphere at a heating rate of 2℃ / min and held at that temperature for 2h. Then it was naturally cooled to room temperature to obtain hollow multi-shell nanospheres loaded with CoP / Re heterostructure.

[0067] Example 7

[0068] Dissolve 1g of Co(CH3COOH)2·4H2O and 0.27g of NH4ReO4 in 4mL of H2O and stir at room temperature for 20min to obtain solution A; weigh 2.4g of PVP and dissolve it in 16mL of LEtOH solution and stir at room temperature for 2h to obtain solution B; add solution A to solution B, stir at room temperature for 10min, add 200μL of HNO3, and stir for 10min to mix evenly to obtain the precursor solution;

[0069] The precursor solution was treated with electrospinning technology (electrospinning conditions: needle size 21, needle-to-receiver plate distance, 12cm receiver, aluminum foil; voltage, 20kV; solution flow rate, 0.08mL / h; electrospinning time, 6h) to obtain solid nanoparticles.

[0070] The precursor was obtained by heating the solid nanoparticles to 500℃ in air at a heating rate of 2℃ / min for 1 hour.

[0071] The precursor was heated to 350°C in an Ar atmosphere at a heating rate of 2°C / min and held at that temperature for 2 hours. Then it was naturally cooled to room temperature to obtain hollow multi-shell nanospheres loaded with CoP / Re heterostructures.

[0072] Example 8

[0073] Dissolve 1g of Co(CH3COOH)2·4H2O and 0.27g of NH4ReO4 in 4mL of H2O and stir at room temperature for 20min to obtain solution A; weigh 2.4g of PVP and dissolve it in 16mL of LEtOH solution and stir at room temperature for 2h to obtain solution B; add solution A to solution B, stir at room temperature for 10min, add 200μL of HNO3, and stir for 10min to mix evenly to obtain the precursor solution;

[0074] The precursor solution was treated with electrospinning technology (electrospinning conditions: needle size 21, needle-to-receiver plate distance, 12cm receiver, aluminum foil; voltage, 20kV; solution flow rate, 0.08mL / h; electrospinning time, 6h) to obtain solid nanoparticles.

[0075] The precursor was obtained by heating the solid nanoparticles to 500℃ in air at a heating rate of 5℃ / min for 1 hour.

[0076] The precursor was heated to 350°C in an Ar atmosphere at a heating rate of 2°C / min and held at that temperature for 2 hours. Then it was naturally cooled to room temperature to obtain hollow multi-shell nanospheres loaded with CoP / Re heterostructures.

[0077] Comparative Example 9

[0078] Dissolve 1g of Co(CH3COOH)2·4H2O in 4mL of H2O and stir at room temperature for 20min to obtain solution A; weigh 2.4g of PVP and dissolve it in 16mL of LEtOH solution and stir at room temperature for 2h to obtain solution B; add solution A to solution B, stir at room temperature for 10min, add 200μL of HNO3, stir for 10min to mix evenly, and obtain the precursor solution;

[0079] The precursor solution was treated with electrospinning technology (electrospinning conditions: needle size 21, needle-to-receiver plate distance, 12cm receiver, aluminum foil; voltage, 20kV; solution flow rate, 0.08mL / h; electrospinning time, 6h) to obtain solid nanoparticles.

[0080] The precursor was obtained by heating the solid nanoparticles to 500℃ in air at a heating rate of 1℃ / min for 1 hour.

[0081] The precursor was heated to 350°C in an Ar atmosphere at a heating rate of 2°C / min and held at that temperature for 2 hours. Then it was naturally cooled to room temperature to obtain a hollow multi-shell nanosphere material with CoP heterostructure, named CoP@HoMS.

[0082] Performance Characterization

[0083] The hollow multi-shell nanospheres with CoP / Re heterostructures prepared in Example 1 were physically characterized using SEM, TEM, HRTEM, XRD, EPR, and XPS.

[0084] From SEM ( Figure 1 As can be seen, the material synthesized in this invention is a hollow nanosphere material.

[0085] TEM Figure 2 This further demonstrates that the present invention synthesizes hollow multi-shell nanosphere materials with a diameter of approximately 250 nm.

[0086] From HRTEM ( Figure 3 As can be seen, the metal nanoparticles have clear heterogeneous interfaces, and the two clear lattice fringes correspond to Re and CoP, respectively. The lattice spacing of 0.21 nm corresponds to the (101) crystal plane of Re, while the lattice spacing of 0.25 nm corresponds to the (200) crystal plane of CoP.

[0087] From XRD patterns ( Figure 4 As can be seen, by comparing with the standard spectra, its diffraction peaks are completely consistent with the standard cards of orthorhombic CoP (JCPDS No. 29-0497) and Re (JCPDS No. 05-0702), indicating that a CoP / Re heterostructure has been formed.

[0088] EPR chart ( Figure 5 The results show that the addition of Re to the prepared hollow multi-shell nanosphere material loaded with CoP / Re heterostructure helps to enhance the strength of O vacancies.

[0089] From the XPS graph ( Figure 6 As can be seen from the paper, the hollow multi-shell nanosphere material with CoP / Re heterostructure prepared in this invention contains Co, Re, P, C, N and O.

[0090] The alkaline hydrogen evolution performance of the materials in Example 1 and Comparative Example 1 was tested. The specific steps were as follows: 5 mg of catalyst was weighed and ultrasonically dispersed in 1 mL of an ethanol-water mixture (water:ethanol volume ratio of 3:1) to prepare catalyst ink. Then, 12 μL of the solution was dropped onto the surface of a glassy carbon electrode and dried in an oven at 40 °C. After drying, 2 μL of Nafion solution was dropped onto the catalyst-coated glassy carbon electrode. Before the HER test, N2 was passed through the 1 MKOH electrolyte for at least 20 min, and before the OER test, N2 was passed through the 1 MKOH electrolyte for at least 20 min to fill the electrolyte. All electrochemical tests were performed using a Shanghai Chenhua 760e electrochemical workstation in a three-electrode system. Subsequently, the linear sweep voltammetry (LSV) test used for the HER and OER tests was carried out in this electrolyte at a scan rate of 5 mV / s. -1 The specific spectra for each electrochemical test are shown below.

[0091] Figure 7 The LSV curves are obtained from the hydrogen evolution reaction performance tests of the hollow multi-shell nanospheres with CoP / Re heterostructures prepared in Example 1 in 1.0 MkOH solution, at 10 mA cm⁻¹. -2 The overpotential at the point is 107mV, which is better than the overpotential of 214mV for pure-phase CoP.

[0092] Figure 9 The LSV curves are obtained from the oxygen evolution reaction performance tests of the hollow multi-shell nanospheres with CoP / Re heterostructures prepared in Example 1 in 1.0 MkOH solution, at 10 mA / cm². -2 The overpotential at this point is 239mV, which is better than the overpotential of 420mV for pure-phase CoP.

[0093] The hydrogen evolution stability of the heterostructure in Example 1 was tested, and the specific steps are as follows: A glassy carbon electrode (GCE, d = 3 mm, S = 0.0706 cm) was used in a three-electrode system. 2 The saturated calomel electrode (SCE) and the reference electrode are used as the working electrode and the reference electrode, respectively, while the carbon rod is used as the auxiliary electrode during the test. Figure 8 This indicates that the hydrogen evolution performance of the catalyst did not decline after the chronocurrent test 12 hours later. Figure 10 This indicates that the oxygen evolution performance of the catalyst did not decline after the chronocurrent test 12 hours later.

[0094] The water splitting performance test utilizes a two-electrode system, with electrodes of hollow multi-shell nanospheres loaded with CoP / Re heterostructures connected to the Chenhua 760e workstation as the anode and cathode. Figure 11 This is a test of the total water splitting performance of hollow multi-shell nanospheres supported on CoP / Re heterostructures. The catalyst achieved a water splitting performance of 10 mA / cm².-2 It requires only an external voltage of 1.57V, which is superior to commercial catalysts.

[0095] In summary, the preparation method of this invention is simple and can be used in large quantities. The hollow multi-shell nanospheres with CoP / Re heterostructures prepared have superior structural characteristics and compositional advantages, with multiple active sites, low overpotential, and good stability. They have broad application prospects as catalysts for water electrolysis.

Claims

1. A method for preparing hollow multi-shell nanospheres supported on CoP / Re heterostructures, characterized in that, Includes the following steps: Step 1: Add the cobalt salt and ammonium perrhenate aqueous solution to a mixed ethanol solution containing polyvinylpyrrolidone (PVP) and nitric acid to prepare a precursor solution; Step 2: The precursor solution is subjected to electrostatic spraying to obtain solid nanoparticles, and then pyrolyzed at high temperature in air at 500 °C to obtain the precursor. Step 3: The precursor is further phosphating in an oxygen-free atmosphere by heating to 300-400 ℃ according to a program. The temperature is maintained to ensure a full reaction, and then the material is naturally cooled to obtain hollow multi-shell nanospheres loaded with CoP / Re heterostructures.

2. The method for preparing hollow multi-shell nanospheres supported on CoP / Re heterostructures according to claim 1, characterized in that, The cobalt salt mentioned in step 1 is cobalt acetate.

3. The method for preparing hollow multi-shell nanospheres supported on CoP / Re heterostructures according to claim 2, characterized in that, The molar ratio of cobalt acetate to ammonium perrhenate is 2:1 to 8:1, and the molecular weight of PVP K30 is 40,000.

4. The method for preparing hollow multi-shell nanospheres supported on CoP / Re heterostructures according to claim 1, characterized in that, The electrostatic spraying conditions described in step 2 are: temperature 15-35℃, syringe injection speed 0.5-1.0 mL·h. -1 Voltage 10-30 kV.

5. The method for preparing hollow multi-shell nanospheres supported on CoP / Re heterostructures according to claim 1, characterized in that, The heating rate of high-temperature pyrolysis in step 2 is 1 ℃ / min.

6. The method for preparing hollow multi-shell nanospheres supported on CoP / Re heterostructures according to claim 1, characterized in that, The phosphating process described in step 3 is as follows: the precursor and sodium hypophosphite are heated to 300-350 ℃ in an oxygen-free atmosphere using a programmed heating method, with a heating rate of 2 ℃ / min, and held for 80-120 min to carry out phosphating. The oxygen-free atmosphere is one or a mixture of nitrogen, argon, or neon.

7. A hollow multi-shell nanosphere material with a CoP / Re heterostructure prepared by the preparation method described in claim 1.

8. The application of a hollow multi-shell nanosphere material with a CoP / Re heterostructure prepared by the preparation method described in claim 1 as a catalyst in alkaline water electrolysis reaction.

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