Nanoflower-like three-phase electrocatalyst, preparation method and application thereof

Abstract

The present application belongs to the technical field of electrocatalytic materials, and particularly relates to a nano-flower-shaped three-phase electrocatalyst as well as a preparation method and application thereof. Coated cobalt nanoparticles are obtained by coating cobalt nanoparticles on carbon nanotubes grown in situ on a self-supporting substrate to obtain a CoFC substrate; nano-flower Bi2O3 with Bi2MoO6 nanoparticles is formed in situ on the CoFC substrate by electrochemical deposition to obtain a nano-flower-shaped three-phase electrocatalyst. The nano-flower-shaped three-phase electrocatalyst prepared by the present application exhibits excellent OER and HER bifunctional electrocatalytic activity in an alkaline medium. A double-electrode electrolytic cell assembled using the nano-flower-shaped three-phase electrocatalyst can reach a current density of 10 mA / cm 2 in a 1M potassium hydroxide electrolyte at only 1.50 V, and can be stably operated for more than 45 hours, exhibiting excellent overall water splitting performance and excellent stability.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic materials technology, specifically relating to a nano-flower-like three-phase electrocatalyst, its preparation method, and its application. Background Technology

[0002] Hydrogen energy, due to its high energy density and zero carbon emissions, is considered a core component of future energy systems. Electrochemical water splitting technology, through the cathode hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER), is a key pathway for achieving large-scale green hydrogen production. However, the kinetics of HER and OER reactions in alkaline media are sluggish and require high overpotentials, resulting in low energy conversion efficiency and severely restricting industrial applications.

[0003] Currently, the most efficient electrocatalysts for HER and OER remain noble metal-based materials, such as platinum for HER and ruthenium oxide or iridium oxide for OER. Despite their excellent catalytic performance, the high cost and scarcity of these materials severely limit their large-scale industrial application. Therefore, the development of non-noble metal-based electrocatalysts, especially transition metal-based electrocatalysts, has become a research focus.

[0004] Bi-based transition metal materials have become highly promising candidate materials due to their high chemical stability, tunable electronic structure, and low cost, and are widely used as effective electrocatalysts in CO2 reduction, oxygen reduction reaction, and reactions related to direct fuel cells. However, the performance of Bi-based transition metal materials in HER catalysis is limited, mainly due to the unfavorable adsorption free energy of hydrogen atoms in alkaline media, which hinders the two-electron transfer pathway. To address this, existing technologies have partially improved charge transfer efficiency and active site exposure by constructing heterojunction structures or modulating morphology, but the catalytic efficiency of materials with dual HER and OER functions is limited, and their stability is insufficient. Summary of the Invention

[0005] To address the limitations of existing technologies that, despite constructing heterojunction structures or modulating morphology, still achieve limited catalytic efficiency and insufficient stability for dual-function HER and OER processes, this invention provides a three-phase electrocatalyst, its preparation method, and its applications.

[0006] The first objective of this invention is to provide a method for preparing a nano-flower-like three-phase electrocatalyst, comprising the following steps:

[0007] A self-supporting substrate was coated with melamine and calcined under a protective atmosphere to allow carbon nanotubes to grow in situ on the substrate and encapsulate cobalt nanoparticles overflowing from the self-supporting substrate, thus obtaining a CoFC substrate. In a mixed solution system of Bi source, Mo source and water, electrochemical deposition was used to deposit nanoflower-like Bi2O3 with Bi2MoO6 nanoparticles in situ on the CoFC substrate, thus obtaining a nanoflower-like three-phase electrocatalyst with Bi2O3 / Bi2MoO6 heterojunction.

[0008] Preferably, Bi in the Bi source 3+ and Mo in Mo source 6+ The molar ratio is 1:0.5–2. When Mo ion doping is too low, although the complete Bi₂O₃ nanoflower morphology can be maintained, the number of Bi₂MoO₆ nanoparticles is insufficient, making it impossible to form a dense Bi₂O₃ / Bi₂MoO₆ heterojunction. Excessive Mo ion doping, on the other hand, will destroy the Bi₂O₃ nanoflower structure. More preferably, the Bi₂MoO₆ nanoflowers in the Bi source... 3+ and Mo in Mo source 6+ The molar ratio is 1:1.

[0009] Preferably, the conditions for the electrochemical deposition are as follows:

[0010] The scanning voltage is -0.9V to -0.3V, the scanning rate is 3mV / s to 10mV / s, and the number of cycles is 5 to 15.

[0011] Preferably, the self-supporting substrate is cobalt foam.

[0012] Preferably, the calcination temperature is 900℃~1000℃ and the time is 2 hours; the calcination temperature is higher than 900℃ in order to allow cobalt nanoparticles to overflow from the cobalt foam and achieve the growth of carbon nanotubes.

[0013] Preferably, the Mo source is phosphomolybdic acid hydrate, wherein the phosphomolybdic acid hydrate is H3[P(Mo3O4]2]2. 10 )4]; The Bi source is bismuth chloride.

[0014] A second objective of this invention is to provide a nanoflower-like three-phase electrocatalyst prepared by the above-described method.

[0015] A third objective of this invention is to provide the application of the above-mentioned nanoflower-like three-phase electrocatalyst in catalytic water electrolysis for hydrogen production.

[0016] The preferred and specific application methods are as follows:

[0017] A two-electrode electrolytic cell was assembled by using a nano-flower-like three-phase electrocatalyst as the anode and cathode, placing the cathode and anode in the electrolyte.

[0018] Preferably, the electrolyte is potassium hydroxide; the concentration of the electrolyte is 1M.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] This invention utilizes carbon nanotubes grown in situ on a self-supporting substrate to encapsulate cobalt nanoparticles, obtaining a CoFC substrate as the conductive "stem." Nanoflower-like Bi2O3 with Bi2MoO6 nanoparticles is then deposited in situ on the CoFC substrate via electrochemical deposition, serving as a catalytic "petal-pollen structure," resulting in a nanoflower-like three-phase electrocatalyst. This invention significantly increases the electrochemically active surface area through its unique petal-pollen structure, promoting efficient mass / charge transfer. Furthermore, the Bi2O3 / Bi2MoO6 interface heterojunction effectively modulates the electronic structure of the active sites, optimizing the adsorption energy of reaction intermediates and further enhancing catalytic efficiency. Simultaneously, the CoFC substrate, acting as the "stem," not only protects the encapsulated cobalt nanoparticles from leaching and aggregation but also establishes an efficient electron transport pathway, synergistically promoting rapid charge transfer at the electrode interface. This addresses the technical problems of existing technologies that, despite constructing heterojunction structures or modulating morphology, still exhibit limited catalytic efficiency and insufficient stability for dual-function HER and OER reactions.

[0021] The nanoflower-like three-phase electrocatalyst prepared in this invention exhibits excellent bifunctional electrocatalytic activity for both OER and HER in alkaline media, at 10 mA / cm². 2 At current densities of 51 mV and 80 mV, respectively, the overpotentials for HER and OER were as low as 51 mV and 80 mV. Even after 45 hours of continuous operation, the catalyst retained 97% of its initial activity and exhibited excellent durability under harsh alkaline conditions. A dual-electrode electrolyzer (BiMo-1@CoFC || BiMo-1@CoFC) assembled using a nanoflower-like three-phase electrocatalyst achieved 10 mA / cm² in 1 M potassium hydroxide electrolyte with only 1.50 V. 2 With a current density of [value missing], the system maintained 97.3% activity over 40 hours, demonstrating excellent overall water splitting performance and outstanding stability, showing great potential for large-scale hydrogen production. Attached Figure Description

[0022] Figure 1 Scanning electron microscope (SEM) images of the nanoflower-like three-phase electrocatalysts prepared on the CoFC substrate, Comparative Example 1, and Example 1; wherein, (a) is the CoFC substrate, (b) is Comparative Example 1, and (c) is Example 1.

[0023] Figure 2Transmission electron microscope (TEM) images and high-resolution TEM images of the nanoflower-like three-phase electrocatalyst prepared in Example 1 are shown. Among them, (a) is a TEM image at the 50 nm scale, (b) is a high-resolution TEM image at the 10 nm scale, and (c) is a high-resolution TEM image at the 5 nm scale.

[0024] Figure 3 Transmission electron microscopy (TEM) images and elemental surface scans of the nanoflower-like three-phase electrocatalyst prepared in Example 1 are shown. (a) is a TEM image at a scale of 50 nm, (b) represents Co, (c) represents Bi, (d) represents Mo, and (e) represents P.

[0025] Figure 4 The XRD pattern of BiMo-1@CoFC prepared in Example 1.

[0026] Figure 5 XPS spectra of BiMo-1@CoFC prepared in Example 1; wherein, (a) is the full XPS spectrum, (b) is the C1s narrow spectrum, (c) is the Co2p narrow spectrum, (d) is the Bi4f narrow spectrum, and (e) is the Mo3d narrow spectrum.

[0027] Figure 6 The OER electrocatalytic performance of the nanoflower-like three-phase electrocatalysts prepared in Examples 1-3 and Comparative Examples 1-2 is shown below; (a) is the LSV polarization curve, (b) is the OER overpotential of the nanoflower-like three-phase electrocatalyst at different current densities, (c) is the Tafel plot, (d) is the Nyquist plot, (e) is the Cdl value, and (f) is the OER overpotential of BiMo-1@CoFC at 10 mA / cm². 2 Long-term stability after 45 hours under the specified conditions.

[0028] Figure 7 The HER electrocatalytic performance of the nanoflower-like three-phase electrocatalysts prepared in Examples 1-3 and Comparative Examples 1-2 is shown below; (a) is the LSV polarization curve, (b) is the HER overpotential of the nanoflower-like three-phase electrocatalysts at different current densities, (c) is the Tafel plot, and (d) is the HER overpotential of BiMo-1@CoFC at 10 mA / cm². 2 Long-term stability after 45 hours under the specified conditions.

[0029] Figure 8 The water splitting performance of the integrated water electrolysis system constructed using the nanoflower-like three-phase electrocatalyst of Example 1 as the anode and cathode is shown; where (a) is the LSV polarization curve and (b) is the time-current method curve. Detailed Implementation

[0030] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0031] Unless otherwise specified, all reagents used in this invention are commercially available, and all methods used are conventional techniques in the art.

[0032] Example 1

[0033] A method for preparing a nanoflower-like three-phase electrocatalyst includes the following steps:

[0034] A 1 cm × 1 cm cobalt foam was sequentially ultrasonically cleaned for 15 minutes each in acetone, deionized water, 1 mol / L hydrochloric acid, and deionized water to thoroughly remove oxides from its surface. The cleaned cobalt foam was then dried in a vacuum oven at 60°C for 4 hours. The dried cobalt foam was evenly spread on a ceramic boat, uniformly covered with 500 mg of melamine, and then the ceramic boat was precisely placed in the center of a quartz tube. Under a nitrogen atmosphere, the mixture was heated to 900°C at a rate of 5°C / min and calcined at this temperature for 2 hours. After naturally cooling to room temperature, the CoFC substrate was obtained.

[0035] Add 1 mmol of H3[P(Mo3O)] to 50 mL of deionized water. 10 )4] and a certain amount of BiCl3 were used to obtain an electrodeposition solution; wherein, Bi in BiCl3 3+ and H3[P(Mo3O) 10 )4]Mo in 6+ The molar ratio was 1:1. Using an Ag / AgCl electrode as the reference electrode, a graphite rod as the counter electrode, and a CoFC substrate as the working electrode, electrodeposition was performed using a three-electrode system. The electrodeposition parameters were set as follows: a voltage of -0.9V to -0.3V, a scan rate of 5mV / s, and 10 electrodeposition cycles. The electrodeposited CoFC substrate was rinsed three times with deionized water and anhydrous ethanol, and then dried in an oven at 60℃ for 6 hours to obtain a nanoflower-like three-phase electrocatalyst, denoted as BiMo-1@CoFC.

[0036] Example 2

[0037] A method for preparing a nanoflower-like three-phase electrocatalyst includes the following steps:

[0038] The difference between Example 2 and Example 1 is as follows:

[0039] BiCl3 contains Bi 3+ and H3[P(Mo3O) 10 )4]Mo in 6+ The molar ratio of the two components was 1:0.5, resulting in a nanoflower-like three-phase electrocatalyst, denoted as BiMo-0.5@CoFC.

[0040] Example 3

[0041] A method for preparing a nanoflower-like three-phase electrocatalyst includes the following steps:

[0042] The difference between Example 3 and Example 1 is as follows:

[0043] BiCl3 contains Bi 3+ and H3[P(Mo3O) 10 )4]Mo in 6+ The molar ratio is 1:2.

[0044] Comparative Example 1

[0045] A method for preparing a nanoflower-like three-phase electrocatalyst includes the following steps:

[0046] A 1 cm × 1 cm cobalt foam was sequentially ultrasonically cleaned for 15 minutes each in acetone, deionized water, 1 mol / L hydrochloric acid, and deionized water to thoroughly remove oxides from its surface. The cleaned cobalt foam was then dried in a vacuum oven at 60°C for 4 hours. The dried cobalt foam was evenly spread on a ceramic boat, uniformly covered with 500 mg of melamine, and then the ceramic boat was precisely placed in the center of a quartz tube. Under a nitrogen atmosphere, the mixture was heated to 900°C at a rate of 5°C / min and calcined at this temperature for 2 hours. After naturally cooling to room temperature, the CoFC substrate was obtained.

[0047] 3 mmol of BiCl3 was added to 50 mL of deionized water to obtain an electrodeposition solution. Using an Ag / AgCl electrode as the reference electrode, a graphite rod as the counter electrode, and the CoFC substrate as the working electrode, electrodeposition was performed using a three-electrode system. The electrodeposition parameters were set as follows: a voltage range of -0.9 V to -0.3 V, a scan rate of 5 mV / s, and 10 electrodeposition cycles. The electrodeposited CoFC substrate was rinsed three times with deionized water and anhydrous ethanol, and then dried in an oven at 60 °C for 6 hours to obtain a nanoflower-like three-phase electrocatalyst, denoted as Bi@CoFC.

[0048] The difference between Comparative Example 1 and Example 1 is as follows:

[0049] H3[P(Mo3O)] was not added to the electrodeposition solution. 10 )4).

[0050] Comparative Example 2

[0051] A method for preparing a nanoflower-like three-phase electrocatalyst includes the following steps:

[0052] A 1 cm × 1 cm cobalt foam was sequentially ultrasonically cleaned for 15 minutes each in acetone, deionized water, 1 mol / L hydrochloric acid, and deionized water to thoroughly remove oxides from its surface. The cleaned cobalt foam was then dried in a vacuum oven at 60°C for 4 hours. The dried cobalt foam was evenly spread on a ceramic boat, uniformly covered with 500 mg of melamine, and then the ceramic boat was precisely placed in the center of a quartz tube. Under a nitrogen atmosphere, the mixture was heated to 900°C at a rate of 5°C / min and calcined at this temperature for 2 hours. After naturally cooling to room temperature, the CoFC substrate was obtained.

[0053] Add 1 mmol of H3[P(Mo3O)] to 50 mL of deionized water. 10 [4], an electrodeposition solution was obtained. Using an Ag / AgCl electrode as the reference electrode, a graphite rod as the counter electrode, and CoFC as the working electrode, electrodeposition was performed using a three-electrode system. The electrodeposition parameters were set as follows: a voltage of -0.9V to -0.3V, a scan rate of 5mV / s, and 10 electrodeposition cycles. The electrodeposited CoFC substrate was rinsed three times with deionized water and anhydrous ethanol, and then dried in an oven at 60℃ for 6 hours to obtain a nanoflower-like three-phase electrocatalyst, denoted as Mo@CoFC.

[0054] The difference between Comparative Example 2 and Example 1 is as follows:

[0055] BiCl3 was not added to the electrodeposition solution.

[0056] Experimental test:

[0057] 1. Surface morphology test.

[0058] Figure 1 Image (a) shows that in-situ grown carbon nanotubes are uniformly wrapped around a cobalt foam framework. This tight carbon nanotube coating effectively inhibits the dissolution and oxidation of cobalt in alkaline electrolytes, while providing a rapid electron transfer channel and a stable substrate for electrodeposition. Cyclic voltammetry deposition of bimetals (Bi, Mo) yielded different morphologies, such as... Figure 1 As shown in (b), pure Bi₂O₃ forms clear nanoflowers, such as... Figure 1 As shown in (c), the co-deposited Bi-Mo forms nanoflowers modified with nanoparticles. This layered design maximizes the accessibility of active sites and promotes electrolyte penetration. Studies of different Mo ion doping ratios revealed that when Mo ion doping is too low, the complete nanoflower morphology can be maintained, but the number of nanoparticles is insufficient, while excessive doping will destroy the nanoflower structure.

[0059] The core-shell crystal structure was further revealed by TEM / HRTEM, such as Figure 2As shown in (b) and (c), a lattice spacing of 0.15 nm corresponds to the (120) crystal plane of Bi₂O₃, and a lattice spacing of 0.16 nm corresponds to the (131) crystal plane of Bi₂MoO₆. Figure 2 As shown in (a), the carbon nanotube “stem” structure encapsulates metallic Co nanoparticles.

[0060] like Figure 3 The EDS results (a)–(e) in the figures confirm that Co, Bi, Mo, and P are uniformly distributed, indicating a synergistic effect among the components. Therefore, the presence of highly efficient ion diffusion channels in carbon nanotubes, the incorporation of Bi / Mo altering the electronic structure and improving bulk conductivity, and the optimized interfacial charge transfer kinetics accelerating the electrocatalytic reaction all contribute to this unique structure, thus enhancing the overall catalytic efficiency.

[0061] 2. XRD test.

[0062] like Figure 4 As shown, the characteristic diffraction peaks observed at 31.84° and 36.93° of BiMo-1@CoFC match the (111) and (200) crystal planes of standard Bi2O3 (PDF#77-0304), respectively. Furthermore, the characteristic diffraction peak at 33.00° is in excellent agreement with the (131) crystal plane of standard Bi2MoO6 (PDF#21-0102). These XRD characterization results are consistent with the analytical data from high-resolution transmission electron microscopy (HR-TEM), jointly confirming the crystal structure composition of the catalyst.

[0063] 3. XPS test.

[0064] The surface chemical state and electronic interaction characteristics of the BiMo-1@CoFC prepared in Example 1 were analyzed using XPS. Figure 5 As shown in (a), the characteristic peaks of C, Co, Bi, P, and Mo are clearly visible in the XPS full-spectrum scan results, fully demonstrating the successful introduction and uniform distribution of these elements in the composite material. Figure 2 As shown in (b), the C1s spectrum of BiMo-1@CoFC can be fitted with three peaks: the peak with a binding energy of 284.3 eV corresponds to CC / C=C, the peak with a binding energy of 288.3 eV corresponds to the CN bond, and the peak with a binding energy of 286.0 eV corresponds to the C-Co bond. Meanwhile, the CN bond in BiMo-1@CoFC promotes effective doping of N atoms, contributing to the formation of abundant active sites, while the formation of C-Co further verifies the successful growth of Co particles in carbon nanotubes. Figure 5 As shown in (c), the typical characteristics of cobalt in the metallic state are observed in the Co2p nuclear level spectrum of BiMo-1@CoFC, with a binding energy at 794.5 eV (Co2p).3 / 2 ) and 779.1 eV (Co2p 1 / 2 A spin-orbit repetition state was observed at ), and satellite peaks were observed at 788.9 eV and 804.7 eV. (For example...) Figure 5 As shown in (d), for the Bi element in BiMo-1@CoFC, the Bi4f spectrum shows 164.2 eV (Bi4f 3 / 2 ) and 158.8 eV (Bi4f 1 / 2 The characteristic peaks of bismuth are shown. These peaks shift to higher binding energies relative to the binding energy of pure metallic bismuth, indicating a decrease in the electron cloud density around Bi atoms, meaning that Bi is in some oxidation state, indirectly proving the existence of Bi₂O₃. Figure 5 As shown in (e), the Mo3d spectrum of BiMo-1@CoFC shows 235.2 eV (Mo3d5 / 2) and 232.1 eV (Mo3d5 / 2). 3 / 2 Characteristic peaks of molybdenum (Mo). 0 Compared to other orbitals, the binding energy of the Mo3d orbital is also relatively high. This phenomenon may be due to the loss of electrons by molybdenum atoms, leading to a change in electron cloud density, which in turn increases the electron binding energy of the Mo3d orbital.

[0065] 4. Electrochemical performance testing of OER.

[0066] The OER electrocatalytic performance of the material was evaluated using a standard three-electrode system in 1M potassium hydroxide electrolyte. Figure 6 As shown in (a) to (b), the infrared-corrected polarization curves indicate that the Bi@CoFC prepared in Comparative Example 1 exhibits high polarization at a current density of 10 mA / cm². 2 The required overpotential is 258mV, at a current density of 100mA / cm. 2 The required overpotential is 390 mV; the Mo@CoFC prepared in Comparative Example 2 requires an overpotential of 10 mA / cm². 2 The required overpotential is 169mV at a current density of 100mA / cm. 2 The required overpotential is 428mV; RuO2 at a current density of 10mA / cm 2 The required overpotential is 482mV, at a current density of 100mA / cm. 2 The required overpotential is 561 mV. However, the BiMo-1@CoFC prepared in Example 1 requires an overpotential of 561 mV at a current density of 10 mA / cm². 2 The required overpotential is 80mV, at a current density of 100mA / cm. 2 At that time, the required overpotential was 327mV; this performance is significantly better than that of Comparative Example 1 and Comparative Example 2 and RuO2 material.

[0067] Tafel slope analysis obtained from LSV curves further revealed the excellent oxygen evolution reaction kinetics of BiMo-1@CoFC, such as... Figure 6 As shown in (c), the Tafel slope of BiMo-1@CoFC is as low as 88.7 mV / dec, indicating its highly efficient catalytic activity. To further investigate the reaction mechanism, electrochemical impedance spectroscopy was performed. Figure 6 The equivalent circuit fitting results in (d) show the solution resistance (R). s ) with a constant phase element (CPE) and a charge transfer resistor (R) in parallel s These factors together constitute the circuit model. Furthermore, BiMo-1@CoFC exhibits a minimum charge transfer resistance of 1.09 Ω, which is highly consistent with the results of Tafel slope analysis, confirming its rapid electron transfer capability and optimized reaction kinetics. In addition, the double-layer capacitance (Cdl) was determined using non-Radidatic cyclic voltammetry to quantify the electrochemical active surface area (ECSA). Figure 6 As shown in (e), the capacitance values ​​of Mo@CoFC, Bi@CoFC, and BiMo-1@CoFC are 42.6 mF / cm. 2 57.1mF / cm 2 and 140.8mF / cm 2 The significantly enhanced electrochemical active area of ​​BiMo-1@CoFC is primarily attributed to the densely packed active sites formed by its unique "petal-pollen" structure. Long-term durability is just as important as oxygen reduction reaction (OER) activity when evaluating the overall performance of electrocatalysts. Figure 6 Electrochemical tests of the (f) system showed that the BiMo-1@CoFC catalyst exhibited excellent stability. At 10 mA / cm², 2 After running continuously for 45 hours at the specified current density, its initial current response remained at 98.2%, and no significant decrease in current density was observed after 3000 cyclic voltammetric scans.

[0068] In summary, the BiMo-1@CoFC prepared in Example 1 exhibits excellent OER catalytic performance, mainly attributed to the ability of metallic cobalt to accelerate electron transport by providing a highly conductive path; the open channels facilitate rapid desorption of O2, avoiding blockage of active sites; Bi2MoO6 contributes to the formation of OO bonds; and the binding energy changes of Bi4f and Mo3d confirm the charge redistribution among the Bi-Mo-Co ternary group. This redistribution synergistically reduces the adsorption energy of reaction intermediates, thereby improving OER catalytic performance.

[0069] 5. Electrochemical performance testing of HER.

[0070] In addition to its excellent OER performance, the BiMo-1@CoFC catalyst also exhibits outstanding HER activity in alkaline media.

[0071] like Figure 7 As shown in (a) to (b), the Bi@CoFC prepared in Comparative Example 1 requires an overpotential of 116 mV to reach 10 mA / cm. 2 The reference current density; the Mo@CoFC prepared in Comparative Example 2 requires an overpotential of 134 mV to reach 10 mA / cm. 2 The reference current density; the BiMo-1@CoFC prepared in Example 1 only requires an overpotential of 51 mV to reach 10 mA / cm. 2 The required overpotential is significantly lower than that of other comparative catalysts, achieving a reference current density of 10 mA / cm². The BiMo-0.5@CoFC prepared in Example 2 requires an overpotential of 115 mV but achieves 10 mA / cm². 2 The reference current density; the BiMo-2@CoFC prepared in Example 3 requires an overpotential of 88 mV to reach 10 mA / cm. 2 The reference current density. Even at higher current densities, 50 mA / cm² 2 and 100mA / cm 2 BiMo-1@CoFC still shows significant advantages at 50 mA / cm². 2 The required overpotential at the current density is 137mV, and at 100mA / cm 2 The required overpotential at the current density is 183 mV; BiMo-0.5@CoFC at 50 mA / cm 2 The required overpotential at the current density is 500mV, and at 100mA / cm 2 The required overpotential at the current density is 561 mV; BiMo-2@CoFC at 50 mA / cm 2 The required overpotential at the current density is 205mV, and at 100mA / cm 2 The required overpotential at the current density is 260mV; Bi@CoFC at 50mA / cm 2 The required overpotential at the current density is 218mV, and at 100mA / cm 2 The required overpotential at the current density is 247 mV; Mo@CoFC at 50 mA / cm 2 The required overpotential at the current density is 208 mV, and at 100 mA / cm 2 The required overpotential at the current density is 244 mV; CoFC at 50 mA / cm 2 The required overpotential at the current density is 223mV, and at 100mA / cm 2The required overpotential at the specified current density is 261 mV. This significant performance improvement is mainly attributed to the optimized hydrogen adsorption free energy resulting from the electronic interaction between Bi and Co, while the synergistic effect of the Bi-Mo bimetallic compound further modulates the adsorption / desorption process of the reaction intermediates, thereby synergistically improving the HER catalytic efficiency. Figure 7 Tafel slope analysis in (c) shows that BiMo-1@CoFC has the lowest kinetic barrier of 97.7 mV / dec. 1 This further confirms its excellent HER catalytic kinetics. For example... Figure 7 As shown in (d), BiMo-1@CoFC exhibits excellent long-term stability in alkaline HER. Potentiostatic testing shows that at 10 mA / cm², [the stability is achieved]. 2 After running continuously for 45 hours at a current density, the potential decay was almost negligible. After 3000 CV cycles, the catalytic activity remained stable, demonstrating its excellent durability. The excellent performance of BiMo-1@CoFC is mainly attributed to its unique "petal-pollen" structure, which not only significantly increases the electrochemical active surface area, but also optimizes the catalytic process through the following mechanisms: (1) the 6s of Bi 2 Lone pairs of electrons can polarize and adsorb H2O molecules, thereby reducing the energy barrier of the Volmer step in basic HER; (2) the polarity of the Bi-O bond promotes the adsorption of H intermediates; (3) Mo 6+ d 0 The electronic configuration creates an internal electric field at the Bi2O3 / Bi2MoO6 interface, accelerating interfacial charge transfer; (4) the synergistic effect of Bi-Mo-Co provides abundant active sites, optimizing the adsorption of reactants and the desorption of products. These characteristics together make BiMo-1@CoFC exhibit great application potential in clean energy systems.

[0072] 6. Full-scale cracking test.

[0073] Utilizing the bifunctional catalytic effect of BiMo-1@CoFC in HER and OER, an integrated water electrolysis system was constructed in this embodiment of the invention. This system employs BiMo-1@CoFC as both the anode and cathode, assembling a dual-electrode electrolyzer. For example... Figure 8 As shown in (a), the system exhibits remarkable efficiency, requiring only 1.50V to achieve 10mA / cm. 2 The reference current density. This performance far exceeds that of commercial systems (1.63V). When the current density increases to 50mA / cm 2 The required voltage is only 1.63V; when the current density increases to 100mA / cm 2 At that time, the required voltage is only 1.73V. For example... Figure 8(b) in the middle is at 10 mA / cm 2 Under these conditions, a 40-hour stability test was conducted, and the battery retention rate reached 97.3%.

[0074] The excellent all-electrolyte performance can likely be attributed to the combination of Bi₂O₃ and Bi₂MoO₆ and the complexation with cobalt foam, which helps optimize the electronic structure of the material. The electronic interactions between different components can modulate the density of electronic states near the Fermi level of the material, improve electron mobility, thereby promoting charge transfer in electrocatalytic reactions and enhancing electrocatalytic activity.

[0075] It should be noted that when numerical ranges are involved in this invention, it should be understood that the two endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described in this invention to avoid redundancy. Although preferred embodiments of this invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments, and all such changes and modifications fall within the scope of this invention.

[0076] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. If these modifications and variations fall within the scope of equivalents of this invention, then this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a nano-flower-like three-phase electrocatalyst, characterized in that, Includes the following steps: A self-supporting substrate was coated with melamine and calcined under a protective atmosphere to allow carbon nanotubes to grow in situ on the substrate and encapsulate cobalt nanoparticles that overflowed from the self-supporting substrate, thus obtaining a CoFC substrate. In a mixed solution system of Bi source, Mo source and water, electrochemical deposition was used to deposit in situ on a CoFC substrate to form nanoflower-like Bi2O3 with Bi2MoO6 nanoparticles, thus obtaining a nanoflower-like three-phase electrocatalyst with Bi2O3 / Bi2MoO6 heterojunction. Bi in the Bi source 3+ Mo in the Mo source 6+ at a molar ratio of 1 : 0.5-2; The self-supporting substrate is cobalt foam; The Mo source is phosphomolybdic acid hydrate; The conditions for electrochemical deposition are: scanning voltage of -0.9V to -0.3V, scanning rate of 3mV / s to 10mV / s, and number of cycles of 5 to 15.

2. The method for preparing the nanoflower-like three-phase electrocatalyst according to claim 1, characterized in that, The calcination temperature is 900℃~1000℃.

3. The method for preparing the nanoflower-like three-phase electrocatalyst according to claim 1, characterized in that, The Bi source is bismuth chloride.

4. A nanoflower-shaped three-phase electrocatalyst, characterized in that, The nano-flower-like three-phase electrocatalyst is prepared by the method described in any one of claims 1 to 3.

5. The use of a nanoflower-shaped three-phase electrocatalyst in the catalytic electrolysis of water to produce hydrogen, characterized in that, The nanoflower-like three-phase electrocatalyst is the nanoflower-like three-phase electrocatalyst according to claim 4.

6. Use of the nanoflower-like tri-phase electrocatalyst according to claim 5 in the catalysis of water electrolysis for hydrogen production, characterized in that, The specific application methods are as follows: A two-electrode electrolytic cell was assembled by using a nano-flower-like three-phase electrocatalyst as the anode and cathode, placing the cathode and anode in an electrolyte.

7. Use of the nanoflower-like tri-phase electrocatalyst according to claim 6 in the catalysis of water electrolysis for hydrogen production, characterized in that, The electrolyte is potassium hydroxide.

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