Self-supporting electrode loaded with pentanary needle-shaped high-entropy molybdate electrocatalyst and preparation method and application thereof

Abstract

The present application relates to the field of electrocatalysis, and in particular to a self-supporting electrode loaded with a five-element needle-shaped high-entropy molybdate electrocatalyst, a preparation method thereof and an application thereof. The five-element needle-shaped high-entropy molybdate electrocatalyst can efficiently and selectively catalyze glycerol oxidation, and the core lies in the synergistic advantages of the unique properties of high-entropy materials and the needle-shaped structure of molybdate. The high-entropy material optimizes the electronic structure and regulates the reaction path through the synergy of the five metals, achieving high selectivity and resistance to poisoning. The conductivity and surface reconstruction ability of molybdate provide a high-activity catalytic surface. The needle-shaped structure can build an efficient material and electron transport channel to maximize the exposure of active sites. The superposition of these effects enables the catalyst to efficiently and selectively convert glycerol into high-value chemicals at a lower overpotential.

Description

Technical Field

[0001] This invention relates to the field of electrocatalysis technology, specifically to a self-supporting electrode for supporting a pentagonal needle-shaped high-entropy molybdate electrocatalyst, its preparation method, and its application. Background Technology

[0002] Overexploitation of fossil fuel resources has led to environmental degradation and an energy crisis, posing significant challenges to societal development. Developing and utilizing renewable biomass resources is a key pathway to achieving sustainable energy goals. With the rapid development of the biodiesel industry, the surplus of glycerol (GLY), a byproduct, urgently needs to be addressed. Electrocatalytic glycerol oxidation (GOR), as an emerging conversion method, can convert glycerol into high-value formic acid. However, due to the presence of multiple hydroxyl groups in glycerol, controlling selectivity and the degree of oxidation poses a challenge to the reaction. Furthermore, insufficient supply of active hydroxyl species and the competitive oxygen evolution reaction (OER) also hinder the improvement of reaction efficiency. Therefore, developing highly active and selective electrocatalysts is crucial for achieving efficient and value-added conversion of glycerol.

[0003] Currently, the catalysts used in the electrocatalytic oxidation of glycerol are mainly noble metal catalysts, such as Au, Pt, and Pd. These noble metals have limited reserves and are expensive, hindering large-scale commercial use. Recently, transition metal oxides have been shown to be suitable for the electrocatalytic oxidation of glycerol. However, due to their inherently low electrocatalytic activity, the performance of single metal compounds falls far short of the requirements for practical applications, making widespread adoption difficult. Summary of the Invention

[0004] To overcome the above problems, the present invention provides a self-supporting electrode supported on a pentagonal needle-shaped high-entropy molybdate electrocatalyst, its preparation method and application.

[0005] To achieve the above technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a self-supporting electrode supported on a pentagonal needle-shaped high-entropy molybdate electrocatalyst, wherein the electrode is based on nickel foam and supported on the pentagonal needle-shaped high-entropy molybdate electrocatalyst. The five-membered needle-shaped high-entropy molybdate electrocatalyst is a five-membered needle-shaped high-entropy molybdate with the structural formula (NiCoMnFeCu)(MoO4). x .

[0006] A second aspect of the present invention provides a method for preparing a self-supporting electrode of the pentagonal needle-shaped high-entropy molybdate electrocatalyst described in the first aspect, comprising the following steps: Iron precursor, cobalt precursor, nickel precursor, copper precursor and manganese precursor, as well as urea and ammonium fluoride are dispersed in water and mixed evenly to obtain a mixed reaction solution. Nickel foam was immersed in a mixed reaction solution and then heat-treated to obtain a self-supporting electrode supported on a pentagonal needle-shaped high-entropy molybdate electrocatalyst precursor. Using a self-supporting electrode with a pentagonal needle-shaped high-entropy molybdate electrocatalyst precursor as the working electrode, an electrochemical surface reconstruction treatment was performed in an alkaline molybdate solution to obtain a self-supporting electrode with a pentagonal needle-shaped high-entropy molybdate electrocatalyst.

[0007] In one or more embodiments, the iron precursor includes Fe(NO3)3·9H2O; In one or more embodiments, the cobalt precursor includes Co(NO3)2·6H2O; In one or more embodiments, the nickel precursor includes Ni(NO3)2·6H2O; In one or more embodiments, the copper precursor includes Cu(NO3)2·3H2O; In one or more embodiments, the manganese precursor includes Mn(NO3)2·4H2O.

[0008] Preferably, the molar ratio of iron, cobalt, nickel, copper and manganese in the iron precursor, cobalt precursor, nickel precursor, copper precursor and manganese precursor is 1:1:1:1:1.

[0009] In one or more embodiments, the molar ratio of iron to urea and ammonium fluoride in the iron precursor is 1:(20~30):(0.8~1.2).

[0010] In one or more embodiments, the nickel foam needs to be pretreated before use, and the pretreatment methods include: Ultrasonic cleaning was performed sequentially using ethanol, water, dilute hydrochloric acid, and water.

[0011] Preferably, the mass fraction of dilute hydrochloric acid is 0.8% to 1.2%, and more preferably 1%.

[0012] In one or more embodiments, the heat treatment temperature is 100~150℃ and the heat treatment time is 10~15 h.

[0013] In one or more embodiments, the precursor of the pentagonal needle-like high-entropy molybdate electrocatalyst is a pentagonal high-entropy hydroxide nanoneedle array NiCoMnFeCu(OH). y .

[0014] In one or more embodiments, when performing electrochemical surface reconstruction treatment, a platinum sheet is used as the counter electrode and an Hg / HgO electrode is used as the reference electrode.

[0015] In one or more embodiments, during the electrochemical surface reconstruction treatment, the working potential is a constant potential of 1.2~1.7 V vs. RHE, and the treatment time is 150~250 s, preferably 200 s.

[0016] In one or more embodiments, the solute in the alkaline molybdate solution includes sodium hydroxide and Na2MoO4; Preferably, the concentration of sodium hydroxide is 0.8~1.2 mol / L; Preferably, the concentration of Na2MoO4 is 0.8~1.2 mol / L.

[0017] A third aspect of the present invention provides the application of the self-supporting electrode of the supported pentagonal needle-shaped high-entropy molybdate electrocatalyst described in the first aspect or the self-supporting electrode of the supported pentagonal needle-shaped high-entropy molybdate electrocatalyst prepared by the preparation method described in the second aspect in the glycerol oxidation reaction.

[0018] The beneficial effects of this invention are as follows: The five-membered needle-shaped high-entropy molybdate electrocatalyst can efficiently and selectively catalyze the oxidation of glycerol. Its core lies in the unique properties of the high-entropy material combined with the synergistic advantages of molybdate and needle-like structure. The high-entropy material, through the synergy of five metals, optimizes the electronic structure and regulates the reaction pathway, achieving high selectivity and resistance to poisoning. The conductivity and surface reconstruction capabilities of molybdate provide a highly active catalytic surface. The needle-like structure can construct efficient material and electron transport channels, maximizing the exposure of active sites. The combined effect of these factors enables the catalyst to efficiently and selectively convert glycerol into high-value-added chemicals at relatively low overpotentials. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 The image shows the morphology of the five-membered needle-shaped high-entropy molybdate electrocatalyst HEM-200s, where A is a scanning electron microscope (SEM) image and B is a transmission electron microscope (TEM) image. Figure 2 Powder diffraction image of HEM-200s, a pentagonal needle-shaped high-entropy molybdate electrocatalyst; Figure 3 LSV curves of HEM-200S in GOR and OER; Figure 4 The cyclic voltammetry (CV) curves for the HEM-200s; Figure 5 The cyclic voltammetry (CV) curves for the HEM-100s; Figure 6 Cyclic voltammetry (CV) curves for HEM-300s; Figure 7 Cyclic voltammetry (CV) curves of the self-supporting electrode of the pentagonal needle-shaped high-entropy molybdate electrocatalyst precursor in Comparative Example 1. Figure 8 The cyclic voltammetry (CV) curves of the HEM-Tube; Figure 9 The cyclic voltammetry (CV) curves for HEM-Hydrothermal; Figure 10 The LSV of the self-supporting electrodes in Examples 1-3 and Comparative Examples 1-3 is normalized in GOR; Figure 11 To utilize 1 Qualitative analysis results of electrolysis products by ¹H NMR; Figure 12 To utilize 1 ¹H NMR results for quantitative analysis of formate in the electrolysis products. Detailed Implementation

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] Currently, the catalysts used in the electrocatalytic oxidation of glycerol are mainly noble metal catalysts, such as Au, Pt, and Pd. These noble metals have limited reserves and are expensive, hindering large-scale commercial use. Recently, transition metal oxides have been shown to be suitable for the electrocatalytic oxidation of glycerol. However, due to their inherently low electrocatalytic activity and the fact that the performance of single metal compounds falls far short of practical application requirements, their widespread practical application remains difficult.

[0024] Five-membered needle-shaped high-entropy molybdate electrocatalysts can efficiently and selectively catalyze the oxidation of glycerol. The core of this is the unique properties of high-entropy materials and the synergistic advantages of molybdate and needle-like structure.

[0025] The inherent advantages of high-entropy materials: the synergistic "cocktail" effect of multiple elements.

[0026] Specifically, high-entropy materials are composed of five or more principal elements, with atoms arranged in a highly disordered manner within the crystal lattice. This results in four core effects that endow them with excellent catalytic performance. Multi-element synergistic effect: This is the most crucial advantage. Different metallic elements each perform their specific functions, producing a synergistic effect greater than the sum of its parts (1+1>2) through a "cocktail effect."

[0027] Ni and Co, as key active sites, promote -OH adsorption and activation, providing essential active species for oxidation reactions. Cu weakens the adsorption of the toxic intermediate CO, mitigating catalyst "poisoning" and deactivation. Mn and Fe can induce lattice distortion, modulating the electronic structure of metal sites (such as d-band centers) and optimizing the adsorption energy for reaction intermediates. Mo, as one of the active centers, works synergistically with other elements.

[0028] High entropy effect and lattice distortion: High configurational entropy makes the material structure more stable and allows for dynamic reconstruction during reactions, forming a truly active phase. Lattice distortion caused by differences in atomic size creates more unsaturated coordinated asymmetric active sites.

[0029] Slow diffusion effect: Atoms diffuse slowly in a high-entropy lattice, which helps maintain structural stability during the reaction and improves the long-term durability of the catalyst.

[0030] The oxidation of glycerol has a complex reaction pathway and can produce multiple products. The core advantage of high-entropy catalysts lies in their ability to precisely control the reaction pathway.

[0031] Optimize the adsorption energy of intermediates: A high-entropy environment can effectively stabilize reaction intermediates and reduce the energy barrier for CH bond activation, guiding the reaction toward the target product.

[0032] Promoting C / C bond cleavage: The synergistic effect of multiple metals can promote the selective cleavage of C / C bonds in glycerol molecules, achieving deep oxidation. For example, similar high-entropy alloy electrodes exhibit high selectivity for formate (C1 product).

[0033] Suppressing side reactions and poisoning: By introducing elements such as Cu to weaken CO adsorption, CO poisoning of the catalyst's active sites can be effectively avoided, ensuring catalytic activity and selectivity. The contribution of molybdate (MoO4): Molybdate itself possesses excellent electrical conductivity and electrochemical activity. The synergistic effect of Mo with metal ions such as Fe can further enhance the reactivity. More importantly, the "electrochemical surface reconstruction treatment" in the preparation method is crucial, as it generates a real active phase (such as hydroxyl oxides) in situ on the catalyst surface, which is the actual site where the catalytic reaction occurs.

[0034] Advantages of needle-like morphology: The needle-like structure grows directly on nickel foam, forming a self-supporting electrode. This ensures a good electron transport path and structural stability. Simultaneously, this three-dimensional open structure maximizes the exposure of active sites and promotes mass transfer between the electrolyte and bubbles, thereby enhancing apparent catalytic activity.

[0035] In summary, the catalyst's superior performance stems from an ingenious system design: high-entropy materials, through the synergy of five metals, optimize the electronic structure and regulate the reaction pathway, achieving high selectivity and resistance to poisoning. The conductivity and surface reconstruction capabilities of molybdate provide a highly active catalytic surface. The needle-like structure enables the construction of efficient material and electron transport channels, maximizing the exposure of active sites. The synergistic effect of these factors allows the catalyst to efficiently and selectively convert glycerol into high-value-added chemicals at relatively low overpotentials.

[0036] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0037] Pretreatment of nickel foam: First, the nickel foam (4 cm × 1 cm) was immersed in ethanol and ultrasonically washed (200 W, 5 min) to remove organic matter from the surface of the nickel foam; then it was ultrasonically washed with deionized water (200 W, 1 min); then it was ultrasonically washed with a 1% dilute hydrochloric acid solution (200 W, 5 min) to remove the oxide layer on the surface; finally, it was ultrasonically washed with deionized water (200 W, 2 min) 3 to 5 times, and then vacuum dried at 40°C for later use to obtain the pretreated nickel foam.

[0038] Example 1 0.1 mmol Fe(NO3)3·9H2O, 0.1 mmol Co(NO3)2·6H2O, 0.1 mmol Ni(NO3)2·6H2O, 0.1 mmol Cu(NO3)2·3H2O and 0.1 mmol Mn(NO3)2·4H2O were dispersed in 35 mL of deionized water with 2.5 mmol urea and 1.0 mmol ammonium fluoride. The mixture was then sonicated (200 W, 5 min) to obtain a mixed reaction solution. The mixed reaction solution was transferred to a 50 mL polytetrafluoroethylene-lined high-pressure reactor. The pretreated nickel foam was immersed in the mixed reaction solution. The high-pressure reactor was sealed and placed in a 120°C oven for heat treatment for 12 h. After the reaction was completed, the solid was collected by solid-liquid separation, which is the self-supporting electrode with the five-element needle-shaped high-entropy molybdate electrocatalyst precursor. A self-supported electrode loaded with a pentagonal needle-shaped high-entropy molybdate electrocatalyst precursor was used as the working electrode, a platinum sheet as the counter electrode, and an Hg / HgO electrode as the reference electrode. The electrolyte was a mixed solution containing 1 M NaOH and 0.1 M Na₂MoO₄. A constant potential of 1.5 V vs. RHE was applied to the working electrode using an electrochemical workstation for 200 s. After the reaction, the product was thoroughly washed with deionized water and ethanol, and then vacuum-dried overnight at 40°C to obtain the self-supported electrode loaded with the pentagonal needle-shaped high-entropy molybdate electrocatalyst, denoted as HEM-200s.

[0039] Figure 1 The image shows the morphology of the pentagonal needle-shaped high-entropy molybdate electrocatalyst prepared in this embodiment. Figure 1 Image A is a scanning electron microscope (SEM) image, and image B is a transmission electron microscope (TEM) image. Figure 1 As can be seen, the pentagonal needle-shaped high-entropy molybdate electrocatalyst has a needle-like structure that grows directly on nickel foam, forming a self-supporting electrode. This ensures a good electron transport path and structural stability. Simultaneously, this three-dimensional open structure maximizes the exposure of active sites and promotes mass transfer between the electrolyte and bubbles, thereby enhancing apparent catalytic activity.

[0040] Figure 2 The powder diffraction image is of the pentagonal needle-shaped high-entropy molybdate electrocatalyst prepared in this embodiment. Figure 2 As can be seen, the five-element needle-shaped high-entropy molybdate electrocatalyst is aligned with the (110) and (220) crystal planes in the standard FeMoO4 phase (JCPDS No. 22-0628), indicating that the molybdate phase was successfully synthesized in the material.

[0041] Example 2 0.1 mmol Fe(NO3)3·9H2O, 0.1 mmol Co(NO3)2·6H2O, 0.1 mmol Ni(NO3)2·6H2O, 0.1 mmol Cu(NO3)2·3H2O and 0.1 mmol Mn(NO3)2·4H2O were dispersed in 35 mL of deionized water with 2.5 mmol urea and 1.0 mmol ammonium fluoride. The mixture was then sonicated (200 W, 5 min) to obtain a mixed reaction solution. The mixed reaction solution was transferred to a 50 mL polytetrafluoroethylene-lined high-pressure reactor. The pretreated nickel foam was immersed in the mixed reaction solution. The high-pressure reactor was sealed and placed in a 120°C oven for heat treatment for 12 h. After the reaction was completed, the solid was collected by solid-liquid separation, which is the self-supporting electrode with the five-element needle-shaped high-entropy molybdate electrocatalyst precursor. A self-supported electrode loaded with a pentagonal needle-shaped high-entropy molybdate electrocatalyst precursor was used as the working electrode, a platinum sheet as the counter electrode, and an Hg / HgO electrode as the reference electrode. The electrolyte was a mixed solution containing 1 M NaOH and 0.1 M Na₂MoO₄. A constant potential of 1.5 V vs. RHE was applied to the working electrode using an electrochemical workstation for 100 s. After the reaction, the product was thoroughly washed with deionized water and ethanol, and then vacuum-dried overnight at 40°C to obtain the self-supported electrode loaded with the pentagonal needle-shaped high-entropy molybdate electrocatalyst, denoted as HEM-100s.

[0042] Example 3 0.1 mmol Fe(NO3)3·9H2O, 0.1 mmol Co(NO3)2·6H2O, 0.1 mmol Ni(NO3)2·6H2O, 0.1 mmol Cu(NO3)2·3H2O and 0.1 mmol Mn(NO3)2·4H2O were dispersed in 35 mL of deionized water with 2.5 mmol urea and 1.0 mmol ammonium fluoride. The mixture was then sonicated (200 W, 5 min) to obtain a mixed reaction solution. The mixed reaction solution was transferred to a 50 mL polytetrafluoroethylene-lined high-pressure reactor. The pretreated nickel foam was immersed in the mixed reaction solution. The high-pressure reactor was sealed and placed in a 120°C oven for heat treatment for 12 h. After the reaction was completed, the solid was collected by solid-liquid separation, which is the self-supporting electrode with the five-element needle-shaped high-entropy molybdate electrocatalyst precursor. A self-supported electrode loaded with a pentagonal needle-shaped high-entropy molybdate electrocatalyst precursor was used as the working electrode, a platinum sheet as the counter electrode, and an Hg / HgO electrode as the reference electrode. The electrolyte was a mixed solution containing 1 M NaOH and 0.1 M Na₂MoO₄. A constant potential of 1.5 V vs. RHE was applied to the working electrode using an electrochemical workstation for 300 s. After the reaction, the product was thoroughly washed with deionized water and ethanol, and then vacuum-dried overnight at 40°C to obtain the self-supported electrode loaded with the pentagonal needle-shaped high-entropy molybdate electrocatalyst, denoted as HEM-300s.

[0043] Comparative Example 1 In this comparative example, the electrode is a self-supporting electrode supported on a pentagonal needle-shaped high-entropy molybdate electrocatalyst precursor.

[0044] Comparative Example 2 The self-supporting electrode of the supported pentagonal needle-shaped high-entropy molybdate electrocatalyst precursor prepared in Example 1 was immersed in a solution containing 0.1 M Na₂MoO₄ and ultrasonically treated (200 W) for 10 min to uniformly adsorb the molybdenum source on the surface of the self-supporting electrode. After removal, it was vacuum dried at 60°C. The dried sample was placed in a tube furnace and heated to 450°C at a rate of 5°C / min under a nitrogen atmosphere (flow rate 50 mL / min). After holding at this temperature for 2 h, it was naturally cooled to room temperature. After the reaction was completed, the product was removed, thoroughly washed with deionized water and ethanol, and vacuum dried overnight at 40°C to obtain the self-supporting electrode, denoted as HEM-Tube.

[0045] Comparative Example 3 The self-supporting electrode of the pentagonal needle-shaped high-entropy molybdate electrocatalyst precursor prepared in Example 1 was immersed in a solution containing 0.1 M Na2MoO4, and then transferred to a 50 mL polytetrafluoroethylene-lined high-pressure reactor. The high-pressure reactor was sealed and heat-treated in an oven at 120°C for 12 h. After the reaction was completed, the solid was collected by solid-liquid separation, thoroughly washed with deionized water and ethanol, and vacuum dried overnight at 40°C to obtain the self-supporting electrode, denoted as HEM-Hydrothermal.

[0046] Example 4 Electrochemical tests were performed at room temperature using a CHI660E electrochemical workstation with a three-electrode system. All potentials were calibrated to the reversible hydrogen electrode, and no infrared correction was applied to the data. The Hg / HgO electrode served as the reference electrode, the platinum mesh electrode (2 cm × 2 cm, 60 mesh) served as the counter electrode, and the self-supporting electrodes from Examples 1-3 and Comparative Examples 1-3 served as the working electrodes, all fixed by glassy carbon electrode clamps.

[0047] Electrochemical tests of the glycerol oxidation reaction (GOR) were performed in a mixed solution of 1 M NaOH and 0.1 M glycerol. The results were measured at 5 mV·s. - Cyclic voltammetry (CV) and linear scan voltammetry (LSV) were performed at scan rates ¹; in addition, different scan rates (20, 40, 60, 80, 100 mV·s) were also performed in the non-redox potential range. - ¹) Cyclic voltammetry tests were performed to evaluate the double-layer capacitance behavior.

[0048] For comparison, the OER performance of HEM-200s was evaluated in 1.0 M NaOH electrolyte.

[0049] Figure 3 The LSV curves of HEM-200S in GOR and OER are shown below. Figure 3As can be seen, HEM-200S exhibits excellent GOR activity. During the GOR process, it achieves 100 mA cm⁻¹. -2 The required current density is only 1.42 V vs. RHE, which is 260 mV lower than the potential required to achieve the same current density in OER.

[0050] Cyclic voltammetry (CV) curves were collected at different scan rates within the non-Radida potential range, and the double-layer capacitance of each supporting electrode was measured. Figures 4-9 The corresponding electrochemical active area was obtained. The current density of the polarization curve was normalized using the obtained electrochemical active area. The normalized polarization test results showed ( Figure 10 The intrinsic current of the catalyst of this invention can reach 1.1 to 1.4 times that of the comparative catalyst, which proves the good intrinsic activity of the high-entropy catalyst.

[0051] HEM-Tube is prepared based on high-temperature solid-state reaction. Since the diffusion coefficients of each metal element are different, the atoms cannot achieve uniform mutual solubility on a scale, and the product will undergo phase separation. At the same time, high temperature will cause the needle array to coarsen and the structure to be destroyed.

[0052] HEM-Hydrothermal is prepared based on liquid-phase reaction. The five metal ions react asynchronously with molybdate, resulting in elemental segregation and an inability to obtain a product with uniform composition. At the same time, the needle-like structure of the precursor is etched in the liquid phase, causing it to collapse and disintegrate.

[0053] This invention employs an electrochemical surface reconstruction strategy, placing a pentagonal high-entropy hydroxide needle-shaped precursor in an alkaline electrolyte containing molybdate for constant-potential polarization treatment. Driven by an electric field, molybdate ions are directionally inserted into the precursor lattice and undergo in-situ transformation, allowing all metal components to react synchronously. This results in a single-phase, homogeneous pentagonal high-entropy molybdate, fundamentally avoiding the problems of uneven solid-phase diffusion at high temperatures and the kinetic differentiation of liquid-phase reactions. The entire transformation process is carried out in a room-temperature solution, avoiding the destructive effects of high-temperature sintering and liquid-phase etching, thus preserving the needle-shaped array of the precursor intact. Simultaneously, constant-potential polarization itself is an electrochemical oxidation process; during molybdate insertion, hydroxyl oxide species are generated in-situ on the electrode surface, precisely forming the intrinsically catalytically active interface necessary for the glycerol oxidation reaction.

[0054] The HEM-200s was subjected to chronoamperometric (CA) testing at five selected potentials: 1.42 V, 1.44 V, 1.46 V, 1.48 V, and 1.50 V vs. RHE. 1 H NMR was used for qualitative and quantitative analysis of the electrolysis products. Figure 11 and 12The results showed that the Faraday efficiency (FE) of formate could reach ~100% at 1.46 V vs. RHE.

[0055] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A self-supporting electrode supported on a pentagonal needle-shaped high-entropy molybdate electrocatalyst, characterized in that, It uses nickel foam as a matrix and supports a pentagonal needle-shaped high-entropy molybdate electrocatalyst; The five-membered needle-shaped high-entropy molybdate electrocatalyst is a five-membered needle-shaped high-entropy molybdate with the structural formula (NiCoMnFeCu)(MoO4). x .

2. The method for preparing the self-supporting electrode of the supported pentagonal needle-shaped high-entropy molybdate electrocatalyst according to claim 1, characterized in that, Includes the following steps: Iron precursor, cobalt precursor, nickel precursor, copper precursor and manganese precursor, as well as urea and ammonium fluoride are dispersed in water and mixed evenly to obtain a mixed reaction solution. Nickel foam was immersed in a mixed reaction solution and then heat-treated to obtain a self-supporting electrode supported on a pentagonal needle-shaped high-entropy molybdate electrocatalyst precursor. Using a self-supporting electrode with a pentagonal needle-shaped high-entropy molybdate electrocatalyst precursor as the working electrode, an electrochemical surface reconstruction treatment was performed in an alkaline molybdate solution to obtain a self-supporting electrode with a pentagonal needle-shaped high-entropy molybdate electrocatalyst.

3. The preparation method according to claim 2, characterized in that, Iron precursors include Fe(NO3)3·9H2O; Alternatively, cobalt precursors may include Co(NO3)2·6H2O; Alternatively, nickel precursors may include Ni(NO3)2·6H2O; Alternatively, the copper precursor may include Cu(NO3)2·3H2O; Alternatively, manganese precursors may include Mn(NO3)2·4H2O.

4. The preparation method according to claim 3, characterized in that, The molar ratio of iron, cobalt, nickel, copper and manganese in the iron precursor, cobalt precursor, nickel precursor, copper precursor and manganese precursor is 1:1:1:1:1; Alternatively, the molar ratio of iron to urea and ammonium fluoride in the iron precursor is 1:(20~30):(0.8~1.2).

5. The preparation method according to claim 3, characterized in that, Nickel foam requires pretreatment before use. Pretreatment methods include: Ultrasonic cleaning was performed sequentially using ethanol, water, dilute hydrochloric acid, and water. Preferably, the mass fraction of dilute hydrochloric acid is 0.8% to 1.2%, and more preferably 1%.

6. The preparation method according to claim 2, characterized in that, The heat treatment temperature is 100~150℃, and the heat treatment time is 10~15 h; Alternatively, the precursor for the pentagonal needle-like high-entropy molybdate electrocatalyst is a pentagonal high-entropy hydroxide nanoneedle array NiCoMnFeCu(OH). y .

7. The preparation method according to claim 2, characterized in that, When performing electrochemical surface reconstruction treatment, a platinum sheet is used as the counter electrode and an Hg / HgO electrode is used as the reference electrode.

8. The preparation method according to claim 2, characterized in that, When performing electrochemical surface reconstruction treatment, the working potential is a constant potential of 1.2~1.7 V vs. RHE, and the treatment time is 150~250 s, preferably 200 s.

9. The preparation method according to claim 2, characterized in that, The solutes in the alkaline molybdate solution include sodium hydroxide and Na₂MoO₄. Preferably, the concentration of sodium hydroxide is 0.8~1.2 mol / L; Preferably, the concentration of Na2MoO4 is 0.8~1.2 mol / L.

10. The application of the self-supporting electrode of the supported pentagonal needle-shaped high-entropy molybdate electrocatalyst according to claim 1 or the self-supporting electrode of the supported pentagonal needle-shaped high-entropy molybdate electrocatalyst prepared by any one of claims 2 to 9 in the glycerol oxidation reaction.

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