High-entropy nano-array for electrocatalytic reduction of nitrate coupled with waste plastic conversion and preparation method thereof

Abstract

A high-entropy nano-array for electrocatalytic nitrate reduction coupling waste plastic conversion is prepared by the following method: (1) immerse the nickel foam into a hydrochloric acid solution to remove the surface oxide layer and oil stains, rinse with deionized water / ethanol three times, and dry for subsequent use; (2) solid powders of sodium chloropalladate, platinum acetylacetate, nickel chloride hexahydrate, copper chloride dihydrate, silver trifluoroacetate and tungsten hexacarbonyl are poured into an N-N dimethylformamide solution, ultrasonic is used to dissolve the solid powders, then glacial acetic acid and the treated nickel foam are added to the above solution, and after ultrasonic, heating in an oven is carried out, after the reaction is completed, water and ethanol solution are used for alternate washing, and drying is carried out, and the high-entropy nano-array catalyst is obtained. A preparation method of a high-entropy nano-array for electrocatalytic nitrate reduction coupling waste plastic conversion is provided. The high-entropy nano-array has excellent electrocatalytic activity and stability.

Description

Technical Field

[0001] This invention relates to a high-entropy nanoarray and its preparation method. This material can be used in the research of a novel coupling system for nitrate reduction and waste plastic conversion. Background Technology

[0002] The accumulation of nitrate-containing industrial wastewater and polyethylene terephthalate (PET) waste plastics in nature has caused a series of environmental problems and posed a threat to human health. To effectively address this situation, a feasible strategy is to upgrade and recycle polluting waste into value-added chemicals, achieving resource utilization. Among various upgrading and recycling technologies, electrocatalysis is a green and sustainable solution. This technology utilizes renewable electricity and operates under mild conditions, efficiently and simultaneously converting nitrate wastewater and PET waste plastics into value-added chemicals such as ammonia and glycolic acid. Therefore, designing high-performance electrocatalysts plays a decisive role in the upgrading and conversion of nitrate wastewater and PET waste plastics.

[0003] High-entropy alloys (HEAs) are novel and unique multi-metallic alloys composed of five or more elements. Due to their unique advantages such as high-entropy effects, lattice distortion effects, and "cocktail" effects, HEAs have attracted widespread attention in electrocatalysis applications. The presence of multiple adjacent elements in HEAs can create new and unique active sites, allowing for optimization of specific performance through precise selection of specific elements and compositions. Therefore, a rational design strategy is crucial for improving the catalytic performance of HEAs for specific reactions. Electrocatalysts with ultrathin sheet-like morphologies exhibit excellent electrocatalytic performance due to their structural anisotropy, rich surface chemistry, and efficient electron diffusion capabilities. Therefore, combining the multi-elemental properties of HEAs with the unique structural advantages of ultrathin two-dimensional nanosheets to construct high-entropy nanoarrays is a new direction for developing advanced high-entropy alloy electrocatalysts. The design of high-entropy nanoarray catalysts offers unique possibilities for novel coupling systems for the electrocatalytic upgrading and conversion of nitrate wastewater and PET waste plastics. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a method for preparing high-entropy nanoarrays, and studies the performance of a novel coupling system for the electrocatalytic conversion of nitrate wastewater and PET waste plastics.

[0005] The technical solution adopted in this invention is:

[0006] A high-entropy nanoarray for electrocatalytic nitrate reduction coupled with waste plastic conversion is prepared by the following method:

[0007] (1) Immerse 1-2cm×1-2cm nickel foam in hydrochloric acid solution to remove surface oxide layer and oil stains, rinse three times with deionized water / ethanol, and dry for subsequent use;

[0008] (2) Pour 10-20 mg sodium chloropalladium, 5-10 mg platinum acetylacetonate, 5-10 mg nickel chloride hexahydrate, 1-3 mg copper chloride dihydrate, 1-3 mg silver trifluoroacetate and 10-20 mg tungsten hexacarbonyl into 4-8 mL of N,N dimethylformamide solution and sonicate for 10-20 minutes to dissolve the solid powder. Then add 1-2 mL of glacial acetic acid and the treated nickel foam to the above solution and sonicate for 3-5 minutes. Then heat in an oven at 120-160 °C for 4-12 hours. After the reaction is complete, wash with water and ethanol solution alternately and dry to obtain the catalyst.

[0009] In this invention, a typical high-entropy nanoarray is prepared by a simple one-step wet chemical method. During the synthesis process, carbon monoxide decomposed from tungsten hexacarbonyl under high temperature conditions acts as a directing agent for the formation of two-dimensional structures, while nickel foam acts as a support and palladium, platinum, copper, nickel, and silver precursors are reduced by glacial acetic acid to form a two-dimensional high-entropy nanosheet array.

[0010] A method for preparing a high-entropy nanoarray for electrocatalytic nitrate reduction coupled with waste plastic conversion includes the following steps:

[0011] (1) Immerse 1-2cm×1-2cm nickel foam in hydrochloric acid solution to remove surface oxide layer and oil stains, rinse three times with deionized water / ethanol, and dry for subsequent use;

[0012] (2) Pour 10-20 mg sodium chloropalladium, 5-10 mg platinum acetylacetonate, 5-10 mg nickel chloride hexahydrate, 1-3 mg copper chloride dihydrate, 1-3 mg silver trifluoroacetate and 10-20 mg tungsten hexacarbonyl into 4-8 mL of N,N dimethylformamide solution and sonicate for 10-20 minutes to dissolve the solid powder. Then add 1-2 mL of glacial acetic acid and the treated nickel foam to the above solution and sonicate for 3-5 minutes. Then heat in an oven at 120-160 °C for 4-12 hours. After the reaction is complete, wash with water and ethanol solution alternately and dry to obtain the catalyst.

[0013] The novel coupling performance of electrocatalytic nitrate wastewater and PET waste plastic upgrading and conversion was tested under normal temperature and pressure. The specific operation process is as follows:

[0014] (1) Preparation of PET degradation electrolyte: Take 50-100g of waste plastic and pour it into 100-200mL of 4-8M potassium hydroxide solution and stir continuously in an oil bath at 60℃ for 48-72 hours to degrade it. After degradation, filter to obtain PET degradation solution for use.

[0015] (2) Cathode Electrocatalytic Nitrate Reduction Test: A three-electrode system was formed using the prepared catalyst as the working electrode, a carbon rod as the counter electrode, and an Hg / HgO electrode as the reference electrode. The cathodic electrocatalytic nitrate reduction performance was tested in 0.1–1 M potassium hydroxide and mixed solutions of 0.1–1 M potassium hydroxide + 0.1–1 M potassium nitrate, respectively. Linear sweep voltammetry, cyclic voltammetry, chronoamperometry, and chronovoltametry were used for testing. UV-Vis spectrophotometer and NMR were used for product detection. Parameters such as the electrochemical active area of ​​the high-entropy nanoarray, the proportion of each product in the total product, the ratio of charge consumed during the formation of each product to the total charge of the working electrode, and the duration of catalytic effect were systematically investigated. The catalytic activity, selectivity, Faradaic efficiency, and catalytic stability of the nitrate reduction to ammonia reaction on the high-entropy nanoarray were comprehensively evaluated. All potentials in this work were converted relative to the standard hydrogen electrode.

[0016] (3) Anodic electrocatalytic oxidation test of PET degradation solution: A three-electrode system was formed using the prepared catalyst as the working electrode, a carbon rod as the counter electrode, and an Hg / HgO electrode as the reference electrode. The anodic electrocatalytic oxidation performance of PET degradation solution was tested in 0.1–1 M potassium hydroxide and PET degradation solution. Linear sweep voltammetry, cyclic voltammetry, chronoamperometry, and chronovoltametry were used for testing. NMR was used for product detection. The electrochemical active area of ​​the high-entropy nanoarray, the proportion of each product in the total product, the ratio of charge consumed in the formation of each product to the total charge of the working electrode, and the duration of catalytic effect were systematically investigated. The catalytic activity, selectivity, Faradaic efficiency, and catalytic stability of the oxidation of PET degradation solution to glycolic acid on the high-entropy nanoarray were comprehensively evaluated. All potentials in this work were converted relative to the standard hydrogen electrode.

[0017] (4) Electrocatalytic Coupling System Testing: The prepared catalyst was used as the cathode and anode, respectively. The electrolytes in the cathode and anode chambers were a mixed solution of 0.1-1M potassium hydroxide + 0.1-1M potassium nitrate and PET degradation solution, respectively, forming a novel coupling system. Linear scanning voltammetry, cyclic voltammetry, chronoamperometry, and chronovoltametry were used for testing. UV-Vis spectrophotometer and NMR were used for product detection. The electrochemical active area of ​​the high-entropy nanoarray, the proportion of each product in the total product, the ratio of charge consumed in the formation of each product to the total charge of the working electrode, and the duration of catalytic effect were systematically investigated. The catalytic activity, selectivity, Faradaic efficiency, and catalytic stability of the reaction of nitrate reduction to ammonia at the cathode and oxidation of PET degradation solution to glycolic acid at the anode on the high-entropy nanoarray were comprehensively evaluated.

[0018] The beneficial effects of this invention are mainly reflected in: (1) a typical high-entropy nanoarray was successfully prepared by a one-pot wet chemical method, and its application in a novel coupling system was demonstrated. (2) the high-entropy nanoarray exhibited excellent cathodic electrocatalytic nitrate reduction and anodic electrocatalytic PET degradation solution oxidation performance in the novel coupling system, and had excellent electrocatalytic activity and stability. Attached Figure Description

[0019] Figure 1 The images shown are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of a high-entropy nanoarray, which are specific embodiments of the present invention.

[0020] Figure 2 This is an X-ray diffraction pattern of a high-entropy nanoarray, which is a specific embodiment of the present invention.

[0021] Figure 3 The atomic percentage of the high-entropy nanoarray in Specific Embodiment 1 of the present invention.

[0022] Figure 4 The linear sweep voltammetric curves of the cathode electrocatalytic reduction of nitrate using a high-entropy nanoarray are shown in Example 1 of the present invention.

[0023] Figure 5 This is a specific embodiment of the present invention, showing the Faraday efficiency and yield of the cathode electrocatalytic reduction of nitrate to ammonia to ammonia under different voltages of a high-entropy nanoarray.

[0024] Figure 6 The linear sweep voltammetric curves of the anodic electrocatalytic oxidation of PET degradation solution using a high-entropy nanoarray are shown in Example 1 of the present invention.

[0025] Figure 7 This invention relates to a specific embodiment 1, which describes the Faraday efficiency and yield of anodic electrocatalytic oxidation of PET degradation solution to glycolic acid at different potentials using a high-entropy nanoarray.

[0026] Figure 8 The linear scanning voltammetric curve of the coupling system of the high-entropy nanoarray is shown in Embodiment 1 of the present invention.

[0027] Figure 9 This is a specific embodiment of the invention, showing the Faraday efficiency and yield of the cathode and anode of a high-entropy nanoarray coupling system under different voltages.

[0028] Figure 10 This is a stability test of the high-entropy nanoarray coupling system in specific embodiment 1 of the present invention.

[0029] Figure 11 The images shown are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the high-entropy nanoarray, a specific embodiment of the present invention.

[0030] Figure 12 The atomic percentage of the high-entropy nanoarray in specific embodiment 2 of the present invention.

[0031] Figure 13 The linear scanning voltammetric curve of the coupling system of the high-entropy nanoarray is shown in Embodiment 2 of the present invention.

[0032] Figure 14 The images shown are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the high-entropy nanoarray in specific embodiment 3 of the present invention.

[0033] Figure 15 The atomic percentage of the high-entropy nanoarray in specific embodiment 3 of the present invention.

[0034] Figure 16 Linear scan voltammetric curves of three high-entropy nanoarray coupling systems are shown as specific embodiments of the present invention. Detailed Implementation

[0035] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0036] Reference Figures 1-10 A high-entropy nanoarray for electrocatalytic nitrate reduction coupled with waste plastic conversion is prepared by the following method:

[0037] (1) Immerse 1-2cm×1-2cm nickel foam in hydrochloric acid solution to remove surface oxide layer and oil stains, rinse three times with deionized water / ethanol, and dry for subsequent use;

[0038] (2) Pour 10-20 mg sodium chloropalladium, 5-10 mg platinum acetylacetonate, 5-10 mg nickel chloride hexahydrate, 1-3 mg copper chloride dihydrate, 1-3 mg silver trifluoroacetate and 10-20 mg tungsten hexacarbonyl into 4-8 mL of N,N dimethylformamide solution and sonicate for 10-20 minutes to dissolve the solid powder. Then add 1-2 mL of glacial acetic acid and the treated nickel foam to the above solution and sonicate for 3-5 minutes. Then heat in an oven at 120-160 °C for 4-12 hours. After the reaction is complete, wash with water and ethanol solution alternately and dry to obtain the catalyst.

[0039] The high-entropy nanoarray coupling performance test in this embodiment was conducted on a CHI 760E electrochemical workstation. The operation procedure was as follows:

[0040] (1) Preparation of PET degradation electrolyte: Take 50-100g of waste plastic and pour it into 100-200mL of 4-8M potassium hydroxide solution and stir continuously in an oil bath at 60℃ for 48-72 hours to degrade it. After degradation, filter to obtain PET degradation solution for use.

[0041] (2) Cathode Electrocatalytic Nitrate Reduction Test: A three-electrode system was formed using the prepared catalyst as the working electrode, a carbon rod as the counter electrode, and an Hg / HgO electrode as the reference electrode. The cathodic electrocatalytic nitrate reduction performance was tested in 0.1–1 M potassium hydroxide and mixed solutions of 0.1–1 M potassium hydroxide + 0.1–1 M potassium nitrate, respectively. Linear sweep voltammetry, cyclic voltammetry, chronoamperometry, and chronovoltametry were used for testing. UV-Vis spectrophotometer and NMR were used for product detection. Parameters such as the electrochemical active area of ​​the high-entropy nanoarray, the proportion of each product in the total product, the ratio of charge consumed during the formation of each product to the total charge of the working electrode, and the duration of catalytic effect were systematically investigated. The catalytic activity, selectivity, Faradaic efficiency, and catalytic stability of the nitrate reduction to ammonia reaction on the high-entropy nanoarray were comprehensively evaluated. All potentials in this work were converted relative to the standard hydrogen electrode.

[0042] (3) Anodic electrocatalytic oxidation test of PET degradation solution: A three-electrode system was formed using the prepared catalyst as the working electrode, a carbon rod as the counter electrode, and an Hg / HgO electrode as the reference electrode. The anodic electrocatalytic oxidation performance of PET degradation solution was tested in 0.1–1 M potassium hydroxide and PET degradation solution. Linear sweep voltammetry, cyclic voltammetry, chronoamperometry, and chronovoltametry were used for testing. NMR was used for product detection. The electrochemical active area of ​​the high-entropy nanoarray, the proportion of each product in the total product, the ratio of charge consumed in the formation of each product to the total charge of the working electrode, and the duration of catalytic effect were systematically investigated. The catalytic activity, selectivity, Faradaic efficiency, and catalytic stability of the oxidation of PET degradation solution to glycolic acid on the high-entropy nanoarray were comprehensively evaluated. All potentials in this work were converted relative to the standard hydrogen electrode.

[0043] (4) Electrocatalytic Coupling System Testing: The prepared catalyst was used as the cathode and anode, respectively. The electrolytes in the cathode and anode chambers were a mixed solution of 0.1-1M potassium hydroxide + 0.1-1M potassium nitrate and PET degradation solution, respectively, forming a novel coupling system. Linear scanning voltammetry, cyclic voltammetry, chronoamperometry, and chronovoltametry were used for testing. UV-Vis spectrophotometer and NMR were used for product detection. The electrochemical active area of ​​the high-entropy nanoarray, the proportion of each product in the total product, the ratio of charge consumed in the formation of each product to the total charge of the working electrode, and the duration of catalytic effect were systematically investigated. The catalytic activity, selectivity, Faradaic efficiency, and catalytic stability of the reaction of nitrate reduction to ammonia at the cathode and oxidation of PET degradation solution to glycolic acid at the anode on the high-entropy nanoarray were comprehensively evaluated.

[0044] Example 1:

[0045] A method for preparing a high-entropy nanoarray for electrocatalytic nitrate reduction coupled with waste plastic conversion, the method comprising the following steps:

[0046] (1) Immerse 1cm×1cm nickel foam in hydrochloric acid solution to remove surface oxide layer and oil stains, rinse three times with deionized water / ethanol, and dry for subsequent use;

[0047] (2) 10 mg sodium chloropalladate, 5 mg platinum acetylacetonate, 5 mg nickel chloride hexahydrate, 1 mg copper chloride dihydrate, 1 mg silver trifluoroacetate and 10 mg tungsten hexacarbonyl were added to a 4 mL NN dimethylformamide solution and sonicated for 10 minutes to dissolve the solid powder. Then 1 mL glacial acetic acid and the treated nickel foam were added to the above solution and sonicated for 3 minutes. The solution was then heated in an oven at 120 °C for 4 hours. After the reaction was completed, the solution was washed alternately with water and ethanol solution and dried to obtain the high-entropy nanoarray catalyst.

[0048] The scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the high-entropy nanoarray obtained in Example 1 are shown below. Figure 1 The X-ray diffraction pattern of the high-entropy nanoarray obtained in Example 1 is shown in the figure. Figure 2 The atomic percentage of the high-entropy nanoarray obtained in Example 1 is referenced. Figure 3 Specific Example 1: Linear Scan Voltammetric Curve of High-Entropy Nanoarray Cathode Electrocatalytic Nitrate Reduction (Ref.) Figure 4 The specific embodiment 1 obtained shows the Faraday efficiency and yield of the cathode electrocatalytic reduction of nitrate to ammonia to ammonia under different voltages of the high-entropy nanoarray. Figure 5 The linear sweep voltammetric curve of the anodic electrocatalytic oxidation of PET degradation solution using a high-entropy nanoarray in Specific Example 1 is shown below. Figure 6 The specific embodiment 1 obtained shows the Faraday efficiency and yield of anodic electrocatalytic oxidation of PET degradation solution to glycolic acid at different potentials using a high-entropy nanoarray. Figure 7 The linear scan voltammetric curve of the coupled system of the high-entropy nanoarray obtained in Specific Example 1 is shown in the figure. Figure 8 The specific embodiment 1 shows the Faraday efficiency and yield of the coupled system cathode and anode of the high-entropy nanoarray under different voltages. Figure 9 The stability test of the high-entropy nanoarray coupling system obtained in Specific Implementation Example 1 was conducted with reference to... Figure 10 .

[0049] First, the morphology and structure of the prepared high-entropy nanoarray were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM images confirmed that the sample consisted of a nanosheet array. TEM images further revealed that the high-entropy nanoarray was composed of ultrathin two-dimensional nanosheets. X-ray diffraction patterns further showed a typical single-phase face-centered cubic structure, indicating the formation of a high-entropy alloy. SEM energy dispersive spectroscopy demonstrated the uniform distribution of Pd, Pt, Cu, Ni, and Ag elements within the high-entropy nanoarray. Next, the cathodic electrocatalytic nitrate reduction and anodic electrocatalytic oxidation of PET degradation solution, as well as the performance of the coupled system, were investigated. Linear scanning voltammetry (SVC) curves for nitrate reduction under alkaline conditions showed that the high-entropy nanoarray exhibited a higher current density in the electrolyte containing potassium nitrate, indicating high catalytic activity for nitrate reduction. In an electrolyte containing 1M potassium hydroxide and 0.1M potassium nitrate, the high-entropy nanoarray achieved an ammonia yield of 0.4 mmol / h at a low voltage (-0.15V vs. Hg / HgO). -1 cm -2The Faraday efficiency for ammonia reached 96.0%, indicating that the high-entropy nanoarray possesses superior activity in the reduction of nitrate to ammonia. Next, linear sweep voltammetry of the PET degradation solution under alkaline conditions revealed that the high-entropy nanoarray exhibited a higher current density in the PET degradation solution, indicating that it also possesses high catalytic activity for the oxidation of the PET degradation solution. The high-entropy nanoarray achieved a glycolic acid yield of 1.5 mmol / h under low voltage (0.8 V vs. Hg / HgO). -1 cm -2 The Faraday efficiency for glycolic acid reached 97.2%, indicating that the high-entropy nanoarray also possesses superior activity in the oxidation of glycolic acid from PET degradation solution. Therefore, we tested the electrochemical performance of the high-entropy nanoarray in a novel coupled system consisting of cathode nitrate reduction and anolyte oxidation from PET degradation solution. Linear sweep voltammetry curves showed that, compared to conventional water electrolysis, the high-entropy nanoarray required only a lower voltage to achieve the same current density in the novel coupled system. In the novel coupled system, the high-entropy nanoarray exhibited excellent cathode nitrate reduction for ammonia synthesis at 1 V, with a yield (96.5%; 0.5 mmol / L h⁻¹). -1 cm -2 The efficiency and yield of synthesizing glycolic acid from anolyte PET degradation solution were 97.5% and 1.4 mmol / h. -1 cm -2 Long-term stability tests were conducted on the high-entropy nanoarray. After 100 hours, the Faraday efficiency and yield of its cathode and anode remained essentially unchanged, indicating that the high-entropy nanoarray has good stability in the novel coupling system.

[0050] Example 2:

[0051] A method for preparing a high-entropy nanoarray for electrocatalytic nitrate reduction coupled with waste plastic conversion, the method comprising the following steps:

[0052] (1) Immerse a 1.5cm×1.5cm piece of nickel foam in hydrochloric acid solution to remove the surface oxide layer and oil stains, rinse three times with deionized water / ethanol, and dry for subsequent use;

[0053] (2) 15 mg sodium chloropalladate, 7.5 mg platinum acetylacetonate, 7.5 mg nickel chloride hexahydrate, 2 mg copper chloride dihydrate, 2 mg silver trifluoroacetate and 15 mg tungsten hexacarbonyl were added to a 6 mL NN dimethylformamide solution and sonicated for 15 minutes to dissolve the solid powder. Then 1.5 mL glacial acetic acid and the treated nickel foam were added to the above solution and sonicated for 4 minutes. The mixture was then heated in an oven at 140 °C for 8 hours. After the reaction was completed, the mixture was washed alternately with water and ethanol solution and dried to obtain the high-entropy nanoarray catalyst.

[0054] First, the morphology and structure of the prepared high-entropy nanoarray were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM images confirmed that the sample consisted of a nanosheet array. TEM images further revealed that the high-entropy nanoarray was composed of ultrathin two-dimensional nanosheets. X-ray diffraction patterns further showed a typical single-phase face-centered cubic structure, indicating the formation of a high-entropy alloy. SEM energy dispersive spectroscopy demonstrated the uniform distribution of Pd, Pt, Cu, Ni, and Ag elements within the high-entropy nanoarray. Next, the cathodic electrocatalytic nitrate reduction and anodic electrocatalytic oxidation of PET degradation solution, as well as the performance of the coupled system, were investigated. Linear scanning voltammetry (SVC) curves for nitrate reduction under alkaline conditions showed that the high-entropy nanoarray exhibited a higher current density in an electrolyte containing potassium nitrate, indicating high catalytic activity for nitrate reduction. In an electrolyte containing 1M potassium hydroxide and 0.1M potassium nitrate, the high-entropy nanoarray achieved an ammonia yield of 0.52 mmol / h at a low voltage (-0.15V vs. Hg / HgO). -1 cm -2 The Faraday efficiency for ammonia reached 96.2%, indicating that the high-entropy nanoarray possesses superior activity in the reduction of nitrate to ammonia. Next, linear sweep voltammetry of the PET degradation solution under alkaline conditions revealed that the high-entropy nanoarray exhibited a higher current density in the PET degradation solution, indicating that it also possesses high catalytic activity for the oxidation of PET degradation solution. The high-entropy nanoarray achieved a glycolic acid yield of 1.6 mmol / h under low voltage (0.8 V vs. Hg / HgO). -1 cm -2 The Faraday efficiency for glycolic acid reached 97.5%, indicating that the high-entropy nanoarray also possesses superior activity in the oxidation of glycolic acid from PET degradation solution. Therefore, we tested the electrochemical performance of the high-entropy nanoarray in a novel coupled system consisting of cathode nitrate reduction and anolyte oxidation from PET degradation solution. Linear sweep voltammetry curves showed that, compared to conventional water electrolysis, the high-entropy nanoarray required only a lower voltage to achieve the same current density in the novel coupled system. In the novel coupled system, the high-entropy nanoarray exhibited excellent cathode nitrate reduction for ammonia synthesis (97.5%; 0.6 mmol / L h⁻¹) at 1 V. -1 cm -2 The efficiency and yield of synthesizing glycolic acid from anolyte and PET degradation solution were 98.1% and 1.4 mmol / h, respectively. -1 cm -2 Long-term stability tests were conducted on the high-entropy nanoarray. After 100 hours, the Faraday efficiency and yield of its cathode and anode remained essentially unchanged, indicating that the high-entropy nanoarray has good stability in the novel coupling system.

[0055] Example 3:

[0056] A method for preparing a high-entropy nanoarray for electrocatalytic nitrate reduction coupled with waste plastic conversion, the method comprising the following steps:

[0057] (1) Immerse 2cm×2cm nickel foam in hydrochloric acid solution to remove surface oxide layer and oil stains, rinse three times with deionized water / ethanol, and dry for subsequent use;

[0058] (2) 20 mg sodium chloropalladate, 10 mg platinum acetylacetonate, 10 mg nickel chloride hexahydrate, 3 mg copper chloride dihydrate, 3 mg silver trifluoroacetate and 20 mg tungsten hexacarbonyl were added to 8 mL of N,N dimethylformamide solution and sonicated for 20 minutes to dissolve the solid powder. Then 2 mL of glacial acetic acid and the treated nickel foam were added to the above solution and sonicated for 5 minutes. The solution was then heated in an oven at 160 °C for 12 hours. After the reaction was completed, the solution was washed alternately with water and ethanol solution and dried to obtain the high-entropy nanoarray catalyst.

[0059] First, the morphology and structure of the prepared high-entropy nanoarray were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM images confirmed that the sample consisted of a nanosheet array. TEM images further revealed that the high-entropy nanoarray was composed of ultrathin two-dimensional nanosheets. X-ray diffraction patterns further showed a typical single-phase face-centered cubic structure, indicating the formation of a high-entropy alloy. SEM energy dispersive spectroscopy demonstrated the uniform distribution of Pd, Pt, Cu, Ni, and Ag elements within the high-entropy nanoarray. Next, the cathodic electrocatalytic nitrate reduction and anodic electrocatalytic oxidation of PET degradation solution, as well as the performance of the coupled system, were investigated. Linear scanning voltammetry (SVC) curves for nitrate reduction under alkaline conditions showed that the high-entropy nanoarray exhibited a higher current density in the electrolyte containing potassium nitrate, indicating high catalytic activity for nitrate reduction. In an electrolyte containing 1M potassium hydroxide and 0.1M potassium nitrate, the high-entropy nanoarray achieved an ammonia yield of 0.60 mmol / h at a low voltage (-0.15V vs. Hg / HgO). -1 cm -2 The Faraday efficiency for ammonia reached 96.3%, indicating that the high-entropy nanoarray possesses superior activity in the reduction of nitrate to ammonia. Next, linear sweep voltammetry of the PET degradation solution under alkaline conditions revealed that the high-entropy nanoarray exhibited a higher current density in the PET degradation solution, indicating that it also possesses high catalytic activity for the oxidation of PET degradation solution. The high-entropy nanoarray achieved a glycolic acid yield of 1.7 mmol / h under low voltage (0.8 V vs. Hg / HgO). -1 cm -2The Faraday efficiency for glycolic acid reached 98.2%, indicating that the high-entropy nanoarray also possesses superior activity in the oxidation of glycolic acid from PET degradation solution. Therefore, we tested the electrochemical performance of the high-entropy nanoarray in a novel coupled system consisting of cathode nitrate reduction and anolyte oxidation from PET degradation solution. Linear sweep voltammetry curves showed that, compared to conventional water electrolysis, the high-entropy nanoarray required only a lower voltage to achieve the same current density in the novel coupled system. In the novel coupled system, the high-entropy nanoarray exhibited excellent cathode nitrate reduction for ammonia synthesis (98.1%; 0.7 mmol / L h⁻¹) at 1 V. -1 cm -2 The efficiency and yield of synthesizing glycolic acid from anolyte PET degradation solution were 98.5% (1.5 mmol / h). -1 cm -2 Long-term stability tests were conducted on the high-entropy nanoarray. After 100 hours, the Faraday efficiency and yield of its cathode and anode remained essentially unchanged, indicating that the high-entropy nanoarray has good stability in the novel coupling system.

Claims

1. A high-entropy nanoarray for electrocatalytic nitrate reduction coupled with waste plastic conversion, prepared by the following method: (1) Immerse 1~2 cm × 1~2 cm nickel foam in hydrochloric acid solution to remove surface oxide layer and oil stains, rinse three times with deionized water / ethanol, and dry for subsequent use; (2) Pour 10-20 mg sodium chloropalladium, 5-10 mg platinum acetylacetonate, 5-10 mg nickel chloride hexahydrate, 1-3 mg copper chloride dihydrate, 1-3 mg silver trifluoroacetate and 10-20 mg tungsten hexacarbonyl into 4-8 mL of N,N dimethylformamide solution and sonicate for 10-20 minutes to dissolve the solid powder. Then add 1-2 mL of glacial acetic acid and the treated nickel foam to the above solution and sonicate for 3-5 minutes. Then heat in an oven at 120-160 °C for 4-12 hours. After the reaction is complete, wash with water and ethanol solution alternately and dry to obtain the high-entropy nanoarray catalyst.

2. A method for preparing a high-entropy nanoarray for electrocatalytic nitrate reduction coupled with waste plastic conversion as described in claim 1, characterized in that, The method consists of the following steps: (1) Immerse 1~2 cm × 1~2 cm nickel foam in hydrochloric acid solution to remove surface oxide layer and oil stains, rinse three times with deionized water / ethanol, and dry for subsequent use; (2) Pour 10-20 mg sodium chloropalladium, 5-10 mg platinum acetylacetonate, 5-10 mg nickel chloride hexahydrate, 1-3 mg copper chloride dihydrate, 1-3 mg silver trifluoroacetate and 10-20 mg tungsten hexacarbonyl into 4-8 mL of N,N dimethylformamide solution and sonicate for 10-20 minutes to dissolve the solid powder. Then add 1-2 mL of glacial acetic acid and the treated nickel foam to the above solution and sonicate for 3-5 minutes. Then heat in an oven at 120-160 °C for 4-12 hours. After the reaction is complete, wash with water and ethanol solution alternately and dry to obtain the high-entropy nanoarray catalyst.

3. The method as described in claim 2, characterized in that, The morphology and crystal structure of the high-entropy nanoarray electrocatalyst were controlled by adjusting the mass of sodium chloropalladate, platinum acetylacetonate, nickel chloride hexahydrate, copper chloride dihydrate, silver trifluoroacetate and tungsten hexacarbonyl, the volume of N,N dimethylformamide and glacial acetic acid, as well as the reaction temperature and time.

Images