Electrode materials, electrolysis devices and their applications

Abstract

This invention discloses an electrode material, an electrolysis device, and their applications. The electrode material comprises a substrate and bismuth nanosheets grown in situ on the substrate. The electrode material is prepared by pretreatment of a metal substrate, bismuth loading via immersion, calcination, electrochemical reduction, and electrochemical reconstruction. Furthermore, this electrode material possesses advantages such as strong controllability in preparation, high activity and selectivity for carbon dioxide reduction, good stability, and the ability to be connected with other electrodes to produce high-value-added products. Simultaneously, this invention also discloses a coupling method for carbon dioxide reduction and HMF oxidation. This method uses a conductive substrate material supported on nickel cobalt oxide as the anode and a metal substrate with bismuth nanosheets grown in situ as the cathode, assembling an electrolysis reaction system for electrolysis. This allows for the selective oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid at the anode and the selective reduction of carbon dioxide to formic acid at the cathode.

Description

Technical Field

[0001] This invention relates to the technical fields of electrodes, electrolysis, and resource recycling, specifically to an electrode material, an electrolysis device, and their applications. Background Technology

[0002] Powered by renewable energy sources (such as wind and solar power), the electrochemical conversion of CO2 into value-added chemicals and fuels holds great promise for applications. To improve the reactivity and energy conversion efficiency of electrocatalytic CO2 reduction, noble or transition metal nanoparticles are typically used as the catalytic active component, supported on a carrier with a large specific surface area using binders. However, these catalysts suffer from drawbacks such as binder loss of active sites, poor nanoparticle structural stability, and poor selectivity. Clearly, currently developed electrocatalytic CO2 reduction catalysts and complete electrolysis systems are limited by low catalytic performance, poor structural stability, and low energy conversion efficiency, preventing them from operating on an industrial scale.

[0003] 2,5-Furandicarboxylic acid (FDCA), the oxidation product of 5-hydroxymethylfurfural (HMF), is a raw material for the preparation of the biopolymer polyethylene furanoisocarboxylate (PEF), thus 2,5-furandicarboxylic acid is considered one of the most valuable chemicals. However, its current production mainly relies on catalytic oxidation processes, which suffer from low resource and energy utilization rates. To ensure that the production and conversion processes of this high-value chemical product meet the higher requirements of green and economical chemistry, it is necessary to seek a green, environmentally friendly, economical, and resource-efficient process for producing 2,5-furandicarboxylic acid.

[0004] Therefore, this invention not only urgently needs to develop an electrode material that is highly controllable, highly active, selective, and stable, and suitable for catalyzing CO2 reduction reactions, but also needs to develop a device and method that can comprehensively utilize carbon dioxide, 5-hydroxymethylfurfural, and electrical energy. Summary of the Invention

[0005] In order to overcome the problems existing in the prior art, the purpose of this invention is to provide an electrode material, an electrolysis device and its application.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides an electrode material comprising a substrate and bismuth nanosheets grown in situ on the substrate.

[0008] Preferably, the substrate is selected from at least one of nickel foam, copper foam, nickel sheet, and copper sheet.

[0009] Preferably, the diameter of the bismuth nanosheets is 200–600 nm.

[0010] More preferably, the diameter of the bismuth nanosheets is 300–500 nm.

[0011] Preferably, the thickness of the bismuth nanosheets is 1–3 nm.

[0012] In a second aspect, the present invention provides a method for preparing the electrode material described in the first aspect, comprising the following steps:

[0013] 1) After pretreating the substrate, it is then immersed in an acidic bismuth salt solution to obtain a bismuth-loaded substrate;

[0014] 2) The bismuth-loaded substrate described in step 1) is calcined under an oxidizing atmosphere to obtain a bismuth oxide-loaded substrate;

[0015] 3) The bismuth oxide-loaded substrate described in step 2) is subjected to electrochemical reduction and electrochemical reconstruction to obtain the electrode material described in the first aspect.

[0016] Preferably, the substrate in step 1) is selected from at least one of nickel foam, copper foam, nickel sheet, and copper sheet.

[0017] Preferably, the pretreatment in step 1) includes: cutting the substrate, degreasing with an organic solvent, removing the oxide layer with an acid pickling solution, and obtaining pretreated foamed copper.

[0018] Preferably, the specific operation of removing the oxide layer with pickling solution is as follows: immerse the substrate in pickling solution and sonicate for 20-40 minutes.

[0019] Preferably, the organic solvent is selected from at least one of acetone, acetonitrile, ethanol, methanol, ethylene glycol, and glycerol.

[0020] Preferably, the acid is selected from at least one of hydrochloric acid, nitric acid, and sulfuric acid.

[0021] Preferably, the concentration of acid in the pickling solution is 0.1 to 3 mol / L.

[0022] Preferably, the method for preparing the acidic bismuth salt solution in step 1) is as follows:

[0023] A soluble bismuth salt, acid, water, and organic solvent are mixed to prepare an acidic bismuth salt solution.

[0024] Preferably, the concentration of soluble bismuth salt in the acidic bismuth salt solution is 0.01–0.5 mol / L, and the concentration of acid in the acidic bismuth salt solution is 0.1–3 mol / L, based on the final concentration.

[0025] Preferably, the soluble bismuth salt is selected from at least one of bismuth nitrate and bismuth nitrate hydrate.

[0026] Preferably, the acid is selected from at least one of hydrochloric acid, nitric acid, and sulfuric acid.

[0027] Preferably, the organic solvent is selected from at least one of acetone, acetonitrile, ethanol, methanol, ethylene glycol, and glycerol.

[0028] Preferably, in step 1), the diameter of the bismuth nanosheets on the bismuth-loaded substrate is 100–300 nm.

[0029] Preferably, in step 1), the thickness of the bismuth nanosheets on the bismuth-loaded substrate is 8–10 nm.

[0030] Preferably, the soaking time in step 1) is 10 to 30 seconds.

[0031] Preferably, the soaking temperature in step 1) is 20-25°C.

[0032] Preferably, the oxidizing atmosphere in step 2) is selected from oxygen or air.

[0033] Preferably, the calcination time in step 2) is 10 to 16 hours.

[0034] More preferably, the calcination time in step 2) is 12 hours.

[0035] Preferably, the calcination temperature in step 2) is 180℃~230℃.

[0036] Preferably, the heating rate for calcination in step 2) is 1–3 °C / min. –1 .

[0037] Preferably, the electrochemical reduction and electrochemical reconstruction process described in step 3) includes the following steps:

[0038] S1: Using the bismuth oxide-loaded substrate described in step 2) as the working electrode, the Ag / AgCl electrode as the reference electrode, and the Pt electrode 1 as the counter electrode, an electrolysis system is constructed with electrolyte. Electrolysis is performed for 3 to 5 hours at a potential of -1.50V vs. Ag / AgCl to -1.20V vs. Ag / AgCl to reduce the bismuth oxide on the bismuth oxide-loaded substrate to metallic bismuth.

[0039] S2: Replace with a new electrolyte and electrolyze for 0.5 to 1.5 hours at a potential of -1.55V vs. Ag / AgCl to -1.65V vs. Ag / AgCl to reconstruct bismuth nanosheets on the substrate to obtain the electrode material;

[0040] In S1 and S2, the electrolyte is selected from at least one of CO2-saturated KHCO3 solution, K2CO3 solution, NaHCO3 solution, and Na2CO3 solution, and the solute concentration in the electrolyte is 0.1–1.0 mol / L. Specifically, the solute refers to at least one of KHCO3, K2CO3 solution, NaHCO3, and Na2CO3.

[0041] Preferably, in S1, an electrolysis system is constructed, first electrolyzing at a potential of –1.50V vs. Ag / AgCl to –1.40V vs. Ag / AgCl for 0.2 to 1 hour, and then electrolyzing at a potential of –1.50V vs. Ag / AgCl to –1.40V vs. Ag / AgCl for 3 to 5 hours, to reduce bismuth oxide on the bismuth oxide-supported substrate to metallic bismuth.

[0042] Thirdly, the present invention provides a coupling method for carbon dioxide reduction and 5-hydroxymethylfurfural oxidation, comprising the following steps:

[0043] Using the electrode material described in the first or second aspect as the cathode, a conductive substrate material loaded with NiCo2O4 as the anode, a 5-hydroxymethylfurfural solution as the anolyte, and a carbon dioxide-saturated carbonate solution as the cathode electrolyte, an electrolytic reaction system is assembled for electrolysis, in which 5-hydroxymethylfurfural is oxidized to 2,5-furandicarboxylic acid at the anode, and carbon dioxide is reduced to formic acid at the cathode.

[0044] Preferably, the coupling method of carbon dioxide reduction and 5-hydroxymethylfurfural oxidation further includes: separating the anolyte and the catholyte with a proton exchange membrane; and during the electrolysis process, introducing carbon dioxide into the catholyte to provide a reaction gas for the cathode.

[0045] Preferably, the electrolysis is performed using a constant voltage method, and the voltage is 1.5 to 4V.

[0046] More preferably, the electrolysis is performed using a constant voltage method, and the voltage is 1.5 to 3V.

[0047] Preferably, during the electrolysis process, the flow rate of carbon dioxide introduced into the cathode chamber is 15-30 mL / min.

[0048] Preferably, the method for preparing the conductive substrate material loaded with NiCo2O4 includes the following steps:

[0049] 1) Dissolve soluble nickel salt, soluble cobalt salt and urea in water to obtain a nickel-cobalt precursor solution;

[0050] 2) The pretreated conductive substrate is immersed in a nickel-cobalt precursor solution, and after hydrothermal reaction and annealing, a conductive substrate material loaded with NiCo2O4 is obtained.

[0051] Specifically, the synergistic effect of the self-supporting electrode substrate and the bimetallic base material can not only further improve the conductivity of the catalyst material, but also expose more active sites on the catalyst, thereby significantly improving its catalytic performance.

[0052] Preferably, the soluble nickel salt in step 1) is one or more of nickel nitrate, nickel nitrate hydrate, nickel chloride, and nickel sulfate.

[0053] Preferably, the soluble cobalt salt in step 1) is one or more of cobalt nitrate and cobalt nitrate hydrate.

[0054] Preferably, the molar ratio of the soluble nickel salt, soluble cobalt salt and urea in step 1) is 1:(1-3):(4-6).

[0055] Preferably, the pretreatment of the conductive substrate after pretreatment in step 2) includes: degreasing, descaling, water washing and alcohol washing.

[0056] Preferably, the temperature of the hydrothermal reaction in step 2) is 110–140°C.

[0057] Preferably, the hydrothermal reaction time in step 2) is 4 to 8 hours.

[0058] Preferably, the annealing in step 2) is carried out in an air atmosphere or an oxygen atmosphere.

[0059] Preferably, the heating rate for annealing in step 2) is 1–3 °C / min. –1 .

[0060] Preferably, the annealing temperature in step 2) is 280–350°C, and the annealing time is 1–5 hours.

[0061] Preferably, the cathode and the anode are immersed in cathode electrolyte and anolyte, respectively. Preferably, the effective area of ​​the cathode to the volume of the cathode electrolyte is (1-5) cm². 2 (10-20) mL. Preferably, the effective area of ​​the anode to the volume ratio of the anolyte is (1-5) cm². 2 : (10~20)mL.

[0062] Preferably, the ratio of the effective area of ​​the cathode to that of the anode is 1:(0.8 to 1.2).

[0063] Preferably, the conductive substrate in the NiCo2O4-loaded conductive substrate material is one or more of carbon cloth, carbon rod, nickel foam, copper foam, copper sheet, and nickel sheet.

[0064] Preferably, the carbon dioxide-saturated carbonate solution is selected from at least one of CO2-saturated KHCO3 solution, K2CO3 solution, NaHCO3 solution, and Na2CO3 solution, and the solute concentration in the electrolyte is 0.1 to 1.0 mol / L.

[0065] Preferably, the concentration of 5-hydroxymethylfurfural in the 5-hydroxymethylfurfural solution is 5–20 mmol / L.

[0066] Preferably, the 5-hydroxymethylfurfural solution further includes 0.5 to 3 mol / L of an alkali, wherein the alkali is selected from at least one of sodium hydroxide and potassium hydroxide.

[0067] More preferably, the 5-hydroxymethylfurfural solution is composed of 5-hydroxymethylfurfural and the base.

[0068] Fourthly, the present invention provides the application of the method described in the third aspect in the production of 2,5-furandicarboxylic acid or the comprehensive utilization of carbon dioxide.

[0069] Fifthly, the present invention provides an electrolysis apparatus comprising the electrode material described in the first aspect or the electrode material obtained in the second aspect.

[0070] Preferably, the electrolysis device includes: a cathode, an anode, a container, a diaphragm, wires, a power supply, and a vent.

[0071] The cathode is the electrode material described in the first or second aspect, the anode is a conductive substrate material loaded with NiCo2O4, the anode electrolyte is a 5-hydroxymethylfurfural solution, and the cathode electrolyte is a carbon dioxide-saturated carbonate solution.

[0072] The diaphragm divides the container into a cathode chamber and an anode chamber; the cathode, power source, and anode are connected in sequence by wires.

[0073] Preferably, the vent is located in the cathode chamber and is used to supply carbon dioxide feed gas to the electrolysis device.

[0074] Preferably, the cathode and the anode are immersed in cathode electrolyte and anolyte, respectively, and the effective area of ​​the cathode and the anode is 1-5 cm². 2 .

[0075] Preferably, the conductive substrate in the NiCo2O4-loaded conductive substrate material is one or more of carbon cloth, carbon rod, nickel foam, copper foam, copper sheet, and nickel sheet.

[0076] Preferably, the carbon dioxide-saturated carbonate solution is selected from at least one of CO2-saturated KHCO3 solution, K2CO3 solution, NaHCO3 solution, and Na2CO3 solution, and the solute concentration in the electrolyte is 0.1 to 1.0 mol / L.

[0077] Preferably, the concentration of 5-hydroxymethylfurfural in the 5-hydroxymethylfurfural solution is 5–20 mmol / L.

[0078] Preferably, the 5-hydroxymethylfurfural solution further includes 0.5 to 3 mol / L of an alkali, wherein the alkali is selected from at least one of sodium hydroxide and potassium hydroxide.

[0079] More preferably, the 5-hydroxymethylfurfural solution is composed of 5-hydroxymethylfurfural and the base.

[0080] Preferably, the power source is either a DC power source or an AC power source.

[0081] Preferably, the power supply is a power supply capable of providing a voltage of 1.1V to 5V.

[0082] More preferably, the power source is a power source capable of providing a voltage of 1.5V to 4V.

[0083] Preferably, the method for preparing the conductive substrate material loaded with NiCo2O4 includes the following steps:

[0084] 1) Dissolve soluble nickel salt, soluble cobalt salt and urea in water to obtain a nickel-cobalt precursor solution;

[0085] 2) The pretreated conductive substrate is immersed in a nickel-cobalt precursor solution, and after hydrothermal reaction and annealing, a conductive substrate material loaded with NiCo2O4 is obtained.

[0086] Specifically, the synergistic effect of the self-supporting electrode substrate and the bimetallic base material can not only further improve the conductivity of the catalyst material, but also expose more active sites on the catalyst, thereby significantly improving its catalytic performance.

[0087] Preferably, the soluble nickel salt in step 1) is one or more of nickel nitrate, nickel nitrate hydrate, nickel chloride, and nickel sulfate.

[0088] Preferably, the soluble cobalt salt in step 1) is one or more of cobalt nitrate and cobalt nitrate hydrate.

[0089] Preferably, the molar ratio of the soluble nickel salt, soluble cobalt salt and urea in step 1) is 1:(1-3):(4-6).

[0090] Preferably, the pretreatment of the conductive substrate after pretreatment in step 2) includes: degreasing, descaling, water washing and alcohol washing.

[0091] Preferably, the temperature of the hydrothermal reaction in step 2) is 110–140°C. Preferably, the time of the hydrothermal reaction in step 2) is 4–8 hours.

[0092] Preferably, the annealing in step 2) is carried out in an air atmosphere or an oxygen atmosphere.

[0093] Preferably, the heating rate for annealing in step 2) is 1–3 °C / min. –1 .

[0094] Preferably, the annealing temperature in step 2) is 280–350°C, and the annealing time is 1–5 hours.

[0095] Preferably, the membrane is a proton exchange membrane. More preferably, the membrane is a Nafion 117 type proton exchange membrane.

[0096] Preferably, the volume of the cathode electrolyte does not exceed two-thirds of the cathode chamber.

[0097] Preferably, the volume of the anolyte does not exceed two-thirds of the anode chamber.

[0098] The beneficial effects of this invention are as follows: The electrode material of this invention comprises a substrate and bismuth nanosheets grown in situ on the substrate. This electrode material is prepared by pretreatment of a metallic substrate, bismuth loading via a soaking method, calcination, electrochemical reduction, and electrochemical reconstruction. Furthermore, this electrode material possesses advantages such as strong controllability in preparation, high activity for carbon dioxide reduction, good selectivity, good stability, and the ability to be connected with other electrodes to produce high-value-added products. Specifically:

[0099] (1) The electrode materials of the present invention do not require adhesives, are environmentally friendly, have stable structures, and are highly controllable in preparation, making them suitable for large-scale preparation and practical applications.

[0100] (2) For the anodic HMF oxidation reaction, this invention prepares an urchin-like NiCo2O4 catalyst (NiCo2O4@NF) grown in situ on the surface of nickel foam, which can efficiently oxidize HMF to FDCA. For the cathode CO2 reduction reaction, this invention prepares a Bi-based catalyst with high selectivity and activity for formate, and the nanosheets on the Bi catalyst have good structural stability, making it suitable for electrocatalytic CO2 reduction.

[0101] (3) The coupling method of HMF oxidation and carbon dioxide reduction of the present invention uses NiCo spinel oxide catalyst (NiCo2O4@NF) grown in situ on nickel foam as the anode and the electrode material of the present invention (i.e. Bi NSs@CF electrode) as the cathode to assemble an electrolytic reaction system for electrolysis. At the anode, 5-hydroxymethylfurfural is selectively oxidized to 2,5-furandicarboxylic acid, and at the cathode, carbon dioxide is selectively reduced to formic acid. The anode electrolyte is an alkaline solution containing 10 mM HMF, the cathode electrolyte is a carbon dioxide-saturated bicarbonate solution, and an ion exchange membrane is provided between the anode electrolyte and the cathode electrolyte in the electrolytic reaction system.

[0102] (4) The electrolysis device and coupling method of the present invention can realize the comprehensive utilization of CO2, HMF and electrical energy, improve the comprehensive utilization rate of resources (including raw materials and energy), and produce 2,5-furandicarboxylic acid products with high added value under the condition of low reactant concentration.

[0103] (5) The electrolysis apparatus or coupling method of the present invention can achieve high Faraday efficiency and yield of the target product at both the cathode and anode under the condition of lower cell voltage. Attached Figure Description

[0104] Figure 1 This is a schematic diagram of the electrolytic device for CO2 reduction and HMF oxidation coupling in this invention.

[0105] Figure 2 The images show the XRD patterns of NiCo2O4@NF in Example 1 and Co3O4@NF in Comparative Example 1.

[0106] Figure 3 This is a SEM image of NiCo2O4@NF from Example 1.

[0107] Figure 4 The image shows the SEM image of Co3O4@NF in Comparative Example 1.

[0108] Figure 5 The LSV curves are for NiCo2O4@NF in Example 1 and Co3O4@NF in Comparative Example 1.

[0109] Figure 6 This is a comparison graph showing the FDCA yield and FDCA Faraday efficiency of NiCo2O4@NF in Example 1 and Co3O4@NF in Comparative Example 1 under different voltages.

[0110] Figure 7 The image shows the XRD pattern of Bi NSs@CF in Example 2.

[0111] Figure 8This is a SEM image of Bi@CF in Example 2.

[0112] Figure 9 The images show the SEM and HRTEM images of Bi NSs@CF in Example 2.

[0113] Figure 10 The LSV curves of Bi NSs@CF and Bi@CF in Example 2 are shown.

[0114] Figure 11 The diagram shows the Faraday efficiency of the formate of Bi NSs@CF and Bi@CF in Example 2.

[0115] Figure 12 The image shows the LSV curve of the NiCo2O4@NF||Bi NSs@CF two-electrode catalytic system in Example 3.

[0116] Figure 13 HCOO in the NiCo2O4@NF||Bi NSs@CF two-electrode catalytic system of Example 3 – The test results of Faraday efficiency, Faraday efficiency of FDCA, and yield of FDCA are shown in the figure. Detailed Implementation

[0117] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the "effective area" in the present invention refers to the macroscopic contact area between the electrode material and the electrolyte.

[0118] Example 1

[0119] This embodiment provides a method for preparing an anode material (NiCo2O4@NF), including the following steps:

[0120] (1) Pretreatment of nickel foam: First, a 2×3cm piece of nickel foam was prepared. 2 The foamed nickel was washed with acetone to remove the oil stains on the surface of the foamed nickel, and the degreased foamed nickel was obtained.

[0121] Then, the degreased nickel foam was transferred to a 1.0M HCl solution, sonicated for 30 minutes, and then rinsed with water and ethanol to obtain pretreated nickel foam.

[0122] (2) Preparation of sea urchin-like NiCo2O4@NF: 1.0 mmol Ni(NO3)2·6H2O, 2.0 mmol Co(NO3)2·6H2O and 5.0 mmol urea were dissolved in 35 ml of ultrapure water and stirred for 20 min to obtain a nickel-cobalt precursor solution.

[0123] The nickel-cobalt precursor solution was transferred to a high-pressure reactor with a capacity of 50 mL. The treated nickel foam was then placed into the high-pressure reactor and ensured to be immersed in the nickel-cobalt precursor solution.

[0124] The reactor was placed in an oven and set at 393K (approximately 120℃) for 6 hours. After it cooled naturally to room temperature, the precipitate was washed several times with distilled water and ethanol to remove the residual metal salts on the surface of the nickel foam.

[0125] After drying the precipitate at 333K (approximately 60℃) for 12 hours, it was then dried in air at 2K for 1 minute. –1 (2℃min –1 The heating rate was increased to 573K (about 300℃), and annealing was carried out for 3 hours to obtain the anode material (denoted as NiCo2O4@NF, morphology: sea urchin-like).

[0126] Comparative Example 1

[0127] This embodiment provides a method for preparing an anode material (Co3O4@NF), including the following steps:

[0128] (1) Pretreatment of nickel foam: First, a 2×3cm piece of nickel foam was prepared. 2 The foamed nickel was washed with acetone to remove the oil stains on the surface of the foamed nickel, and the degreased foamed nickel was obtained.

[0129] Then, the degreased nickel foam was transferred to a 1.0M HCl solution, sonicated for 30 minutes, and then rinsed with water and ethanol to obtain pretreated nickel foam.

[0130] (2) Preparation of Co3O4@NF: 3.0 mmol Co(NO3)2·6H2O and 5.0 mmol urea were dissolved in 35 ml of ultrapure water and stirred for 20 min to obtain a nickel-cobalt precursor solution;

[0131] The nickel-cobalt precursor solution was transferred to a high-pressure reactor with a capacity of 50 mL. The treated nickel foam was then placed into the high-pressure reactor and ensured to be immersed in the nickel-cobalt precursor solution.

[0132] The reactor was placed in an oven and set at 393K (approximately 120℃) for 6 hours. After it cooled naturally to room temperature, the precipitate was washed several times with distilled water and ethanol to remove the residual metal salts on the surface of the nickel foam.

[0133] After drying the precipitate at 333K (approximately 60℃) for 12 hours, it was then dried in air at 2K for 1 minute. –1 (2℃min –1The heating rate was increased to 573K (approximately 300℃), and annealing was carried out for 3 hours to obtain the anode material (denoted as Co3O4@NF).

[0134] Characterization and performance testing of anode materials:

[0135] 1. X-ray diffraction (XRD) patterns of NiCo2O4@NF in Example 1 and Co3O4@NF in Comparative Example 1, as shown below. Figure 2 As shown.

[0136] Depend on Figure 2 As can be seen from the figure, the prepared NiCo2O4@NF exhibits XRD diffraction peaks at 2θ = 31.1°, 36.7°, 44.6°, 59.1°, and 65.0°, while the prepared Co3O4@NF electrode exhibits obvious XRD diffraction peaks at 2θ = 31.3°, 36.9°, 44.8°, 59.4°, and 65.2°, corresponding to NiCo2O4 (PDF#20-0781) and Co3O4 (PDF#42-1467), respectively. This indicates that Example 1 and Comparative Example 1 successfully in-situ loaded NiCo2O4 and Co3O4 onto nickel foam material via hydrothermal method.

[0137] 2. Scanning Electron Microscope (SEM) image of NiCo2O4@NF in Example 1, as shown below. Figure 3 As shown. The SEM image of Co3O4@NF in Comparative Example 1 is shown below. Figure 4 As shown.

[0138] Depend on Figure 3 and Figure 4 As can be seen from the SEM image of NiCo2O4@NF, in Example 1, through hydrothermal reaction and high-temperature calcination, the surface of the nickel foam is covered with a dense nano-sea urchin structure, and the nano-sea urchin structure is mainly composed of petal-like, relatively uniformly sized nanofibers. This indicates that Example 1 successfully prepared a NiCo2O4@NF electrode material with a three-dimensional nano-sea urchin structure.

[0139] Through further amplification and analysis, the sea urchin-structured NiCo2O4@NF electrode material of Example 1 was found to be assembled from NiCo2O4 nanoneedles with diameters of approximately 50 nm and lengths of approximately 960 nm. Furthermore, Example 1 involved the epitaxial growth of a large number of NiCo2O4 nanoneedles from the center outwards on a nickel foam surface to form a sea urchin-like structure. This unique structure gives NiCo2O4 a larger specific surface area, which is beneficial for exposing more active sites and thus improving catalyst activity.

[0140] From the SEM image of the Co3O4@NF electrode, it can be observed that the Co3O4 grown in situ on nickel foam in Comparative Example 1 is a mixture of large-diameter nanosheets and nanoneedles, and the arrangement of these nanostructures is disordered. 3.

[0142] Test samples: NiCo2O4@NF from Example 1 and Co3O4@NF from Comparative Example 1

[0143] The electrocatalytic HMF oxidation test method using a single electrode (anode) is as follows:

[0144] All electrochemical tests in this experiment were conducted using a CHI 760e electrochemical workstation under ambient temperature (20–25°C) and normal pressure (100–102 kPa).

[0145] (1) The H-type electrolytic cell was divided into two parts using an anion exchange membrane (FAA-PK-130); both the cathode and anode chambers were filled with 16 mL of 1.0 M KOH solution, with an effective area of ​​1 × 1 cm. 2 The test sample was directly used as the working electrode, Pt sheet electrode (1×1cm) 2 A three-electrode system was constructed by using an Ag / AgCl electrode (3M saturated KCl solution) as the counter electrode and an Ag / AgCl electrode as the reference electrode.

[0146] (2) Testing of Faraday efficiency and yield of FDCA: During the electrochemical HMF oxidation test, a certain amount of HMF was added to the anolyte to make the initial HMF concentration of the anolyte 10mM, and the performance of electrochemical HMF oxidation was tested under different constant voltage modes.

[0147] Meanwhile, HMF and its products were quantitatively analyzed using a Shimadzu high-performance liquid chromatograph (HPLC) equipped with a detector of λ = 265 nm and a C18 column. The HPLC mobile phase settings were as follows: 5 mM ammonium formate aqueous solution and methanol, with a volume ratio of 7:3, and a flow rate of 0.5 mL / min. –1 The column temperature was 40℃; quantitative and qualitative analyses were performed using external standard calibration curves based on pure components of known concentrations.

[0148] Through testing and analysis, the measured FDCA yield and FDCA Faraday efficiency are as follows: Figure 6 As shown.

[0149] LSV curve testing: Using either a 1.0M KOH solution without HMF (denoted as OER) or a 1.0M KOH solution containing 10mM HMF (5-hydroxymethylfurfural) (denoted as HMFOER) as the anolyte, the LSV curves of NiCo2O4@NF and Co3O4@NF under different conditions were obtained by using the three-electrode system in (1) at 1.0V to 1.6V and a scan rate of 5mV / s. The results are as follows. Figure 5 As shown.

[0150] Test results:

[0151] LSV curves of NiCo2O4@NF and Co3O4@NF, as shown Figure 5 As shown.

[0152] Depend on Figure 5 It can be seen that: From Figure 5 It can be clearly observed that without the addition of HMF, the catalyst activity is low, and the onset potential of the OER reaction is greater than 1.45V. Compared with the OER group, after adding HMF, the potential of the same test sample (catalyst) at the same current density decreased significantly. Moreover, the test results show that under the test conditions of HMFOR, the electro-oxidation activity of NiCo2O4@NF is higher than that of Co3O4@NF.

[0153] A comparison of FDCA yield and FDCA Faraday efficiency of NiCo2O4@NF and Co3O4@NF at different voltages, as shown in the figure. Figure 6 As shown in the figure, the bar chart represents the change in FDCA Faraday efficiency under different voltages, and the curve chart represents the change in FDCA yield under different voltages.

[0154] Depend on Figure 6 It can be known that: Figure 6 The changes in Faraday efficiency and yield of FDCA during HMFOR of NiCo2O4@NF and Co3O4@NF in the range of 1.25 to 1.50 V vs. RHE were recorded.

[0155] Within a potential range of 1.30V to 1.35V, NiCo2O4@NF exhibits FDCA Faradaic efficiency and yield both exceeding 90%. At 1.35V, both FDCA Faradaic efficiency and yield reach 97.3%, while Co3O4@NF achieves the highest FDCA Faradaic efficiency and yield at 1.40V, at 94.8% and 87.8%, respectively.

[0156] However, as the potential gradually increases, the competing effect of the oxygen evolution reaction (OER) of water becomes more pronounced. The FDCA Faraday efficiency and yield of NiCo2O4@NF gradually decrease; at 1.50V, the FDCA Faraday efficiency is less than 70%, and the FDCA yield is less than 80%.

[0157] These results clearly demonstrate that 1.35 V is the optimal potential for NiCo2O4@NF catalytic oxidation of HMF.

[0158] Example 2

[0159] This embodiment provides a method for preparing a cathode material (Bi NSs@CF), including the following steps:

[0160] (1) Pretreatment of copper foam: First, take a 1×3cm piece of copper foam... 2 The foamed copper was washed with acetone to remove the oil stains on the surface of the foamed copper, and the degreased foamed copper was obtained.

[0161] Then, the degreased copper foam was transferred to a 1.0M HCl solution, sonicated for 30 minutes, and then rinsed with water and ethanol to obtain pretreated copper foam.

[0162] (2) Preparation of Bi@CF: The pretreated copper foam was immersed in a bismuth salt solution containing 0.1M Bi(NO3)3 and 1.0M HNO3 (the solvent consisted of water and acetonitrile in a volume ratio of 1:1). The color of the copper foam immediately changed from reddish-brown to light gray. After immersion for 20 seconds, the copper foam was removed from the solution, rinsed with water and ethanol, and dried with nitrogen to obtain bismuth-loaded copper foam (denoted as Bi@CF).

[0163] (3) Preparation of Bi2O3@CF: Bi@CF was placed in a tube furnace and heated at 2K min. –1 (2℃min –1 The heating rate was increased to 473K (approximately 200℃), and calcination was controlled in an air atmosphere for 12 hours. After natural cooling to room temperature, copper foam loaded with bismuth oxide (denoted as Bi2O3@CF, color: yellow) was obtained.

[0164] (4) Preparation of Bi NSs@CF: Bi NSs@CF is prepared by electrochemical reduction and in-situ reconstruction of Bi2O3@CF.

[0165] Using Bi2O3@CF as the working electrode, Ag / AgCl as the reference electrode, and Pt sheet as the counter electrode, in a CO2-saturated 0.5M KHCO3 solution, electrolysis was first performed at a potential of –1.45V vs. Ag / AgCl for 0.5 hours, and then at a potential of –1.25V vs. Ag / AgCl for 4 hours to initially reduce Bi2O3@CF to Bi.

[0166] Subsequently, a new electrolyte (i.e., a 0.5M KHCO3 solution) was replaced, and CO2 was introduced until saturation. Then, electrolysis was carried out for another hour at a potential of –1.6V vs. Ag / AgCl to obtain the cathode material (denoted as Bi NSs@CF).

[0167] Through testing and analysis, the cathode material was determined to be Bi NSs@CF with a stable nanosheet structure.

[0168] Characterization and performance testing of cathode materials:

[0169] 1. The XRD pattern of Bi NSs@CF in Example 2, as shown below. Figure 7 As shown.

[0170] Depend on Figure 7 It can be seen that the XRD spectrum of Bi NSs@CF in Example 2 shows diffraction peaks at 2θ = 27.3°, 38.1°, 39.7°, 48.9° and 56.3°, which are consistent with the (012), (104), (110), (202) and (024) crystal planes in the Bi standard card PDF#85-1331, proving that the substance on the copper foam is metallic Bi.

[0171] 2. SEM image of Bi@CF in Example 2, as shown Figure 8 As shown. The SEM image and high-resolution transmission electron microscope (HRTEM) image of Bi NSs@CF in Example 2 are shown below. Figure 9 As shown in (a) and (b) in the figure.

[0172] Depend on Figure 8 and Figure 9 It can be known that: Figure 8SEM images of Bi@CF are shown, revealing irregularly shaped Bi nanosheets tightly grown on the copper foam surface. The Bi nanosheets in Bi@CF have a diameter of approximately 100–300 nm and a thickness of approximately 8–10 nm. Although the initially reduced Bi@CF already possesses a nanosheet structure, the Bi on the initially reduced Bi@CF undergoes in-situ reconstruction during the electrocatalytic CO2 reduction process, resulting in poor structural stability and hindering practical applications.

[0173] To prepare a Bi-based catalyst (Bi NSs@CF) with a stable nanosheet structure, the preparation process of Bi NSs@CF in this invention requires first oxidizing Bi@CF to Bi2O3@CF, and then reducing it to Bi NSs@CF with a nanosheet structure under electrochemical reduction conditions. After the initial electrochemical reduction, it is necessary to replace the CO2-saturated KHCO3 with Bi NSs@CF and electrolyze it for one hour at a potential of –1.6 V vs. Ag / AgCl (i.e., the potential for carbon dioxide reduction). This ensures the formation of a stable, predominantly vertically growing Bi nanosheet morphology on copper foam (see...). Figure 9 ).

[0174] Figure 9 Image (a) shows a SEM image of BiNSs@CF, from which multiple fan-shaped Bi nanosheets can be observed growing in groups on the copper foam surface, with a diameter of approximately 400 nm and a thickness of approximately 2 nm. Under these reaction conditions, the Bi nanosheets only underwent morphological changes through reconstruction, forming Bi nanosheets with larger diameters, greater stability, and better suitability for carbon dioxide reduction. Figure 9 (b) shows an HRTEM image of Bi NSs@CF, which shows that the nanosheets on Bi NSs@CF are self-assembled from particles with a diameter of about 5 nm.

[0175] Because the Bi nanosheets on Bi NSs@CF are thin and have a large diameter, with pores between particles, they are beneficial for increasing the specific surface area, increasing the number of exposed active reaction sites, promoting mass transfer, and improving electron transport efficiency, thereby enhancing the catalytic performance of the cathode. Moreover, while nanoparticles generally have high potential energy and poor structural stability, the Bi nanosheets assembled from nanoparticles on Bi NSs@CF exhibit good stability during carbon dioxide reduction, making them suitable for practical application.

[0176] 3. Test samples: Bi NSs@CF and Bi@CF from Example 2

[0177] The performance testing method for the electrocatalytic reduction of carbon dioxide at the cathode (single electrode) is as follows:

[0178] Unless otherwise specified, all CO2RR tests in this invention were conducted using a CHI 760e electrochemical workstation under ambient temperature (20–25°C) and normal pressure (100–102 kPa).

[0179] In this experiment, the sealed H-type electrolytic cell was divided into two parts by a proton exchange membrane (Nafion 117).

[0180] (1) The test sample was used directly as the working electrode (effective area 1×1cm). 2 Pt sheet electrode (1×1cm) 2 A three-electrode system was constructed by using an Ag / AgCl electrode (3M saturated KCl solution) as the counter electrode and the reference electrode, respectively.

[0181] Pour 16 mL of 0.5 M KHCO3 solution into both the cathode and anode chambers; control the volume of the cavity at the top of the electrolytic cell to 16 mL for buffering and facilitating the entry and exit of gases;

[0182] Before conducting the electrocatalytic carbon dioxide reduction test, high-purity CO2 gas was introduced into the cathode chamber and anode chamber for 30 minutes until saturation.

[0183] (2) Activation treatment: To avoid the consumption of electricity due to oxides formed spontaneously by air oxidation on the catalyst surface during electrocatalytic carbon dioxide reduction tests and linear scan voltammetry tests, the test samples were first activated by cyclic voltammetry. The activation conditions were as follows: scan potential range of -0.6 to 0 V vs. RHE, scan rate of 50 mV s. -1 Activation is complete when the cyclic voltammetry curves nearly overlap.

[0184] (3) Faraday efficiency test of formate: After activation, the scan rate was set to 5 mV / s in the linear scan voltammetry test. -1 Subsequently, constant potential electrolysis was performed at different potentials. Electrolysis was stopped when the charge reached 5C, and the liquid in the cathode chamber was collected. Formate was quantitatively analyzed using an ion chromatograph equipped with an anion exchange column (Metrosep A Supp 5-150 / 4.0). 4 to 5 mL of diluted electrolyte was manually injected using a syringe, and 10 μL of the chromatograph was automatically sampled and injected into the analytical column for detection. The calculated and analyzed results are as follows: Figure 11 As shown.

[0185] LSV curve testing: Using 0.5M KHCO3 solution saturated with Ar or CO2 as the electrolyte, the three-electrode system in test method (1) was used, with a scan rate of 5 mV s in the voltage range of -0.6 to -1.2 V vs. RHE. -1 Under the test conditions, the LSV curves of Bi NSs@CF and Bi@CF were measured respectively.

[0186] Test results:

[0187] The LSV curves of Bi NSs@CF and Bi@CF are as follows: Figure 10 As shown.

[0188] Depend on Figure 10 It can be seen that: From Figure 10 It can be observed that within the voltage range of -0.6 to -1.2 V vs. RHE, the current density of BiNSs@CF is consistently higher than that of BiCF. In an Ar-saturated electrolyte, at a voltage of –0.75 V vs. RHE, the current density of BiNSs@CF is 9.7 mA cm-1. –2 In a CO2-saturated electrolyte, Bi NSs@CF can achieve a current of 34.2 mA cm⁻¹ at this potential. –2 The current density is higher than that of Bi@CF, which is only 2.4 mA cm⁻¹. –2 The results show that Bi NSs@CF exhibits higher CO2RR activity compared to Bi@CF.

[0189] To evaluate the product selectivity of BiNSs@CF and Bi@CF for CO2RR, electrolysis experiments were conducted using a potentiostatic method within a voltage range of –0.6 to –0.8 V vs. RHE. The Faraday efficiency comparison of the formates of BiNSs@CF and Bi@CF in Example 2 is shown in the figure below. Figure 11 As shown.

[0190] Depend on Figure 11 It can be seen that at a potential of –0.75V vs. RHE, the formate exhibits the highest Faraday efficiency, reaching 94.1%. Meanwhile, the formate of Bi@CF at this potential has a Faraday efficiency of 81.1%.

[0191] This indicates that Bi NSs@CF can reduce CO2 to formate with higher selectivity compared to Bi@CF.

[0192] Example 3

[0193] This embodiment provides an electrolytic device for CO2 reduction and HMF oxidative coupling (see...). Figure 1This is essentially an H-type electrolytic cell, which includes: NiCo2O4@NF (cathode, effective area: 1×1cm) as described in Example 1. 2 In Example 2, BiNSs@CF (anode, effective area: 1×1cm) 2 The following components are required: 1M KOH solution containing 10mM 5-hydroxymethylfurfural (HMF) (anolyte), 0.5M KHCO3 solution saturated with carbon dioxide (cathode electrolyte), container, Nafion 117 proton exchange membrane, wires, power supply, and vent.

[0194] A container consisting of a 50 mL anode chamber and a 50 mL cathode chamber, with the anode chamber and cathode chamber separated by a Nafion 117 type proton exchange membrane;

[0195] In Example 1, NiCo2O4@NF (cathode) and in Example 2, Bi NSs@CF (anode) were immersed in cathode electrolyte and anolyte, respectively, and the cathode, power supply and anode were connected by wires.

[0196] The vent is located in the cathode chamber and is used to supply the cathode electrolyte with a raw material gas containing carbon dioxide.

[0197] In this embodiment, the power supply in the electrolysis device only needs to provide a voltage of 1.5 to 4V.

[0198] This electrolysis unit is used to simultaneously oxidize 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid (FDCA) and reduce carbon dioxide to formic acid, thereby producing high-value FDCA and achieving the goal of recovering and comprehensively utilizing carbon dioxide resources.

[0199] This embodiment also provides a method for CO2 reduction and HMF oxidative coupling (see...). Figure 1 The process includes the following steps:

[0200] (1) Construction of the electrolysis device: H-type electrolysis cell was selected as the electrolysis device. The cathode chamber and anode chamber of the electrolysis cell were separated by Nafion 117 type proton exchange membrane, and the volume of both the cathode chamber and the anode chamber was 32 mL.

[0201] Pour 16 mL of 1 M KOH solution containing 10 mM HMF into the anode chamber;

[0202] After pouring 16 mL of 0.5 M KHCO3 solution into the cathode chamber, continuously introduce carbon dioxide gas into the 0.5 M KHCO3 solution in the cathode chamber through the vent, and ensure that the air in the cathode chamber is removed, so that the electrolyte in the cathode chamber is saturated with carbon dioxide (ventilation time is 30 min).

[0203] With an effective area of ​​1×1cm 2 Bi NSs@CF was used as the anode, with an effective area of ​​1×1 cm. 2 NiCo2O4@NF was used as the cathode; and the cathode, power source, and anode were connected sequentially with wires to assemble a NiCo2O4@NF||Bi NSs@CF two-electrode catalytic system (see...). Figure 1 This is how the electrolysis device of this embodiment is constructed.

[0204] (2) Operation of the device: Control the electrolyte in the cathode chamber to flow at a rate of 20 mL / min. -1 By continuously introducing carbon dioxide gas and simultaneously turning on the power for electrolysis, the electro-oxidation of 5-hydroxymethylfurfural (HMF) and the electrocatalytic reduction of CO2 can be achieved.

[0205] After electrolysis to a charge level of 87C, the anode products were quantitatively detected using high performance liquid chromatography, and the cathode products were quantitatively detected using gas chromatography and ion chromatography.

[0206] A schematic diagram of the electrolytic device for CO2 reduction and HMF oxidative coupling in this invention is shown below. Figure 1 As shown.

[0207] Depend on Figure 1 It is understood that this invention provides a method for coupling CO2 reduction and HMF oxidation, which couples two electrocatalytic reaction processes. Specifically, it uses a NiCo spinel oxide catalyst (NiCo2O4@NF) grown in situ on nickel foam as the anode and a Bi NSs@CF electrode as the cathode to assemble a dual-electrode catalytic reaction system for electrolysis. At the anode, 5-hydroxymethylfurfural is selectively oxidized to 2,5-furandicarboxylic acid, and at the cathode, carbon dioxide is selectively reduced to formic acid.

[0208] The anolyte is a potassium hydroxide solution containing 5-hydroxymethylfurfural, and the catholyte is a carbon dioxide-saturated bicarbonate solution (e.g., potassium bicarbonate solution); an ion exchange membrane is provided between the anolyte and the catholyte in the electrolysis reaction system.

[0209] Performance testing:

[0210] Using the electrolysis apparatus of Example 3, and by varying only the HMF content in the anolyte, LSV curves of the NiCo2O4@NF||Bi NSs@CF two-electrode catalytic system were tested with and without HMF in the anolyte to evaluate the coupled HMF oxidation and carbon dioxide reduction reactions. The test results are as follows: Figure 12 As shown.

[0211] Depend on Figure 12It can be seen that, compared with the electrolysis device without HMF, the cell voltage of the electrolysis device containing HMF is significantly reduced, and the current is significantly increased. This indicates that the electrolysis device or method can drive the HMF oxidation and carbon dioxide reduction reactions at a voltage of 1.25V, and the NiCo2O4@NF||Bi NSs@CF two-electrode catalytic system has good catalytic activity.

[0212] Using the electrolysis apparatus of Example 3, the NiCo2O4@NF||Bi NSs@CF two-electrode catalytic system in Example 3 was used to catalyze HCOO within a cell voltage range of 1.5 to 2.1 V. – Faraday efficiency, test results of Faraday efficiency and yield of FDCA, such as... Figure 13 As shown.

[0213] Depend on Figure 13 It can be seen that the Faradaic efficiency of formate and FDCA first increases and then decreases with the increase of electrolytic cell voltage, and the Faradaic efficiency is the highest at 1.9V. At this time, the Faradaic efficiency of FDCA in the electro-oxidation reaction of HMF at the anode is 90.7%, and the Faradaic efficiency of formate in the electro-reduction reaction of CO2 at the cathode can also reach 85.1%, and the yield of FDCA also reaches 90%.

[0214] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An electrode material, characterized in that, It includes the substrate and bismuth nanosheets grown in situ on the substrate; The preparation method of the electrode material includes the following steps: 1) After pretreating the substrate, it is then immersed in an acidic bismuth salt solution to obtain a bismuth-loaded substrate; 2) The bismuth-loaded substrate described in step 1) is calcined in an oxidizing atmosphere to obtain a bismuth oxide-loaded substrate; 3) The bismuth oxide-loaded substrate described in step 2) is subjected to electrochemical reduction and electrochemical reconstruction to obtain the electrode material described above; Step 3) describes the electrochemical reduction and electrochemical reconstruction process, which includes the following steps: S1: Using the bismuth oxide-loaded substrate described in step 2) as the working electrode, the Ag / AgCl electrode as the reference electrode, and Pt electrode 1 as the counter electrode and electrolyte to construct an electrolysis system, electrolyze for 3 to 5 hours at a potential of –1.50 V vs. Ag / AgCl to –1.20 V vs. Ag / AgCl to obtain the electrochemically reduced material; S2: Replace with a new electrolyte and electrolyze for 0.5 to 1.5 hours at a potential of -1.55 V vs. Ag / AgCl to -1.65 V vs. Ag / AgCl to reconstruct bismuth nanosheets on the substrate to obtain the electrode material; In S1 and S2, the electrolyte is selected from at least one of CO2-saturated KHCO3 solution, K2CO3 solution, NaHCO3 solution, and Na2CO3 solution, and the solute concentration in the electrolyte is 0.1~1.0 mol / L.

2. The electrode material according to claim 1, characterized in that: The substrate is selected from at least one of nickel foam, copper foam, nickel sheet, and copper sheet; the bismuth nanosheet has a diameter of 200~600nm.

3. The method for preparing the electrode material according to claim 1 or 2, characterized in that, Includes the following steps: 1) After pretreating the substrate, it is then immersed in an acidic bismuth salt solution to obtain a bismuth-loaded substrate; 2) The bismuth-loaded substrate described in step 1) is calcined in an oxidizing atmosphere to obtain a bismuth oxide-loaded substrate; 3) The bismuth oxide-loaded substrate described in step 2) is subjected to electrochemical reduction and electrochemical reconstruction to obtain the electrode material described above; Step 3) describes the electrochemical reduction and electrochemical reconstruction process, which includes the following steps: S1: Using the bismuth oxide-loaded substrate described in step 2) as the working electrode, the Ag / AgCl electrode as the reference electrode, and Pt electrode 1 as the counter electrode and electrolyte to construct an electrolysis system, electrolyze for 3 to 5 hours at a potential of –1.50 V vs. Ag / AgCl to –1.20 V vs. Ag / AgCl to obtain the electrochemically reduced material; S2: Replace with a new electrolyte and electrolyze for 0.5 to 1.5 hours at a potential of -1.55 V vs. Ag / AgCl to -1.65 V vs. Ag / AgCl to reconstruct bismuth nanosheets on the substrate to obtain the electrode material; In S1 and S2, the electrolyte is selected from at least one of CO2-saturated KHCO3 solution, K2CO3 solution, NaHCO3 solution, and Na2CO3 solution, and the solute concentration in the electrolyte is 0.1~1.0 mol / L.

4. The method for preparing the electrode material according to claim 3, characterized in that, Includes the following steps: Step 2) The oxidizing atmosphere is selected from oxygen or air; Step 2) The calcination temperature is 180℃~230℃; Step 2) The calcination time is 10~16h.

5. A coupling method for carbon dioxide reduction and 5-hydroxymethylfurfural oxidation, characterized in that, Includes the following steps: Using the electrode material prepared by the method described in claim 3 or 4 as the cathode, a conductive substrate material loaded with NiCo2O4 as the anode, a 5-hydroxymethylfurfural solution as the anode electrolyte, and a carbon dioxide-saturated carbonate solution as the cathode electrolyte, an electrolytic reaction system is assembled for electrolysis. At the anode, 5-hydroxymethylfurfural is oxidized to 2,5-furandicarboxylic acid, while at the cathode, carbon dioxide is reduced to formic acid.

6. The coupling method for carbon dioxide reduction and 5-hydroxymethylfurfural oxidation according to claim 5, characterized in that: The method for preparing the conductive substrate material loaded with NiCo2O4 includes the following steps: 1) Dissolve soluble nickel salt, soluble cobalt salt and urea in water to obtain a nickel-cobalt precursor solution; 2) The pretreated conductive substrate is immersed in a nickel-cobalt precursor solution, and after hydrothermal reaction and annealing, a conductive substrate material loaded with NiCo2O4 is obtained. In step 1), the molar ratio of the soluble nickel salt, the soluble cobalt salt, and urea is 1:(1~3):(4~6). The hydrothermal reaction temperature in step 2) is 110~140℃; the annealing in step 2) is carried out in an air atmosphere or an oxygen atmosphere; the annealing temperature in step 2) is 280~350℃.

7. The coupling method for carbon dioxide reduction and 5-hydroxymethylfurfural oxidation according to claim 5 or 6, characterized in that: The voltage used for electrolysis is 1.5~4V; the carbon dioxide saturated carbonate solution is selected from at least one of CO2 saturated KHCO3 solution, K2CO3 solution, NaHCO3 solution, and Na2CO3 solution.

8. The application of the coupling method according to any one of claims 5 to 7 in the production of 2,5-furandicarboxylic acid or the comprehensive utilization of carbon dioxide.

9. An electrolysis apparatus, characterized in that, The electrolysis device includes: a cathode, an anode, a container, a diaphragm, wires, a power supply, and a vent. The cathode is an electrode material prepared by the method described in claim 3 or 4, the anode is a conductive substrate material loaded with NiCo2O4, the anode electrolyte is a 5-hydroxymethylfurfural solution, and the cathode electrolyte is a carbon dioxide-saturated carbonate solution. The diaphragm divides the container into a cathode chamber and an anode chamber; the cathode, power source, and anode are connected in sequence by wires; and the vent is located in the cathode chamber.

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