Paired electrode and preparation method thereof, and method for producing hydrogen by electrocatalytic oxidation of 5-hydroxymethylfurfural through coupling

Abstract

The invention relates to the technical field of electrochemistry, and particularly discloses paired electrodes, a preparation method of the paired electrodes and a method for producing hydrogen through electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) coupling. The electrodeposition reaction is synchronously carried out on the counter electrode and the working electrode through the constant-voltage deposition method, the cathode and the anode are prepared at a time, and the electrode preparation efficiency is effectively improved; the prepared paired electrodes show higher catalytic activity, stability and energy conversion efficiency in an electrocatalytic oxidation 5-hydroxymethylfurfural coupling hydrogen evolution reaction, HMF oxidation and hydrogen production processes can be coupled, and HMF oxidation and hydrogen production are simultaneously realized in an electrocatalytic mode; and a new technical approach and a new solution are provided for efficiently utilizing biomass resources and realizing green energy conversion.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical technology, and in particular to a paired electrode and a preparation method thereof, and a method for electrocatalytic oxidation of 5-hydroxymethylfurfural coupled with hydrogen production. Background Art

[0002] With the rapid development of the global economy, human demand for energy and chemicals continues to rise. Currently, it mainly relies on the utilization and conversion of fossil fuels, which has not only triggered an energy crisis, but also brought about serious environmental problems such as the greenhouse effect and air pollution. Therefore, it is urgent to find sustainable alternatives to petrochemical products. Lignocellulosic biomass has become a highly anticipated alternative resource due to its abundant reserves, biorenewability and carbon neutrality, and has a wide geographical distribution around the world. 5-Hydroxymethylfurfural (HMF), as an important bio-based C6 platform molecule, can be obtained from lignocellulosic biomass or fructose in an environmentally friendly manner.

[0003] Due to the unique structure of the coexistence of hydroxymethyl and formyl groups on the furan ring in the HMF molecule, it has high chemical transformation potential and can be oxidized into a series of high-value-added chemicals, including 2,5-diformylfuran (DFF), 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), 5-formyl-2-furancarboxylic acid (FFCA), and 2,5-furandicarboxylic acid (FDCA). Among them, FDCA, as the final oxidation product of HMF, is a key precursor for the production of polymers, pharmaceuticals, and fine chemicals, and is expected to replace the petroleum derivative terephthalic acid in the production of polyethylene terephthalate.

[0004] Currently, traditional HMF oxidation methods primarily include chemical oxidation and biological oxidation. Chemical oxidation typically requires the use of strong oxidants, such as potassium permanganate and potassium dichromate, resulting in harsh reaction conditions, the generation of numerous byproducts, and environmental pollution. While biological oxidation offers environmental advantages, it suffers from slow reaction rates and stringent requirements for reaction conditions, making large-scale industrial production difficult. For hydrogen production, water electrolysis is a commonly used technology, but this process suffers from high energy consumption and low efficiency. Coupling HMF oxidation with hydrogen production, achieving both HMF oxidation and hydrogen production through electrocatalysis, offers promising research opportunities, both addressing the challenges of HMF conversion and improving energy efficiency. However, existing electrocatalytic systems suffer from insufficient catalytic activity and stability of electrode materials and complex electrode preparation processes, resulting in low efficiency for HMF-coupled electrocatalytic oxidation coupled with hydrogen production, making it difficult to meet practical application requirements. Therefore, developing novel, efficient paired electrodes and their preparation methods to explore optimal HMF-coupled electrocatalytic oxidation coupled with hydrogen production technologies holds significant theoretical and practical value. Summary of the Invention

[0005] To address the problems of insufficient catalytic activity and stability of electrode materials in existing electrocatalytic systems, as well as complex electrode preparation processes, resulting in low efficiency in the electrocatalytic oxidation of HMF coupled to hydrogen production, making it difficult to meet practical application requirements, the present invention provides a paired electrode, a preparation method thereof, and a method for the electrocatalytic oxidation of 5-hydroxymethylfurfural coupled to hydrogen production. The present invention uses nickel foam as both the counter electrode and the working electrode, and synchronously prepares the cathode and anode via a constant voltage deposition method in a nickel-molybdenum bimetallic salt system. This paired electrode is used in the electrocatalytic oxidation of 5-hydroxymethylfurfural coupled to hydrogen evolution, significantly improving the efficiency of the HMF electrooxidation reaction and hydrogen production, providing a practical solution to energy issues.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0007] In the first aspect, the present invention provides a method for preparing a pair of electrodes, using nickel foam as a counter electrode and a working electrode, respectively. In a three-electrode system and a nickel-molybdenum bimetallic salt solution, a constant voltage deposition method is used to simultaneously carry out an electrodeposition reaction on the counter electrode and the working electrode to obtain a cathode and an anode.

[0008] Compared with the prior art, the preparation method of the paired electrodes provided by the present invention uses nickel foam as the substrate, and constructs a cathode and anode of a specific structure by constant voltage deposition in a three-electrode system and a nickel-molybdenum bimetallic salt solution. The prepared cathode has a deep foam porous structure and a large specific surface area, which can significantly increase the number of active sites of the hydrogen evolution reaction (HER), promote the full contact between the reactants and the active sites, accelerate the hydrogen generation rate, and its abundant pore channels contribute to the rapid desorption of hydrogen, reduce the reaction resistance, and improve the reaction kinetics of HER. The anode has a layered NiMoO4-Ni(OH)2 heterostructure, which utilizes the synergistic effect at the heterogeneous interface to effectively regulate the electron distribution and transfer, enhance the adsorption and activation ability of 5-hydroxymethylfurfural (HMF) molecules, and thus greatly improve the selectivity and conversion rate of the HMF electrooxidation reaction.

[0009] The present invention uses a constant voltage deposition method to simultaneously carry out electrodeposition reactions on the counter electrode and the working electrode, preparing the cathode and anode at one time, effectively improving the electrode preparation efficiency. The prepared paired electrodes show higher catalytic activity, stability and energy conversion efficiency in the electrocatalytic oxidation of 5-hydroxymethylfurfural coupled with the hydrogen evolution reaction, and can couple the HMF oxidation and hydrogen production processes, thereby simultaneously achieving HMF oxidation and hydrogen production through electrocatalysis, providing a new technical approach and solution for the efficient utilization of biomass resources and the realization of green energy conversion.

[0010] Furthermore, the method for preparing the paired electrodes specifically comprises the following steps:

[0011] Step a, using nickel foam as the counter electrode and working electrode, and Ag / AgCl as the reference electrode, to form a three-electrode system;

[0012] Step b: placing the three-electrode system in a nickel-molybdenum bimetallic salt solution, and synchronously electrodepositing a nickel-molybdenum alloy active layer on the counter electrode and the working electrode under constant voltage conditions to form a cathode and an anode.

[0013] The simultaneous preparation of the cathode and anode is crucial for controlling the cathode structure. During the electrodeposition process, the hydrogen evolution reaction (HE) occurs simultaneously at the cathode. The hydrogen bubbles generated by the HER promote the formation of a deep, porous foam structure at the cathode as they escape. This structure provides more active sites and gas diffusion pathways for the HER reaction, enhancing its electrocatalytic performance.

[0014] The layered NiMoO4-Ni(OH)2 heterostructure of the anode not only strengthens the adsorption force of the electrode to HMF molecules, but also makes the CH bonds near the aldehyde and hydroxyl groups more easily activated, significantly reduces the energy barrier of the oxidation reaction, and greatly improves the selectivity and conversion rate of HMF oxidation to the target product.

[0015] This coordinated design of the cathode and anode components enables the entire electrocatalytic system to have a smaller hydrogen evolution overpotential (η HER =43mV@10mA / cm -2 ), achieving 99.9% HMF conversion and 96.4% FDCA selectivity at 1.5 V (vs. RHE), significantly outperforming traditional noble metal electrodes.

[0016] It should be noted that the nickel foam was pretreated before use by ultrasonically cleaning the nickel foam in hydrochloric acid, deionized water and anhydrous ethanol to remove oxides and impurities on the surface.

[0017] Specifically, the concentration of the hydrochloric acid is 2 mol / L to 3 mol / L.

[0018] Furthermore, in step b, the total metal ion concentration in the nickel-molybdenum bimetallic salt solution is 0.03 mol / L to 0.05 mol / L.

[0019] Furthermore, in step b, the nickel-molybdenum bimetallic salt solution contains Ni 2+ and Mo 6+ The molar ratio is (1~4):(1~4).

[0020] Specifically, in step b, the nickel source in the nickel-molybdenum bimetallic salt solution is nickel nitrate, and the molybdenum source is ammonium molybdate. The nickel-molybdenum bimetallic salt solution also includes urea at a concentration of 0.1 mol / L to 0.15 mol / L.

[0021] Furthermore, in step b, the initial potential of the constant voltage is (-1 to -2) V (vs Ag / AgCl), and the deposition time is 2000 s to 4000 s.

[0022] Lower ion concentration and longer deposition time are conducive to more uniform deposition of metal ions, gradually building a more delicate and ordered cathode deep foam porous structure and anode layered NiMoO4-Ni(OH)2 heterostructure.

[0023] In a second aspect, the present invention provides a paired electrode, which is prepared by any of the above-mentioned methods for preparing a paired electrode.

[0024] In a third aspect, the present invention further provides an electrochemical device comprising the above-mentioned paired electrodes.

[0025] In a fourth aspect, the present invention further provides the use of the above-mentioned paired electrodes or electrochemical devices in the electrocatalytic oxidation of 5-hydroxymethylfurfural coupled with hydrogen production.

[0026] In a fifth aspect, the present invention further provides a method for electrocatalytic oxidation of 5-hydroxymethylfurfural coupled with hydrogen production, comprising the following steps:

[0027] The paired electrodes and the reference electrode are placed in an alkaline electrolyte containing 5-hydroxymethylfurfural, and a voltage is applied to carry out an electrocatalytic oxidation reaction.

[0028] The method for coupled hydrogen production by electrocatalytic oxidation of 5-hydroxymethylfurfural provided by the present invention uses a cathode and anode prepared simultaneously in the same system. The cathode rapidly produces hydrogen at a low overpotential due to its abundant active sites and excellent hydrogen evolution catalytic performance; the anode accelerates the oxidation reaction of 5-hydroxymethylfurfural (HMF) through the strong adsorption and activation capabilities of the heterojunction. The two operate synchronously in the same electrocatalytic system, achieving efficient coupling of oxidation and reduction reactions, greatly improving the overall reaction rate and energy conversion efficiency.

[0029] Furthermore, the concentration of 5-hydroxymethylfurfural in the alkaline electrolyte is 5 mmol / L to 20 mmol / L.

[0030] Furthermore, the voltage of the electrocatalytic oxidation reaction is (1.46-1.51) V (vs RHE).

[0031] In summary, the present invention simultaneously obtains a cathode and anode with excellent performance through a constant voltage deposition method, and applies them to the electrocatalytic oxidation of 5-hydroxymethylfurfural coupled with hydrogen production system. This not only breaks through the bottleneck of low catalytic activity and poor stability of traditional electrode materials, but also significantly improves the coupling efficiency of HMF oxidation and hydrogen evolution reaction through the synergistic effect of the anode and cathode reactions, achieving the dual goals of green chemical production and clean energy generation, and has high application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a scanning electron microscope image of the cathode (DF / cNF) electrode material prepared in Example 1 of the present invention;

[0033] Figure 2 This is a scanning electron microscope image of the anode (Ni-Mo / aNF) electrode material prepared in Example 1 of the present invention;

[0034] Figure 3 This is a scanning transmission microscopy image of the cathode (DF / cNF) electrode material prepared in Example 1 of the present invention, and the upper right corner is a selected area electron diffraction pattern;

[0035] Figure 4 This is a scanning transmission microscope image of the anode (Ni-Mo / aNF) electrode material prepared in Example 1 of the present invention, and the upper right corner is a selected area electron diffraction pattern;

[0036] Figure 5 This is a comparison chart of hydrogen evolution performance of the electrode pairs prepared in Example 1 of the present invention, Comparative Examples 1-2, and a pure nickel foam substrate;

[0037] Figure 6 This is a comparison of the HMF electrooxidation activities of the electrode pairs prepared in Example 1 of the present invention, Comparative Examples 1-2, and a pure nickel foam substrate;

[0038] Figure 7 This is a concentration trend diagram of HMF and its oxidation products when the electrolysis charge of the electrode pair prepared in Example 1 of the present invention increases;

[0039] Figure 8 This is a comparison chart of the activity of the electrode pair prepared in Example 1 of the present invention in complete water splitting and HMF electrocatalytic oxidation coupled hydrogen evolution. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0041] In order to better illustrate the present invention, further examples are given below.

[0042] Example 1

[0043] This embodiment provides a method for preparing a paired electrode, comprising the following steps:

[0044] S1, immersing the nickel foam in a 2 mol / L hydrochloric acid solution, ultrasonically cleaning for 30 min, then rinsing with deionized water and anhydrous ethanol in sequence, and immersing the pretreated nickel foam in anhydrous ethanol for later use;

[0045] S2, dissolving nickel nitrate, ammonium molybdate and urea in deionized water to obtain a nickel-molybdenum bimetallic salt solution; wherein the total metal ion concentration in the nickel-molybdenum bimetallic salt solution is 0.04 mol / L, Ni 2+ and Mo 6+ The molar ratio is 4:1, and the urea concentration is 0.11 mol / L;

[0046] S3, two pretreated nickel foams were cut into 2cm*1.5cm electrode sheets as the counter electrode and working electrode, respectively, with Ag / AgCl as the reference electrode to form a three-electrode system. Electrolysis was carried out at a voltage of -2V (vs Ag / AgCl) for 4000s. The samples were washed with deionized water and dried to obtain the cathode (DF / cNF) and anode (NiMo / aNF) as a pair of electrodes.

[0047] The SEM images of the cathode material and anode material prepared in this embodiment are Figure 1 and Figure 2 As shown in the figure, both the cathode and anode materials have obvious large-scale pores with irregular morphology, thick pore walls, and relatively rough surfaces, presenting a three-dimensional porous structure. This porous structure can increase the specific surface area of ​​the electrode, providing more active sites for electrocatalytic reactions, facilitating the adsorption and diffusion of reactants, and improving reaction efficiency.

[0048] Scanning transmission microscopy and selected area electron diffraction patterns of cathode materials are shown in Figure 2. Figure 3 As shown in the figure, periodic lattice fringes are clearly shown, and the interplanar spacing is 0.205nm, corresponding to the (111) crystal plane of Ni.

[0049] The scanning transmission microscopy and selected area electron diffraction patterns of the anode material are shown in Figure 2. Figure 4 As shown, the interplanar spacing of 0.189 nm corresponds to the (004) plane of Ni(OH)2, and the interplanar spacing of 0.206 nm corresponds to the (330) plane of NiMoO4, confirming the formation of a NiMoO4-Ni(OH)2 heterojunction. The lattice fringes of the two phases are in close contact at the interface (the yellow dashed area), and the high clarity of the diffraction rings indicates that the lattice matching at the heterojunction interface is high, which is conducive to efficient charge transfer across the heterojunction and reduces energy loss.

[0050] Example 2

[0051] This embodiment provides a method for preparing a paired electrode, comprising the following steps:

[0052] S1, immersing the nickel foam in a 2 mol / L hydrochloric acid solution, ultrasonically cleaning for 30 min, then rinsing with deionized water and anhydrous ethanol in sequence, and immersing the pretreated nickel foam in anhydrous ethanol for later use;

[0053] S2, dissolving nickel nitrate, ammonium molybdate and urea in deionized water to obtain a nickel-molybdenum bimetallic salt solution; wherein the total metal ion concentration in the nickel-molybdenum bimetallic salt solution is 0.03 mol / L, Ni 2+ and Mo 6+ The molar ratio is 2:1, and the urea concentration is 0.15 mol / L;

[0054] S3, two pretreated nickel foams were cut into 2cm*1.5cm electrode sheets as the counter electrode and working electrode, respectively, with Ag / AgCl as the reference electrode to form a three-electrode system. Electrolysis was carried out at a voltage of -1.8V (vs Ag / AgCl) for 3000s. The samples were washed with deionized water and dried to obtain the cathode (DF / cNF) and anode (NiMo / aNF) as the counter electrode.

[0055] Example 3

[0056] This embodiment provides a method for preparing a paired electrode, comprising the following steps:

[0057] S1, immersing the nickel foam in a 2 mol / L hydrochloric acid solution, ultrasonically cleaning for 30 min, then rinsing with deionized water and anhydrous ethanol in sequence, and immersing the pretreated nickel foam in anhydrous ethanol for later use;

[0058] S2, dissolving nickel nitrate, ammonium molybdate and urea in deionized water to obtain a nickel-molybdenum bimetallic salt solution; wherein the total metal ion concentration in the nickel-molybdenum bimetallic salt solution is 0.05 mol / L, Ni 2+ and Mo 6+ The molar ratio is 1:4, and the urea concentration is 0.13 mol / L;

[0059] S3, two pretreated nickel foams were cut into 2cm*1.5cm electrode sheets as the counter electrode and working electrode, respectively, with Ag / AgCl as the reference electrode to form a three-electrode system. Electrolysis was carried out at a voltage of -1.5V (vs Ag / AgCl) for 2000s. The samples were washed with deionized water and dried to obtain the cathode (DF / cNF) and anode (NiMo / aNF) as the counter electrode.

[0060] Example 4

[0061] This embodiment provides a method for preparing a paired electrode, comprising the following steps:

[0062] S1, immersing the nickel foam in a 2 mol / L hydrochloric acid solution, ultrasonically cleaning for 30 min, then rinsing with deionized water and anhydrous ethanol in sequence, and immersing the pretreated nickel foam in anhydrous ethanol for later use;

[0063] S2, dissolving nickel nitrate, ammonium molybdate and urea in deionized water to obtain a nickel-molybdenum bimetallic salt solution; wherein the total metal ion concentration in the nickel-molybdenum bimetallic salt solution is 0.04 mol / L, Ni 2+ and Mo 6+ The molar ratio is 1:2, and the urea concentration is 0.1 mol / L;

[0064] S3, two pretreated nickel foams were cut into 2cm*1.5cm electrode sheets as the counter electrode and working electrode, respectively, with Ag / AgCl as the reference electrode to form a three-electrode system. Electrolysis was carried out at a voltage of -2V (vs Ag / AgCl) for 3500s. The samples were washed with deionized water and dried to obtain the cathode (DF / cNF) and anode (NiMo / aNF) as a pair of electrodes.

[0065] Comparative Example 1

[0066] This comparative example provides a method for preparing a paired electrode, which is different from Example 1 only in that the electrodeposition solution is a single metal salt solution, and specifically includes the following steps:

[0067] S1, immersing the nickel foam in a 2 mol / L hydrochloric acid solution, ultrasonically cleaning for 30 min, then rinsing with deionized water and anhydrous ethanol in sequence, and immersing the pretreated nickel foam in anhydrous ethanol for later use;

[0068] S2, dissolving nickel nitrate and urea in deionized water to obtain a nickel salt solution; wherein Ni 2+ The concentration is 0.04 mol / L, and the urea concentration is 0.11 mol / L;

[0069] S3, two pretreated nickel foams were cut into 2cm*1.5cm electrode sheets as the counter electrode and working electrode, respectively, with Ag / AgCl as the reference electrode to form a three-electrode system. Electrolysis was carried out at a voltage of -2V (vs Ag / AgCl) for 4000s. The samples were washed with deionized water and dried to obtain the cathode (DF / cNF) and anode (Ni / aNF) as the counter electrode.

[0070] Comparative Example 2

[0071] This comparative example provides a method for preparing a paired electrode, which is different from Example 1 only in that the electrodeposition solution is a single metal salt solution, and specifically includes the following steps:

[0072] S1, immersing the nickel foam in a 2 mol / L hydrochloric acid solution, ultrasonically cleaning for 30 min, then rinsing with deionized water and anhydrous ethanol in sequence, and immersing the pretreated nickel foam in anhydrous ethanol for later use;

[0073] S2, dissolving ammonium molybdate and urea in deionized water to obtain a molybdenum salt solution; wherein, Mo in the molybdenum salt solution 6+The concentration is 0.04 mol / L, and the urea concentration is 0.11 mol / L;

[0074] S3, two pretreated nickel foams were cut into 2cm*1.5cm electrode sheets as the counter electrode and working electrode, respectively, with Ag / AgCl as the reference electrode to form a three-electrode system. Electrolysis was carried out at a voltage of -2V (vs Ag / AgCl) for 4000s. The samples were washed with deionized water and dried to obtain the cathode (DF / cNF) and anode (Mo / aNF) as the counter electrode.

[0075] Application Examples

[0076] This application example provides the performance test of the paired electrodes prepared in Example 1 and Comparative Examples 1-2. RHE =E Ag / AgCl The formula for pH is 0.197 + 0.0591 × pH, and the potential is measured using a reversible hydrogen electrode (RHE), as follows:

[0077] (1) Test method for hydrogen evolution catalytic performance: In 1.0 M KOH solution, a three-electrode system was used, with each cathode (DF / cNF) prepared as described above as the working electrode, an Ag / AgCl electrode as the reference electrode, and a graphite rod as the counter electrode. Linear cyclic voltammetry was performed at a scan rate of 5 mV / s. The IR compensation rate of the linear sweep voltammogram (LSV) was 96%.

[0078] The cathodes prepared in Example 1 and Comparative Examples 1 and 2 were tested for their hydrogen evolution catalytic performance according to this method. Figure 5 As shown. Among them, the nickel foam matrix exhibits poor hydrogen evolution activity. The cathode prepared in Example 1 has a low hydrogen evolution activity at 10 mA / cm -2 , 100mA / cm -2 and 500mA / cm -2 It showed good catalytic activity under the conditions of 10 =43mV,η 100 =178mV and η 5000 =272mV, which is much smaller than the cathode obtained in Comparative Example 2 (η 10 =61mV,η 100 =196mV, η 500 =300mV) and the cathode obtained in Comparative Example 1 ((η 10 =84mV,η 100 =223mV,η 500 =326mV). According to XRD and XPS analysis, the composition of the cathode obtained in Example 1 is the same as that of the blank nickel foam support, with the only difference being that the cathode obtained in Example 1 has a deep foaming morphology, which fully demonstrates the influence of the geometric effect on the hydrogen evolution activity.

[0079] (2) Test method for the electrocatalytic oxidation performance of 5-hydroxymethylfurfural (HMF): HMF oxidation was measured in 1.0 mM KOH and 10 mM HMF solution using a three-electrode system with the anode prepared in Example 1 and Comparative Examples 1-2 as the working electrode, an Ag / AgCl electrode as the reference electrode, and a carbon rod as the counter electrode. Linear cyclic voltammetry was performed at a scan rate of 5 mV / s, and the IR compensation rate of the linear sweep voltammogram (LSV) was 96%.

[0080] In an electrolyte of 1M KOH and 10mM HMF, the HMF electrooxidation activities of the anodes prepared in Example 1 and Comparative Examples 1-2 and the nickel foam substrate were compared. Figure 6 The anode NiMo / aNF prepared in Example 1 was -2 The voltage of the anode (Ni / aNF) prepared in Comparative Example 1 was 1.248V at 10mA / cm -2 The voltage of the anode (Mo / aNF) prepared in Comparative Example 2 was 1.359V at 10mA / cm -2 The voltage is 1.371V, and the nickel foam substrate is 10mA / cm -2 The voltage is 1.413 V, which proves that the anode prepared in Example 1 has better oxidation performance for HMF. It proves that the NiMoO4-Ni(OH)2 heterojunction of the NiMo / aNF sample obtained in Example 1 promotes electron transfer during the oxidation of HMF.

[0081] (3) Test method for the coupled hydrogen evolution performance of HMF electrocatalytic oxidation: The coupled reaction of HMF oxidation and hydrogen evolution was measured in a 1.0 M KOH and 10 mM HMF solution. A three-electrode system was used, with the DF / cNF prepared in Example 1 as the cathode, the NiMo / aNF as the anode, and the Ag / AgCl electrode as the reference electrode. The electrocatalytic oxidation of HMF was carried out at a voltage of 1.46 V.

[0082] NiMo / aNF exhibited excellent electrocatalytic activity, with a HMF conversion of 99.6%, a selectivity of 96.4% for the final product FDCA, and a Faradaic efficiency of 98.2%. Figure 7 shown.

[0083] At the same time, a water electrolysis experiment was conducted on the double electrode. The electrolyte was an alkaline electrolyte containing 5-HMF (1.0M KOH and 10mM 5-HMF), the voltage window was 1.0-1.8V, and the scan rate was 5mV / s. The results are as follows: Figure 8 shown.

[0084] The voltage required for water electrolysis is relatively high, reaching 10mA / cm -2 , 50mA / cm -2 , 100mA / cm-2 and 200mA / cm -2 The current density required is 1.35V, 1.543V, 1.582V and 1.624V respectively. However, after adding HMF, the voltage required for the electrolysis system is significantly lower than that of the simple electrolysis of water. -2 , 50mA / cm -2 , 100mA / cm -2 and 200mA / cm -2 The current densities of the dual electrolysis system were 1.276 V, 1.416 V, 1.447 V, and 1.458 V, respectively. This demonstrates that the dual electrolysis system also exhibits high FE and good cycling stability.

[0085] In summary, we have designed a novel and efficient tandem paired electrode strategy for catalyst preparation, hydrogen production and acquisition of high value-added products. The paired electrodes prepared in the embodiment of the present invention exhibit excellent HER and biomass oxidation activities, resulting in a small overpotential (η HER =43mV@mA / cm -2 ) and high biomass conversion rate (the yield of HMF to FDCA was 96.4%).

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a paired electrode, characterized in that: Using nickel foam as the counter electrode and working electrode respectively, in a three-electrode system and a nickel-molybdenum bimetallic salt solution, a constant voltage deposition method is used to simultaneously carry out electrodeposition reactions on the counter electrode and the working electrode to obtain a cathode and an anode.

2. The method for preparing the paired electrodes according to claim 1, characterized in that: The specific steps include: Step a, using nickel foam as the counter electrode and working electrode, and Ag / AgCl as the reference electrode, to form a three-electrode system; Step b: placing the three-electrode system in a nickel-molybdenum bimetallic salt solution, and synchronously electrodepositing a nickel-molybdenum alloy active layer on the counter electrode and the working electrode under constant voltage conditions to form a cathode and an anode.

3. The method for preparing a paired electrode according to claim 2, wherein: In step b, the total metal ion concentration in the nickel-molybdenum bimetallic salt solution is 0.03 mol / L to 0.05 mol / L.

4. The method for preparing a paired electrode according to claim 4, wherein: In step b, the nickel-molybdenum bimetallic salt solution contains Ni 2+ and Mo 6+ The molar ratio is (1~4):(1~4).

5. The method for preparing a paired electrode according to claim 2, wherein: In step b, the initial potential of the constant voltage is (-1 to -2) V (vs Ag / AgCl), and the deposition time is 2000 s to 4000 s.

6. A paired electrode, characterized in that: The paired electrodes are prepared by the method for preparing the paired electrodes according to any one of claims 1 to 5.

7. An electrochemical device, characterized in that Comprising the paired electrodes according to claim 6.

8. Use of the paired electrodes according to claim 6 or the electrochemical device according to claim 7 in the electrocatalytic oxidation of 5-hydroxymethylfurfural coupled with hydrogen production.

9. A method for electrocatalytic oxidation of 5-hydroxymethylfurfural coupled with hydrogen production, characterized in that: The steps include: The paired electrodes and the reference electrode according to claim 6 are placed in an alkaline electrolyte containing 5-hydroxymethylfurfural, and a voltage is applied to carry out an electrocatalytic oxidation reaction.

10. The method for electrocatalytic oxidation of 5-hydroxymethylfurfural coupled with hydrogen production according to claim 9, characterized in that: The concentration of 5-hydroxymethylfurfural in the alkaline electrolyte is 5 mmol / L to 20 mmol / L; and / or The voltage of the electrocatalytic oxidation reaction is (1.46-1.51) V (vs RHE).

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