A Ni 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode and its preparation method

Abstract

The application discloses a kind of Ni 11 (HPO3)8(OH)6 / Mo8O 23 / foam nickel bifunctional composite electrode and preparation method thereof, utilize simple one-step hydrothermal reaction, in-situ growth Ni 11 (HPO3)8(OH)6 nanosheet and Mo8O 23 Nanosheet assembly of multistage structure composite microspheres, construct self-supporting composite electrode, in-situ growth on the surface of metal foam nickel, give catalyst more exposed active site and more interface transfer active site, beneficial to the diffusion of electrolyte, proton multi-site adsorption and the rapid escape of generated H2.In addition, the construction of self-supporting electrode greatly improves the charge transfer efficiency, effectively avoids the falling of catalyst, increases the stability of electrode.The composite electrode preparation process is simple, low in cost.It is used for electrocatalytic decomposition of water to produce hydrogen, electrocatalytic biomass oxidation to prepare high value-added fine chemicals, electrocatalytic urea oxidation, electrocatalytic degradation of organic dyes, organic chemical wastewater treatment, etc., all show excellent electrocatalytic activity and stability.

Description

Technical Field

[0001] This invention belongs to the fields of new energy, environment and biomass conversion, and relates to a composite electrode and its preparation method. Specifically, it relates to a Ni electrode grown in situ on a nickel foam metal framework. 11 (HPO3)8(OH)6 nanosheets and Mo8O 23 Furthermore, this relates to a Ni nanosheet heterojunction composite electrode for hydrogen renewable energy production and biomass conversion. 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode and its preparation method. Background Technology

[0002] Hydrogen, as a clean and renewable energy carrier, is widely recognized as the best alternative to traditional energy sources. Water electrolysis is a sustainable and efficient method for producing hydrogen. However, the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode during water electrolysis are thermodynamically and kinetically slow, requiring a high overpotential. Therefore, there is an urgent need to develop electrocatalysts with high catalytic activity and high chemical stability for water electrolysis hydrogen production. Among the published technologies, transition metal compounds are widely used as catalysts for water electrolysis hydrogen production. Transition metal phosphate catalysts are typical representatives of emerging non-precious metal catalysts due to their low cost, environmental friendliness, high stability, unique physicochemical properties, and tunable multifunctionality. However, the poor conductivity and non-ideal porosity of transition metal phosphates limit their ability to further improve catalytic activity, necessitating modification. Molybdenum oxide is an important material in many fields (as an electrocatalyst, photocatalyst, and other catalysts). Due to the variable state of molybdenum and its easy combination with various anions, molybdenum oxide-based materials have diverse applications in different fields. Among them, Mo8O... 23 It is a multifunctional molybdenum oxide that has attracted attention in the field of catalysis. Based on the above research, this invention utilizes Ni 11 (HPO3)8(OH)6 and Mo8O 23 Composite materials are used to prepare highly efficient composite electrocatalysts. However, current methods for preparing Mo8O₂ are limited. 23 Either a high-temperature reaction is required, or it is difficult to prepare single-phase Mo8O. 23 Either expensive reagents are required, production costs are high, and the process is complex, making it difficult to prepare Ni. 11 (HPO3)8(OH)6 / Mo8O 23 Composite electrocatalysts. Therefore, further research and development are needed to explore and develop efficient, stable, and durable nickel phosphate / Mo8O composites with simple preparation processes and excellent performance. 23 Composite electrocatalyst.

[0003] Furthermore, the inherently slow kinetics and high reaction energy barrier of the anode OER (Optical Eruption Reactor) limit the electrolysis of water. Simultaneously, the oxygen produced by OER has no significant commercial value, and its removal after mixing with H2 is energy-intensive and time-consuming. In this context, replacing anode OER with anodic biomass oxidation has attracted attention due to its low overpotential and high commercial value. 5-Hydroxymethylfurfural (HMF) is an important biomass platform molecule that can be further converted into various useful substances through oxidation reactions, such as the oxidation products of 2,5-furandicarboxylic acid (FDCA). In the field of polymer materials, FDCA can replace terephthalic acid in the production of biodegradable and high-performance bio-based polyesters. Since electrocatalytic HMF oxidation is thermodynamically and kinetically more favorable than OER, it can improve energy conversion efficiency. Therefore, replacing OER with electrocatalytic HMF oxidation is an effective strategy, reducing the applied voltage for hydrogen evolution at the cathode while producing high-value-added biomass fine chemicals at the anode.

[0004] This invention designs a novel Ni 11 (HPO3)8(OH)6 / Mo8O 23 A composite electrocatalyst was prepared and grown in situ on a nickel foam current collector to produce Ni. 11 (HPO3)8(OH)6 / Mo8O 23 The nickel foam self-supporting composite electrode exhibits excellent electrochemical performance in electrocatalytic hydrogen production at the cathode, electrocatalytic HMF oxidation to FDCA at the anode, electrocatalytic oxidation of organic matter in water, and electrocatalytic degradation of organic dyes. Summary of the Invention

[0005] This invention addresses the existing methods for preparing Mo8O 23 In electrocatalyst technology, it is difficult to prepare pure-phase Mo8O. 23 The process is demanding, complex, and costly, making it difficult to achieve tight interfacial coupling. It also results in low active sites, low electrocatalytic efficiency, limited application functions, poor stability, and difficulty in preparing Ni using a one-step reaction. 11 (HPO3)8(OH)6 / Mo8O 23 The self-supported composite electrode of nickel foam nanosheets / nanosheets has shortcomings, so a new Ni 11 (HPO3)8(OH)6 / Mo8O 23 / Ni foam bifunctional composite electrode and its preparation method: Ni is prepared using a simple one-step hydrothermal reaction. 11 (HPO3)8(OH)6 / Mo8O 23 / Ni foam bifunctional composite electrode, characterized in that the composite electrode is composed of Ni grown in situ on the surface of metallic nickel foam. 11 (HPO3)8(OH)6 nanosheets and Mo8O23 A self-supporting electrode composed of multi-level composite microspheres assembled from nanosheets is used as a bifunctional composite electrode for cathode water reduction to produce hydrogen and anode selective oxidation of 5-hydroxymethylfurfural to prepare 2,5-furandicarboxylic acid, a fine chemical, as well as for the electro-oxidation purification of organic chemical wastewater. The preparation of the composite electrode includes the following steps:

[0006] (1) The nickel foam (1-10cm*1-10cm in size) was ultrasonically cleaned in sequence with acetone, 0.1M hydrochloric acid, deionized water and ethanol respectively;

[0007] (2) Dissolve 0.1-10 mmol of NiCl2·6H2O, 0.1-10 mmol of Na2MoO4·2H2O and 0.5-50 mmol of urea in 15-150 mL of deionized water with stirring;

[0008] (3) Dissolve 0.1-20 mmol of sodium hypophosphite in 15-150 mL of deionized water to obtain a sodium hypophosphite solution, and add this solution to the mixed solution obtained in step (2) while stirring.

[0009] (4) Transfer the mixed solution obtained in step (3) and 1-10 pieces of nickel foam treated in step (1) together into a stainless steel reactor with a Teflon liner. Keep the sealed reactor at 80-200℃ for 0.5-48 hours. After the reactor cools to room temperature, remove the nickel foam and rinse it thoroughly with deionized water and ethanol to obtain Ni. 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode.

[0010] The advantages of this invention are: the preparation method is simple and low-cost; Ni is constructed in one step. 11 (HPO3)8(OH)6 / Mo8O 23 / Ni foam bifunctional composite electrode, this electrode is made of Ni 11 (HPO3)8(OH)6 nanosheets and Mo8O 23 Multi-level structured microspheres assembled from nanosheets are grown in situ on the surface of nickel foam, endowing the catalyst with more exposed active sites and more interfacial transfer active sites, which is beneficial for electrolyte diffusion, multi-site adsorption of protons, and rapid escape of generated H2. Furthermore, the construction of a self-supporting electrode significantly improves charge transfer efficiency, effectively prevents catalyst detachment, and increases electrode stability. It exhibits excellent electrocatalytic activity and stability in applications such as electrocatalytic water splitting for hydrogen production, electrocatalytic biomass oxidation for the preparation of high-value-added fine chemicals, electrocatalytic urea oxidation, electrocatalytic degradation of organic dyes, and organic chemical wastewater treatment. Attached Figure Description

[0011] Figure 1 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 XRD patterns of the nickel foam composite electrode and the Ni11(HPO3)8(OH)6 / nickel foam electrode prepared by the method described in Comparative Example 1.

[0012] Figure 2 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 / SEM image of nickel foam composite electrode.

[0013] Figure 3 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 / TEM and HRTEM images of the nickel foam composite electrode.

[0014] 1. Figure 4 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam composite electrode and Ni prepared by the method described in Comparative Example 1 11 XPS spectrum of (HPO3)8(OH)6 / nickel foam electrode.

[0015] Figure 5 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 Linear sweep voltammetric curves of hydrogen generation HER at the cathode of the nickel foam composite electrode and the electrodes prepared by the methods described in Comparative Examples 1 and 2.

[0016] Figure 6 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 Potential-time curve of nickel foam composite electrode under constant current.

[0017] Figure 7 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 / The curves showing the HMF conversion rate and the yield of its oxidation products as a function of charge on the anode of the nickel foam composite electrode (a) and the cycle stability experiment (b).

[0018] Figure 8 Ni prepared by the method described in Example 1 11(HPO3)8(OH)6 / Mo8O 23 / Comparison of polarization curves of urea oxidation and OER of nickel foam composite electrode anolyte. Detailed Implementation

[0019] The present invention will be further described in detail below through embodiments:

[0020] Example 1:

[0021] (1) The nickel foam (2cm*3cm) was ultrasonically cleaned using acetone, 0.1M hydrochloric acid, deionized water and ethanol respectively;

[0022] (2) Dissolve 1 mmol of NiCl2·6H2O, 1 mmol of Na2MoO4·2H2O and 5 mmol of urea in 15 mL of deionized water with stirring;

[0023] (3) Dissolve 2 mmol of sodium hypophosphite in 15 mL of deionized water to obtain a sodium hypophosphite solution. Add this solution to the mixed solution obtained in step (2) while stirring.

[0024] (4) Transfer the mixed solution obtained in step (3) and the one piece of nickel foam treated in step (1) together into a stainless steel reactor with a Teflon liner. The sealed reactor is kept at 180°C for 10 hours. After the reactor cools to room temperature, the nickel foam is removed and rinsed with deionized water and ethanol to obtain Ni. 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode.

[0025] Example 2:

[0026] (1) The nickel foam (2cm*3cm) was ultrasonically cleaned using acetone, 0.1M hydrochloric acid, deionized water and ethanol respectively;

[0027] (2) Dissolve 0.2 mmol of NiCl2·6H2O, 0.1 mol of Na2MoO4·2H2O and 1 mmol of urea in 15 mL of deionized water with stirring;

[0028] (3) Dissolve 4 mmol of sodium hypophosphite in 15 mL of deionized water to obtain a sodium hypophosphite solution. Add this solution to the mixed solution obtained in step (2) while stirring.

[0029] (4) Transfer the mixed solution obtained in step (3) and the two pieces of nickel foam treated in step (1) together into a stainless steel reactor with a Teflon liner. The sealed reactor is kept at 180°C for 10 hours. After the reactor cools to room temperature, the nickel foam is removed and rinsed with deionized water and ethanol to obtain Ni. 11(HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode.

[0030] Example 3:

[0031] (1) The nickel foam (1cm*1cm) was ultrasonically cleaned using acetone, 0.1M hydrochloric acid, deionized water and ethanol respectively;

[0032] (2) Dissolve 3 mmol of NiCl2·6H2O, 10 mmol of Na2MoO4·2H2O and 10 mmol of urea in 30 mL of deionized water with stirring.

[0033] (3) Dissolve 5 mmol of sodium hypophosphite in 30 mL of deionized water to obtain a sodium hypophosphite solution. Add this solution to the mixed solution obtained in step (2) while stirring.

[0034] (4) Transfer the mixed solution obtained in step (3) and the 10 pieces of nickel foam treated in step (1) together into a stainless steel reactor with a Teflon liner. The sealed reactor is kept at 80°C for 48 hours. After the reactor cools to room temperature, the nickel foam is removed and rinsed with deionized water and ethanol to obtain Ni. 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode.

[0035] Example 4:

[0036] (1) The nickel foam (2cm*10cm) was ultrasonically cleaned using acetone, 0.1M hydrochloric acid, deionized water and ethanol respectively;

[0037] (2) Dissolve 10 mmol of NiCl2·6H2O, 10 mmol of Na2MoO4·2H2O and 20 mmol of urea in 150 mL of deionized water with stirring.

[0038] (3) Dissolve 15 mmol of sodium hypophosphite in 150 mL of deionized water to obtain a sodium hypophosphite solution. Add this solution to the mixed solution obtained in step (2) while stirring.

[0039] (4) Transfer the mixed solution obtained in step (3) and the 10 pieces of nickel foam treated in step (1) together into a stainless steel reactor with a Teflon liner. The sealed reactor is kept at 200°C for 5 hours. After the reactor cools to room temperature, the nickel foam is removed and rinsed with deionized water and ethanol to obtain Ni. 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode.

[0040] Example 5:

[0041] (1) The nickel foam (2cm*10cm) was ultrasonically cleaned using acetone, 0.1M hydrochloric acid, deionized water and ethanol respectively;

[0042] (2) Dissolve 2 mmol of NiCl2·6H2O, 2 mol of Na2MoO4·2H2O and 10 mmol of urea in 150 mL of deionized water with stirring.

[0043] (3) Dissolve 4 mmol of sodium hypophosphite in 150 mL of deionized water to obtain a sodium hypophosphite solution. Add this solution to the mixed solution obtained in step (2) while stirring.

[0044] (4) Transfer the mixed solution obtained in step (3) and the two pieces of nickel foam treated in step (1) together into a stainless steel reactor with a Teflon liner. The sealed reactor is kept at 200°C for 5 hours. After the reactor cools to room temperature, the nickel foam is removed and rinsed with deionized water and ethanol to obtain Ni. 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode.

[0045] Example 6:

[0046] (1) The nickel foam (2cm*3cm) was ultrasonically cleaned using acetone, 0.1M hydrochloric acid, deionized water and ethanol respectively;

[0047] (2) Dissolve 1 mmol of NiCl2·6H2O, 1 mmol of Na2MoO4·2H2O and 5 mol of urea in 15 mL of deionized water with stirring;

[0048] (3) Dissolve 2 mmol of sodium hypophosphite in 15 mL of deionized water to obtain a sodium hypophosphite solution. Add this solution to the mixed solution obtained in step (2) while stirring.

[0049] (4) Transfer the mixed solution obtained in step (3) and the two pieces of nickel foam treated in step (1) together into a stainless steel reactor with a Teflon liner. Keep the sealed reactor at 200°C for 24 hours. After the reactor cools to room temperature, remove the nickel foam, rinse it with deionized water and ethanol to obtain Ni. 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode.

[0050] Example 7:

[0051] (1) The nickel foam (4cm*6cm) was ultrasonically cleaned using acetone, 0.1M hydrochloric acid, deionized water and ethanol respectively;

[0052] (2) Dissolve 10 mmol of NiCl2·6H2O, 10 mmol of Na2MoO4·2H2O and 20 mmol of urea in 150 mL of deionized water with stirring.

[0053] (3) Dissolve 20 mmol of sodium hypophosphite in 150 mL of deionized water to obtain a sodium hypophosphite solution. Add this solution to the mixed solution obtained in step (2) while stirring.

[0054] (4) Transfer the mixed solution obtained in step (3) and the 5 pieces of nickel foam treated in step (1) together into a stainless steel reactor with a Teflon liner. The sealed reactor is kept at 100°C for 36 hours. After the reactor cools to room temperature, the nickel foam is removed and rinsed with deionized water and ethanol to obtain Ni. 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode.

[0055] Compare with Example 1:

[0056] (1) The nickel foam (2cm*3cm) was ultrasonically cleaned using acetone, 0.1M hydrochloric acid, deionized water and ethanol respectively;

[0057] (2) Dissolve 2 mmol of NiCl2·6H2O and 5 mmol of urea in 30 mL of deionized water with stirring;

[0058] (3) Dissolve 2 mmol of sodium hypophosphite in 15 mL of deionized water to obtain a sodium hypophosphite solution. Add this solution to the mixed solution obtained in step (2) while stirring.

[0059] (4) Transfer the mixed solution obtained in step (3) and the one piece of nickel foam treated in step (1) together into a stainless steel reactor with a Teflon liner. The sealed reactor is kept at 180°C for 10 hours. After the reactor cools to room temperature, the nickel foam is removed and rinsed with deionized water and ethanol to obtain Ni. 11 (HPO3)8(OH)6 / nickel foam composite electrode.

[0060] Compare with Example 2:

[0061] Nickel foam (2cm*3cm in size) was ultrasonically cleaned using acetone, 0.1M hydrochloric acid, deionized water, and ethanol, respectively, to obtain nickel foam electrodes.

[0062] Figure 1 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam composite electrode and Ni prepared by the method described in Comparative Example 111 XRD pattern of (HPO3)8(OH)6 / nickel foam electrode. In Figure (a), the diffraction peaks at 44.5°, 51.8°, and 76.4° are attributed to the (111), (200), and (220) crystal planes of the nickel foam substrate (PDF 04-0850), respectively. The diffraction peaks observed at 28.2° and 32.7° correspond to Ni… 11 The (220) and (420) crystal planes of (HPO3)8(OH)6 (PDF 81-1065). The diffraction peaks at 21.9° and 34.3° are Mo8O. 23 (PDF 05-0339) crystal planes (400) and (213). The diffraction peaks in Figure (b) correspond to metallic nickel (PDF 04-0850) and Ni, respectively. 11 The diffraction peaks of (HPO3)8(OH)6 (PDF 81-1065) correspond to those of Ni. XRD results indicate that this invention successfully synthesized Ni. 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam composite electrode.

[0063] Figure 2 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 SEM image of a nickel foam composite electrode. Figure 2 As shown in Figures a and b, the sample grows uniformly on a nickel foam framework and consists of numerous microspheres with a multi-level structure. The magnified SEM image (Figure c) reveals that the microspheres are assembled from even smaller secondary units with an uneven surface. This surface assembly of smaller secondary units not only provides a larger specific surface area for the reaction but also exposes more active sites on the catalyst, thus contributing to improved electrocatalytic activity.

[96] .

[0064] Figure 3 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 TEM and HRTEM images of the nickel foam composite electrode. Figure 3 The TEM image in a shows that Ni 11 (HPO3)8(OH)6 / Mo8O 23 The composite catalyst microsphere structure, which is consistent with Figure 2 The SEM results for c are consistent, showing that the surface of the microspheres is uneven and has a burr-like structure. Figure 3 b is Ni 11 (HPO3)8(OH)6 / Mo8O 23HRTEM images of the composite catalyst show that the surface of the burr-structured microspheres is composed of Ni. 11 (HPO3)8(OH)6 nanosheets and Mo8O 23 It is assembled from nanosheets, many of which are translucent. The lattice fringes with a spacing of 0.32 nm correspond to Ni. 11 The (220) crystal plane of (HPO3)8(OH)6 (PDF 81-1065) has lattice fringes with a spacing of 0.26 nm as Mo8O. 23 The (213) crystal plane of (PDF 05-0339) is consistent with the XRD results. Meanwhile, abundant heterostructures are also observed in the HRTEM images. Individual nanosheets exhibit a single-crystal structure but possess edge defects, and edge dislocations and defects are observed at the interfaces. The single-crystal structure of the nanosheets facilitates electron transport. The presence of these heterostructures and edge defects provides more active sites for the catalytic reaction, and the strong interaction between the two components contributes to the redistribution of surface charge, increasing the charge conduction rate and thus enhancing the electrocatalytic activity of the catalyst.

[0065] Figure 4 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam composite electrode and Ni prepared by the method described in Comparative Example 1 11 XPS spectrum of (HPO3)8(OH)6 / nickel foam electrode. Figure (a) shows the Ni... 11 (HPO3)8(OH)6 / Mo8O 23 The XPS full spectrum of the nickel foam composite electrode shows that the sample surface is mainly composed of elements such as Ni, Mo, O, and P. In the high-resolution spectrum of Ni2p in Figure (b), the peaks located at approximately 855.6 eV and 873.3 eV are attributed to Ni2p. 3 / 2 Orbital and Ni 2p 1 / 2 The orbital electron binding energy, with two satellite peaks appearing around 861.2 and 879.5 eV, indicates that the nickel on the two electrode surfaces is converted into Ni. 2+ The ionic form exists. The XPS high-resolution spectrum of P 2p in Figure (c) shows a peak around 132.8 eV indicating a PO bond, meaning the P element exists in its oxidized state on both electrode surfaces. Comparing the binding energies of the two electrodes in Figures (b) and (c), it can be seen that the Ni in Example 1... 11 (HPO3)8(OH)6 / Mo8O 23 The Ni 2p and P 2p binding energies of the nickel foam composite electrode are compared with those of the comparative example Ni. 11Compared to (HPO3)8(OH)6 / nickel foam electrodes, both shifted by 0.2 eV towards lower binding energies. This indicates that Ni 11 (HPO3)8(OH)6 and Mo8O 23 After coupling, more electrons accumulate in Ni. 11 Multiple interfaces are formed around (HPO3)8(OH)6. This charge redistribution optimizes the intermediate adsorption / dissociation energy, lowers the reaction energy barrier for H2O activation, and helps improve catalytic performance. Figure (d) shows the XPS spectrum of Mo 3d, from which four peaks can be fitted. The peaks at 230.1 eV and 232.1 eV are attributed to Mo 3d. 5 / 2 The binding energies, with peaks at 232.9 eV and 235.1 eV, are attributed to Mo 3d. 3 / 2 Binding energy. The O 1s spectrum in Figure (e) shows three peaks at 529.6 eV, 530.5 eV, and 531.6 eV, corresponding to MO (M = Ni, Mo), OH, and PO bonds, respectively.

[0066] Figure 5 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 Linear sweep voltammetric curves of hydrogen generation HER at the cathodes of the nickel foam composite electrode (performance test cut size 1cm*1cm, hereinafter the same) and electrodes prepared by the methods described in Comparative Examples 1 and 2 (performance test cut size 1cm*1cm, hereinafter the same) were obtained. The HER performance of each electrode was tested using an H-type three-electrode system in an alkaline medium (1.0M KOH solution). As shown in the figure, the Ni of this invention… 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam composite electrode reaches 10 mA / cm 2 At a current density of [value missing], the overpotential is only 76mV, far lower than that of the comparative example Ni [value missing]. 11 (HPO3)8(OH)6 / nickel foam electrode (131mV) and contrast electrode 2 (180mV). Current density reaches 200mA / cm². 2 At that time, the overpotential of the composite electrode in Example 1 was only 254mV, which was still lower than that of the Ni in Comparative Example 1. 11 (HPO3)8(OH)6 / foamed nickel electrode and comparative nickel foam electrode. This illustrates the Ni... 11 (HPO3)8(OH)6 / Mo8O 23 The nickel foam composite electrode exhibits excellent HER performance.

[0067] Figure 6 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O23 Potential-time curves of nickel foam composite electrodes under constant current. This was achieved by testing Ni under constant current. 11 (HPO3)8(OH)6 / Mo8O 23 The HER stability of the nickel foam composite electrode is measured by the change in potential over time. The figure shows that at 10 mA / cm², the HER stability is... 2 20mA / cm 2 and 50mA / cm 2 The chronopotential curves under different current densities did not change significantly, confirming that Ni... 11 (HPO3)8(OH)6 / Mo8O 23 The nickel foam composite electrode exhibits excellent HER stability.

[0068] Figure 7 Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 The conversion rate of HMF and the yield of its oxidation products as a function of charge in the HMF oxidation process of the nickel foam composite electrode anode are shown in curve (a) and the cycle stability experiment is shown in (b). The Ni... 11 (HPO3)8(OH)6 / Mo8O 23 The selectivity and stability of the nickel foam composite electrode during electrocatalytic anodic HMF oxidation, for Ni 11 (HPO3)8(OH)6 / Mo8O 23 A constant voltage was applied to the working electrode of nickel foam, and HMF was electro-oxidized in a 1.0 M KOH electrolyte containing 10 mM HMF. High-performance liquid chromatography (HPLC) was used to detect the products during the oxidation process. Figure (a) shows the concentration of HMF and its different oxidation products as a function of charge during the electrocatalytic oxidation of HMF. As shown, after a charge of 60 C, HMF was completely oxidized, and the yield of FDCA reached 99.36%, close to 100%. This indicates that Ni... 11 (HPO3)8(OH)6 / Mo8O 23 The nickel foam composite electrode exhibits excellent electrocatalytic HMF oxidation performance and excellent FDCA selectivity. Figure (b) shows the Ni... 11 (HPO3)8(OH)6 / Mo8O 23 The cycling stability diagram of the nickel foam composite electrode during HMF oxidation to prepare FDCA shows that Ni 11 (HPO3)8(OH)6 / Mo8O 23 The nickel foam composite electrode exhibits good stability for the electrocatalytic oxidation of HMF to prepare FDCA.

[0069] Figure 8Ni prepared by the method described in Example 1 11 (HPO3)8(OH)6 / Mo8O 23 / Comparison of polarization curves of urea oxidation and OER at the anode of the nickel foam composite electrode. In an alkaline medium containing 0.5M urea, using an H-type three-electrode system, the Ni prepared by the method described in Example 1 of this invention... 11 (HPO3)8(OH)6 / Mo8O 23 A nickel foam composite electrode was used for the urea oxidation reaction (UOR) at the anolyte, with a comparison made to the pure water electrolysis OER without urea. As shown in the figure, only an applied voltage of 1.46V was required to achieve 200mA / cm during the urea oxidation reaction (UOR). 2 The current density is [not specified]. The OER used for water oxidation reaches 200 mA / cm². 2 The required current density necessitates an applied voltage of 1.76V. This illustrates the Ni prepared by the method described in Example 1. 11 (HPO3)8(OH)6 / Mo8O 23 The urea oxidation process using a foamed nickel composite electrode exhibits significant kinetic advantages. Some organic wastewaters contain large amounts of urea pollutants, and the products of urea oxidation (UOR) are only non-toxic N2, CO2, and H2O, making it a green and environmentally friendly wastewater treatment method. Simultaneously, it can be coupled with cathode hydrogen production to generate green energy, hydrogen gas.

[0070] Ni prepared by the method described in this invention 11 (HPO3)8(OH)6 / Mo8O 23 / The nickel foam composite electrode material is used for the electrocatalytic oxidation degradation of organic dyes in aqueous solutions, and also exhibits excellent electrocatalytic degradation performance, making it suitable for the electrocatalytic oxidation treatment of organic wastewater. The Ni prepared by the method described in this invention... 11 (HPO3)8(OH)6 / Mo8O 23 / Foamed nickel composite electrode materials are used for the electrocatalytic oxidation of organic matter and also have excellent electrocatalytic oxidation performance, which can be used for the electrocatalytic oxidation of organic matter to synthesize new substances.

[0071] 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 other changes, substitutions, simplifications, etc. made without departing from the principle and process of the present invention are equivalent substitutions and should be included within the protection scope of the present invention.

Claims

1. A Ni 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode, characterized in that The composite electrode is made of Ni grown in situ on the surface of nickel foam. 11 (HPO3)8(OH)6 nanosheets and Mo8O 23 A self-supporting electrode composed of multi-level composite microspheres assembled from nanosheets is used for the cathode water reduction to produce hydrogen and the anode selective oxidation of 5-hydroxymethylfurfural to produce 2,5-furandicarboxylic acid, as well as the electro-oxidation purification of organic chemical wastewater. The preparation of the composite electrode includes the following steps: (1) Acetone, 0.1 M hydrochloric acid, deionized water and ethanol were used to ultrasonically clean nickel foam with a size of 1-10 cm * 1-10 cm in sequence. (2) Dissolve 0.1–10 mmol of NiCl2·6H2O, 0.1–10 mmol of Na2MoO4·2H2O and 0.5–50 mmol of urea in 15–150 mL of deionized water with stirring; (3) Dissolve 0.1–20 mmol of sodium hypophosphite in 15–150 mL of deionized water to obtain a sodium hypophosphite solution, and add this solution to the mixed solution obtained in step (2) while stirring; (4) Transfer the mixed solution obtained in step (3) and 1–10 pieces of nickel foam treated in step (1) together into a stainless steel reactor with a Teflon liner. Seal the reactor and heat it at 80–200 °C. o The reactor was kept at a constant temperature for 0.5–48 h. After the reactor cooled to room temperature, the nickel foam was removed and rinsed with deionized water and ethanol to obtain Ni. 11 (HPO3)8(OH)6 / Mo8O 23 / Nickel foam bifunctional composite electrode.

Images