Anion-modified NiCo hydroxide electro-catalytic material and application thereof

Abstract

The invention relates to the field of electrocatalytic materials, in particular to an anion modified NiCo hydroxide electrocatalytic material and application thereof. The NiCo hydroxide modified by phosphate radicals and other anions is synthesized through a two-step hydrothermal method, and the performance of the NiCo hydroxide for preparing amide through electro-catalysis ethanolamine oxidative coupling is studied. Taking the NiCo hydroxide modified by phosphate as an example, under the optimal condition, the productivity and Faraday efficiency of acetamide achieved by the NiCoPO catalyst reach the maximum value and are superior to those reported at present. It is found that the catalytic activity and stability of the catalyst can be remarkably improved through introduction of anions, and the yield and Faraday efficiency of acetamide in five cycles are kept relatively stable. Meanwhile, NiCoPO can efficiently catalyze oxidative coupling of other long-chain alcohols and aromatic ring alcohols with ammonia. The invention provides a new thought and method for developing an efficient and stable electrocatalyst, and also provides powerful support for industrial application of alcohol oxidative coupling preparation of organic compounds such as amide and the like.

Description

Technical Field

[0001] This application relates to the field of electrocatalytic materials, and more particularly to an anion-modified NiCo hydroxide electrocatalytic material and its applications. Background Technology

[0002] Alcohols (such as ethanol and glycerol) serve as important platform molecules for biomass conversion. Their electrocatalytic oxidation reactions can not only replace traditional high-energy-consuming and high-polluting chemical oxidation processes, but also directionally synthesize high-value-added chemicals (such as carboxylic acids and amides). At the same time, they can couple hydrogen evolution and energy storage processes, thus possessing the dual advantages of environmental friendliness and economic value.

[0003] Integrating the oxidation and upgrading of biomass alcohol molecules with a metal-air battery to construct a novel hybrid air battery holds promise for alleviating the problems of low energy efficiency and poor cycle stability in traditional reversible zinc-air batteries. Therefore, it represents a promising new energy conversion device with significant application potential in energy storage and conversion. Furthermore, the oxidative coupling of biomass alcohol molecules with other molecules to construct complex high-value molecules has important applications in synthetic chemistry, energy, and materials. For example, amides, as an important class of organic compounds, have wide applications in medicine, pesticides, dyes, and polymer materials. Electrocatalytic alcohol oxidation and upgrading to amides avoids the drawbacks of traditional synthesis methods such as high temperature, high pressure, and high pollution; however, it still suffers from low product Faradaic efficiency, low catalyst selectivity, and poor stability. In addition, zinc-alcohol-air batteries still need to satisfy the cathode ORR and anolyte alcohol oxidation reactions within the same space.

[0004] Noble metals (such as Pd, Ir, and Ru) exhibit excellent catalytic activity in alcohol oxidation reactions (AOR), typically achieving high current densities and low Tafel slopes during catalysis. However, the scarcity of precious metal resources, their high cost, and potential problems such as dissolution, agglomeration, and poisoning during operation limit their widespread adoption in practical applications.

[0005] Transition metals, as a class of elements with rich chemical properties and wide applications, have varied valence states and unique electronic structures, enabling them to participate in a variety of redox reactions. Therefore, the search for transition metal catalysts to replace noble metals has become a current research hotspot. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this application provides an anion-modified NiCo hydroxide electrocatalytic material and its applications.

[0007] To achieve the above objectives, the technical solution of this application is as follows: An anion-modified NiCo hydroxide electrocatalytic material, the preparation method of which includes the following steps: Urea, cobalt nitrate hexahydrate and ammonium fluoride were dispersed in water to obtain a first solution. The first solution and nickel foam were reacted with water to obtain the precursor NiCo(OH)2. Anion-modified NiCo hydroxide electrocatalytic materials were obtained by hydrothermal reaction of the precursor NiCo(OH)2 and anionic salt aqueous solution.

[0008] Preferably, the anion is one or more of phosphate, pyrophosphate, molybdate, and borate.

[0009] Preferably, the anion is phosphate.

[0010] Preferably, the anionic salt is NaH2PO4.

[0011] Preferably, the concentration of cobalt nitrate hexahydrate is 0.5-2 mmol per 30 mL; and the concentration of NaH2PO4 in the anionic salt aqueous solution is 0.05-0.4 M.

[0012] Preferably, the concentration of cobalt nitrate hexahydrate is 1 mmol per 30 mL; and the concentration of NaH2PO4 in the anionic salt aqueous solution is 0.1 M.

[0013] The application of the anion-modified NiCo hydroxide electrocatalytic material in the electrocatalytic alcohol oxidation reaction, as described above.

[0014] The above-mentioned anion-modified NiCo hydroxide electrocatalytic material is used for the electrocatalytic coupling of alcohol and ammonia oxidation.

[0015] A method for preparing acetamide, which involves electrocatalyzing the oxidative coupling of alcohol and ammonia using an anion-modified NiCo hydroxide electrocatalytic material as described above.

[0016] Preferably, the electrocatalytic reaction system includes a working electrode and an electrolyte. The working electrode comprises anion-modified NiCo hydroxide electrocatalytic material as described in any one of claims 1-6. The electrolyte comprises KOH, ethanol, and NH3. The concentration of KOH is 0.5 M-1.5 M, the concentration of ethanol is 0.10 M-0.25 M, the concentration of NH3 is 6 M-12 M, and the electrolysis potential is 0.60-0.75 V vs. Hg / HgO.

[0017] The beneficial effects of this application are as follows: This application synthesizes phosphate and other anion-modified NiCo hydroxides via a two-step hydrothermal method, and studies their electrocatalytic performance in the oxidative coupling of ethanolamine to prepare amides. Taking phosphate-modified NiCo hydroxide as an example, under optimal conditions—ammonia concentration of 9.0 M, ethanol concentration of 0.2 M, KOH concentration of 1.0 M, and electrolysis potential of 0.70 V vs. Hg / HgO—the NiCoPO catalyst exhibits the highest catalytic activity, with an acetamide production rate of 427 μmol / cm³. 2 Both the yield of acetamide ( / h) and the Faradaic efficiency (34%) reached their maximum values, surpassing previously reported levels. This invention reveals that the introduction of anions significantly enhances the catalytic activity and stability of the catalyst, with the yield of acetamide and the Faradaic efficiency (FE) remaining relatively stable across five cycles. Simultaneously, NiCoPO exhibits highly efficient catalytic coupling of other long-chain alcohols and aromatic alcohols with ammonia. Therefore, this invention provides new ideas and methods for developing efficient and stable electrocatalysts, and also strongly supports the industrial application of oxidative coupling of alcohols to prepare amides and other organic compounds. Furthermore, this research lays a solid foundation for further exploration and understanding of the impact mechanism of anion modification on catalyst performance, and is expected to drive future research progress in related fields. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0019] Figure 1 (a) SEM image of NiCo(OH)2, (d) TEM image of NiCo(OH)2, (b, c) SEM image of NiCoPO, (e, f) TEM image of NiCoPO; Figure 2 (a) High-resolution transmission electron microscopy (HRTEM) image of NiCoPO, (b) HRTEM image of NiCoPO and (c) corresponding EDS elemental distribution map; Figure 3 (a) XRD pattern of NiCo(OH)2, (b) XRD pattern of NiCoPO, (c) Raman spectrum of NiCo(OH)2, (d) Raman spectrum of NiCoPO; Figure 4 (a) Isothermal adsorption-desorption curves and (b) pore size distribution of NiCoPO; Figure 5 XPS spectra of NiCo(OH)2 and NiCoPO: (a) full spectrum, (b) fine Ni 2p spectrum, (c) fine Co 2p spectrum, and (d) fine NiCoPO 2p spectrum. Figure 6 (a) Co K-edge XANES spectrum, (b) Co K-edge Fourier transform EXAFS spectrum, (c) EXAFS R-space fitting result of Co in NiCoPO, (d) Ni K-edge XANES spectrum, (e) Ni K-edge Fourier transform EXAFS spectrum, and (f) EXAFS R-space fitting result of Ni in NiCoPO for NiCoPO, Co foil, CoO and Co2O3. Figure 7 (a) Co of NiCoPO, (b) Co foil, (c) Ni of NiCoPO, and (d) Ni foil wavelet transform diagrams; Figure 8 LSV curves of NiCoPO materials in different electrolytes with varying concentrations of cobalt nitrate: (a) 1.0 M KOH, (b) 1.0 M KOH + 0.1 M Ethanol, (c) 0.1 M KOH + ethanol + 2.0 M NH3; Figure 9 LSV curves of NiCoPO materials in different electrolytes with varying concentrations of NaH2PO4: (a) 1.0 M KOH, (b) 1.0 M KOH + 0.1 M Ethanol, (c) 0.1 M KOH + Ethanol + 2.0 M NH3; Figure 10 LSV curves of NiCo(OH)2 and NiCoPO in (a) 1.0 M KOH, (b) 1.0 M KOH + 0.1 M Ethanol, and (c) 1.0 M KOH + 0.1 M Ethanol + 2.0 M NH3; Figure 11 LSV curves of NiCoPO in (a) 1.0 M KOH electrolyte containing (0.02 M-0.15 M) ethanol and (b) 1.0 M KOH electrolyte containing (0.20 M-3.00 M) ethanol; Figure 12 LSV curves of NiCoPO on 1.0 M KOH + 0.1 M Ethanol electrolyte containing different concentrations of ammonia; Figure 13(a) ¹H NMR spectrum of NiCoPO after electrolysis at a constant potential of 0.65 V vs. Hg / HgO for 2 h in a single-port electrolytic cell containing 0.1 M Ethanol and 9.0 M NH3 KOH electrolytes; (b) Faraday efficiency and yield of acetamide. Figure 14 The following graphs show the Faradaic efficiency and yield of acetamide after electrolysis of NiCoPO for 2 h at a constant potential of 0.65 V vs. Hg / HgO in a single-port electrolyzer containing different concentrations of NH3 (0.1 M Ethanol and 1.0 M KOH), the Faradaic efficiency and yield of acetamide after electrolysis of NiCoPO for 2 h at a constant potential of 0.65 V vs. Hg / HgO in a single-port electrolyzer containing different concentrations of ethanol (9.0 M NH3 and 1.0 M KOH), and the it curves and Faradaic efficiency and yield of acetamide after electrolysis of NiCoPO for 2 h at different potentials in a single-port electrolyzer containing 1.0 M KOH + 0.2 M Ethanol + 9.0 M NH3. Figure 15 XPS results of NiCoPO after different reaction times: (a) Co 2p fine spectrum, (b) Ni 2p fine spectrum. (c) XRD patterns of NiCoPO before and after reaction. XPS results of NiCoPO before and after reaction: (d) Ni 2p fine spectrum, (e) Co 2p fine spectrum, (f) P 2p fine spectrum; Figure 16 (a) Reaction pathway of the COR process; (b) Acetamide FE and yield graph of NiCo(OH)2, NiCoPO and NF in a single-port electrolytic cell containing 1.0 M KOH + 0.2 M Ethanol + 9.0 M NH3 electrolyte, electrolyzed at constant potential of 0.70 V vs. Hg / HgO for 2 h each time; (c) Cyclic stability graph of NiCoPO in a single-port electrolytic cell containing 1.0 M KOH + 0.2 M Ethanol + 4.0 M NH3 electrolyte, electrolyzed at constant potential of 0.70 V vs. Hg / HgO each time; (d) LSV curves of NiCo hydroxide modified with different anions; (e) Acetamide FE and yield graph. Figure 17 (a) SEM image of NiCoP2O7, (b) SEM image of NiCoMoO4, (c) SEM image of NiCoBO, (d) TEM image of NiCoP2O7, (e) TEM image of NiCoMoO4, (f) TEM image of NiCoBO. Figure 18(a) XRD spectrum of NiCoP2O7, (b) XRD spectrum of NiCoMoO4, (c) XRD spectrum of NiCoBO, (d) Raman spectrum of NiCoP2O7, (e) Raman spectrum of NiCoMoO4, (f) Raman spectrum of NiCoBO. Detailed Implementation

[0020] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0022] Example 1: Preparation of cobalt-nickel hydroxide (NiCoPO) catalyst: (1) Pretreatment of nickel foam: Place a piece of nickel foam in a beaker, add 5.0 M HCl, acetone, and deionized water respectively, and ultrasonically clean for 10 minutes to remove surface grease and oxides. Let it dry before use.

[0023] (2) Preparation of NiCo(OH)2: Weigh out 0.60 g (1 mmol) of urea, 0.296 g (1.00 mmol) of cobalt nitrate hexahydrate, and 0.154 g (0.4 mmol) of ammonium fluoride using an electronic balance and place them in a 50 ml clean beaker. Add 30 mL of deionized water and stir magnetically for 30 min. Then transfer the mixture to a polytetrafluoroethylene-lined autoclave and add the treated nickel foam (NF). Seal the autoclave and place it in an oven. React at 120 °C for 6 hours. After the autoclave has cooled to room temperature naturally, remove it, wash it with deionized water, and then dry it in a 60 °C oven to obtain NiCo(OH)₂ for later use.

[0024] (3) Preparation of NiCoPO: Weigh 1.5 mmol of sodium dihydrogen phosphate using an electronic balance and place it in a 50 ml clean beaker. Add 30 mL of deionized water and stir magnetically for 30 min until dissolved. Then transfer the solution to a polytetrafluoroethylene-lined autoclave and add the NiCo(OH)2 prepared in (2) into the autoclave. Seal the autoclave and place it in an oven. React at 140 °C for 4 hours. After the autoclave has cooled naturally, remove it, wash it with deionized water, and dry it in an oven at 60 °C to obtain the target catalyst NiCoPO for later use.

[0025] Figure 1 (a, d) show the SEM and TEM images of NiCo(OH)2 obtained after a hydrothermal reaction, where a dense array of nanoneedles can be seen growing vertically on the surface of nickel foam. Figure 1 (b, c) shows the NiCo phosphate obtained by hydrothermally heating NaH2PO4 and NiCo hydroxide precursor again, which transforms into a nanosheet structure. Figure 1 (b,c,e,f)), which interweave to form a rich porous structure. This unique nanosheet structure not only increases the specific surface area of ​​the catalyst and provides more active sites, but may also promote the effective diffusion of reactants and products, thereby improving catalytic performance.

[0026] Further HRTEM images revealed lattice fringes of NiCoPO with a spacing of 0.77 nm, corresponding to the (110) crystal plane of Co3(PO4)2(H2O)8, confirming the successful synthesis of nickel cobalt phosphate. Figure 2 (a)). Simultaneously, the elemental mapping diagram of energy scattering spectroscopy (EDS) ( Figure 2 (b,c) shows the uniform distribution of Co, Ni, P and O elements on the nanosheets, indicating that the phosphate was successfully prepared.

[0027] To determine the phase composition and crystal structure of NiCoPO and its comparative sample NiCo(OH)2, a multi-faceted analysis was conducted using XRD combined with Raman spectroscopy. Figure 3 (a) shows the XRD pattern of NiCo(OH)2. By comparison, it can be found that the diffraction peaks of NiCo(OH)2 are consistent with the standard card of Co(OH)2 (PDF#97-006763), indicating that nickel cobalt hydroxide was successfully synthesized and the introduction of Ni did not significantly change the lattice spacing. Figure 3 Characteristic diffraction peaks were observed at 11.2°, 13.3°, 28.4°, and 30.1° in (b), corresponding to the (110), (020), (310), and (201) crystal planes of Co3(PO4)2(H2O)8, respectively (PDF#04-009-3836). (Compared with HRTEM images...) Figure 2(a) The consistent lattice fringes (0.77 nm) observed in the inset confirm the successful synthesis of cobalt nickel phosphate. Furthermore, no other impurity peaks were observed in the XRD pattern, indicating the high purity of the prepared NiCoPO sample. Raman spectroscopy was used to analyze the molecular vibrational modes and chemical bond information of NiCo(OH)₂ and NiCoPO. Figure 3 (c) is the Raman spectrum of NiCo(OH)2, where the image at 460 cm⁻¹ can be observed. -1 and 524 cm -1 The two nearby characteristic peaks correspond to the stretching vibration peaks of Ni-OH and Co-OH, respectively, confirming the synthesis of nickel-cobalt hydroxide. For example... Figure 3 (d) is located at 900-1100 cm -1 The broad peak at the surface PO4 is attributed to both symmetric and asymmetric stretching vibrations of the PO bond, proving that the PO4 at the surface... 3- The presence of these characteristic peaks confirms the successful preparation of phosphate.

[0028] In addition, to understand the content of each component in NiCoPO, ICP-MS and elemental analysis were performed, and the results are shown in Table 1. Furthermore, the specific surface area of ​​phosphate was calculated to be 24.807 m² using BET analysis. 2 / g, with an average pore size of 3.954 nm ( Figure 4 (a) indicates that the catalyst has a suitable specific surface area and pore structure, which is beneficial to the catalytic reaction.

[0029] Table 1. Content of each element in NiCoPO.

[0030] Note: The superscript 'a' represents the ICP-AES test result, and 'b' represents the elemental analysis test result.

[0031] The differences in surface elemental composition, chemical state, and electronic structure between NiCo(OH)2 and NiCoPO were investigated using X-ray photoelectron spectroscopy (XPS). Figure 5 (a) Characteristic peaks of Co, Ni, and O elements can be observed in the full spectrum of NiCo(OH)2, and additional characteristic peaks of P element are detected in the full spectrum of NiCoPO, consistent with the EDS elemental mapping results. Ni 2p spectrum ( Figure 5 (b) shows that NiCo(OH)₂ has two characteristic peaks at binding energies of 856.1 eV and 873.8 eV, which are attributed to Ni 2p, respectively. 3 / 2 and Ni 2p 1 / 2This confirms that Ni exists in the +2 valence state. The two vibrational peaks at 861.61 eV and 879.96 eV are satellite peaks (labeled "Sat."). The Ni 2p spectrum of NiCoPO (…) Figure 5 (b)) Ni 2p 3 / 2 and Ni 2p 1 / 2 The binding energies are 854.9 eV and 872.7 eV, respectively, indicating that Ni mainly exists in the +2 valence state. The binding energies shift by 1.16 eV and 0.07 eV compared to NiCo(OH)2, respectively, suggesting a change in the electronic interaction of the Ni-O bond. The Co 2p spectrum of NiCo(OH)2 (…) Figure 5 (c) Co2p 3 / 2 (781.5 eV) and Co 2p 1 / 2 The main peak (797.1 eV) corresponds to the electron binding energy of the 2p orbital of Co²⁺, while the satellite peaks at 786.61 eV and 802.49 eV are charge transfer peaks of the Co-OH bond. In the high-resolution XPS spectrum of Co 2p in NiCoPO, Co 2p... 3 / 2 (781.1 eV) and Co 2p 1 / 2 The main peak (796.9 eV) indicates that Co still predominates in the +2 valence state. The binding energy shifts by approximately 0.45 eV and 0.17 eV compared to NiCo(OH)2, respectively, indicating that the electronic structure of the Co-O bond has been restructured due to the introduction of PO4³⁻. The p 2p spectrum of NiCoPO (…) Figure 5 (d) shows only a PO bond characteristic peak of 132.75 eV (corresponding to PO4). 3- No metal-phosphorus bonds (such as the 398 eV peak of the Ni-P bond) were detected, confirming that phosphorus exists stably in the form of phosphate. The introduction of phosphate leads to changes in the electronic structure of Ni and Co, which may affect the active sites of the catalyst and thus its catalytic performance.

[0032] Table 2. K-edge EXAFS fitting parameters (S0) of Co, Co foil, CoO, and Co2O3 in NiCoPO samples 2 =0.73) Table 3. K-edge EXAFS fitting parameters (S0) of Ni, Ni foil and Ni(OH)2 in NiCoPO samples 2 =0.97) Note: CN: coordination number, R: bond length; σ 2 Debye-Waller factor; ΔE0: energy shift; R factor: goodness of fit.

[0033] To further investigate the chemical state and coordination structure of the NiCoPO sample, X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) were characterized using a synchrotron radiation source, and compared with standard samples of Co foil, CoO, and Co2O3. Figure 6 (a) shows that the CoK-edge absorption edge of NiCoPO is higher than that of Co foil and closer to CoO, indicating that the valence state of Co in NiCoPO is close to +2, consistent with the XPS results. In addition, EXAFS reveals the local coordination structure of NiCoPO. Figure 6 The peaks at approximately 1.57 Å and 2.64 Å in (b) are attributed to the first shell of the Co-O bond and the single scattering path of the Co-Co bond, respectively. Fitting with Athena and Artmis software (Table 2) yielded a coordination number of 4.7 for the Co-O bond and 9 for the Co-Co bond. Notably, no Co-P coordination peak was detected, indicating that phosphate is primarily coordinated with Co via MO bonds. Figure 7 The dominant peaks at 7.4 Å⁻¹ and 8.0 Å⁻¹ in the wavelet transform (WT) analysis further validate the local coordination environment of the Co-O bond. Similarly, Figure 6 (d) The Ni K-edge absorption edge in NiCoPO is higher than that of Ni foil and close to that of Ni(OH)2, indicating that the valence state of Ni species in NiCoPO is close to +2, which further confirms the valence state analysis results of XPS. Figure 6 In (e), the main peak at 1.60 Å corresponds to the first shell of the Ni-O bond, and the peak at 2.83 Å belongs to the single scattering path of the Ni-Ni bond. The fitting results (Table 3) show that the coordination number of the Ni-O bond is 6.4. Wavelet transform ( Figure 7 The peak at 6.15 Å⁻¹ further supports the localized coordination structure of the Ni-O bond. Combining XAS and XPS data, the Ni in NiCo phosphate... 2+ With Co 2+ via PO4 3- The O atoms form a bridging structure (Ni-O-Co), and this electronic coupling effect is different from that of NiCo hydroxide. It is expected that the introduction of P will significantly improve the activity of the catalyst.

[0034] Example 2 The electrochemical performance of the materials was tested using a CHI 760E workstation with a three-electrode system. All tests were conducted in a single-port electrolytic cell, using a Pt sheet as the counter electrode, Hg / HgO (filled with 1.0 M KOH solution) as the reference electrode, and the prepared catalyst as the working electrode with an area of ​​1 × 0.5 cm².2 All electrochemical curves in this experiment were obtained directly without correction. All test electrodes were activated first using cyclic voltammetry (CV) in 1.0 M KOH solution at a scan rate of 10 mV / s within the range of (-0.8–1.3) V vs. Hg / HgO for 20 cycles. Linear sweep voltammetry (LSV) was performed at a scan rate of 5 mV / s, using 1.0 M KOH, ethanol (ETOH), and NH3 as the electrolyte. Potentiostatic (it) testing was conducted over 2 hours, and the electrolyte was collected after the reaction was complete to detect the products. Electrochemical impedance spectroscopy (EIS) was performed at 10 mV / s. -1 Up to 10 5 The measurements were taken within a frequency range of Hz, with an amplitude of 10 mV. Electrochemical stability was tested at a voltage of 0.7 V, with the electrolyte replaced every 2 hours. The test results are as follows.

[0035] 1. Effect of the molar amount of cobalt nitrate hexahydrate on the electrochemical performance of the material: Based on Example 1, while keeping other synthesis conditions of NiCoPO unchanged, the molar amount of cobalt nitrate hexahydrate (denoted as X) was varied. Electrochemical LSV tests were performed on the prepared samples in 1.0 M KOH, 1.0 M KOH + 0.1 M Ethanol, and 1.0 M KOH + 0.1 M Ethanol + 2.0 M NH3 to evaluate and screen for the catalyst with the highest activity. Figure 8 As shown, the catalyst exhibits the highest oxidation peak current density when the molar amount of cobalt nitrate (X = 1.00 mmol), indicating that the catalyst at this molar amount has the best electrochemical activity. Furthermore, by comparing the LSV curves in different electrolyte solutions, it can be observed that the oxidation peak current density of the catalyst is significantly increased in alkaline solutions containing ethanol and ammonia, which further confirms the high efficiency of the NiCoPO catalyst in the alcohol oxidation upgrade reaction.

[0036] 2. Effect of NaH₂PO₄ molar amount on the electrochemical performance of the material: Based on Example 1, with other conditions unchanged and the molar amount of cobalt nitrate fixed at 1.00 mmol, the concentration of NaH₂PO₄ added was varied (denoted as X). Electrochemical LSV tests were performed on the prepared samples in 1.0 M KOH, 1.0 M KOH + 0.1 M Ethanol, and 1.0 M KOH + 0.1 M Ethanol + 2.0 M NH₃ to evaluate and screen for the catalyst with the highest activity. As X increased from 0.05 M to 0.40 M, the electrochemical performance of the material increased. Figure 9As shown, the onset potential of the catalyst in 1.0 M KOH, 1.0 M KOH + 0.1 M Ethanol, or 1.0 M KOH + 0.1 M Ethanol + 2.0 M NH3 solutions all showed a trend of first increasing and then decreasing. The peak current density increased most significantly when the NaH2PO4 concentration increased to 0.10 M, indicating the highest catalytic activity. Therefore, X = 0.10 M was selected as the optimal phosphating amount. The NiCoPO4 used in subsequent studies was synthesized under conditions of (1.00 mmol) cobalt nitrate hexahydrate and (0.10 M) NaH2PO4.

[0037] 3. Changes in the electrochemical performance of the catalyst before and after anion modification: LSV tests were performed on unmodified NiCo(OH)₂ and phosphate-modified NiCo hydroxide under the same conditions. For example... Figure 10 As shown, in a 1.0 M KOH electrolyte, the NiCoPO catalyst exhibited a higher oxidation peak current density than NiCo(OH)2, indicating that the phosphate-modified catalyst possesses superior electrochemical activity. Furthermore, in alkaline solutions containing ethanol and ammonia, the current density of the NiCoPO catalyst was further increased compared to that of NiCo(OH)2. Figure 10 (b,c)). This further confirms that phosphate modification has a positive impact on the electrochemical performance of NiCo hydroxide in the alcohol-ammonia oxidation upgrade reaction.

[0038] 4. The effect of ethanol and ammonia concentrations in the electrolyte on the electrochemical performance of the material: Figure 11 The LSV curves show that the oxidation peak current density of the NiCoPO catalyst first increases and then decreases with increasing ethanol concentration. Figure 12 The figure shows the LSV curves of NiCoPO catalyst in 1.0 M KOH + 0.1 M Ethanol solutions containing different concentrations of ammonia. As can be seen from the figure, the onset potential gradually increases and the current density gradually decreases as the concentration of ammonia increases.

[0039] 5. Analysis of electrocatalytic oxidative coupling products of ethanolamines: The effect of different concentrations of KOH on the oxidative coupling reaction of ethanolamines was systematically studied in a single-port electrolyzer using a constant potential electrolysis method. Figure 13 (a) is the 1H NMR spectrum of the product obtained after electrolysis at a constant potential of 0.65 V vs. Hg / HgO for 2 h, which proves that the oxidative coupling products are acetamide, acetate and acetonitrile. Figure 13(b) is a graph showing the Faradaic efficiency (FE) and yield of acetamide obtained after 2 h of constant potential electrolysis at different KOH concentrations. As the KOH concentration increases from 0.5 M to 1.5 M, the yield of acetamide first increases and then decreases, reaching a maximum at 1.0 M (yield of 336.0 μmol / cm³). 2 / h, FE is 34%). This may be because KOH, as an electrolyte, increases in concentration, which enhances the conductivity of the solution, thereby promoting the electrocatalytic reaction. However, when the KOH concentration is too high, excessive OH-... - Ions may compete with ethanol molecules for adsorption on the catalyst surface, leading to a reduction in the amount of ethanol adsorbed and thus affecting the oxidative coupling reaction of ethanol. Therefore, 1.0 M KOH was chosen as the optimal electrolyte concentration.

[0040] 6. Effect of ammonia concentration on acetamide yield and Faradaic efficiency (FE): such as Figure 14 As shown in (a), under the conditions of a fixed KOH concentration of 1.0 M and an ethanol concentration of 0.2 M, the acetamide production first increases and then decreases with increasing ammonia concentration, reaching a maximum at 9.0 M (productivity of 231.4 μmol / cm² / h, FE of 26%). Therefore, 9.0 M NH₃ is selected as the optimal concentration.

[0041] 7. Effect of ethanol concentration (0.1-0.5 M) on acetamide yield: The effect of ethanol concentration (0.1-0.5 M) on acetamide yield was further investigated in the optimized ammonia (9.0 M) and KOH (1.0 M) system. Figure 14 As shown in (b), the yield of acetamide also showed a trend of first increasing and then decreasing with increasing ethanol concentration. When the ethanol concentration was 0.2 M, the yield of acetamide was 336.0 μmol / cm³. 2 The concentration of ethanol (0.2 M ethanol) and Faraday efficiency (34%) reached their highest values. Therefore, 0.2 M ethanol was chosen as the optimal concentration.

[0042] 8. Effect of electrolysis potential on acetamide yield: In an electrolyte of 1.0 M KOH + 0.2 M Ethanol + 9.0 M NH3, the potential dependence of acetamide yield was investigated by changing the potential. Figure 14 (c) shows that the current density gradually increases with increasing applied potential. Specifically, as... Figure 14As shown in (d), the yield and Faraday efficiency of acetamide are both low at lower potentials, possibly due to the slow electron transfer rate, which leads to insufficient utilization of the active sites on the catalyst surface, affecting the oxidative coupling reaction of ethanol. With increasing potential, the yield and Faraday efficiency of acetamide gradually increase. When the potential reaches 0.70 V vs. Hg / HgO, the yield of acetamide (427.0 μmol / cm³) is significantly higher. 2 / h) and FE (34%) reach their maximum values. Therefore, 0.70 V vs. Hg / HgO is chosen as the optimal electrolysis potential.

[0043] 9. Investigation of phosphate-modified NiCo hydroxyoxides (NiCoPO) generated by in-situ phosphate reconstruction: XPS tests were conducted under optimal testing conditions (1.0 M KOH + 0.2 M Ethanol + 9.0 M NH3, 0.70 V vs. Hg / HgO), as shown in Figure (16 (a,b)). NiCoPO showed a significant peak shift after 2 min of reaction, and the Co 2p and Ni 2p peaks remained essentially unchanged at different reaction times. This indicates that the Ni and Co elements in NiCoPO underwent a strong interaction with the reaction medium in the early stages of the reaction, leading to a change in their electronic structure, and this transformation was largely completed within a short time. The Co 2p peak shifted towards lower binding energies, while the Ni 2p peak shifted towards higher binding energies. Figure 15 As shown in (d, e), the Ni after the NiCoPO reaction is composed of Ni... 2+ To Ni 3+ A transformation occurred; the Co after the NiCoPO reaction was converted into Co. 2+ Mostly towards Co 3+ The transformation indicates that during the electrocatalytic oxidative coupling of alcohols and ammonia, Ni and Co ions on the NiCoPO surface underwent oxidation, forming high-valence Ni and Co active species. These high-valence Ni and Co active species typically exhibit higher catalytic activity because they can more effectively accept and transfer electrons, thereby promoting the reaction. Furthermore, phosphate ions on the surface of phosphate-modified NiCo hydroxyoxides (NiCoPO) may also participate in the electrocatalytic process, such as... Figure 15 As shown in (f), a small amount of P remains after the electrocatalytic COR reaction, and the binding energy position remains essentially unchanged. XRD analysis was performed on NiCoPO before and after the reaction. Figure 15 (c) indicates that the catalyst after the reaction does not exist in the form of phosphate, but in the form of NiCo hydroxy oxide.

[0044] 10. Properties of NiCo hydroxyoxides before and after anion (phosphate) modification: The reaction pathway of the COR process is as follows Figure 16As shown in (a), ethanol is first oxidized to acetaldehyde intermediate, which is then attacked by NH3 as a nucleophile to form an aminoethanol species. Subsequently, the aminoethanol undergoes dehydrogenation or dehydration to form acetamide or aldimine species, and the aldimine undergoes dehydrogenation to form a nitrile. To compare the performance of NiCo hydroxyoxides before and after anion (phosphate) modification, the electrocatalytic acetamide production performance of NiCoPO and NiCo(OH)2 under optimal test conditions was studied. Figure 16 As shown in (b), the acetamide yield of NiCoPO (427.0 μmol / cm³) 2 The concentration of 215 μmol / cm³ was significantly higher than that of NiCo(OH)₂ (215.0 μmol / cm³). 2 / h) and bare substrate NF (36.0 μmol / cm 2 The figure ( / h) indicates that phosphate modification can enhance catalytic activity. The high performance of NiCoPO may be attributed to the fact that the introduction of phosphate anions optimizes the surface electronic structure of the catalyst, thereby improving its catalytic activity for ethanol oxidation and ammonia nucleophilic attack.

[0045] 11. Stability and cycling performance evaluation of NiCoPO catalysts: such as Figure 16 (c) shows that in the electrolyte of 1.0 M KOH + 0.2 MEtOH + 4.0 M NH3, NiCoPO underwent five cycles at a potential of 0.70 V vs. Hg / HgO. The current density did not decrease significantly, and the acetamide yield and Faradaic efficiency remained at a high level. This indicates that the NiCoPO catalyst has good stability and repeatability in the electrolysis process and can continuously and effectively catalyze the oxidative coupling reaction of ethanol to produce acetamide.

[0046] 12. Universality of NiCoPO catalyst in diverse alcohol-ammonia oxidative coupling reactions: Benzyl alcohol (aromatic alcohol) and n-propanol (long-chain aliphatic alcohol) were selected as model substrates, and extended experiments were conducted based on the ethanol-ammonia coupling system (1.0 M KOH + 0.2 M Ethanol + 9.0 M NH3, 0.70 V vs. Hg / HgO). Experimental results showed that the oxidative coupling of long-chain alcohols and aromatic alcohols with ammonia could achieve high Faradaic efficiency and high yields. Specifically, the propionamide method achieved an FE of 33.4% with a yield of 366.4 μmol / cm² / h, while the benzamide method achieved an FE as high as 41.9% with a yield of 564.4 μmol / cm² / h.

[0047] The following examples demonstrate the construction of NiCo hydroxy oxide systems with different anion modifications.

[0048] Example 3: Preparation of NiCoP2O7: Weigh 1.5 mmol of sodium pyrophosphate using an electronic balance and place it in a 50 ml clean beaker. Add 30 mL of deionized water and stir magnetically for 30 min until dissolved. Then transfer the solution to a polytetrafluoroethylene-lined autoclave and add the NiCo(OH)2 prepared in (2) into the autoclave. Seal the autoclave and place it in an oven. React at 140 °C for 4 hours. After the autoclave has cooled naturally, remove it, wash it with deionized water, and dry it in an oven at 60 °C to obtain the target catalyst NiCoP2O7 for later use.

[0049] Example 4: Preparation of NiCoMoO4: Weigh 1.5 mmol of sodium molybdate using an electronic balance and place it in a 50 ml clean beaker. Add 30 mL of deionized water and stir magnetically for 30 min until dissolved. Then transfer the solution to a polytetrafluoroethylene-lined autoclave and add the NiCo(OH)2 prepared in (2) into the autoclave. Seal the autoclave and place it in an oven. React at 140 °C for 4 hours. After the autoclave has cooled naturally, remove it, wash it with deionized water, and dry it in an oven at 60 °C to obtain the target catalyst NiCoMoO4 for later use.

[0050] Example 5: Preparation of NiCoBO: Weigh 1.5 mmol of sodium borate using an electronic balance and place it in a 50 ml clean beaker. Add 30 mL of deionized water and stir magnetically for 30 min until dissolved. Then transfer the solution to a polytetrafluoroethylene-lined autoclave and add the NiCo(OH)2 prepared in (2) into the autoclave. Seal the autoclave and place it in an oven. React at 140 °C for 4 hours. After the autoclave has cooled naturally, remove it, wash it with deionized water, and dry it in an oven at 60 °C to obtain the target catalyst NiCoBO for later use.

[0051] Examples 3-5 further expanded the application to other anions (pyrophosphate (P2O7)). 4- ), molybdate (MoO4) and borate (B(OH)4) - The morphological changes, phase composition and local structural differences of NiCo hydroxide systems modified by (e.g.) were analyzed by SEM, TEM, XRD and Raman spectroscopy. Figure 17 (a) NiCoP2O7 exhibits a nanoflower-like structure, while NiCoMoO4 ( Figure 17 (b) exhibits a nanoneedle-like structure similar to NiCo(OH)₂, but the needle-like structure is relatively dispersed. NiCoBO₂ Figure 17 (c) then exhibits a distinct nanoneedle-like structure. Figure 17The TEM morphology shown in (b, e, f) is consistent with that of SEM. The introduction of these anions significantly alters the morphology of the original NiCo(OH)2. These different morphologies may have a significant impact on the activity, selectivity and stability of the catalyst.

[0052] Figure 18 (a) The XRD pattern of NiCoP2O7 shows a high degree of agreement with the CoCo2(P2O7) standard card (PDF#97-005-9291), indicating that the NiCo hydroxide was successfully modified with pyrophosphate. Raman spectroscopy ( Figure 18 In (d), 1051 cm -1 The peak corresponds to the stretching vibration of the terminal PO bond of the pyrophosphate group, 750 cm⁻¹. -1 The peaks are attributed to the symmetrical vibrations of the POP bridging bond, further verifying the P2O7... 4- The introduction of . Figure 18 (b) The XRD pattern of NiCoMoO4 is consistent with the CoMoO4 standard card (PDF#97-002-3808), proving that the molybdate modification was successful. Raman spectroscopy ( Figure 18 (e) 900 cm -1 The peak can be attributed to the stretching vibration of the Mo-O bond, confirming the successful introduction of molybdate. Figure 18 (c) The XRD pattern of NiCoBO showed a low match with the standard card, possibly due to its low crystallinity. Further analysis using Raman spectroscopy... Figure 18 (f) Analysis, 684 cm -1 The peak corresponds to the collective stretching vibration of the BO bond, 530 cm⁻¹ -1 The peaks were attributed to BOB bridging vibrations, providing indirect evidence for borate modification. These results further facilitated the successful synthesis of NiCo hydroxide samples modified with different anions.

[0053] Electrochemical comparison of NiCo hydroxy oxide systems modified with different anions: Extended research on NiCo hydroxy oxide systems modified with molybdate, pyrophosphate, borate and other anions ( Figure 16 (d) First, LSV analysis was performed, and it was found that the current density of these anion-modified NiCo hydroxy oxides was higher than that of NiCo(OH)₂, indicating that anion modification can effectively improve the electrocatalytic activity of the catalyst. Figure 16 As shown in (e), under optimal test conditions, the yield of acetamide produced by molybdate-modified NiCo hydroxyoxide (NiCoMoO4) is 348.0 μmol / cm³. 2 The yield of pyrophosphate-modified NiCo hydroxy oxides (NiCoP2O7) was 382.0 μmol / cm³ / h. 2 / h, the borate-modified NiCo hydroxyoxide (NiCoBO) concentration was 368.8 μmol / cm³. 2 / h, both are superior to unmodified NiCo(OH)2 (215.0 μmol / cm). 2 The result ( / h) indicates that anion modification can significantly enhance the oxidative coupling performance of alcohols and ammonia.

[0054] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An anion-modified NiCo hydroxide electrocatalytic material, characterized in that, Its preparation method includes the following steps: Urea, cobalt nitrate hexahydrate and ammonium fluoride were dispersed in water to obtain a first solution. The first solution and nickel foam were reacted with water to obtain the precursor NiCo(OH)2. Anion-modified NiCo hydroxide electrocatalytic materials were obtained by hydrothermal reaction of the precursor NiCo(OH)2 and anionic salt aqueous solution.

2. The anion-modified NiCo hydroxide electrocatalytic material according to claim 1, characterized in that, The anion is one or more of phosphate, pyrophosphate, molybdate, and borate.

3. The anion-modified NiCo hydroxide electrocatalytic material according to claim 2, characterized in that, The anion is phosphate.

4. The anion-modified NiCo hydroxide electrocatalytic material according to claim 3, characterized in that, The anionic salt is NaH2PO4.

5. The anion-modified NiCo hydroxide electrocatalytic material according to claim 1, characterized in that, The concentration of cobalt nitrate hexahydrate is 0.5-2 mmol per 30 mL; the concentration of NaH2PO4 in the anionic salt aqueous solution is 0.05-0.4 M.

6. The anion-modified NiCo hydroxide electrocatalytic material according to claim 1, characterized in that, The concentration of cobalt nitrate hexahydrate is 1 mmol per 30 mL; the concentration of NaH2PO4 in the anionic salt aqueous solution is 0.1 M.

7. The application of the anion-modified NiCo hydroxide electrocatalytic material as described in any one of claims 1-6 in the electrocatalytic oxidation of alcohols.

8. The application of the anion-modified NiCo hydroxide electrocatalytic material as described in any one of claims 1-6 in the electrocatalytic coupling of alcohol and ammonia oxidation.

9. A method for preparing acetamide, characterized in that, It is prepared by electrocatalytic coupling of alcohol and ammonia oxidation using an anion-modified NiCo hydroxide electrocatalytic material as described in any one of claims 1-6.

10. The method for preparing acetamide according to claim 9, characterized in that, The electrocatalytic reaction system includes a working electrode and an electrolyte. The working electrode comprises anion-modified NiCo hydroxide electrocatalytic material as described in any one of claims 1-6. The electrolyte comprises KOH, ethanol, and NH3. The concentration of KOH is 0.5 M-1.5 M, the concentration of ethanol is 0.10 M-0.25 M, the concentration of NH3 is 6 M-12 M, and the electrolysis potential is 0.60-0.75 V vs. Hg / HgO.

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