Preparation and application of ferro-nickel layered hydroxide with bridging mortise and tenon joint structure

Abstract

The invention belongs to the technical field of catalysts, and particularly relates to preparation and application of a ferro-nickel layered hydroxide with a bridging tenon-and-mortise structure. According to the composite material, nickel-iron layered hydroxide is used as a substrate, and groups on the two sides of parachlorobenzoic acid are in mortise and tenon joint between layers of the nickel-iron layered hydroxide in a bridging mode through a one-step hydrothermal method. In the prepared composite material, the layered structure of the ferro-nickel layered hydroxide is stabilized by a unique bridging structure, and the interface electronic structure is regulated and controlled by carboxylic acid and chlorine atom groups, so that the dissolution of metal ions is inhibited, and the proton transfer path is optimized. According to the invention, the optimization strategy of the catalytic activity of the nickel-iron layered hydroxide electrocatalyst is enriched, and the commercial application value of the nickel-iron layered hydroxide electrocatalyst is expanded.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalysts, and in particular relates to a preparation method of a nickel-iron layered hydroxide catalyst with a bridged mortise and tenon structure and an application of the catalyst in an electrocatalytic water decomposition and oxygen production process. Background Art

[0002] Water electrolysis technology achieves efficient decomposition of water molecules through the cathode hydrogen evolution reaction (HER) and the anode oxygen evolution reaction (OER). Its core bottleneck lies in the activity, stability and cost of electrode catalysts. Currently, mainstream catalysts rely on precious metal materials (such as IrO2 and RuO2 for OER and Pt for HER), which are limited by resource scarcity and high costs. Non-precious metal catalysts (such as transition metal compounds and carbon-based materials) can reduce raw material costs, but they are not effective at high current densities (>1A / cm 2 ) or in strong acid / alkali electrolysis environments, and the active sites are not fully utilized, resulting in overpotential (OER@10mA / cm 2 >300mV, HER@10mA / cm 2 The current state of the art in green hydrogen production is limited by its high sensitivity (>100mV) and industrial-grade stability (<1000 hours). While existing technologies such as nanostructure control, defect engineering, and single-atom dispersion strategies can partially improve catalytic performance, they are still limited by poor compatibility with large-scale preparation processes and weak adaptability to dynamic operating conditions.

[0003] The layered structure of NiFe-LDH has the advantages of being controllable and easy to synthesize, but it still has problems such as poor activity and metal ion dissolution. To improve these problems, Li et al. introduced terephthalic acid into the interlayer of NiFe-LDH, inducing interfacial electron redistribution, accelerating proton transfer, and promoting hydroxyl adsorption, activation, and dissociation (Angewandte Chemie, 2021, 60, 18129-18137); Lin et al. used lithium acetate to regulate the electronic structure of NiFe-LDH, stabilize the *OOH intermediate, and optimize the proton transfer pathway (Advanced Functional Materials, 2025, 35, 2413533); Hu et al. modified NiFe-LDH with porphyrin to increase the dissolution barrier and enhance self-repair ability to inhibit Fe dissolution (Advanced Functional Materials, 2023, 14, 6714). Based on this, the present invention provides a NiFe-LDH catalytic material with a bridged mortise and tenon structure, which stabilizes the layered structure of nickel-iron bimetallic layered hydroxide, inhibits the dissolution of metal ions under alkaline conditions, optimizes the proton transfer path, exhibits excellent electrocatalytic oxygen evolution performance and stability, and is suitable for the field of catalyst technology. Summary of the Invention

[0004] The present invention provides a method for preparing a nickel-iron layered hydroxide catalyst with a bridged mortise and tenon structure, which utilizes a bridging ligand to optimize the layered structure of the nickel-iron bimetallic layered hydroxide, inhibit the dissolution of strongly alkaline metal ions, optimize the proton transfer pathway, and enhance the electrocatalytic oxygen evolution activity and stability.

[0005] The nickel-iron layered hydroxide catalyst with a bridged mortise and tenon structure of the present invention is prepared by mixing a mixed solution of nickel salt and iron salt with a bridging ligand solution, adjusting the pH to a weakly alkaline state with a pH regulator, and then synthesizing the nickel-iron layered hydroxide composite material with a bridged mortise and tenon structure by a one-step hydrothermal method.

[0006] The preparation method of the nickel-iron layered hydroxide catalyst with a bridged mortise and tenon structure of the present invention comprises the following steps:

[0007] 1. Dissolve nickel salt and iron salt in deionized water and stir evenly to add solution A;

[0008] 2. Dissolve the bridging ligand in anhydrous ethanol and stir to obtain solution B;

[0009] 3. Mixing homogeneous solution A and homogeneous solution B and stirring them uniformly to obtain solution C;

[0010] 4. Use a pH adjuster to adjust the pH of solution C to a weak alkaline state;

[0011] 5. Solution C was transferred to a Teflon-lined reactor and a nickel-iron layered hydroxide with a bridged mortise and tenon structure was synthesized by a one-step hydrothermal method.

[0012] Furthermore, the preparation method of the nickel-iron layered hydroxide catalyst with the bridged mortise and tenon structure is as follows:

[0013] (1) Dissolve 0.6-0.8 mmol of nickel salt and 0.2-0.35 mmol of iron salt in 10 ml of deionized water and stir for 10-25 minutes;

[0014] (2) Dissolve 0.5-0.8 mmol of the bridging ligand in 15 mL of anhydrous ethanol and stir for 10-25 min;

[0015] (3) Mix the homogeneous solutions obtained in (1) and (2) and stir for 15 to 30 minutes;

[0016] (4) After the solution in (3) is stirred evenly, the pH of the solution is adjusted to 9.5-10.5 using a pH adjuster and stirred for 10-25 minutes;

[0017] (5) The pH-adjusted solution was transferred to a Teflon-lined reactor and heated at 100-130°C for 11-14 hours using a one-step hydrothermal method.

[0018] Preferably, in step (1), the molar mass of the nickel salt is 0.7-0.8 mmol, and the molar mass of the iron salt is 0.2-0.3 mmol.

[0019] Preferably, in step (2), the molar mass of the bridging ligand is 0.5 to 0.7 mmol.

[0020] Preferably, in step (3), the mixed solution is stirred for 20 to 30 minutes.

[0021] Preferably, in step (5), the temperature of the hydrothermal method is 110-120° C., and the insulation time is 11-13 h.

[0022] Furthermore, after the heat preservation is completed and the reaction is completed, the nickel-iron layered hydroxide with a bridged mortise and tenon structure is taken out and washed and dried. It is washed and centrifuged three times with deionized water and anhydrous ethanol respectively, and placed in a vacuum oven at 60° C. and vacuum dried for 10 to 15 hours.

[0023] In the nickel-iron layered hydroxide catalyst with a bridged mortise and tenon structure described in the present invention, the functional groups on both sides of the bridging ligand are anchored at both ends of the nickel-iron layered hydroxide, thereby stabilizing the catalyst structure.

[0024] The nickel-iron layered hydroxide catalyst with a bridged mortise and tenon structure described in the present invention has a unique group connection mode of the bridging ligand that optimizes the interlayer electronic structure, inhibits the dissolution of metal ions in the nickel-iron layered hydroxide, and improves stability.

[0025] Compared with the existing technology, the advantages and positive effects of the present invention are:

[0026] The present invention innovatively uses bridging ligands to anchor at both ends of nickel-iron layered hydroxide, thereby stabilizing the structure of the catalyst. The electronic effect of the bridging ligand regulates the interfacial electronic structure, optimizes the electron transport pathway, increases the energy barrier for metal ion dissolution, inhibits metal dissolution, improves catalytic performance, and shows excellent commercial prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0028] Figure 1 This is an SEM image of the nickel-iron layered hydroxide with a bridged mortise and tenon structure prepared in Example 1 of the present invention;

[0029] Figure 2 LSV curve of nickel-iron layered hydroxide with bridged mortise and tenon structure prepared in Example 1 of the present invention;

[0030] Figure 3 The off-situ XRD patterns of nickel-iron layered hydroxide before and after adding the bridging ligand in Example 1 of the present invention;

[0031] Figure 4 TEM spectra of nickel-iron layered hydroxide before and after adding the bridging ligand in Example 1 of the present invention;

[0032] Figure 5 This is the Raman spectrum of nickel-iron layered hydroxide before and after adding the bridging ligand in Example 1 of the present invention;

[0033] Figure 6 The XPS spectra of nickel-iron layered hydroxide before and after adding the bridging ligand in Example 1 of the present invention; DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to the embodiments, which will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several variations and improvements can be made without departing from the scope of the present invention, and all of these fall within the scope of protection of the present invention.

[0035] Example 1

[0036] A nickel-iron layered hydroxide catalyst with a bridged mortise and tenon structure, the preparation method of which comprises the following steps:

[0037] (1) Dissolve 0.75 mmol of nickel chloride and 0.25 mmol of ferric chloride in 10 mL of deionized water and stir magnetically for 10 min.

[0038] (2) Dissolve 0.6 mmol of p-chlorobenzoic acid (CA) in 15 mL of anhydrous ethanol and stir magnetically for 10 min;

[0039] (3) The homogeneous solutions obtained in (1) and (2) were mixed and magnetically stirred for 20 min;

[0040] (4) After the solution in (3) is stirred evenly, the pH of the solution is adjusted to 9.5-10.5 using a pH adjuster and stirred for 20 minutes;

[0041] (5) The pH-adjusted solution was transferred to a Teflon-lined reactor and heated at 120 °C for 12 h using a one-step hydrothermal method.

[0042] (6) After the reaction is completed, the obtained nickel-iron layered hydroxide precipitate with a 4-chlorobenzoic acid bridged mortise and tenon structure (NiFe-LDH-CA) is washed with deionized water and anhydrous ethanol and centrifuged three times, and then placed in a vacuum oven at 60°C for 12 hours.

[0043] Figure 1 The SEM spectrum of the nickel-iron layered hydroxide with a bridged mortise and tenon structure prepared in Example 1 of the present invention shows that the synthesized catalyst grows uniformly without abnormal nucleation;

[0044] Figure 2 This is the LSV curve of NiFe-LDH-CA prepared in Example 1 of the present invention, indicating that the introduction of the bridging ligand successfully improved the electrochemical performance;

[0045] Figure 3 The off-situ XRD patterns of nickel-iron layered hydroxide before and after adding the bridging ligand in Example 1 of the present invention indicate successful phase transformation of the catalytic material.

[0046] Figure 4 TEM spectra of nickel-iron layered hydroxide before and after adding the bridging ligand in Example 1 of the present invention, indicating that the introduction of the bridging ligand expands the interlayer spacing of the nickel-iron layered hydroxide;

[0047] Figure 5 The Raman spectra of nickel-iron layered hydroxide before and after adding the bridging ligand in Example 1 of the present invention indicate that the bridging ligand has successfully entered the interlayer;

[0048] Figure 6 The Cl 2p of the nickel-iron layered hydroxide before and after adding the bridging ligand in Example 1 of the present invention is 3 / 2 The XPS spectrum shows that the bridging ligand group is successfully anchored between the layers;

[0049] Example 2

[0050] A nickel-iron layered hydroxide catalyst with a bridged mortise and tenon structure, the preparation method of which comprises the following steps:

[0051] (1) Dissolve 0.75 mmol of nickel chloride and 0.25 mmol of ferric chloride in 10 mL of deionized water and stir magnetically for 10 min.

[0052] (2) Dissolve 0.5 mmol of p-chlorobenzoic acid (CA) in 15 mL of anhydrous ethanol and stir magnetically for 10 min;

[0053] (3) The homogeneous solutions obtained in (1) and (2) were mixed and magnetically stirred for 20 min;

[0054] (4) After the solution in (3) is stirred evenly, the pH of the solution is adjusted to 9.5-10.5 using a pH adjuster and stirred for 20 minutes;

[0055] (5) The pH-adjusted solution was transferred to a Teflon-lined reactor and heated to 100°C for 12 h using a one-step hydrothermal method.

[0056] (6) After the reaction is completed, the obtained nickel-iron layered hydroxide precipitate with a 4-chlorobenzoic acid bridged mortise and tenon structure (NiFe-LDH-CA) is washed with deionized water and anhydrous ethanol and centrifuged three times, and then placed in a vacuum oven at 60°C for 12 hours.

[0057] Example 3

[0058] A nickel-iron layered hydroxide catalyst with a bridged mortise and tenon structure, the preparation method of which comprises the following steps:

[0059] (1) Dissolve 0.6 mmol of nickel chloride and 0.2 mmol of ferric chloride in 10 mL of deionized water and stir magnetically for 10 min.

[0060] (2) Dissolve 0.6 mmol of p-chlorobenzoic acid (CA) in 15 mL of anhydrous ethanol and stir magnetically for 10 min;

[0061] (3) The homogeneous solutions obtained in (1) and (2) were mixed and magnetically stirred for 25 min;

[0062] (4) After the solution in (3) is stirred evenly, the pH of the solution is adjusted to 9.5-10.5 using a pH adjuster and stirred for 20 minutes;

[0063] (5) The pH-adjusted solution was transferred to a Teflon-lined reactor and heated at 120 °C for 12 h using a one-step hydrothermal method.

[0064] (6) After the reaction is completed, the obtained nickel-iron layered hydroxide precipitate with a 4-chlorobenzoic acid bridged mortise and tenon structure (NiFe-LDH-CA) is washed with deionized water and anhydrous ethanol and centrifuged three times, and then placed in a vacuum oven at 60°C for 12 hours.

[0065] Example 4

[0066] A nickel-iron layered hydroxide catalyst with a bridged mortise and tenon structure, the preparation method of which comprises the following steps:

[0067] (1) Dissolve 0.75 mmol of nickel chloride and 0.25 mmol of ferric chloride in 10 mL of deionized water and stir magnetically for 10 min.

[0068] (2) Dissolve 0.7 mmol of p-chlorobenzoic acid (CA) in 15 mL of anhydrous ethanol and stir magnetically for 10 min;

[0069] (3) The homogeneous solutions obtained in (1) and (2) were mixed and magnetically stirred for 30 min;

[0070] (4) After the solution in (3) is stirred evenly, the pH of the solution is adjusted to 9.5-10.5 using a pH adjuster and stirred for 20 minutes;

[0071] (5) The pH-adjusted solution was transferred to a Teflon-lined reactor and heated at 130 °C for 11 h using a one-step hydrothermal method.

[0072] (6) After the reaction is completed, the obtained nickel-iron layered hydroxide precipitate with a 4-chlorobenzoic acid bridged mortise and tenon structure (NiFe-LDH-CA) is washed with deionized water and anhydrous ethanol and centrifuged three times, and then placed in a vacuum oven at 60°C for 12 hours.

[0073] Example 5

[0074] A nickel-iron layered hydroxide catalyst with a bridged mortise and tenon structure, the preparation method of which comprises the following steps:

[0075] (1) Dissolve 0.75 mmol of nickel chloride and 0.25 mmol of ferric chloride in 10 mL of deionized water and stir magnetically for 10 min.

[0076] (2) Dissolve 0.8 mmol of p-chlorobenzoic acid (CA) in 15 mL of anhydrous ethanol and stir magnetically for 20 min;

[0077] (3) The homogeneous solutions obtained in (1) and (2) were mixed and magnetically stirred for 20 min;

[0078] (4) After the solution in (3) is stirred evenly, the pH of the solution is adjusted to 9.5-10.5 using a pH adjuster and stirred for 20 minutes;

[0079] (5) The pH-adjusted solution was transferred to a Teflon-lined reactor and heated at 120 °C for 14 h using a one-step hydrothermal method.

[0080] (6) After the reaction is completed, the obtained nickel-iron layered hydroxide precipitate with a 4-chlorobenzoic acid bridged mortise and tenon structure (NiFe-LDH-CA) is washed with deionized water and anhydrous ethanol and centrifuged three times, and then placed in a vacuum oven at 60°C for 12 hours.

[0081] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above-disclosed technical content to modify or modify the present invention into equivalent embodiments with equivalent variations. Any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention shall remain within the scope of protection of the present invention.

Claims

1. Preparation and application of nickel-iron layered hydroxide with a bridged mortise and tenon structure, characterized in that: The nickel-iron layered hydroxide catalyst is a powdered catalyst prepared by mixing a mixed solution of nickel salt and iron salt with an organic bridging ligand solution, then adjusting the solution to a weak alkaline state, and finally synthesizing the catalyst by a one-step hydrothermal method to express NiFe-LDH-BL.

2. The method for preparing a nickel-iron layered hydroxide with a bridged mortise and tenon structure according to claim 1, characterized in that The following steps are included: (1) Mixing nickel salt and iron salt in different proportions into a uniform solution; (2) dissolving the bridging ligand and mixing it with a mixed solution of nickel salt and iron salt; (3) adjusting the pH of the mixed solution to a weak alkaline state; (4) Nickel-iron layered hydroxide with a bridged mortise and tenon structure was synthesized in one step using a hydrothermal method.

3. The method for preparing a nickel-iron layered hydroxide with a bridged mortise and tenon structure according to claim 2, wherein: The nickel salt in step (1) is one of nickel chloride, nickel sulfate and nickel nitrate, and the concentration is 0.03-0.1 mol / L.

4. The method for preparing a nickel-iron layered hydroxide with a bridged mortise and tenon structure according to claim 2, wherein: The iron salt in step (1) is one of ferric chloride, ferric sulfate and ferric nitrate, and the concentration is 0.01-0.4 mol / L.

5. The method for preparing a nickel-iron layered hydroxide with a bridged mortise and tenon structure according to claim 2, wherein: The bridging ligand in step (2) is one of p-chlorobenzoic acid, terephthalic acid or o-chlorobenzoic acid.

6. The method for preparing a nickel-iron layered hydroxide with a bridged mortise and tenon structure according to claim 2, wherein: The concentration of the bridging ligand in step (2) is 0.3-0.6 mol / L.

7. The method for preparing a nickel-iron layered hydroxide with a bridged mortise and tenon structure according to claim 2, wherein: The pH value in step (3) is 9.5 to 10.5, and the pH regulator is one of sodium bicarbonate, urea and ammonium fluoride.

8. The method for preparing a nickel-iron layered hydroxide with a bridged mortise and tenon structure according to claim 2, wherein: The temperature of the hydrothermal method in step (4) is 110-140° C. and the time is 10-15 hours.

9. Nickel-iron layered hydroxide nanomaterial with a bridged mortise and tenon structure prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the nickel-iron layered hydroxide nanomaterial with a bridged mortise and tenon structure as claimed in claim 9 in electrocatalytic water decomposition and oxygen evolution.

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