A bimetallic organogel material made of iron and nickel and its preparation method

Abstract

This invention provides an iron-nickel bimetallic organic gel material and its preparation method, belonging to the field of oxygen evolution through water electrolysis application technology. This invention uses a simple one-step aqueous phase synthesis method, through Fe... 3+ Solution, Ni 2+ The solution and the organic ligand solution are mixed, allowed to stand, and then freeze-dried to obtain the target gel material. The gel material prepared by this invention has an open pore structure, good electrical conductivity, and iron-nickel bimetallic active sites, exhibiting high activity and stability in the catalytic electrolysis of water for oxygen evolution under alkaline conditions. Furthermore, the catalytic active sites are non-precious metals, saving production costs.

Description

Technical Field

[0001] This invention relates to the interdisciplinary fields of materials chemistry, electrochemistry, and catalysis chemistry, and specifically to a bimetallic organogel electrocatalytic material and its preparation method. Background Technology

[0002] Hydrogen energy, as a novel renewable energy system, boasts advantages such as high energy density and pollution-free combustion, and holds promise for replacing traditional fossil fuels. Furthermore, hydrogen can be used not only as fuel but also in industrial production, chemical feedstocks, and biomedicine, possessing high economic value. Utilizing renewable energy sources, such as solar and wind power, to convert into electricity for water electrolysis is a green and clean method of hydrogen production. Traditional water electrolysis methods are inefficient and require large amounts of electricity; improving efficiency and reducing costs are key to promoting the commercialization of hydrogen energy. Developing novel catalytic materials can improve water electrolysis efficiency, reduce energy consumption, and help lower costs, making its widespread application possible. In the process of water electrolysis for hydrogen production, the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode occur simultaneously. The slow four-electron transfer process at the anode, the OER, reduces the overall efficiency of water splitting. Utilizing highly active and stable electrocatalysts can improve catalytic performance and energy utilization. Currently, Ru-based catalysts typically exhibit excellent OER catalytic performance, with RuO2 often serving as the benchmark catalyst for OER. However, due to the scarcity, low durability, and high cost of Ru-based catalysts, there is still an urgent need to develop novel catalytic materials that are low-cost, highly active, and stable for large-scale commercial applications. In recent years, abundant and inexpensive non-precious metal electrocatalytic materials have also demonstrated excellent performance in overall water electrolysis catalysis. In particular, Co-based, Fe-based, and Ni-based materials are continuously being developed and hold promise as low-cost industrial electrocatalysts. Summary of the Invention

[0003] The purpose of this invention is to address the problems of high cost and limited applicability in existing water electrolysis reactions, where the anolyte OER half-reaction often uses Ru-based catalysts. This invention provides an iron-nickel bimetallic organogel electrocatalyst (FeNi-MOG) and its preparation method. The organometallic gel possesses a tunable porous structure, multifunctional ligands, and defined metal active centers. The optimized organometallic gel exhibits good conductivity, a simple synthesis method, and is easy to apply on a large scale. The FeNi-MOG electrocatalyst demonstrates excellent catalytic activity in alkaline electrolytes.

[0004] The technical solution adopted in this invention is to provide an iron-nickel bimetallic organogel electrocatalytic material, characterized by Fe 3+ and Ni 2+After undergoing a coordination reaction with the organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diisophthalic acid in an aqueous phase, the target product FeNi-MOG was obtained by freeze-drying.

[0005] The preparation method of the iron-nickel bimetallic organic gel electrocatalytic material is as follows:

[0006] Step 1: Dissolve iron salt and nickel salt separately in deionized water to prepare Fe salts of the same concentration. 3+ Solution and Ni 2+ Solution; the molar ratio of metallic iron salt, metallic nickel salt and deionized water is 1:1:2000-3000;

[0007] Step 2: Add the organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diphthalic acid and the organic base to deionized water, disperse by ultrasonication, and prepare a mixed solution; the molar ratio of the organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diyldiimino)diphthalic acid, the organic base, and deionized water is 1:0.05~0.1:2000~3000;

[0008] Step 3: Take an equal volume of the Fe prepared in Step 1 3+ Solution and Ni 2+ The solution was added dropwise to a mixed solution of the organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diisophthalic acid and an organic base prepared in step two. After stirring evenly, the mixture was allowed to stand at 20–50°C for 1–5 hours. The resulting gel-like product was freeze-dried for 12–24 hours. The solid product was washed 3–5 times with deionized water and dried at 50–100°C under a vacuum of 133 Pa for 10–12 hours to obtain the target product FeNi-MOG. 3+ Solution, Ni 2+ The volume ratio of the solution and the mixed solution of organic ligand and organic base is 1:1:0.8 to 1.2.

[0009] The preferred iron and nickel salts are ferric chloride and nickel chloride.

[0010] The organic base is preferably ethylenediamine or triethylamine.

[0011] The freeze-drying time is preferably 24 hours.

[0012] The beneficial effects of this invention are:

[0013] The iron-nickel bimetallic organogel electrocatalytic material prepared by the synthesis method provided in this invention has the following advantages:

[0014] (1) The iron-nickel metal salt raw materials used are inexpensive and easy to obtain. The synthesis conditions are mild, the operation is simple, and the yield is high, which is conducive to large-scale production and application.

[0015] (2) During the electrocatalytic process, the metal active sites generated by the in-situ electrochemical reconstruction of the FeNi-MOG bimetallic organic gel undergo synergistic coupling, which makes the FeNi-MOG electrocatalyst have better catalytic activity and stability in alkaline electrolyte. Attached Figure Description

[0016] Figure 1 Transmission electron microscopy image of FeNi-MOG prepared in Example 1;

[0017] Figure 2 X-ray diffraction pattern of FeNi-MOG prepared in Example 1;

[0018] Figure 3 Thermogravimetric analysis of FeNi-MOG prepared in Example 1;

[0019] Figure 4 X-ray photoelectron spectrum of FeNi-MOG prepared in Example 1;

[0020] Figure 5 Oxidation polarization curve of FeNi-MOG prepared in Example 1 in 1.0 mol / L KOH solution during water electrolysis;

[0021] Figure 6 Chronoamperometry results of FeNi-MOG prepared in Example 1 in 1.0 mol / L KOH solution. Detailed Implementation

[0022] The present invention will be further described in detail with reference to the accompanying drawings and embodiments. It should be noted that the purpose of this description is only to better understand the content of the present invention and not to limit the scope of protection of the present invention.

[0023] Example 1

[0024] Step 1: Dissolve 0.01 mol ferric chloride and 0.01 mol nickel chloride separately in 500 mL of deionized water to prepare Fe solutions of equal concentration. 3+ Solution and Ni 2+ Solution;

[0025] Step 2: Add 0.01 mol of the organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diisophthalic acid and 0.0005 mol of triethylamine to 500 mL of deionized water, disperse by ultrasonication, and prepare a mixed solution;

[0026] Step 3: Take the Fe prepared in Step 1 3+1 mL of solution and Ni 2+ 1 mL of solution was added dropwise to 2 mL of a mixed solution of organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diisophthalic acid and triethylamine prepared in step two. After stirring evenly, the mixture was allowed to stand at 20 °C for 2 hours. The gel product was freeze-dried for 24 hours, and the solid product was washed three times with deionized water. After drying at 50 °C for 12 hours under a vacuum of 133 Pa, the target product FeNi-MOG was obtained.

[0027] The structure, composition, and water electrolysis oxidation performance of the FeNi-MOG synthesized in Example 1 were characterized.

[0028] Figure 1 The image shows a transmission electron microscope image of the FeNi-MOG prepared in Example 1. As can be seen from the image, the gel exhibits a nanofiber structure. This unique structure not only enhances the conductivity but also promotes mass transfer between the reactants and the active sites of the catalyst.

[0029] Figure 2 The X-ray diffraction pattern of FeNi-MOG prepared in Example 1 shows a broad peak at around 26.7°, with no other obvious high-intensity diffraction peaks, indicating that the synthesized gel material has low crystallinity and is an amorphous phase material.

[0030] Figure 3 The thermogravimetric analysis (TGA) curve of FeNi-MOG prepared in Example 1 is shown. It can be seen from the curve that there are two obvious weight loss segments. It is speculated that the first segment of weight loss is due to the evaporation of a small amount of residual solvent in the sample, and the second segment is due to the decomposition of the sample under high temperature conditions.

[0031] Figure 4 The image shows the X-ray photoelectron spectrum of the FeNi-MOG prepared in Example 1; the presence of C, N, O, Fe and Ni elements can be seen from the image.

[0032] Figure 5 The graph shows the electrocatalytic oxygen evolution polarization curve of the FeNi-MOG catalyst prepared in Example 1 in a 1.0 mol / L KOH solution; it can be seen from the graph that at 10 mA / cm 2 At a given current density, FeNi-MOG requires a small overpotential of 320 mV, demonstrating that FeNi-MOG exhibits excellent electrocatalytic oxygen evolution performance.

[0033] Figure 6 The FeNi-MOG catalyst prepared in Example 1 was subjected to chronoamperometry in a 1.0 mol / L KOH solution. As can be seen from the figure, FeNi-MOG has good stability. At an overpotential of 320 mV, the current density decreased by only 7.8% after 240,000 seconds.

[0034] Example 2

[0035] Step 1: Dissolve 0.01 mol ferric chloride and 0.01 mol nickel chloride separately in 550 mL of deionized water to prepare Fe solutions of equal concentration. 3+ Solution and Ni 2+ Solution;

[0036] Step 2: Add 0.01 mol of the organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diisophthalic acid and 0.0006 mol of triethylamine to 500 mL of deionized water, disperse by ultrasonication, and prepare a mixed solution;

[0037] Step 3: Take the Fe prepared in Step 1 3+ 1 mL of solution and Ni 2+ 1 mL of solution was added dropwise to 2 mL of a mixed solution of organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diisophthalic acid and triethylamine prepared in step two. After stirring evenly, the mixture was allowed to stand at 30 °C for 5 hours. The gel product was freeze-dried for 12 hours, and the solid product was washed three times with deionized water. After drying at 50 °C for 12 hours under a vacuum of 133 Pa, the target product FeNi-MOG was obtained.

[0038] The FeNi-MOG catalyst was tested for electrocatalytic oxygen evolution in a 1.0 mol / L KOH solution, requiring a current density of 10 mA / cm² to be achieved at 344 mV. 2 .

[0039] Example 3

[0040] Step 1: Dissolve 0.01 mol ferric chloride and 0.01 mol nickel chloride separately in 600 mL of deionized water to prepare Fe solutions of equal concentration. 3+ Solution and Ni 2+ Solution;

[0041] Step 2: Add 0.01 mol of the organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)di-isophthalic acid and 0.0005 mol of ethylenediamine to 500 mL of deionized water, disperse by ultrasonication, and prepare a mixed solution.

[0042] Step 3: Take the Fe prepared in Step 1 3+ 1 mL of solution and Ni 2+1 mL of solution was added dropwise to 2 mL of a mixed solution of organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diisophthalic acid and triethylamine prepared in step two. After stirring evenly, the mixture was allowed to stand at 50 °C for 2 hours. The gel product was freeze-dried for 12 hours, and the solid product was washed three times with deionized water and dried at 50 °C for 12 hours under a vacuum of 133 Pa to obtain the target product FeNi-MOG.

[0043] The FeNi-MOG catalyst was tested for electrocatalytic oxygen evolution in a 1.0 mol / L KOH solution, requiring 352 mV to achieve a current density of 10 mA / cm². 2 .

[0044] Example 4

[0045] Step 1: Dissolve 0.01 mol ferric chloride and 0.01 mol nickel chloride separately in 500 mL of deionized water to prepare Fe solutions of equal concentration. 3+ Solution and Ni 2+ Solution;

[0046] Step 2: Add 0.01 mol of the organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diisophthalic acid and 0.001 mol of ethylenediamine to 500 mL of deionized water, disperse by ultrasonication, and prepare a mixed solution.

[0047] Step 3: Take the Fe prepared in Step 1 3+ 1 mL of solution and Ni 2+ 1 mL of solution was added dropwise to 2 mL of a mixed solution of organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diisophthalic acid and triethylamine prepared in step two. After stirring evenly, the mixture was allowed to stand at 20 °C for 5 hours. The gel product was freeze-dried for 20 hours, and the solid product was washed three times with deionized water. After drying at 50 °C for 12 hours under a vacuum of 133 Pa, the target product FeNi-MOG was obtained.

[0048] The FeNi-MOG catalyst was tested for electrocatalytic oxygen evolution in a 1.0 mol / L KOH solution, requiring a current density of 10 mA / cm² to be achieved at 338 mV. 2 .

[0049] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. Those skilled in the art can make corresponding changes and substitutions based on the technical solutions and inventive concepts of the present invention, and any modifications or substitutions with the same performance or purpose should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an iron-nickel bimetallic organogel electrocatalytic material, characterized in that... Includes the following steps: Step 1: Prepare Fe salts of the same concentration by dissolving iron and nickel salts separately in deionized water. 3+ Solution and Ni 2+ Solution; the molar ratio of metallic iron salt, metallic nickel salt and deionized water is 1:1:2000~3000; Step 2: Add the organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diphthalic acid and the organic base to deionized water, disperse by ultrasonication, and prepare a mixed solution; the molar ratio of the organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diyldiimino)diphthalic acid, the organic base, and deionized water is 1:0.05~0.1:2000~3000; Step 3: Take an equal volume of the Fe prepared in Step 1 3+ Solution and Ni 2+ The solution was added dropwise to a mixed solution of the organic ligand 5,5'-(6-(4-carboxyphenylamino)-1,3,5-triazine-2,4-diimino)diisophthalic acid and an organic base prepared in step two. After stirring evenly, the mixture was allowed to stand at 20-50°C for 1-5 hours. The resulting gel-like product was freeze-dried for 12-24 hours. The solid product was washed 3-5 times with deionized water and dried at 50-100°C under a vacuum of 133 Pa for 10-12 hours to obtain the target product FeNi-MOG. 3+ Solution, Ni 2+ The volume ratio of the solution and the mixed solution of organic ligand and organic base is 1:1:0.8~1.

2.

2. The preparation method of the iron-nickel bimetallic organogel electrocatalytic material according to claim 1, characterized in that: The iron and nickel salts used in step one are ferric chloride and nickel chloride.

3. The preparation method of the iron-nickel bimetallic organogel electrocatalytic material according to claim 1, characterized in that: The first step involves preparing Fe. 3+ Solution and Ni 2+ The solutions have the same concentration.

4. The preparation method of the iron-nickel bimetallic organogel electrocatalytic material according to claim 1, characterized in that: The organic bases used in step two are ethylenediamine and triethylamine.

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