Nano self-supporting nickel-iron-manganese material and application thereof in electrolytic hydrogen production

Abstract

The invention relates to the technical field of electrolytic hydrogen production, and discloses a nanometer self-supporting nickel-iron-manganese material and application thereof in the field of electrolyzed water, the nanometer self-supporting nickel-iron-manganese material is a material which can be generated through direct reaction under the condition of normal temperature, and a self-supporting nanosphere structure grows on the surface of the nanometer self-supporting nickel-iron-manganese material in situ; according to the nanometer self-supporting nickel-iron-manganese material, a commercial foamed nickel material serves as a substrate, the foamed nickel substrate is directly placed in a mixture of potassium permanganate, oxalic acid and ferric nitrate drugs, and potassium permanganate, oxalic acid and ferric nitrate can autonomously and violently react to release heat to provide a reaction environment for material synthesis. According to the method, the cheap commercial foamed nickel substrate is rapidly converted into the high-activity and high-stability oxygen evolution catalyst in a value-added manner. A stable self-supporting structure can be generated, and the problems that an existing OER electrocatalyst is tedious in manufacturing, unstable in structure, prone to falling off, reduced in performance and the like are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic hydrogen production, in particular to a nano self-supporting nickel-iron-manganese material and its application in the field of water electrolysis. Background Art

[0002] Fossil fuels—non-renewable resources such as coal, oil, and natural gas—have been a major contributor to global climate change. The increasing global energy crisis and environmental pollution have spurred significant attention to the development of renewable energy transitions. In the pursuit of low-carbon, efficient renewable energy, hydrogen, as a high-energy, low-carbon energy carrier, holds great potential as a viable alternative to traditional fossil fuels. Among various hydrogen production technologies, water electrolysis has attracted significant attention due to its minimal greenhouse gas emissions, flexible operation, and high product purity. To date, water electrolysis in alkaline media has been significantly applied to industrial hydrogen production. This technology has achieved a high level of commercialization and holds promising prospects for application in combination with renewable energy sources.

[0003] However, compared with the two-electron transfer hydrogen evolution reaction (HER), the slow kinetics of the four-electron transfer oxygen evolution reaction (OER) greatly hinder the electrochemical process and further reduce the electrochemical performance. Its high overpotential hinders the development of electrolytic hydrogen production in the industrial field. Therefore, it is crucial to select efficient electrocatalysts that can reduce the reaction energy barrier. IrO2 and RuO2 are well-known OER electrocatalysts. However, as precious metals, their limited reserves and high cost have restricted their development. In addition, at high current densities, limited active sites, low electronic conductivity and poor durability have also hindered the large-scale application of OER performance. In the past few decades, researchers have turned their attention to the earth-abundant transition metal-based catalysts. They found that oxides and hydroxides of the latter row of transition metals (Mn, Fe, Co, Ni) exhibit good performance. As a result, a large number of low-cost and highly active transition metal-based materials have been developed, such as catalysts based on Ni and Fe-based oxides or hydroxides. It was also found that hydroxides containing both Ni and Fe show excellent low overpotentials under alkaline conditions. In addition, they can serve as precursors to derive other compounds such as oxides, nitrides, sulfides and phosphides. Their efficient synergistic effect and scalability make Ni, Fe-based alloy catalysts stand out.

[0004] Here, we proposed a spontaneous reaction that utilizes the interaction between chemical substances to successfully synthesize a nickel-iron-manganese material on commercial metal foam nickel, significantly improving the oxygen evolution performance of the catalyst in alkaline water electrolysis. Summary of the Invention

[0005] <Technical Problems Solved by the Invention>

[0006] It is used to solve the problems of poor performance, high cost, unstable structure and performance degradation of OER catalysts in the existing technology.

[0007] <Technical solution adopted by the present invention>

[0008] In view of the above technical problems, the purpose of the present invention is to provide a nano self-supporting nickel-iron-manganese material and its application in the field of water electrolysis.

[0009] The specific contents are as follows:

[0010] First, the present invention provides a nano self-supporting nickel-iron-manganese material.

[0011] The nano self-supporting nickel-iron-manganese material is prepared by mixing a commercial nickel foam substrate and the reaction chemicals at room temperature with ferric nitrate, potassium permanganate and oxalic acid as reaction chemicals. After the mixture reacts autonomously, the mixture is cooled to room temperature and washed.

[0012] Second, the present invention provides an application of the aforementioned nano self-supporting nickel-iron-manganese material in electrolytic hydrogen production.

[0013] <Beneficial Effects of the Invention>

[0014] The nano self-supporting nickel-iron-manganese material of the present invention is prepared by injecting Fe, Mn and O elements into a foam nickel substrate when the foam nickel substrate participates in the reaction of oxalic acid, potassium permanganate and ferric nitrate, so that the material grows a self-supporting nanosphere structure. Compared with traditional powder catalysts, self-supporting catalytic electrodes have many advantages, including abundant catalytic sites, enhanced electron transfer ability, and excellent durability under high current. The morphology of its nanospheres has the highest surface area and can expose more active sites. The introduction of the Fe element can regulate the coordination environment and electronic structure of Ni on the catalyst surface, inducing Ni to self-reconstruct into NiOOH, which is the key provider of OER activity. The Mn element can also promote the speed and efficiency of the Fe element's induction process on Ni, and regulate the adsorption strength of the reaction intermediates in the catalytic process to improve the OER activity and long-term durability.

[0015] At present, for the electrode material preparation technology widely available on the market, all cannot do without additional energy supply, such as various high temperatures, high pressures, long periods of time and other means. These methods not only waste a lot of energy, but also increase the reaction cost because of the use of various precision reaction equipment. The synthesized catalyst is often low in output, and is difficult to achieve the balance between activity and economic cost, not to mention industrial application. The nano self-supporting nickel-iron-manganese material of the present invention only needs to be reacted and prepared at room temperature, and the time used is short (a few minutes), which is very attractive to industrial application.

[0016] Nano-free-standing nickel-iron-manganese materials (Fe1Mn0.5 O1) possesses a large number of electrochemically active sites, excellent electrical conductivity, strong interface binding force, and ultimately provides significant OER performance and long-term stability. Fe1Mn 0.5 O1overpotential of 235 mV at 10 mA cm-2in 1 mol KOH electrolyte, which is much lower than that of commercial IrO2(320 mV). The overpotential of NF-KFe is 267 mV at 100 mA cm-2. -2 O1overpotential of 235 mV at 10 mA cm-2in 1 mol KOH electrolyte, which is much lower than that of commercial IrO2(320 mV). The overpotential of NF-KFe is 267 mV at 100 mA cm-2. -2 O1overpotential of 235 mV at 10 mA cm-2in 1 mol KOH electrolyte, which is much lower than that of commercial IrO2(320 mV). The overpotential of NF-KFe is 267 mV at 100 mA cm-2. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The overpotential test results of oxygen evolution of catalysts generated by reacting different quality medicines with a foam nickel substrate;

[0018] Figure 2 The overpotential of oxygen evolution reaction (OER) of each catalyst; DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If specific conditions are not indicated in the embodiments, conventional conditions or manufacturer recommended conditions are used. If the reagents or instruments used are not indicated by the manufacturer, they are all conventional products that can be purchased on the market.

[0020] <TECHNICAL SCHEME>

[0021] Firstly, the present application provides a nano self-supporting nickel-iron-manganese material,

[0022] The commercial foam nickel used herein belongs to a three-dimensional macroporous metal foam. It has high electrical conductivity, large specific surface area and strong mechanical strength, and can effectively avoid the shortcomings of two-dimensional plane substrates. The self-supporting structure exposes more electrochemically active sites due to the absence of non-conductive adhesives, which is beneficial to the close contact of the electrolyte and the active sites, improves the reaction performance, and also retains the parent skeleton structure, prevents the electrode surface from falling off and peeling off during the bubble escape process, thereby improving the stability. The low-cost and scalable process method provided in the present application is used to synthesize a nano self-supporting nickel-iron-manganese material with excellent OER performance to the minimum extent, which becomes the key to the industrialization of water electrolysis hydrogen production.

[0023] Specifically, the nano self-supporting nickel-iron-manganese material,

[0024] is obtained by reacting a commercial foam nickel substrate in a mixture of oxalic acid, potassium permanganate and iron nitrate medicines. The surface has a uniform self-supporting structure grown in situ.

[0025] In the present invention, the optimal mass ratio of ferric nitrate, oxalic acid and potassium permanganate in the reaction chemicals is 1g:0.5g:1g.

[0026] In the present invention, the size of the nickel foam substrate is: 1.5 cm in length×1 cm in width×0.15 cm in thickness.

[0027] In the present invention, the reaction is carried out directly at room temperature without the need for additional heating or other reaction conditions.

[0028] In the present invention, the post-processing step is to take out the catalytic material after the reaction, fully wash it with deionized water, and dry it.

[0029] Second, the present invention provides an application of the aforementioned nano self-supporting nickel-iron-manganese material in electrolytic hydrogen production.

[0030] <Example>

[0031] Example

[0032] The detailed preparation method of the nano self-supporting nickel-iron-manganese material includes the following steps: mixing commercial nickel foam with a length of 1.5 cm, a width of 1 cm, and a thickness of 0.15 cm with oxalic acid, potassium permanganate, and ferric nitrate. The oxalic acid, potassium permanganate, and ferric nitrate will react to generate heat. After the reaction is completed (a few minutes) and cooled to room temperature, the sample is removed and then rinsed with deionized water and dried at 40°C to obtain a sample. The sample obtained under the optimal synthesis conditions of oxalic acid, potassium permanganate, and ferric nitrate mixed in a ratio of 0.5g:1g:1g is labeled as Fe1Mn. 0.5 O1.

[0033] The ratios of the specific parameters in the examples are shown in Table 1.

[0034] Table 1 Parameter ratio table of the embodiment

[0035] Sample number Oxalic acid (g) Potassium permanganate (g) Ferric nitrate (g) <![CDATA[Fe1Mn 0.5 O1]]> 0.5 1 1

[0036] <Comparative Example>

[0037] Comparative Example

[0038] The difference between this comparative example and the embodiment is that oxalic acid, potassium permanganate and ferric nitrate in different mass ratios are reacted with commercial nickel foam, and the samples are dried at 40° C.

[0039] The ratios of the specific parameters in the examples are shown in Table 2.

[0040] Table 1 Parameter ratio table of comparative examples

[0041] Sample number Oxalic acid (g) Potassium permanganate (g) Ferric nitrate (g) <![CDATA[Fe1Mn 1.5 O1]]> 1 0.5 1 <![CDATA[Fe1Mn1O1]]> 1 1 1 <![CDATA[Fe1Mn1O2]]> 2 1 1

[0042] <Test Example>

[0043] LSV

[0044] The performance test was carried out on the embodiment and the comparative example. The specific results are shown in Table 3 and Figure 1-Figure 2

[0045] The test process is as follows: In 1M KOH electrolyte (prepared with deionized water), a three-electrode system is used, with the electrocatalytic material sample as the working electrode, a saturated Hg / HgO electrode as the reference electrode, and a platinum sheet as the counter electrode. At room temperature, all electrocatalytic materials are tested for oxygen evolution overpotential using a Wuhan Cost CS2350M electrochemical workstation. The test results are shown in Table 3 and Figure 1-2 The results show that when potassium thiocyanate and ferric nitrate are used as reaction chemicals, the oxygen evolution performance is greatly enhanced. Taking into account the reaction performance, synthesis time, synthesis energy consumption and cost, the optimal reaction conditions are 0.5g:1g:1g of oxalic acid, potassium permanganate and ferric nitrate in the embodiment.

[0046] Table 2 Oxygen evolution overpotential test results

[0047]

[0048] Figure 1 Fe1Mn in the embodiment 0.5 LSV polarization curves of O1 and comparative example. It can be seen from the figure that Fe1Mn 0.5 O1 has excellent OER performance compared with other samples.

[0049] Figure 2 Fe1Mn in the embodiment 0.5 Overpotential diagram of O1 and comparative example, from the figure we can see that Fe1Mn 0.5 O1 at 10mAcm -2 and 50mA cm -2 At the current density of , the overpotentials are 237mV and 2354mV respectively, which are significantly better than other samples. 0.5 O1 at a current density of 100 mA cm -2 The lower overpotential is only 249mV.

[0050] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. Nano self-supporting nickel-iron-manganese material, characterized in that: The commercial nickel foam substrate is placed in a mixture of potassium permanganate, oxalic acid and ferric nitrate as reaction chemicals to react.

2. The nano self-supporting nickel-iron-manganese material according to claim 1, characterized in that Among the reaction chemicals, the optimal mass ratio of ferric nitrate, oxalic acid and potassium permanganate is 1g:0.5g:1g.

3. The nano self-supporting nickel-iron-manganese material according to claim 1, characterized in that The reaction is carried out directly at room temperature without the need for additional heating, pressurization or other reaction conditions.

4. The nano self-supporting nickel-iron-manganese material according to claim 1, characterized in that When the mixed chemicals react completely (the reaction temperature drops to room temperature), the materials can be taken out and cleaned to obtain the materials.

5. The nano self-supporting nickel-iron-manganese material according to claim 1, characterized in that The dimensions of the nickel foam substrate used were: 1.5 cm in length×1 cm in width×0.15 cm in thickness.

6. The nano self-supporting nickel-iron-manganese material according to claim 1, characterized in that The surface of commercial nickel foam shows obvious changes.

7. Use of the nano self-supporting nickel-iron-manganese material according to any one of claims 1 to 6 in hydrogen production by electrolysis.

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