Self-supporting NiFe-LDH oxygen evolution electrode based on through hole structure porous transmission layer and preparation and application of self-supporting NiFe-LDH oxygen evolution electrode

Abstract

The invention relates to a self-supporting NiFe-LDH oxygen evolution electrode based on a through hole structure porous transmission layer and preparation and application of the self-supporting NiFe-LDH oxygen evolution electrode, an AEM water electrolysis anode electrode can be prepared in a low-cost, environment-friendly and large-batch mode, the defect that an electrode preparation method in the same field is tedious at present is overcome, and the prepared electrode is high in catalytic activity and good in stability and has good application prospects. The commercialized development of an anion exchange membrane water electrolysis hydrogen production technology is expected to be promoted.

Description

Technical Field

[0001] The invention belongs to the field of electrochemistry, and particularly relates to a self-supporting NiFe-LDH oxygen evolution electrode based on a porous transmission layer with a through-hole structure, and a preparation method and application thereof. Background Art

[0002] As an efficient and clean energy carrier, hydrogen energy has the advantages of zero emission and high energy density. Among the many water electrolysis hydrogen production technologies, although the proton exchange membrane (PEM) water electrolysis hydrogen production technology has many advantages, it has strict requirements on electrode materials and can only use expensive precious metals and their oxide catalysts as electrode materials, such as Ru, Ir, RuO2 and IrO2, which are recognized as the best OER electrocatalysts in acidic media, but their high prices and scarce reserves limit their commercial development. In contrast, the reaction conditions of anion exchange membrane (AEM) water electrolysis are alkaline, and non-precious metal catalysts can be used as electrode materials, such as double metal hydroxides of Fe, Co, Ni, and Mo, which significantly reduces the cost of ion exchange membrane water electrolysis and is expected to bring about a breakthrough in large-scale renewable energy water electrolysis hydrogen production.

[0003] The base of the self-supporting material for AEM water electrolysis is usually nickel felt or nickel foam, but nickel felt is expensive and nickel foam has low strength. In addition, the self-supporting electrodes currently developed based on nickel felt or nickel foam have complicated preparation processes and are difficult to prepare in large quantities, which limits the commercial application of AEM water electrolysis. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a self-supporting NiFe-LDH oxygen evolution electrode based on a porous transport layer with a through-hole structure and the preparation and application thereof.

[0005] The present invention provides a method for preparing a self-supporting NiFe-LDH electrode based on a porous transmission layer with a through-hole structure, comprising: (1) mixing a divalent nickel source, a divalent iron source, an alcohol, and water, and stirring to obtain a mixed solution;

[0006] (2) placing the porous transport layer substrate with a through-hole structure in the mixed solution of step (1), reacting at room temperature, and drying to obtain an electrode.

[0007] Preferably, the divalent nickel source in step (1) is various salts of nickel (II) as the nickel source; and the divalent iron source is various salts of iron (II) as the ferrous source.

[0008] Furthermore, in the step (1), the divalent nickel source is one or more of nickel nitrate hexahydrate and nickel chloride hexahydrate; and the divalent iron source is one or more of ferrous chloride tetrahydrate and ferrous sulfate heptahydrate.

[0009] Preferably, the alcohol in step (1) is one or more of anhydrous ethanol, isopropanol, n-propanol, and ethylene glycol.

[0010] Preferably, in step (1), the molar ratio of the divalent nickel source to the divalent iron source is 1-10:1; and the volume ratio of the alcohol to water is 1:1-5.

[0011] Preferably, the stirring in step (1) is performed at room temperature for 15-30 min.

[0012] Preferably, the material of the porous transmission layer of the through-hole structure in step (2) is Ni or NiFe substrate.

[0013] Preferably, the porous transport layer substrate with a through-pore structure in step (2) is a pretreated porous transport layer substrate with a through-pore structure, wherein the pretreatment comprises the porous transport layer substrate with a through-pore structure treated with hydrochloric acid.

[0014] Furthermore, the pretreatment is to place the porous transport layer substrate with a through-hole structure in hydrochloric acid for ultrasonic treatment for 5-20 minutes, and then use ultrapure water and anhydrous ethanol for ultrasonic treatment for 5-20 minutes respectively.

[0015] Preferably, the stirring in step (2) is performed at room temperature for 18 to 36 hours; and the drying is performed at room temperature under vacuum for 5 to 18 hours.

[0016] In the step (2), washing is performed before drying.

[0017] The present invention provides a self-supporting NiFe-LDH electrode based on a porous transport layer with a through-pore structure, prepared by the method described in claim 1.

[0018] The present invention provides an application of the self-supporting NiFe-LDH electrode based on a porous transport layer with a straight-through pore structure in the technical field of anion exchange membrane AEM water electrolysis.

[0019] The present invention discloses a method for preparing a self-supporting NiFe-LDH oxygen evolution electrode based on a porous transport layer with a straight-through pore structure and its application in anion exchange membrane water electrolysis technology. The present invention uses a nickel-based porous transport layer with a straight-through pore structure as a substrate, combined with a self-grown NiFe-LDH material, to prepare an electrode that not only has the advantages of efficient mass transfer and low contact resistance, but also the catalytic performance of NiFe-LDH and the high binding force of the substrate complement each other, significantly improving the performance and stability of the electrode in the oxygen evolution reaction.

[0020] The self-supporting NiFe-LDH porous transport electrode (NiFe-LDH / PTE) obtained by the present invention has high activity and stability, and the through-hole structure provides high transmission efficiency, showing unique performance advantages in electrocatalytic applications.

[0021] Beneficial Effects

[0022] The electrode provided by the present invention not only enhances the efficiency of the electrochemical reaction, but also ensures the long-term stability of the material, and is suitable for efficient and sustainable water electrolysis applications. This method has the characteristics of room temperature, repeatability, energy saving and environmental protection, and easy large-scale production, showing good industrial prospects.

[0023] The NiFe-LDH / PTE provided by the present invention can be used in AEM water electrolysis technology. In an AEM electrolytic cell, the performance reaches 2.6A / cm2@2.0V@60°C.

[0024] The NiFe-LDH / PTE obtained by the present invention is in-situ grown on a porous transport layer substrate, and the catalyst layer and the substrate have good bonding strength and conductivity, and can be directly used without adding a conductive agent or adhesive, which simplifies the preparation steps of the membrane electrode and avoids the problem of decreased catalytic activity caused by the addition of inactive substances.

[0025] The present invention can prepare AEM water electrolysis anode electrodes at low cost, in an environmentally friendly and large-scale manner, overcoming the drawbacks of the current complicated electrode preparation methods in the same field. The prepared electrodes have high catalytic activity and good stability, and are expected to promote the commercial development of anion exchange membrane water electrolysis hydrogen production technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 : Scanning electron microscope (SEM) image of nickel-based porous transport layer with through-hole structure;

[0027] Figure 2 : Scanning electron microscope (SEM) photo of NiFe-LD / PTE prepared in Example 1;

[0028] Figure 3 : Polarization curve of NiFe-LDH / PTE prepared in Example 1 in an AEM electrolytic cell; wherein the test temperature is 60°C and the electrolyte is 1 mol / L KOH;

[0029] Figure 4 : The NiFe-LDH / PTE prepared in Example 1 was subjected to a constant current (1 A / cm 2 ) stability data; the test temperature was 60°C and the electrolyte was 1 mol / L KOH. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0031] Example 1

[0032] A method for preparing a self-supporting NiFe-LDH oxygen evolution electrode based on a porous transport layer with a through-pore structure comprises the following steps:

[0033] (1) Substrate pretreatment: The nickel-based porous transport layer with a through-hole structure was cut into a square of 2.2 cm × 2.2 cm, and then ultrasonically treated in 1 mol / L hydrochloric acid for 15 min, and then ultrasonically treated in ultrapure water and anhydrous ethanol for 15 min respectively to remove the oxide on the surface of the material and enhance the conductivity of the material. The treated nickel-based porous transport layer substrate with a through-hole structure was soaked in anhydrous ethanol for later use.

[0034] (2) Solution preparation: Nickel chloride hexahydrate and ferrous sulfate heptahydrate were mixed in a molar ratio of 1:1, added to a mixed solution of isopropanol and ultrapure water in a volume ratio of 1:1, and stirred vigorously for 30 minutes to obtain a reaction solution.

[0035] (3) Preparation of NiFe-LDH / PTE: The pretreated through-pore structure nickel-based porous transport layer (1) was placed in the mixed solution (2) and stirred at room temperature for 18 hours. The through-pore structure nickel-based porous transport layer was then taken out (with NiFe-LDH loaded on the surface), washed with ethanol and water three times each, and vacuum dried at room temperature for 12 hours to finally obtain a self-supporting NiFe-LDH electrocatalytic electrode based on a through-pore structure porous transport layer (referred to as NiFe-LDH / PTE) for AEMWE anode oxygen evolution reaction.

[0036] Some structural and performance studies were carried out on the materials prepared by the above method.

[0037] like Figure 1 Shown is a scanning electron microscope (SEM) photograph of a nickel-based porous transport layer with a through-hole structure.

[0038] like Figure 2 Shown is a scanning electron microscope (SEM) photograph of NiFe-LD / PTE.

[0039] The prepared NiFe-LDH / PTE was used as anode to evaluate the AEMWE activity and stability. Here, it is pointed out that the electrolyte is 1 mol / L KOH, the test temperature is 60°C, and the cathode catalyst is Pt / C, where the platinum loading is 0.3 mg / cm2 The cathode gas diffusion layer is carbon paper with an active area of ​​5 cm 2 .

[0040] like Figure 3 The polarization curve of NiFe-LDH / PTE in AEM electrolytic cell is shown. The test results show that NiFe-LDH / PTE has high activity in AEM electrolytic cell. At 2.0V voltage, the current density reaches 2.6A / cm 2 .

[0041] like Figure 4 The figure shows the stability curve of NiFe-LDH / PTE in AEM electrolytic cell. The test results show that NiFe-LDH / PTE has high stability in AEM electrolytic cell. 2 At a current density of 1.5 %, the electrolyzer can operate stably for more than 250 hours.

[0042] Example 2

[0043] This example is the same as Example 1, except that the molar ratio of nickel chloride hexahydrate to ferrous sulfate heptahydrate is changed to 10:1, and the obtained NiFe-LDH / PTE is used in an AEM electrolytic cell, and the electrolytic cell performance reaches 2.6 A / cm 2 @2V, indicating that adjusting the ratio of nickel (II) and iron (II) within this range will not affect the performance of the electrode.

[0044] Example 3

[0045] This example is the same as Example 1. Isopropyl alcohol and ultrapure water are mixed in a volume ratio of 1:5. The obtained NiFe-LDH / PTE is used in an AEM electrolytic cell. The electrolytic cell performance reaches 2.5A / cm 2 @2V, indicating that adjusting the alcohol-water volume ratio within this range will not affect the performance of the electrode.

[0046] Example 4

[0047] This example is the same as Example 1, except that the stirring reaction time is adjusted to 36 hours, and the obtained NiFe-LDH / PTE is used in an AEM electrolytic cell, and the electrolytic cell performance reaches 2.6A / cm 2 @2V, indicating that adjusting the response time within this range will not affect the performance of the electrode.

[0048] Example 5

[0049] This example is the same as Example 1, except that the nickel source is changed to nickel nitrate hexahydrate, and the obtained NiFe-LDH / PTE is used in an AEM electrolytic cell, and the electrolytic cell performance reaches 2.6A / cm 2@2V, indicating that changing the nickel source will not affect the performance of the electrode.

[0050] Example 6

[0051] This example is the same as Example 1, except that the ferrous source is changed to ferrous chloride tetrahydrate, and the obtained NiFe-LDH / PTE is used in an AEM electrolytic cell, and the electrolytic cell performance reaches 2.5A / cm 2 @2V, indicating that changing the iron source will not affect the performance of the electrode.

[0052] Example 7

[0053] This example is the same as Example 1, except that isopropanol is replaced with one of anhydrous ethanol, n-propanol, and ethylene glycol, and the obtained NiFe-LDH / PTE is used in an AEM electrolytic cell, and the electrolytic cell performance reaches 2.6A / cm 2 @2V, indicating that changing the type of alcohol will not affect the performance of the electrode.

Claims

1. A method for preparing a self-supporting NiFe-LDH electrode based on a porous transport layer with a through-hole structure, comprising: (1) mixing a divalent nickel source, a divalent iron source, alcohol, and water, and stirring to obtain a mixed solution; (2) placing a porous transport layer substrate with a through-hole structure in the mixed solution of step (1), stirring for reaction, and drying to obtain an electrode.

2. The preparation method according to claim 1, characterized in that: In the step (1), the divalent nickel source is one or more of nickel nitrate hexahydrate and nickel chloride hexahydrate; the divalent iron source is one or more of ferrous chloride tetrahydrate and ferrous sulfate heptahydrate.

3. The preparation method according to claim 1, characterized in that: In the step (1), the alcohol is one or more of anhydrous ethanol, isopropanol, n-propanol, and ethylene glycol.

4. The preparation method according to claim 1, characterized in that: In the step (1), the molar ratio of the divalent nickel source to the divalent iron source is 1-10:1; and the volume ratio of the alcohol to water is 1:1-5.

5. The preparation method according to claim 1, characterized in that: The stirring in step (1) is performed at room temperature for 15-30 min.

6. The preparation method according to claim 1, characterized in that: The material of the porous transmission layer of the through-hole structure in step (2) is Ni or NiFe.

7. The preparation method according to claim 1, characterized in that: The porous transport layer substrate with a through-pore structure in step (2) is a pre-treated porous transport layer substrate with a through-pore structure, wherein the pre-treatment comprises the porous transport layer substrate with a through-pore structure treated with hydrochloric acid.

8. The preparation method according to claim 1, characterized in that: The stirring in the step (2) is performed at room temperature for 18 to 36 hours; and the drying is performed at room temperature under vacuum for 5 to 18 hours.

9. A self-supporting NiFe-LDH electrode based on a porous transport layer with a through-pore structure prepared by the method according to any one of claims 1 to 8.

10. Application of the self-supporting NiFe-LDH electrode based on a porous transport layer with a through-pore structure as claimed in claim 9 in the field of anion exchange membrane (AEM) water electrolysis technology.

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