A self-supporting anode for hydrogen production by alkaline water electrolysis and its preparation method and application

Abstract

The present invention relates to the technical field of water electrolysis, and more specifically, to a self-supporting anode for hydrogen production by alkaline water electrolysis, and its preparation method and application. The preparation method of the self-supporting anode for hydrogen production by alkaline water electrolysis of the present invention comprises the following steps: 1) bonding a porous nickel material to the S pole surface of a permanent magnet using a conductive adhesive, inserting the S pole bonded with the porous nickel material and the N pole of another permanent magnet into an electromagnetic plating solution as electrodes, and applying power to the two electrodes for electromagnetic plating to form a deposition layer on the surface of the porous nickel material; the electromagnetic plating solution contains Fe 3+ ions and Ta 5+ ions; 2) treating the porous nickel material with the deposited layer formed on the surface with microwave heating to obtain the self-supporting anode for producing hydrogen by alkaline water electrolysis prepared by the present invention has strong operating stability under large current.

Description

Technical Field

[0001] The present invention relates to the technical field of water electrolysis, and in particular to a self-supporting anode for producing hydrogen by alkaline water electrolysis, and a preparation method and application thereof. Background Art

[0002] With the widespread use of fossil fuels, environmental pollution is becoming increasingly serious, and clean energy is gaining increasing attention. Traditional clean energy sources such as solar and wind power have the advantages of large total resources but the limitations of low energy density. Hydrogen energy, on the other hand, offers a less restricted form of energy. Currently, there are many different hydrogen production technologies, among which water electrolysis is a relatively ideal and environmentally friendly method.

[0003] At present, the four mainstream water electrolysis hydrogen production technologies include: alkaline water electrolysis hydrogen production technology, proton exchange membrane water electrolysis hydrogen production technology, anion exchange membrane water electrolysis hydrogen production technology and high-temperature solid oxide water electrolysis hydrogen production technology. Among them, alkaline water electrolysis hydrogen production technology is the most mature and has the highest economic benefits, so it is widely used. For the alkaline water electrolysis reaction, the oxygen evolution reaction (OER) at the anode during the electrolysis of water is limited by factors such as high overpotential and relatively slow kinetics. Therefore, reasonable electrode design is particularly important in improving the efficiency of water decomposition.

[0004] Most water electrolysis hydrogen production catalysts use polymer adhesives to connect them to electrodes. This method not only masks the active sites of the catalyst, but also reduces its conductivity. Moreover, it is easy to fall off after long-term use, which cannot meet the needs of practical applications. In comparison, self-supporting electrodes do not require additional binders, conductive agents, and current collectors, and can be used directly as electrodes. They have high active sites, good mechanical properties, higher specific capacity and energy density, and have obvious advantages. However, most of the current self-supporting electrodes cannot be used stably for a long time, especially when operating stably at higher currents. Summary of the Invention

[0005] The present invention provides a self-supporting anode for producing hydrogen by alkaline water electrolysis, and a preparation method and application thereof, in order to solve the problem of poor stability of the self-supporting electrode in the prior art.

[0006] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0007] A method for preparing a self-supporting anode for hydrogen production by alkaline water electrolysis comprises the following steps:

[0008] 1) A porous nickel material is bonded to the S pole surface of a permanent magnet using a conductive adhesive, the S pole bonded with the porous nickel material and the N pole of another permanent magnet are both inserted into an electromagnetic plating solution as electrodes, and electromagnetic plating is performed on the two electrodes to form a deposition layer on the surface of the porous nickel material; the electromagnetic plating solution contains Fe3+ ions and Ta 5+ ion;

[0009] 2) The porous nickel material with a deposition layer formed on the surface is subjected to microwave heating treatment to obtain a self-supporting anode for hydrogen production by alkaline water electrolysis.

[0010] Preferably, in step 1), the porous nickel material is subjected to plasma cleaning pretreatment before use; the frequency of the plasma cleaning pretreatment is 200kHz-400kHz, and the power is 100W-1000W.

[0011] Further preferably, the cleaning pretreatment is performed using a plasma cleaning machine; the gas flow rate of the plasma cleaning machine is 0.1m 3 / h-20m 3 / h; gas pressure is 1bar-10bar; vacuum degree of plasma cleaning machine is 10-10 4 Torr; cleaning time is 5-10min.

[0012] Preferably, in step 1), the porous nickel material is nickel foam or nickel mesh.

[0013] More preferably, the pore size of the nickel foam is 50-300 μm, the nickel foam is a nickel foam sheet with a thickness of 0.5-2 mm, the mesh size of the nickel mesh is 60-300 mesh, and the diameter of the nickel wire of the nickel mesh is 100-300 μm.

[0014] Preferably, in step 1), Fe 3+ The concentration of the ions is 0.3-0.6 mol / L. Furthermore, the iron salt used in the preparation of the electromagnetic plating solution is one or more of ferric chloride, ferric nitrate, and ferric sulfate.

[0015] Preferably, in step 1), Ta in the electromagnetic plating solution 5+ The concentration of the ions is 0.3-0.6 mol / L. Furthermore, the tantalum salt used in the preparation of the electromagnetic plating solution is tantalum chloride.

[0016] Preferably, in step 1), Fe 3+ ions and Ta 5+ The molar ratio of the ions is 1:1.

[0017] Preferably, in step 1), the current of electromagnetic plating is 100-200 mA cm -2 of constant current.

[0018] Preferably, in step 1), the electromagnetic plating time is 10-20 minutes.

[0019] Preferably, in step 2), the microwave heating treatment time is 10-20 minutes.

[0020] A self-supporting anode for producing hydrogen by alkaline water electrolysis, prepared by the above-mentioned preparation method.

[0021] An application of the above-mentioned alkaline water electrolysis hydrogen production self-supporting anode in water electrolysis.

[0022] The technical solution of the present invention has the following advantages and beneficial effects:

[0023] The conductive substrate of the present invention is made of porous nickel material (nickel mesh or nickel foam). On the one hand, nickel mesh, nickel foam and other products are relatively mature, and the mesh size and thickness of the nickel mesh and the pore size and thickness of the nickel foam can be well controlled; on the other hand, the porous substrate can provide more metal binding sites during the ion etching process.

[0024] The high-energy plasma cleaning used in the present invention increases the specific surface area of ​​the porous conductive substrate and forms an active layer on the surface of the material, which can give the material excellent adhesion properties so that it can be well combined with the catalyst later. The present invention uses an external voltage to cause a reduction reaction on the electrode while adding two magnets to introduce an external magnetic field, so that the charged particles are accelerated in the magnetic field and more firmly bonded to the surface of the nickel metal carrier. The dual electromagnetic effect not only improves the catalyst binding degree but also can directionalize the electron arrangement. Therefore, the electrode has excellent oxygen evolution catalytic performance and long-term stability at high current density, which meets the industrial demand for high current stability of water electrolysis anode materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a SEM image of the self-supporting anode of Example 1 of the present invention;

[0026] Figure 2 This is a SEM image of the self-supporting anode of Example 2 of the present invention;

[0027] Figure 3 1 and 2 are LSV curves of the self-supporting anodes of Examples 1 and 2 of the present invention;

[0028] Figure 4 These are stability test curves of the self-supporting anodes of Examples 1 and 2 of the present invention. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the present invention more clear, the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] Example 1

[0031] The method for preparing the self-supporting anode for hydrogen production by alkaline water electrolysis of this embodiment comprises the following steps:

[0032] 1) Take a nickel foam sheet with a pore size of 110um and a thickness of 1.7mm, and cut it into a rectangular nickel foam sheet of 1*2cm. Put the cut nickel foam sheet into a plasma cleaning instrument for cleaning, and use plasma technology to perform surface treatment on the nickel foam sheet. Under the bombardment of high-speed electric field plasma, the specific surface area of ​​the material structure surface is increased, and an active layer is formed on the surface of the material. Specifically, the parameters of the plasma cleaning instrument are: frequency of 300kHz, power of 500W, gas flow of 100m 3 / h, gas pressure is 5 bar, vacuum degree is 102 Torr, and cleaning time is 10 min.

[0033] 2) Mix 300 mmol / L Fe(NO3)3 solution and 300 mmol / L TaCl5 solution in a volume ratio of 1:1, stir magnetically for 10 minutes to obtain a mixed solution, and use the mixed solution as an electromagnetic plating solution;

[0034] Prepare two permanent magnets, each measuring 4*4*2 cm. Cover the S side of the permanent magnets with double-sided conductive adhesive. Attach the nickel foam material treated in step 1) to their surfaces. Apply voltage to both ends of the magnets. Close the two magnets together to generate current. Insert the closed magnets into the electromagnetic plating solution and perform electromagnetic plating for 10 minutes. While the cathode is reducing, the N-S pole of the magnet can simultaneously attract anions and cations in the electromagnetic plating solution, and the S pole can adsorb iron and tantalum ions.

[0035] 3) The material after electromagnetic plating in step 2) was taken out, dried, and then transferred to a microwave oven for rotary heating. The microwave oven was set to high heat and the heating time was 10 minutes to finally obtain a FeTaOx / Ni self-supporting electrode.

[0036] Example 2

[0037] The difference between this embodiment and embodiment 1 is that the nickel foam sheet is replaced with a nickel mesh with a mesh size of 300 and a nickel wire diameter of 100 μm. Other aspects are the same as those in embodiment 1.

[0038] Example 3

[0039] The method for preparing the self-supporting anode for hydrogen production by alkaline water electrolysis of this embodiment comprises the following steps:

[0040] 1) Take a nickel foam sheet with a pore size of 110um and a thickness of 1.7mm, and cut it into a rectangular nickel foam sheet of 1*2cm. Put the cut nickel foam sheet into a plasma cleaning instrument for cleaning, and use plasma technology to perform surface treatment on the nickel foam sheet. Under the bombardment of high-speed electric field plasma, the specific surface area of ​​the material structure surface is increased, and an active layer is formed on the surface of the material. Specifically, the parameters of the plasma cleaning instrument are: frequency of 300kHz, power of 500W, gas flow of 100m 3 / h, gas pressure is 5 bar, vacuum degree is 102 Torr, and cleaning time is 10 min.

[0041] 2) Mix 600 mmol / L Fe(NO3)3 solution and 600 mmol / L TaCl5 solution in a volume ratio of 1:1, stir magnetically for 10 minutes to obtain a mixed solution, and use the mixed solution as an electromagnetic plating solution;

[0042] Prepare two permanent magnets, each measuring 4*4*2 cm. Cover the S side of the permanent magnets with double-sided conductive adhesive. Attach the nickel foam material treated in step 1) to their surfaces. Apply voltage to both ends of the magnets. Close the two magnets together to generate current. Insert the closed magnets into the electromagnetic plating solution and perform electromagnetic plating for 20 minutes. While the cathode is reducing, the N-S pole of the magnet can simultaneously attract anions and cations in the electromagnetic plating solution, and the S pole can adsorb iron and tantalum ions.

[0043] 3) The material after electromagnetic plating in step 2) was taken out, dried, and then transferred to a microwave oven for rotary heating. The microwave oven was set to high heat and the heating time was 20 minutes to finally obtain a FeTaOx / Ni self-supporting electrode.

[0044] Comparative Example

[0045] The pure nickel foam sheet in Example 1 and the pure nickel mesh in Example 2 were used as comparative electrode examples.

[0046] Experimental example

[0047] (1) Morphology test

[0048] The self-supporting electrodes prepared in Example 1 and Example 2 were subjected to SEM tests respectively. The results are as follows: Figure 1 and Figure 2 shown.

[0049] Depend on Figure 1 and Figure 2It can be seen that the electrode catalyst presents a nanowire (tube) structure, and a nanowhisker structure also grows on the nanowire.

[0050] (2) OER performance test

[0051] The self-supporting electrodes obtained in Example 1 (Case 1) and Example 2 (Case 2) were used as anodes to test the OER performance. The results are as follows: Figure 3 shown.

[0052] from Figure 3 The LSV curves in the figure show that the self-supporting materials of Example 1 and Example 2 have a maximum current of 700 mA / cm 2 The excellent performance of current density is far ahead of pure nickel mesh and pure nickel foam in electrochemical performance. In addition, the LSV of the electrode of the present invention does not fluctuate under high current environment, indicating that it has excellent stability under high current environment.

[0053] Furthermore, the stability test results of the self-supporting electrodes prepared in Example 1 (Case 1) and Example 2 (Case 2) are as follows: Figure 4 shown.

[0054] from Figure 4 It can be clearly seen that the self-supporting materials of Example 1 and Example 2 are 2 Under normal circumstances, it can remain stable for more than 2500 hours without degradation, which greatly meets the current industrial demand for the stability of water electrolysis oxygen evolution materials.

[0055] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a self-supporting anode for hydrogen production by alkaline water electrolysis, characterized in that: The steps include: 1) A porous nickel material is bonded to the S pole surface of a permanent magnet using a conductive adhesive, the S pole bonded with the porous nickel material and the N pole of another permanent magnet are both inserted into an electromagnetic plating solution as electrodes, and electromagnetic plating is performed on the two electrodes to form a deposition layer on the surface of the porous nickel material; the electromagnetic plating solution contains Fe 3+ ions and Ta 5+ ion; 2) The porous nickel material with a deposition layer formed on the surface is subjected to microwave heating treatment to obtain a self-supporting anode for hydrogen production by alkaline water electrolysis.

2. The method for preparing a self-supporting anode for hydrogen production by alkaline water electrolysis according to claim 1, wherein: In step 1), the porous nickel material is subjected to plasma cleaning pretreatment before use; the frequency of the plasma cleaning pretreatment is 200kHz-400kHz, and the power is 100W-1000W.

3. The method for preparing a self-supporting anode for hydrogen production by alkaline water electrolysis according to claim 1, wherein: In step 1), the porous nickel material is nickel foam or nickel mesh.

4. The method for preparing a self-supporting anode for hydrogen production by alkaline water electrolysis according to claim 1, wherein: In step 1), Fe 3+ The concentration of ions is 0.3-0.6 mol / L.

5. The method for preparing a self-supporting anode for hydrogen production by alkaline water electrolysis according to claim 4, wherein: In step 1), Ta in the electromagnetic plating solution 5+ The concentration of ions is 0.3-0.6 mol / L.

6. The method for preparing a self-supporting anode for hydrogen production by alkaline water electrolysis according to claim 5, wherein: In step 1), Fe 3+ ions and Ta 5+ The molar ratio of the ions is 1:

1.

7. The method for preparing a self-supporting anode for hydrogen production by alkaline water electrolysis according to claim 1, wherein: In step 1), the current of electromagnetic plating is 100-200mAcm -2 of constant current.

8. The method for preparing a self-supporting anode for hydrogen production by alkaline water electrolysis according to claim 1, wherein: In step 2), the microwave heating treatment time is 10-20 minutes.

9. A self-supporting anode for hydrogen production by alkaline water electrolysis, prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the self-supporting anode for producing hydrogen by alkaline water electrolysis as claimed in claim 9 in water electrolysis.

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