Preparation method of nickel alloy-metal oxide composite hydrogen evolution electrode

Abstract

The invention relates to the technical field of hydrogen energy, and provides a preparation method of a nickel alloy-metal oxide composite hydrogen evolution electrode. Comprising the following steps: performing pretreatment on a nickel substrate to remove oil stains and surface oxides, preparing a mixed solution with nickel salt and metal oxide nanoparticles as main components, and performing uniform ultrasonic dispersion; performing electrochemical deposition in the mixed solution by taking a nickel substrate as a working electrode; after an intermediate layer is deposited for a certain time, adding a solution containing molybdenum or molybdenum tungsten into a deposition solution, uniformly stirring, and then carrying out second-stage electro-deposition; and after deposition is finished, taking out the electrode, and drying to obtain the nickel-molybdenum or nickel-molybdenum-tungsten and metal oxide composite electrode. The prepared composite electrode is high in hydrogen evolution electrocatalytic activity and good in stability, the hydrogen production rate of alkaline electrolysis hydrogen production equipment is increased, and the hydrogen production cost is reduced. The preparation method of the composite electrode is simple, free of high-temperature and high-pressure processes, low in cost and suitable for large-scale industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen energy, and in particular to a method for preparing a nickel alloy-metal oxide composite hydrogen evolution electrode. Background Art

[0002] As the costs of wind and solar power continue to decline, green hydrogen produced by electrolysis of renewable electricity will gradually develop into the main way to produce green hydrogen. Hydrogen produced by electrolysis of renewable electricity is also an important way to achieve the dual carbon goals.

[0003] Alkaline water electrolysis is the main method of commercial hydrogen production. In the future, hydroxyl ion exchange membrane water electrolysis also has excellent development prospects. Both of these methods of hydrogen production can use non-precious metal catalysts and have the significant advantage of low electrode cost. In alkaline systems, hydrogen evolution electrodes generally use nickel-based materials, such as twill nickel mesh, stretched diamond nickel mesh, foam nickel mesh or nickel-aluminum, nickel-molybdenum, nickel-cobalt alloys, etc.

[0004] In order to reduce the voltage of hydrogen production by alkaline water electrolysis, researchers increased the hydrogen evolution current density and reduced the overpotential by loading a catalytic layer on a nickel substrate. Chinese patent CN201910402757.6 discloses a method for preparing an alloy hydrogen evolution electrode loaded on a foam transition metal. First, the three-dimensional foam transition metal substrate electrode is degreased and pickled for pretreatment, and then the treated porous foam transition metal is placed in a glow plasma infiltration furnace as a substrate, and a molybdenum plate with a purity of 99.99% is used as a sputtering target. A molybdenum-molybdenum transition metal alloy hydrogen evolution electrode is generated on the surface of the foam transition metal. However, this type of method requires expensive equipment, and the hydrogen evolution activity and stability of the prepared electrode still need to be improved. Chinese patent CN202211064473.9 discloses a method for preparing a nickel-molybdenum-tungsten loaded porous nickel-based self-supporting catalytic hydrogen evolution cathode material, in which a porous nickel foam (NF) is used as a substrate, and the substrate is modified with a nickel-molybdenum-tungsten ternary alloy coating by an electrochemical deposition method, and then heat-treated to obtain the final NiMoW@NF hydrogen evolution electrode. However, alloy electrodes obtained by direct electrodeposition have insufficient stability due to coating stress or the easy dissolution of Mo element itself under alkaline conditions.

[0005] In summary, the current alkaline water nickel-based hydrogen evolution electrodes have the problems of high preparation cost or insufficient hydrogen evolution activity and stability of the prepared electrodes. Summary of the invention

[0006] In view of this, the present invention provides a method for preparing a nickel alloy-metal oxide composite hydrogen evolution electrode. The present invention adopts the following specific scheme:

[0007] (1) Pre-treat the nickel substrate to remove oil stains and surface oxides.

[0008] The nickel substrate is a commercially common twill nickel mesh, stretched diamond nickel mesh, foam nickel mesh or nickel fiber felt material.

[0009] The pre-treatment is achieved by chemical degreasing, pickling or sandblasting.

[0010] (2) A mixed solution containing nickel salt and insoluble metal oxide nanoparticles as main components is prepared and dispersed evenly by ultrasonic stirring; then, the treated nickel substrate is used as a working electrode and the prepared mixed solution is used as a deposition solution to perform electrochemical deposition. Through this step, a transition composite layer (intermediate layer) of nickel metal and metal oxide is pre-deposited on the nickel substrate.

[0011] The nickel salt is one of nickel chloride, nickel nitrate, nickel acetate and nickel sulfate, and its concentration range is 10-500mM.

[0012] The insoluble metal oxide (MO x ) is one or two of titanium dioxide, cerium dioxide, zirconium dioxide, hafnium dioxide, niobium pentoxide, tantalum pentoxide, and chromium trioxide, and its mass concentration range is 0.2 to 10 g / L;

[0013] The mixed solution also contains trisodium citrate and a surfactant, wherein the concentration of the trisodium citrate is in the range of 5 to 300 mM; the surfactant is one of polyvinyl pyrrolidone, sodium dodecyl sulfate or sodium benzoate, and the concentration range is 0.1 to 5 g / L.

[0014] The electrochemical deposition uses constant current to achieve nickel ion reduction and metal oxide co-deposition, the applied cathode current density ranges from 10 to 500 mA cm-2, and the deposition time is 10 to 120 minutes.

[0015] (3) After step 2 is completed, a molybdenum salt solution or a mixed solution of molybdenum salt and tungsten salt is added to the deposition solution, stirred evenly, and then a second-stage electrodeposition is performed to further deposit a highly active outer layer of nickel-molybdenum (or nickel-molybdenum-tungsten) and metal oxide on the outer layer;

[0016] The molybdenum salt refers to ammonium molybdate and sodium molybdate, and the concentration range of the molybdenum salt is 5-300mM; the tungsten salt refers to ammonium tungstate, ammonium metatungstate, sodium tungstate, and the concentration range of the tungsten salt is 3-200mM.

[0017] The two-stage electrodeposition uses a constant current to achieve the reduction of nickel ions and molybdenum ions and the co-deposition of metal oxides. The applied current density is 10 to 500 mA cm-2 and the deposition time is 15 to 120 minutes.

[0018] (4) After step 3 is completed, the electrode is taken out and dried to finally obtain a composite electrode of nickel-molybdenum or nickel-molybdenum-tungsten and metal oxide.

[0019] The drying is vacuum drying or forced air drying. The drying temperature is room temperature to 100°C.

[0020] The hydrogen evolution electrode prepared by the method for preparing a nickel alloy-metal oxide composite hydrogen evolution electrode of the present invention is mainly used in hydrogen production by alkaline water electrolysis, hydrogen production by hydroxide ion exchange membrane electrolysis, chlor-alkali industry, etc. It can significantly increase the current density under the same voltage, help to increase the hydrogen production rate of alkaline water hydrogen production equipment under the same hydrogen production power consumption, and reduce the cost of hydrogen production.

[0021] The prepared electrode material has Ni-MO pre-deposited between the nickel substrate and the surface catalyst layer. x The composite oxide intermediate layer reduces the stress between the outer catalytic layer and the substrate, reduces the mismatch between the active layer and the substrate, and improves the bonding force between the active layer and the substrate; the nickel-molybdenum (or nickel-molybdenum-tungsten) and metal oxide composite active layer deposited on the outer layer not only increases the reaction area and active sites, but also further improves the stability of the electrode; the hydrogen evolution electrode has the advantages of high current density, low overpotential and good stability.

[0022] The preparation process of the hydrogen evolution electrode is simple and easy to operate, does not involve high temperature and high pressure, has good safety and low cost, is easy to scale up industrially, and has excellent commercial prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The SEM image of the nickel-molybdenum-cerium dioxide composite hydrogen evolution electrode prepared by the present invention;

[0024] Figure 2 The XRD diagram of the nickel-molybdenum-cerium dioxide composite hydrogen evolution electrode prepared by the present invention;

[0025] Figure 3 This is a SEM image of the nickel-molybdenum-tungsten-zirconium dioxide composite hydrogen evolution electrode prepared by the present invention;

[0026] Figure 4 The XRD diagram of the nickel-molybdenum-tungsten-zirconium dioxide composite hydrogen evolution electrode prepared by the present invention;

[0027] Figure 5 The graph is a comparison of the electrochemical polarization curves of (1) nickel-molybdenum-cerium dioxide composite hydrogen evolution electrode, (2) nickel-molybdenum-tungsten-zirconium dioxide composite hydrogen evolution electrode, (3) commercial Pt / C and (4) commercial nickel substrate electrode prepared by the present invention.

[0028] Figure 6 The constant current step comparison diagram of (1) nickel-molybdenum-cerium dioxide composite hydrogen evolution electrode, (2) nickel-molybdenum-tungsten-zirconium dioxide composite hydrogen evolution electrode, (3) commercial Pt / C and (4) commercial nickel substrate electrode prepared by the present invention. DETAILED DESCRIPTION

[0029] The technical solutions of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention, but they should not be construed as limiting the protection scope of the present invention.

[0030] Example 1

[0031] (1) A commercial twill nickel mesh electrode with a size of 10 cm*10 cm was subjected to ultrasonic degreasing treatment at room temperature in a 0.5 M sodium carbonate-0.5 M sodium hydroxide mixed solution for 30 min. After the degreasing was completed, the residual degreasing solution was washed away with deionized water; then the degreased twill nickel mesh was ultrasonically pickled in a 10% HCl solution for 10 min. After the pickling was completed, the twill nickel mesh was rinsed with deionized water and dried.

[0032] (2) Prepare a mixture of 2g / L CeO2, 100mM nickel chloride, 100mM trisodium citrate, and 0.5g / L polyvinyl pyrrolidone, and ultrasonically disperse for 30 minutes to evenly suspend CeO2 particles in the hot mixed solution. Then use the surface-treated twill nickel mesh as the working electrode, the commercial titanium mesh as the auxiliary electrode, and the mixed solution as the electrochemical deposition solution. Under stirring conditions, apply a cathode current of 15A for 30 minutes. A nickel substrate (Ni-CeO2 / Ni) with a Ni-CeO2 composite intermediate layer is obtained.

[0033] (3) Add 20 mM ammonium molybdate solution to the electrolyte after step 2. Then continue to apply a cathode current of 10 A for 40 minutes under stirring. Finally, a nickel-molybdenum-cerium dioxide composite hydrogen evolution electrode is obtained, named NiMo-CeO2 / Ni-CeO2 / Ni (referred to as NiMo-CeO2 / Ni).

[0034] The SEM electron microscope characterization and XRD characterization of the NiMo-CeO2 / Ni composite hydrogen evolution electrode prepared in this example are as follows Figure 1 and Figure 2 shown.

[0035] Example 2

[0036] (1) A nickel foam electrode with a size of 4 cm*5 cm was subjected to ultrasonic degreasing treatment at room temperature in a 0.5 M sodium carbonate-0.5 M sodium hydroxide mixed solution for 30 min. After the degreasing was completed, the residual degreasing solution was washed away with deionized water; then the degreasing twill nickel mesh was subjected to ultrasonic pickling in a 10% HCl solution for 20 min. After the pickling was completed, the twill nickel mesh was rinsed with deionized water and dried.

[0037] (2) Prepare a mixture of 1g / L ZrO2, 100mM nickel chloride, 100mM trisodium citrate, and 0.3g / L sodium dodecyl sulfate, and ultrasonically disperse for 30 minutes to evenly suspend the ZrO2 particles in the hot mixture. Then use the surface-treated twill nickel mesh as the working electrode, the commercial titanium mesh as the auxiliary electrode, and the mixture as the electrochemical deposition solution. Under stirring conditions, apply a cathode current of 4A for 20 minutes. A nickel substrate (Ni-ZrO2 / Ni) with a Ni-ZrO2 composite intermediate layer is obtained.

[0038] (3) Add an equal volume of 10 mM ammonium molybdate-10 mM sodium tungstate mixed solution to the electrolyte after step 2. Then continue to apply a cathode current of 3 A for 30 minutes under stirring. Finally, a composite hydrogen evolution electrode loaded with nickel, molybdenum, tungsten and cerium dioxide is obtained, named NiMoW-ZrO2 / Ni-ZrO2 / Ni (referred to as NiMoW-ZrO2 / Ni).

[0039] The SEM electron microscope characterization and XRD characterization of the NiMoW-ZrO2 / Ni composite hydrogen evolution electrode prepared in this example are as follows Figure 3 and Figure 4 shown.

[0040] The three-electrode test was performed with the prepared (1) NiMo-CeO2 / Ni composite hydrogen evolution electrode, (2) NiMoW-ZrO2 / Ni composite hydrogen evolution electrode, (3) nickel substrate coated with commercial Pt / C, and (4) commercial nickel substrate as working electrodes. The electrolyte was 1M potassium hydroxide, the electrolysis temperature was 25°C, and the LSV curves of the four electrodes were as follows: Figure 5 The NiMo-CeO2 / Ni composite hydrogen evolution electrode and the NiMoW-ZrO2 / Ni composite hydrogen evolution electrode of the present invention not only exhibit low overpotential and high current density characteristics close to those of commercial Pt / C catalysts, but also Figure 6 The step test also verified that the high activity and high stability of the hydrogen evolution performance of the NiMo-CeO2 / Ni composite hydrogen evolution electrode and the NiMoW-ZrO2 / Ni composite hydrogen evolution electrode are comparable to or even better than those of commercial Pt / C.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a nickel alloy-metal oxide composite hydrogen evolution electrode. Characterized in that: The following steps are involved: (1) Pre-treating the nickel substrate to remove oil stains and surface oxides; (2) preparing a mixed solution with soluble nickel salt and insoluble metal oxide nanoparticles as main components, and uniformly dispersing them by ultrasonic stirring; using the treated nickel substrate as a working electrode and the prepared mixed solution as a deposition solution, and performing electrochemical deposition, through which an intermediate composite layer of nickel metal and metal oxide is pre-deposited on the nickel substrate; (3) After step 2 is completed, a molybdenum salt solution or a mixed solution of molybdenum salt and tungsten salt is added to the original deposition solution, stirred evenly, and then a second-stage electrodeposition is performed to further deposit a highly active outer layer of nickel molybdenum (or nickel molybdenum tungsten) and metal oxide on the outer layer; (4) After step 3 is completed, the electrode is taken out and dried to finally obtain a composite electrode of nickel-molybdenum or nickel-molybdenum-tungsten and metal oxide.

2. The method for preparing a nickel alloy-metal oxide composite hydrogen evolution electrode according to claim 1, characterized in that: The nickel substrate described in step (1) is a commercially common twill nickel mesh, stretched diamond nickel mesh, foam nickel mesh or nickel fiber felt material.

3. The method for preparing a nickel alloy-metal oxide composite hydrogen evolution electrode according to claim 1, characterized in that: The insoluble metal oxide in step (2) is one or two of titanium dioxide, cerium dioxide, zirconium dioxide, hafnium dioxide, niobium pentoxide, tantalum pentoxide, and chromium trioxide, and the concentration range is 0.2-10 g / L; the nickel salt is one of nickel chloride, nickel nitrate, nickel acetate, and nickel sulfate, and the concentration range is 10-500 mM; the mixed solution also contains trisodium citrate and a surfactant, wherein the concentration range of trisodium citrate is 5-300 mM; the surfactant is one of polyvinyl pyrrolidone, sodium dodecyl sulfate, or sodium benzoate, and the concentration range is 0.1-5 g / L.

4. The method for preparing a nickel alloy-metal oxide composite hydrogen evolution electrode according to claim 1, characterized in that: The electrochemical deposition described in step (2) uses constant current to achieve the reduction of nickel ions and the co-deposition of metal oxides, the applied cathode current density is 10 to 500 mA cm-2, and the deposition time is 10 to 120 min.

5. The method for preparing a nickel alloy-metal oxide composite hydrogen evolution electrode according to claim 1, characterized in that: The molybdenum salt described in step (3) refers to ammonium molybdate and sodium molybdate, and the concentration range of the molybdenum salt is 5 to 300 mM; the tungsten salt refers to ammonium tungstate, ammonium metatungstate, sodium tungstate, and the concentration range of the tungsten salt is 3 to 200 mM.

6. The method for preparing a nickel alloy-metal oxide composite hydrogen evolution electrode according to claim 1, characterized in that: The two-stage electrodeposition described in step (3) uses a constant current to achieve the reduction of nickel ions and molybdenum ions and the co-deposition of metal oxides. The applied current density is 10 to 500 mA cm-2 and the deposition time is 15 to 120 min.

7. The method for preparing a nickel alloy-metal oxide composite hydrogen evolution electrode according to claim 1, characterized in that: The drying is vacuum drying or forced air drying. The drying temperature is room temperature to 100°C.

8. Use of the hydrogen evolution electrode prepared by the method for preparing a nickel alloy-metal oxide composite hydrogen evolution electrode according to any one of claims 1 to 7 in hydrogen production by electrolysis of water.

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