Electrolytic bath electrode preparation method and system

Abstract

The invention provides an electrolytic bath electrode preparation method and system.The method comprises the steps that a nickel-containing metal matrix is soaked in an acid solution, and after soaking is completed, the metal matrix is taken out to be washed and dried; dissolving metal salt containing Fe < 2 + > to obtain a metal salt solution precursor; and soaking the treated nickel-containing metal matrix in the metal salt solution precursor, introducing oxygen and / or compressed air to disturb the solution, and washing and drying after soaking to obtain the electrolytic cell electrode. The raw materials are low in cost, the preparation process is simple, and the purpose of meter-scale large-size large-scale production can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic hydrogen production, and in particular to a method and system for preparing an electrolytic cell electrode. Background Art

[0002] Hydrogen production by water electrolysis is the mainstream choice in the field of hydrogen production technology. After years of research and development and progress, water electrolysis hydrogen production technology has derived a variety of process paths. Alkaline water electrolysis hydrogen production technology has gradually gained favor in the industry due to its high maturity, low equipment cost and ability to achieve large-scale hydrogen production. However, as the core component of alkaline water electrolysis hydrogen production technology, alkaline water electrolyzers face development bottlenecks such as high energy consumption for hydrogen production, low current density and limited component processing capabilities. To meet these challenges, the industry has adopted two main strategies: one is to increase the size of the electrolyzer, and the other is to increase the current density.

[0003] Compared with increasing the size of the electrolyzer, it is more feasible and economical to improve the performance and reduce the cost of the electrolyzer by developing high-performance electrodes.

[0004] Traditional electrolytic cell anodes usually use nickel optical mesh, but due to its high oxygen evolution overpotential and slow reaction rate, the anode has become one of the key factors limiting the performance improvement of the electrolytic cell.

[0005] In order to promote the nucleation of new phases on the surface of nickel-containing metal substrates in the prior art, patent CN114941158A uses organic solvents to induce nucleation, which poses the risk of environmental pollution caused by the volatilization of organic solvents; hydrochloric acid is used to remove the oxide layer on the surface of the metal substrate, but for meter-scale process electrolytic cells, the cost of using, storing and post-processing hydrochloric acid is relatively high.

[0006] The current problems that need to be solved are to promote the nucleation of new phases on the surface of nickel-containing metal substrates, improve electrode stability, reduce environmental pollution, lower production costs, and achieve large-scale production at the meter level. Summary of the invention

[0007] The embodiments of the present invention provide a method and system for preparing an electrolytic cell electrode, which at least partially solve the above-mentioned problems in the prior art.

[0008] In order to solve the above problems, the present invention provides a method for preparing an electrolytic cell electrode, comprising the following steps:

[0009] Electrode substrate pretreatment: immerse the nickel-containing metal substrate in an acidic solution, take out the metal substrate after immersion, wash and dry it;

[0010] Preparation of metal salt solution precursor: dissolving a metal salt containing Fe2+ to obtain a metal salt solution precursor;

[0011] Preparation of the catalytic material base layer: soak the pretreated nickel-containing metal substrate in the metal salt solution precursor, and introduce oxygen and / or compressed air to disturb the solution. After soaking, washing and drying, the electrolytic cell electrode is obtained. Electrode substrate pretreatment can remove the oxide layer and stains on the surface of the nickel-containing metal substrate, improve the substrate roughness, and increase the electrode bonding strength. The introduction of O2 and / or compressed air can promote the Fe 2+ The oxidation rate is increased and nucleation is promoted, thereby reducing the reaction temperature for the formation of NiFe-LDH.

[0012] In a preferred embodiment, H2O2 is added to a metal salt solution precursor, the pretreated nickel-containing metal substrate is immersed in the metal salt solution precursor containing H2O2, and oxygen and / or compressed air are introduced to disturb the solution. After immersion, washing and drying, an electrolytic cell electrode with a heterojunction structure is obtained.

[0013] In a preferred embodiment, the pretreated nickel-containing metal substrate is immersed in a metal salt solution precursor containing H2O2 and irradiated with ultraviolet light. The ultraviolet light source can significantly promote the decomposition of H2O2 into ·OH and reduce the reaction temperature of the heterojunction structure NiFe-LDH / FeOOH.

[0014] In a preferred embodiment, one or more of nickel nitrate, nickel chloride, nickel sulfate, ferric nitrate, ferric sulfate, ferric chloride, cobalt nitrate, cobalt sulfate, cobalt chloride, molybdenum chloride, ammonium molybdate and sodium molybdate are added during the preparation of the metal salt solution precursor. MoO4 can be generated in the above-mentioned catalyst material base layer preparation step. 2- , NiCo-LDH, NiMo-LDH, NiFeCo-LDH, NiFeMo-LDH, NiCoMo-LDH, etc., among which MoO4 2- Adsorbed on the electrode interface, as oxygen-containing anions, it improves the stability of anode electrolysis, NiCo-LDH, NiMo-LDH, NiFeCo-LDH, NiFeMo-LDH, NiCoMo-LDH, etc., increases the active sites of the electrode and enhances the electrode activity.

[0015] In a preferred embodiment, the method further comprises: modifying the electrode, comprising:

[0016] The electrolytic cell electrode is immersed in a modified solvent containing one or more of silver ions, boron ions, and phosphorus ions, and then the immersed electrode is taken out, washed, and dried. The modification can dope the electrode with silver ions, boron ions, and phosphorus ions, which are used to adjust the distribution of NiFe-LDH / FeOOH oxygen vacancies at Ni and Fe sites, regulate the electronic distribution of Fe atoms as reaction active sites, promote the analysis of intermediate products of oxygen evolution reaction, and improve the performance and stability of the electrode.

[0017] In a preferred embodiment, the ultraviolet light has a wavelength of 160 nm to 254 nm.

[0018] In a preferred embodiment, the acidic solution is an oxalic acid solution. Oxalic acid has low usage, storage and post-processing costs.

[0019] In a preferred embodiment, the nickel-containing metal matrix comprises a metal mesh, a metal fiber felt and / or a foam metal material.

[0020] In a preferred embodiment, the detergent used for washing includes one or more of deionized water and ethanol, containing Fe 2+ The solvent used for dissolving the metal salt includes deionized water. Deionized water is safe and pollution-free as a solvent and has low cost.

[0021] The present invention also provides a system for preparing an electrolytic cell electrode using the above electrolytic cell electrode preparation method, comprising:

[0022] Substrate pretreatment equipment, used to immerse the nickel-containing metal substrate in an acid solution, and after the immersion is completed, take out the metal substrate for washing and drying;

[0023] Metal salt solution precursor preparation equipment, used to prepare Fe 2+ The metal salt is dissolved to obtain a metal salt precursor solution;

[0024] Catalytic material base layer preparation equipment is used to immerse the pretreated nickel-containing metal substrate in a metal salt solution precursor, and introduce oxygen and / or compressed air to disturb the solution, and obtain the electrolytic cell electrode after immersion, washing and drying.

[0025] In the solution provided by the embodiment of the present invention, oxygen and / or compressed air are used to disturb the solution so that the nickel-containing metal matrix 2+ A reaction occurs in a metal salt solution to prepare an electrolytic cell electrode. This method has low raw material costs and a simple preparation process, and can achieve large-scale production goals of meter-level sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. For illustrative purposes, these drawings may not be drawn completely to scale.

[0027] Figure 1 It is a schematic flow chart of a method for preparing an electrolytic cell electrode provided in Example 1 of the present invention.

[0028] Figure 2This is a microscopic morphology of the NiFe catalytic material base layer taken by Zeiss Merlin field emission scanning electron microscope in Example 4 of the present invention.

[0029] Figure 3 This is a high-resolution microscope scanning image of the base layer of the NiFe-LDH / FeOOH heterojunction catalytic material in Example 4 of the present invention.

[0030] Figure 4 This is a microscopic morphology of the electrode modified in the NiFe-LDH / FeOOH heterojunction catalytic material base layer using a field emission scanning electron microscope in Example 4 of the present invention.

[0031] Figure 5 It is the oxygen evolution polarization curve diagram of Example 4 of the present invention.

[0032] Figure 6 This is a microscopic morphology image of the base layer of the NiFe catalyst material taken using a field emission scanning electron microscope in Example 5 of the present invention.

[0033] Figure 7 It is a cyclic voltammetry sweep curve diagram of Example 5 of the present invention after constant current electrolysis for different time periods. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to understand the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a product or device containing a series of units is not necessarily limited to those units clearly listed, but may include other units that are not clearly listed or inherent to these products or devices.

[0036] In the present invention, the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0037] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0038] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] Example 1

[0041] The present invention provides a method for preparing an electrolytic cell electrode. Figure 1 As shown, including:

[0042] Step S1: Pretreatment of the electrode substrate: immersing the nickel-containing metal substrate in an acidic solution, and after immersion, taking out the metal substrate, washing and drying it.

[0043] Specifically, in this step, the nickel-containing metal matrix includes one or more of nickel, nickel-iron alloy, nickel-containing stainless steel, and nickel-aluminum alloy, and the nickel-containing metal matrix structure includes a metal mesh, a metal fiber felt and / or a foam metal. In this step, the acidic solution is preferably an oxalic acid solution, and other acidic solutions can also remove the oxide layer and stains on the surface of the nickel-containing metal matrix, improve the roughness of the matrix, and increase the electrode binding force. The use, storage and post-processing costs of oxalic acid are low. In this step, the mass fraction of the oxalic acid solution is preferably 1% to 15%, and more preferably 5% to 10%; the temperature is preferably 60°C to 100°C, and more preferably 85°C to 95°C; the metal matrix immersion time is preferably 5 minutes to 120 minutes, and more preferably 30 minutes to 60 minutes. The above numerical range is a preferred numerical value, and the metal matrix structure is a preferred structure, which does not mean that other numerical ranges and other metal matrix structures cannot achieve the preparation method described in the present invention. Among them, the detergent used for washing includes deionized water and ethanol.

[0044] Step S2: Preparation of metal salt solution precursor: 2+ The metal salt is dissolved, fully mixed and stirred to prepare a metal salt solution precursor.

[0045] Specifically, in this step, Fe 2+ The metal salt includes one or more combinations of ferrous nitrate, ferrous sulfate, and ferrous chloride. The solvent includes deionized water. The concentration of the metal salt solution obtained by configuration is 10 mmol / L to 1000 mmol / L. This solvent and concentration range are preferred solutions, and do not mean that other solvents and other concentration ranges cannot achieve the preparation method of the present invention. There is no strict order between step S1 and step S2.

[0046] Preferably, in the Fe-containing 2+ The metal salt is dissolved in the solvent and one or more of nickel nitrate, nickel chloride, nickel sulfate, ferric nitrate, ferric sulfate, ferric chloride, cobalt nitrate, cobalt sulfate, cobalt chloride, molybdenum chloride, ammonium molybdate and sodium molybdate are added, and the metal salt can be reacted in the following step S3: the step of preparing the catalytic material base layer to generate MoO4 2- , NiCo-LDH, NiMo-LDH, NiFeCo-LDH, NiFeMo-LDH, NiCoMo-LDH, etc. The principle is that Mo ions form MoO4 2- They are adsorbed on the electrode interface and act as oxygen-containing anions to improve the electrolytic stability of the anode; while Co ions, Mo ions, and Fe ions form NiCo-LDH, NiMo-LDH, NiFeCo-LDH, NiFeMo-LDH, NiCoMo-LDH, etc. during the electrolysis process, which increases the active sites of the electrode and enhances the electrode activity.

[0047] Step S3: Preparation of catalytic material base layer: Immerse the pretreated nickel-containing metal substrate in a Fe-containing 2+ Oxygen and / or compressed air are introduced into the metal salt solution to disturb the solution, and the electrolytic cell electrode is obtained after soaking, washing and drying.

[0048] Specifically, in this step, the Fe content is maintained during the preparation process. 2+ The temperature of the metal salt solution is preferably 50°C to 120°C; the content of Fe per liter 2+ The amount of O2 or compressed air introduced into the metal salt solution is preferably 0.01ml / min to 100ml / min, and more preferably 5ml / min, 10ml / min, and 20ml / min per liter; the compressed air pressure is preferably 0.1Mpa to 0.2Mpa. The purpose of introducing the gas is to maintain the dissolved oxygen environment in the metal salt solution on the one hand, and to disturb the electrolyte on the other hand to promote the nucleation of the catalytic material. The immersion time of the metal matrix is ​​preferably 0.1h to 48h. After the immersion is completed, the electrode is taken out and rinsed with deionized water or ethanol, and then dried at a preferred temperature of 0°C to 60°C. The drying time is preferably 0.1h to 24h. The above numerical range is a preferred numerical value, which does not mean that other numerical ranges cannot achieve the preparation method described in the present invention. The metal salt solution precursor used in this step can be reused, and only Fe needs to be supplemented the next time it is used. 2+ Metal ions can reduce production costs.

[0049] The reaction principle is Fe 2+ First oxidized by O2 to Fe 3+ , then Fe 3+ Reoxidize the Ni matrix and form Ni 2+ with Fe 2+ , at this time Fe 2+ , Fe 3+ with Ni 2+ The reaction forms a NiFe-LDH structure containing Fe(II) and Fe(III). At this time, the amount of O2 or compressed air introduced can be adjusted by using a gas flow control valve or other control methods to promote the Fe 2+ The oxidation rate is increased and the nucleation is promoted, thereby reducing the reaction temperature for the formation of NiFe-LDH.

[0050] Preferably, the method may further include:

[0051] Step S4: modifying the electrode obtained in step S3.

[0052] The modification process includes the following steps:

[0053] The electrode is immersed in a modified solvent containing one or more silver ions, boron ions, and phosphorus ions at a preferred concentration of 10mmol / L to 1000mmol / L, and the concentration is further preferably 0.05mol / L, 0.1mol / L, and 0.2mol / L; the immersion temperature is 0℃ to 90℃, and the immersion time is 2h to 24h. After that, the immersed electrode is taken out and washed with deionized water 2 to 5 times, and dried at 0℃ to 60℃. The modification can be doped with silver ions, boron ions, and phosphorus ions to adjust the distribution of NiFe-LDH / FeOOH oxygen vacancies at Ni and Fe sites, regulate the electronic distribution of the active sites (Ni, Fe, O) of the catalytic material, promote the analysis of the intermediate products of the oxygen evolution reaction, and improve the performance and stability of the electrode. Among them, the modified solvent is selected from one or more of sodium phosphite, potassium phosphite, sodium hypophosphite, potassium hypophosphite, sodium borohydride, potassium borohydride, boric acid, phosphoric acid, silver nitrate, etc. The above numerical ranges and modified solvents are preferred numerical values ​​and preferred solvents, and do not mean that other numerical ranges and modified solvents cannot achieve the preparation method of the present invention.

[0054] Through the steps S1, S2 and S3 of this embodiment, an electrolytic cell electrode can be prepared. Step S4 modifies the electrode so that the surface active sites of the catalytic material are increased, thereby improving the electrode performance. 2+ The metal salt solution can be recycled and has the advantage of low cost.

[0055] Example 2

[0056] An embodiment of the present invention provides a method for preparing an electrolytic cell electrode, comprising:

[0057] Step S1: Pretreatment of the electrode substrate: immersing the nickel-containing metal substrate in an acidic solution, and after immersion, taking out the metal substrate, washing and drying it.

[0058] The specific operation of the electrode substrate pretreatment in this step is the same as that in Example 1 and will not be repeated here.

[0059] Step S2: Preparation of metal salt solution precursor: 2+ The metal salt is dissolved, and H2O2 is added and mixed thoroughly and stirred to prepare a metal salt solution.

[0060] Preferably, H2O2 with a concentration of 10% to 40% is added to the metal salt solution obtained in the preparation of the metal salt solution precursor, and 2ml to 4ml of H2O2 is preferably added to every 100ml of the metal salt solution. The above numerical range is a preferred numerical range, and does not mean that other numerical ranges cannot achieve the preparation method of the present invention.

[0061] The reaction process is Fe 2+ Can react with H2O2 to generate Fe 3+ and OH -and ·OH, while O2 can further promote Fe 2+ Oxidized to Fe 3+ At this time, Fe 3+ OH obtained by decomposition with H2O2 - The reaction produces FeOOH.

[0062] Step S3: Preparation of catalytic material base layer: Immerse the treated nickel-containing metal substrate in a Fe-containing 2+ Oxygen and / or compressed air are introduced into the metal salt and H2O2 solution to disturb the solution, and after soaking, washing and drying, an electrolytic cell electrode with a heterojunction structure is prepared.

[0063] Specifically, in this step, the Fe content is maintained during the preparation process. 2+ The temperature of the metal salt solution is preferably 50°C to 120°C; the content of Fe per liter 2+ The amount of O2 or compressed air introduced into the metal salt solution is preferably 0.01ml / min to 100ml / min, and more preferably 5ml / min, 10ml / min, and 20ml / min per liter; the compressed air pressure is preferably 0.1Mpa to 0.2Mpa. The purpose of introducing the gas is to maintain the dissolved oxygen environment in the metal salt solution on the one hand, and to disturb the electrolyte on the other hand to promote the nucleation of the catalytic material. The immersion time of the metal matrix is ​​preferably 0.1h to 48h. After the immersion is completed, the electrode is taken out and rinsed with deionized water or ethanol, and then dried at a preferred temperature of 0°C to 60°C. The drying time is preferably 0.1h to 24h. The above numerical range is a preferred numerical value, which does not mean that other numerical ranges cannot achieve the preparation method described in the present invention. The metal salt solution precursor used in this step can be reused, and only Fe needs to be supplemented the next time it is used. 2+ Metal ions can reduce production costs.

[0064] The reaction process is that the matrix Ni is oxidized by OH to generate Ni 2+ , and further with Fe 3+ The reaction generates a NiFe-LDH structure, and an electrolytic cell electrode having a heterojunction structure of NiFe-LDH / FeOOH is prepared.

[0065] The embodiment of the present invention may further include step S4: modifying the electrode obtained in step S3.

[0066] This step is the same as in Example 1 and will not be repeated here.

[0067] Example 3

[0068] The embodiment of the present invention provides a method for preparing an electrolytic cell electrode, wherein step S3 of the method is different from that in embodiment 2, and the other steps are the same as those in embodiment 2.

[0069] Step S3 includes: immersing the pretreated nickel-containing metal substrate in a Fe-containing 2+ When the metal salt solution is stirred, oxygen and / or compressed air is introduced and ultraviolet light is used at the same time.

[0070] Specifically, in this step, ultraviolet light irradiation is added, and the wavelength of ultraviolet light is preferably 160nm to 254nm. During the preparation process, the Fe-containing 2+ The temperature of the metal salt solution is preferably 0°C to 90°C, more preferably 25°C, 35°C, 45°C. The other reaction conditions are the same as step S3 in Example 2 and will not be repeated here. The above-mentioned wavelength values ​​of ultraviolet light and solution temperature are preferred values, which does not mean that other numerical ranges cannot achieve the preparation method described in the present invention. After adding ultraviolet light, the ultraviolet light source can significantly promote the decomposition of H2O2 into ·OH, and further promote the formation of heterojunction structure NiFe-LDH / FeOOH, and ultraviolet light irradiation can reduce the formation temperature of heterojunction structure NiFe-LDH / FeOOH. The principle is that H2O2 in Fe 2+ Fenton reaction occurs under low temperature, but the decomposition rate of H2O2 is still slow, and the general reaction temperature needs to be 50-120℃; UV light can promote the decomposition of H2O2, and it reacts with Fe 2+ The synergistic effect can further reduce the decomposition temperature of H2O2 and accelerate its decomposition. Therefore, under the synergistic effect of ultraviolet light, the decomposition rate of H2O2 can be accelerated, thereby reducing the reaction temperature.

[0071] Example 4

[0072] An embodiment of the present invention provides a method for preparing an electrolytic cell electrode, comprising:

[0073] Step S1: Pretreatment of the electrode substrate: immersing the nickel-containing metal substrate in an acidic solution, and after immersion, taking out the metal substrate, washing and drying it.

[0074] Specifically, in this step, a nickel metal mesh with a size of 5 cm×5 cm is cut, and the nickel metal mesh is immersed in an oxalic acid solution with a mass fraction of 5 wt % and a temperature of 90° C. for 30 minutes, and then taken out and rinsed with clean water to serve as the base material.

[0075] Step S2: Preparation of metal salt solution precursor: 2+ The metal salt is dissolved, fully mixed and stirred to prepare a metal salt solution.

[0076] Specifically, in this step, 5.257 g of NiSO4·6H2O and 2.224 g of FeSO4·7H2O were weighed with a spoon and dissolved in 100 ml of deionized water, and 4 ml of 30% H2O2 solution was added. The mixture was stirred at 500 rpm and a 0.2 mol / L Ni 2+ With 0.8 mol / L Fe 2+ of metal salt solution.

[0077] Step S3: Preparation of catalytic material base layer: Immerse the pretreated nickel-containing metal substrate in a Fe-containing 2+ Oxygen and / or compressed air are introduced into the metal salt and H2O2 solution to disturb the solution, and after soaking, washing and drying, an electrolytic cell electrode with a heterojunction structure is prepared.

[0078] Specifically, in this step, the nickel metal mesh is immersed in the Ni and Fe metal salt solution for 2 hours, compressed air is introduced during the static process, the electrode immersion temperature is 25°C, and ultraviolet light is used during the immersion process to induce the generation of NiFeLDH / FeOOH heterojunction structure. After the immersion is completed, the electrode is taken out and rinsed with deionized water.

[0079] Step S4: modifying the electrode obtained in step S3.

[0080] Specifically, the rinsed electrode is immersed in a 0.5 mol / L NaBH4 solution for 2 hours, taken out and dried. In this step, the strong reducing ability of NiBH4 is used to dope oxygen vacancies in NiFe-LDH, and a NiFeB-LDH / FeOOH electrode material doped with a certain concentration of B element is prepared.

[0081] Figure 2 This is a microscopic morphology image of the base layer of the NiFe catalytic material taken using a Zeiss Merlin field emission scanning electron microscope, which shows the microscopic morphology of the base layer of the NiFe catalytic material. From the image, it can be observed that the catalytic material has a layered structure, and the spacing between each layer structure is about 0.5μm. Figure 3 This is a high-resolution microscope scan of the base layer of the NiFe-LDH / FeOOH heterojunction catalytic material. The left figure is a transmission electron microscope image of the lamellar catalytic material, and the right figure shows a high-resolution projection electron microscope scan of the dotted square area in the left figure. It can be seen that a heterojunction structure in which crystalline and amorphous phases coexist is produced on the prepared catalytic material base layer. Figure 4 This is a microscopic morphology of the electrode modified in the base layer of the NiFe-LDH / FeOOH heterojunction catalyst material using a field emission scanning electron microscope, showing the microscopic morphology of NiFe-LDH / FeOOH after doping with B. It can be seen that after modification with 0.5 mol NaBH4 solution, the spacing between the layers is shortened. At this time, the active sites on the surface of the catalytic material also increase.

[0082] At 0.8A / cm 2 The electrode was subjected to an accelerated electrolysis test under electrical density, the test electrolyte was 30wt% KOH, the test temperature was room temperature, and the oxygen evolution polarization curve of the electrode was tested every 24 hours. Figure 5 is the oxygen evolution polarization curve, the horizontal axis represents the voltage, the unit is V vs. RHE is volts compared to the reversible hydrogen electrode, and the vertical axis represents the current density, the unit is A cm -2 ADT@30wt%KOH 0.8A / cm 2 ADT in RT stands for accelerated life test, @ stands for the electrolyte, density and room temperature conditions used in the test, and RT stands for room temperature, showing 30wt% KOH and 0.8A / cm 2 The accelerated life test was carried out under constant current electrolysis. After different time periods, the performance of NiFe-LDH / FeOOH doped with B changed. It can be observed that the performance of NiFe-LDH / FeOOH doped with B changed in 1 mol / L KOH solution and 0.4 A / cm 2 Under the condition of high current density, the oxygen evolution overpotential of the prepared electrode was 392 mV, and after 24 h of electrolysis, the oxygen evolution overpotential of the electrode decreased to 419 mV. During the electrolysis for 192 h, the electrode performance remained basically stable.

[0083] Example 5

[0084] An embodiment of the present invention provides a method for preparing an electrolytic cell electrode, comprising:

[0085] Step S1: Pretreatment of the electrode substrate: immersing the nickel-containing metal substrate in an acidic solution, and after immersion, taking out the metal substrate, washing and drying it.

[0086] Specifically, in this step, a nickel metal mesh with a size of 5 cm×5 cm is cut, and the nickel metal mesh is immersed in an oxalic acid solution with a mass fraction of 5 wt % and a temperature of 90° C. for 30 minutes, and then taken out and rinsed with clean water to serve as the base material.

[0087] Step S2: Preparation of metal salt solution precursor: 2+ The metal salt is dissolved, fully mixed and stirred to prepare a metal salt solution.

[0088] Specifically, in this step, 5.257 g of NiSO4·6H2O and 2.224 g of FeSO4·7H2O were weighed with a spoon, dissolved in 100 ml of deionized water, and 4 ml of 30% H2O2 solution was added. Then, the mixture was stirred at 500 rpm to prepare a 0.2 mol / L Ni 2+ With 0.8 mol / L Fe 2+ of metal salt solution.

[0089] Step S3: Preparation of catalytic material base layer: Immerse the pretreated nickel-containing metal substrate in a Fe-containing 2+ Oxygen and / or compressed air are introduced into the metal salt and H2O2 solution to disturb the solution, and after soaking, washing and drying, an electrolytic cell electrode with a heterojunction structure is prepared.

[0090] Specifically, in this step, the nickel metal mesh is immersed in the Ni and Fe metal salt solution for 2 hours, compressed air is introduced during the static process, the electrode immersion temperature is 25°C, and ultraviolet light is used during the immersion process to induce the production of a heterojunction structure. After the immersion is completed, the electrode is taken out and rinsed with deionized water.

[0091] Step S4: modifying the electrode obtained in step S3.

[0092] Specifically, in this step, the rinsed electrode is immersed in a 0.05 mol / L AgNO3 solution for 2 h, taken out and dried, and finally a doped NiFeAg electrode material is obtained. Figure 6 This is a microscopic morphology of the base layer of the NiFe catalytic material taken using a field emission scanning electron microscope, showing the microscopic morphology of the surface of the electrolytic cell electrode doped with NiFeAg.

[0093] At 0.8A / cm 2 The electrode was subjected to an accelerated electrolysis test under electrical density, the test electrolyte was 30wt% KOH, the test temperature was room temperature, and the cyclic Fu'an curve of the electrode was tested every 24 hours. Figure 7 The cyclic voltammetry curves of this embodiment after constant current electrolysis for different times are shown in Figure 1. The horizontal axis represents the voltage, and the unit is Vvs.RHE, which is volts compared to the reversible hydrogen electrode. The vertical axis represents the current density, and the unit is Acm -2 is amperes per square centimeter, showing 30 wt% KOH and 0.8 A / cm at room temperature 2 The performance of Ag-doped NiFe-LDH / FeOOH changes after constant current electrolysis for different times. It can be observed from the figure that in 1 mol / L KOH solution and 0.4 A / cm 2 Under the condition of high current density, the oxygen evolution overpotential of the prepared electrode was 479 mV. During the 72 h of electrolysis, this data remained basically unchanged.

[0094] Example 6

[0095] Based on the same technical concept as the above-mentioned method embodiments, the embodiment of the present invention also provides an industrial alkaline electrolytic cell electrode preparation system, comprising:

[0096] The substrate pretreatment equipment is used to immerse the nickel-containing metal substrate in an acidic solution, and take out the metal substrate after immersion, wash and dry it; the specific implementation can refer to the operations involved in step S1 in any of the above embodiments, which will not be repeated here.

[0097] Metal salt solution precursor preparation equipment, used to prepare Fe 2+ The metal salt is dissolved to obtain a metal salt solution precursor; the specific implementation can refer to the operations involved in step S2 in any of the above embodiments, which will not be repeated here.

[0098] The catalytic material base layer preparation equipment is used to immerse the pretreated nickel-containing metal substrate in a metal salt solution precursor, and introduce oxygen and / or compressed air to disturb the solution, and after immersion, washing and drying, an electrolytic cell electrode is obtained. The specific implementation can refer to the operations involved in step S3 in any of the above embodiments, which will not be repeated here.

[0099] Also includes:

[0100] The modification equipment is used to soak the electrode in a modification solvent containing one or more of silver ions, boron ions, and phosphorus ions, and then take out the soaked electrode for washing and drying. The specific implementation can refer to the operation involved in step S4 in any of the above embodiments, which will not be repeated here.

[0101] Electrolyzer electrodes can be prepared by using substrate pretreatment equipment, metal salt solution precursor preparation equipment, and catalytic material base layer preparation equipment to implement the operation method involved in the above embodiment. By introducing O2 or compressed air, Fe 2+ The oxidation rate is increased and nucleation is promoted, thereby reducing the reaction temperature for generating NiFe-LDH. In addition, the raw material cost is low and the preparation process is simple, which reduces the production cost and enables the goal of large-scale production of meter-level sizes.

[0102] Preferably, H2O2 is added to the metal salt solution precursor to generate an electrolytic cell electrode having a heterojunction structure NiFe-LDH / FeOOH.

[0103] It is further preferred that ultraviolet light is used to irradiate the treated nickel-containing metal substrate while it is immersed in a metal salt solution precursor containing H2O2, so as to further promote the formation of the heterojunction structure NiFe-LDH / FeOOH, and ultraviolet light irradiation can reduce the formation temperature of the heterojunction structure NiFe-LDH / FeOOH.

[0104] By using the modification equipment to implement the operation method involved in the above embodiment, the electrolytic cell electrode prepared by the above equipment can be modified so that the active sites on the surface of the catalytic material of the electrode are increased, thereby improving the electrode performance.

[0105] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some of the technical features thereof may be replaced by equivalents; these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an electrolytic cell electrode, characterized in that: include: Electrode substrate pretreatment: immerse the nickel-containing metal substrate in an acidic solution, take out the metal substrate after immersion, wash and dry it; Preparation of metal salt solution precursor: 2+ The metal salt is dissolved to obtain a metal salt solution precursor; Preparation of the catalytic material base layer: soak the pretreated nickel-containing metal substrate in the metal salt solution precursor, and introduce oxygen and / or compressed air to disturb the solution. After soaking, washing and drying, the electrolytic cell electrode is obtained.

2. The method for preparing an electrolytic cell electrode according to claim 1, characterized in that: H2O2 is added to a metal salt solution precursor, a pretreated nickel-containing metal substrate is immersed in the metal salt solution precursor containing H2O2, and oxygen and / or compressed air are introduced to disturb the solution. After immersion, washing and drying, an electrolytic cell electrode with a heterojunction structure is obtained.

3. The method for preparing an electrolytic cell electrode according to claim 2, characterized in that: The pretreated nickel-containing metal substrate is immersed in a metal salt solution precursor containing H2O2 and irradiated with ultraviolet light.

4. The method for preparing an electrolytic cell electrode according to claim 1, characterized in that: One or more of nickel nitrate, nickel chloride, nickel sulfate, ferric nitrate, ferric sulfate, ferric chloride, cobalt nitrate, cobalt sulfate, cobalt chloride, molybdenum chloride, ammonium molybdate and sodium molybdate are added during the preparation of the metal salt solution precursor.

5. The method for preparing an electrolytic cell electrode according to claim 1, characterized in that: Also includes: Electrode modification treatment, including: The electrolytic cell electrodes are immersed in a modified solvent containing one or more of silver ions, boron ions and phosphorus ions, and then the immersed electrodes are taken out, washed and dried.

6. The method for preparing an electrolytic cell electrode according to claim 3, characterized in that: The wavelength of the ultraviolet light is 160nm to 254nm.

7. The method for preparing an electrolytic cell electrode according to claim 1, characterized in that: The acidic solution is an oxalic acid solution.

8. The method for preparing an electrolytic cell electrode according to claim 1, characterized in that: The nickel-containing metal matrix includes a metal mesh, a metal fiber felt and / or a foam metal material.

9. The method for preparing an electrolytic cell electrode according to any one of claims 1 to 8, characterized in that: The detergent used for washing includes one or more of deionized water, ethanol, and Fe 2+ The solvent used for dissolving the metal salt includes deionized water.

10. A system for preparing an electrode using the method for preparing an electrolytic cell electrode according to any one of claims 1 to 9, comprising: Substrate pretreatment equipment, used to immerse the nickel-containing metal substrate in an acid solution, and after the immersion is completed, take out the metal substrate for washing and drying; Metal salt solution precursor preparation equipment, used to prepare Fe 2+ The metal salt is dissolved to obtain a metal salt precursor solution; Catalytic material base layer preparation equipment is used to immerse the pretreated nickel-containing metal substrate in a metal salt solution precursor, and introduce oxygen and / or compressed air to disturb the solution, and obtain the electrolytic cell electrode after immersion, washing and drying.

Images