Method for prolonging service life of AEM water electrolysis hydrogen production and oxygen evolution catalyst and application of AEM water electrolysis hydrogen production and oxygen evolution catalyst

Abstract

The invention discloses a method for prolonging the service life of an AEM water electrolysis hydrogen production and oxygen evolution catalyst and application of the method. The method comprises the following steps: firstly, preparing a functional electrolyte, then spraying a film solution on the surface of an OER catalyst to construct a protective layer, and finally, placing an installed electrolytic tank in an electrochemical workstation, and circularly executing a constant current mode and an anode electrochemical deposition mode. By optimizing the coordination environment and dynamically regulating and controlling, the service lives of the catalyst and the anionic membrane are prolonged, and the industrial applicability is improved. The method comprises the following steps: functionalizing an electrolyte, reducing dissolution of iron ions, capturing dissolved Fe < 3 + > in real time, anchoring the Fe < 3 + > to a catalyst again, constructing a protective layer on the surface of NiFe-LDH, reducing contact between the iron ions and an anionic membrane, delaying oxidative degradation of the anionic membrane, adopting an intermittent potential reduction method, and periodically changing an electrode potential or an electrolysis mode, so that the oxidation degradation of the anionic membrane is delayed. The catalyst deactivation is effectively inhibited; the long-term stability is improved. And the service life of the whole electrolytic cell is greatly prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production by electrolysis of water, and in particular to a method for improving the service life of an AEM (Aluminum Electrolyzed Electron Molecular Electron) (AEM) hydrogen production and oxygen evolution catalyst and its application. Background Art

[0002] The oxygen evolution reaction (OER) plays a crucial role in hydrogen production via water electrolysis, and efficient OER catalysts are one of the key factors in achieving these technologies. In recent years, transition metal-based catalysts have attracted widespread attention due to their low cost and high activity. Among them, nickel-iron layered double hydroxides (NiFe-LDHs) have shown significant advantages in the OER in alkaline electrolytes due to their excellent electrocatalytic performance.

[0003] However, despite the high catalytic activity of NiFe-LDHs, stability issues have gradually emerged in practical applications. Especially for catalysts containing iron, iron precipitation is a major factor in reducing catalyst life. Iron loss not only reduces the number of effective active sites in the catalyst but also may damage the catalyst structure, thereby affecting its long-term stability and reducing its industrial applicability.

[0004] Currently, the influencing mechanisms of iron precipitation are:

[0005] 1. Reduced active sites: Iron is one of the key components of NiFe-LDHs, and its presence and distribution play a decisive role in the overall performance of the catalyst. When iron precipitates from the surface or interior of the catalyst, it leads to a reduction in the originally efficient active sites, thereby reducing the catalytic efficiency of the entire catalyst.

[0006] 2. Structural changes: Iron loss can cause changes in the catalyst's microstructure, such as grain growth and agglomeration, which can further weaken the catalyst's stability. For example, after long-term operation, sulfur-doped nickel-iron layered double hydroxides may only exhibit slight deformation, but this change can still affect performance.

[0007] 3. Side reactions: The release of iron ions may also trigger a series of side reactions. For example, iron ions react with other components in the electrolyte to form insoluble precipitates, which cover the catalyst surface, hinder the electron transfer path, and ultimately lead to catalyst deactivation. In addition, iron ions can also trigger the Fenton effect, causing the hydrogen peroxide produced in the electrolysis process to decompose into hydroxyl radicals (·OH). Hydroxyl radicals will attack the anion membrane and accelerate the oxidative degradation of the anion membrane. Summary of the Invention

[0008] Based on the technical problems existing in the background technology, the present invention proposes a method and application for improving the life of an AEM electrolysis water hydrogen production and oxygen evolution catalyst.

[0009] The present invention proposes a method for improving the life of an AEM electrolysis water hydrogen evolution catalyst, comprising the following steps:

[0010] S1, preparation of functionalized electrolyte;

[0011] S2, spraying the membrane solution on the surface of the OER catalyst to build a protective layer;

[0012] S3, placing the installed electrolytic cell in a preset electrochemical testing device, and cyclically executing a constant current mode and an anodic electrochemical deposition mode.

[0013] Furthermore, the step of preparing the functionalized electrolyte includes:

[0014] Add deionized water to a pre-set beaker, and add 1 mol / L KOH, 5 mmol / L-50 mmol / L K3PO4, and 1 mmol / L-10 mmol / L EDDHA-K;

[0015] Stir to dissolve;

[0016] Keep sealed.

[0017] Furthermore, the step of spraying a membrane solution on the surface of the OER catalyst to construct a protective layer includes:

[0018] Preparing a membrane solution: dissolving the predetermined anionic membrane fragments in an organic solvent to obtain a membrane solution; wherein the organic solvent is one or more of ethanol, isopropanol, DMSO, NMP, and DMF;

[0019] Spraying or scraping the membrane solution onto the surface of a NiFe-LDH catalyst electrode of a preset size;

[0020] The NiFe-LDH catalyst electrode was placed at 60°C and dried for 2 hours, and the dry basis loading of the NiFe-LDH catalyst electrode was set at 0.2 mg / cm 2 -1.0mg / cm 2 .

[0021] Furthermore, the step of placing the installed electrolytic cell in a preset electrochemical testing device and cyclically executing the constant current mode and the anodic electrochemical deposition mode includes:

[0022] Set the scanning frequency and scanning potential, and perform cyclic voltammetry scanning to the preset number of cycles;

[0023] Et scans were performed by intermittent potentiostatic reduction method.

[0024] Furthermore, the step of performing Et scanning by intermittent potential reduction method includes:

[0025] Constant current mode: Run at a preset working current density until the preset scan time; wherein the scan time is 10min-360min;

[0026] Anodic electrochemical deposition mode: reduction to the preset reduction time at the preset reduction potential;

[0027] The constant current mode and the anodic electrochemical deposition mode are repeatedly performed.

[0028] Furthermore, the number of turns is 100; the scanning frequency is 100 mV / s; the scanning potential is 1-2 V; the reduction potential is 0.4 V-1.23 V; and the reduction time is 1 min-10 min.

[0029] The present invention also provides an AEM electrolyte prepared by the above steps.

[0030] The present invention also provides an AEM water electrolysis hydrogen production and oxygen evolution catalyst, which is prepared according to the method for improving the service life of the AEM water electrolysis hydrogen production and oxygen evolution catalyst.

[0031] The present invention also provides an AEM water electrolysis hydrogen production and oxygen evolution catalyst electrode, which is prepared by the above steps.

[0032] The present invention also provides an AEM water electrolysis hydrogen production and oxygen evolution electrolytic cell, which is prepared by stacking the AEM electrolyte and the AEM water electrolysis hydrogen production and oxygen evolution catalyst electrode.

[0033] The present invention has the following beneficial effects:

[0034] This application can extend the service life of the catalyst, anion membrane and electrolyzer by optimizing the coordination environment, interface design and dynamic regulation, and improve industrial applicability. By functionalizing the electrolyte, the dissolution of iron ions is reduced and the dissolved Fe is captured in real time. 3+ , re-anchoring to the catalyst and building a protective layer on the NiFe-LDH surface, reducing direct contact between iron ions and the anion membrane and delaying its oxidative degradation. Furthermore, by periodically changing the electrode potential or electrolysis mode through intermittent potential reduction, the catalyst deactivation is effectively suppressed and its long-term stability is improved. This increases the operating life of the entire electrolyzer by 5-10 times, and reduces the voltage decay rate to 0.2mV / h to 0.5mV / h after 100 hours of continuous operation of the entire stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A flow chart of the steps of a method for improving the life of an AEM electrolysis water hydrogen production and oxygen evolution catalyst proposed by the present invention;

[0036] Figure 2The Et (constant current) curves of Example 1, Example 2 and Comparative Example 1 of the present invention after continuous electrolysis for 15 h are shown;

[0037] Figure 3 The Et (constant current) curves of Examples 3, 4, 5 and Comparative Example 1 of the present invention after continuous electrolysis for 15 h are shown;

[0038] Figure 4 The Et (constant current) curves of Examples 6, 7, 8 and Comparative Example 1 of the present invention after continuous electrolysis for 15 h are shown;

[0039] Figure 5 The Et (constant current) curves of Example 9 of the present invention and Comparative Example 1 after continuous electrolysis for 100 h are shown. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] Refer to the attached Figure 1 , is a method for improving the life of an AEM water electrolysis hydrogen evolution catalyst in one embodiment of the present invention, which includes the following steps:

[0043] S1, preparation of functionalized electrolyte;

[0044] S2, spraying the membrane solution on the surface of the OER catalyst to build a protective layer;

[0045] S3, placing the installed electrolytic cell in a preset electrochemical testing device, and cyclically executing a constant current mode and an anodic electrochemical deposition mode.

[0046] In the above steps, a functionalized electrolyte is first prepared to reduce the dissolution of iron ions and to capture the dissolved Fe in real time. 3+And re-anchored to the catalyst; then a layer of membrane solution is sprayed on the surface of the OER catalyst to construct a protective layer; wherein, OER is an oxygen evolution reaction. In a specific embodiment, the OER catalyst is nickel-iron layered double hydroxide (NiFe-LDHs). Constructing a protective layer on the surface of NiFe-LDH can reduce the direct contact between iron ions and the anion membrane and delay the oxidative degradation of the anion membrane. Finally, the installed electrolytic cell is placed in a preset electrochemical test device, and an intermittent potential reduction method is used for anodic electrochemical deposition. By periodically changing the electrode potential or electrolysis mode, the catalyst deactivation is effectively suppressed and its long-term stability is improved. Among them, the electrochemical test equipment is an electrochemical workstation, and the electrochemical workstation includes a single-channel workstation and a multi-channel workstation.

[0047] In one embodiment, the step of preparing the functionalized electrolyte includes:

[0048] Add deionized water to a pre-set beaker, and add 1 mol / L KOH, 5 mmol / L-50 mmol / L K3PO4, and 1 mmol / L-10 mmol / L EDDHA-K;

[0049] Stir to dissolve;

[0050] Keep sealed.

[0051] In this embodiment, first, take a large beaker and add deionized water, then add 1 mol / L KOH, 5 mmol / L-50 mmol / L K3PO4, and 1 mmol / L-10 mmol / L EDDHA-K, stir to dissolve, and seal for storage; wherein, EDDHA-K is potassium ethylenediamine di-o-hydroxyphenyl acetate and is a chelating agent.

[0052] Specifically, potassium phosphate migrates to the anode under the influence of the electric field and combines with Fe 3+ Combined to form a stable ferric hydroxyphosphate, during the electrolysis process, the solubility of ferric hydroxyphosphate is lower than that of ferric oxyhydroxide, thereby enhancing stability and reducing the dissolution of iron. EDDHA-K acts as a chelating agent, through coordination with the dissolved Fe 3+ Forming a stable soluble complex to prevent Fe(OH)3 precipitation from covering the active sites. At the same time, through the dynamic balance in the electrolyte, the chelated Fe 3+ It can be re-anchored to the catalyst surface to achieve in situ repair of active sites.

[0053] Furthermore, a protective layer is constructed on the surface of NiFe-LDH (nickel-iron layered double hydroxide).

[0054] Specifically, in one embodiment, the step of spraying a membrane solution on the surface of the OER catalyst to form a protective layer includes:

[0055] Preparing a membrane solution: dissolving the predetermined anionic membrane fragments in an organic solvent to obtain a membrane solution; wherein the organic solvent is one or more of ethanol, isopropanol, DMSO, NMP, and DMF;

[0056] Spraying or scraping the membrane solution onto the surface of a NiFe-LDH catalyst electrode of a preset size;

[0057] The NiFe-LDH catalyst electrode was dried at 60 °C for 2 h, and the dry basis loading of the NiFe-LDH catalyst electrode was 0.2 mg / cm 2 -1.0mg / cm 2 .

[0058] In this example, anionic membrane fragments are prepared and dissolved in an organic solvent to produce a membrane solution. The organic solvent is one or more of ethanol, isopropanol, DMSO, NMP, and DMF, and the membrane solution is prepared to a 5% concentration. DMSO is dimethyl sulfoxide, NMP is N-methyl-2-pyrrolidone, and DMF is N,N-dimethylformamide. 5% indicates that the dry anionic membrane accounts for 5% of the total membrane solution by mass, and the calculation formula is:

[0059] Dry anion membrane weight / (solvent weight+dry anion membrane weight)*100%;

[0060] Next, prepare a 10cm*10cm FeNi-LDH catalyst electrode and spray or scrape the above membrane solution onto the surface of the FeNi-LDH catalyst electrode. Then, dry the catalyst electrode sprayed with the membrane solution at 60°C for 2 hours, and control the membrane dry basis loading of the FeNi-LDH catalyst electrode to 0.2mg / cm 2 -1.0mg / cm 2 In a specific embodiment, the catalyst electrode is dried in an oven, and the temperature of the oven is set to 60°C.

[0061] More specifically, a membrane solution is applied to the surface of the catalyst electrode, and a protective layer is formed after drying. The protective layer can act as an insulator, preventing the catalytic layer of the electrode from directly contacting the anion membrane. When hydroxyl radicals are generated, they preferentially attack the protective layer, thereby delaying the oxidative degradation of the anion membrane.

[0062] After building the protective layer, an anodic electrochemical deposition strategy was employed.

[0063] Specifically, in one embodiment, the installed electrolytic cell is placed in a preset electrochemical testing device, and the steps of cyclically performing a constant current mode and an anodic electrochemical deposition mode include:

[0064] Set the scanning frequency and scanning potential, and perform cyclic voltammetry scanning to the preset number of cycles;

[0065] Et scans were performed by intermittent potentiostatic reduction method.

[0066] The steps of performing Et scanning by intermittent potentiostatic reduction method include:

[0067] Constant current mode: Run at the preset working current density until the preset scan time; the scan time is 10min-360min;

[0068] Anodic electrochemical deposition mode: reduction to the preset reduction time at the preset reduction potential;

[0069] The constant current mode and the anodic electrochemical deposition mode were performed repeatedly.

[0070] In this embodiment, the assembled electrolytic cell is placed in an electrochemical workstation for electrode polarization and stability testing. Specifically, a cyclic voltammetry scan is first performed. Among them, the voltammetry scan is CV (Cyclic Voltammetry), which applies a linearly varying voltage to the working electrode and the reference electrode, and the voltage gradually increases from an initial value to a maximum value, and then decreases from the maximum value to the initial value, and forms a cycle. During the voltage change process, the current flowing through the working electrode is tested, and the relationship between voltage and current is recorded and presented to obtain a voltammetric curve. The change in current can reflect the redox behavior of the substance.

[0071] More specifically, the scanning frequency is set to 100mV / s, the scanning potential is set to 1-2V, and 100 circles are scanned to stabilize the electrode. Then, the intermittent potential reduction method is used to perform Et scanning; wherein, Et is a curve of potential and time, that is, a constant current is applied and the relationship between potential and time is recorded. Specifically, at the working current density, it runs for 10min-360min, and the change of potential with time is recorded. Then the reduction potential is set at 0.4V-1.23V, reduced to 1min-10min, and then continued to run at the working current density for 10min-360min, and again reduced at the reduction potential of 0.4V-1.23V for 1min-10min, and this cycle is repeated. Using the intermittent potential reduction method to periodically change the electrode potential or electrolysis mode can regulate the surface state of the catalyst, effectively inhibit the deactivation of the catalyst, and improve its long-term stability.

[0072] Furthermore, through the anodic electrochemical deposition strategy, the process from dissolution to redeposition is controlled, and the iron ions dissolved in the electrolyte are electrochemically deposited onto the surface of the anode electrode, which can reduce the compensation active sites and increase the service life of the catalyst. By performing cyclic voltammetry (CV) scanning in the low potential range, a controllable structural transformation of the catalyst surface is induced. Specifically, for example, in the non-OER potential range of -0.3-0.7V vs. RHE, Fe2O3 / NiO is subjected to CV scanning treatment to induce the migration of Fe species on the surface to the NiO shell, forming a FeOOH / Ni-Fe-O heterostructure on the surface, which can optimize the adsorption of intermediates and enhance stability.

[0073] The present invention also provides an AEM electrolyte, which is prepared by first adding deionized water into a preset beaker, and then adding 1 mol / L KOH, 5 mmol / L-50 mmol / L K3PO4 and 1 mmol / L-10 mmol / L EDDHA-K; stirring to dissolve, and sealing for storage.

[0074] The present invention provides an AEM water electrolysis hydrogen production and oxygen evolution catalyst, which is prepared by configuring a functional electrolyte, constructing a protective layer on the catalyst surface, and adopting an electrochemical deposition strategy at the anode.

[0075] The present invention provides an AEM water electrolysis hydrogen production and oxygen evolution catalyst electrode, comprising: first preparing a membrane solution: dissolving preset anion membrane fragments in an organic solvent to obtain a membrane solution; wherein the organic solvent is one or more of ethanol, isopropanol, DMSO, NMP, and DMF; then spraying or scraping the membrane solution onto the surface of a NiFe-LDH catalyst electrode of preset size; drying the NiFe-LDH catalyst electrode at 60°C for 2h, and ensuring that the membrane dry basis loading of the NiFe-LDH catalyst electrode is 0.2mg / cm 2 -1.0mg / cm 2 .

[0076] The present invention provides an AEM water electrolysis hydrogen production and oxygen evolution electrolytic cell, which is prepared by stacking the above-mentioned AEM electrolyte and the above-mentioned AEM water electrolysis hydrogen production and oxygen evolution catalyst electrode.

[0077] In summary, by optimizing the coordination environment, interface design and dynamic regulation, the service life of the catalyst and anion membrane can be extended to improve its industrial applicability. By configuring the functional electrolyte, constructing a protective layer on the surface of the NiFe-LDH catalyst and the anode electrochemical deposition strategy, the operating life of the entire electrolyzer can be increased by 5-10 times. After testing, it was found that when the above method was not used for electrolysis, the voltage decay rate of the entire stack when it was continuously operated for 100h was 2mV / h-3mV / h, and the method of the present application was used to reduce the voltage decay rate to 0.2mV / h-0.5mV / h.

[0078] Refer to the attached Figure 1 , is a method for improving the life of an AEM electrolysis water hydrogen production and oxygen evolution catalyst in one embodiment of the present invention, wherein,

[0079] Example 1

[0080] A method for improving the life of an AEM water electrolysis hydrogen evolution catalyst is prepared according to the following steps:

[0081] S1, prepare functionalized electrolyte: add deionized water into a beaker, add 1mol / L KOH, 5mmol / L K3PO4 and 1mmol / L LEDDHA-K, stir and dissolve, and prepare for electrolysis test;

[0082] In step S2, the electrolyte and NiFe-LDH electrode were stacked into an electrolytic cell, which was then placed in an electrochemical workstation for electrode polarization and stability testing. Cyclic voltammetry was first performed, with a scan rate of 100 mV / s and a potential of 1-2 V for 100 cycles to stabilize the electrode.

[0083] S3, using the constant current method, at a working current density of 1.0A / cm 2 Run continuously for 15 hours.

[0084] Example 2

[0085] A method for improving the life of an AEM water electrolysis hydrogen evolution catalyst is prepared according to the following steps:

[0086] S1, prepare functionalized electrolyte: add deionized water into a beaker, add 1mol / L KOH, 20mmol / L K3PO4 and 5mmol / L LEDDHA-K, stir and dissolve, and prepare for electrolysis test;

[0087] In step S2, the electrolyte and NiFe-LDH electrode were stacked into an electrolytic cell, which was then placed in an electrochemical workstation for electrode polarization and stability testing. Cyclic voltammetry was first performed, with a scan rate of 100 mV / s and a potential of 1-2 V for 100 cycles to stabilize the electrode.

[0088] S3, using the constant current method, at a working current density of 1.0A / cm 2 Run continuously for 15 hours.

[0089] That is, the same as Example 1, except that the concentrations of K3PO4 and EDDHA-K are adjusted.

[0090] Example 3

[0091] A method for improving the life of an AEM water electrolysis hydrogen evolution catalyst is prepared according to the following steps:

[0092] S1, prepare functionalized electrolyte: add deionized water into a beaker, add 1 mol / L KOH, and stir to dissolve for electrolysis test;

[0093] S2, prepare anionic membrane fragments and dissolve them in ethanol to prepare a 5% membrane solution;

[0094] S3, the membrane solution was sprayed on the surface of the FeNi-LDH catalyst electrode with a size of 10 cm*10 cm and dried in an oven at 60°C for 2 h. The membrane dry basis loading was controlled at 0.2 mg / cm 2 ;

[0095] In step S4, the electrolyte and NiFe-LDH electrode were stacked into an electrolytic cell and placed in an electrochemical workstation for electrode polarization and stability testing. Cyclic voltammetry was first performed at a scan rate of 100 mV / s and a potential of 1-2 V for 100 cycles to stabilize the electrode.

[0096] S5, using the constant current method, the working current density is 1.0A / cm 2 Run continuously for 15 hours.

[0097] The method is the same as Example 1, except that only deionized water and 1 mol / L KOH are added to the beaker to prepare a membrane solution, which is then sprayed onto the surface of the FeNi-LDH catalyst electrode and dried.

[0098] Example 4

[0099] A method for improving the life of an AEM water electrolysis hydrogen evolution catalyst is prepared according to the following steps:

[0100] S1, prepare functionalized electrolyte: add deionized water into a beaker, add 1 mol / L KOH, and stir to dissolve for electrolysis test;

[0101] S2, prepare anionic membrane fragments and dissolve them in ethanol to prepare a 5% membrane solution;

[0102] S3, the membrane solution was sprayed on the surface of the FeNi-LDH catalyst electrode with a size of 10 cm*10 cm and dried in an oven at 60°C for 2 h. The membrane dry basis loading was controlled at 0.6 mg / cm 2 ;

[0103] In step S4, the electrolyte and NiFe-LDH electrode were stacked into an electrolytic cell and placed in an electrochemical workstation for electrode polarization and stability testing. Cyclic voltammetry was first performed at a scan rate of 100 mV / s and a potential of 1-2 V for 100 cycles to stabilize the electrode.

[0104] S5, using the constant current method, the working current density is 1.0A / cm 2 Run continuously for 15 hours.

[0105] Same as Example 3, except that the membrane dry basis loading is increased from 0.2 mg / cm 2 Adjusted to 0.6 mg / cm 2 .

[0106] Example 5

[0107] A method for improving the life of an AEM water electrolysis hydrogen evolution catalyst is prepared according to the following steps:

[0108] S1, prepare functionalized electrolyte: add deionized water into a beaker, add 1 mol / L KOH, and stir to dissolve for electrolysis test;

[0109] S2, prepare anionic membrane fragments and dissolve them in ethanol to prepare a 5% membrane solution;

[0110] S3, spray the membrane solution on the surface of the FeNi-LDH catalyst electrode with a size of 10cm*10cm and dry it in an oven at 60℃ for 2h. The membrane dry basis loading was controlled at 1.0mg / cm 2 ;

[0111] In step S4, the electrolyte and NiFe-LDH electrode were stacked into an electrolytic cell and placed in an electrochemical workstation for electrode polarization and stability testing. Cyclic voltammetry was first performed at a scan rate of 100 mV / s and a potential of 1-2 V for 100 cycles to stabilize the electrode.

[0112] S5, using the constant current method, the working current density is 1.0A / cm 2 Run continuously for 15 hours.

[0113] Same as Example 3, except that the membrane dry basis loading is increased from 0.2 mg / cm 2 Adjusted to 1.0 mg / cm 2 .

[0114] Example 6

[0115] A method for improving the life of an AEM water electrolysis hydrogen evolution catalyst is prepared according to the following steps:

[0116] S1, prepare functionalized electrolyte: add deionized water into a beaker, add 1 mol / L KOH, and stir to dissolve for electrolysis test;

[0117] In step S2, the electrolyte and NiFe-LDH electrode were stacked into an electrolytic cell, which was then placed in an electrochemical workstation for electrode polarization and stability testing. Cyclic voltammetry was first performed, with a scan rate of 100 mV / s and a potential of 1-2 V for 100 cycles to stabilize the electrode.

[0118] S3, the intermittent potential reduction method was used for constant current scanning. First, the working current density was 1.0 A / cm 2 The reaction mixture was run continuously for 1 h at a reduction potential of 0.77 V, and then reduced at a reduction potential of 0.77 V for 5 min, and this cycle was repeated 15 times.

[0119] The method is the same as Example 2, except that the intermittent potential reduction method is used for constant current scanning.

[0120] Example 7

[0121] A method for improving the life of an AEM water electrolysis hydrogen evolution catalyst is prepared according to the following steps:

[0122] S1, prepare functionalized electrolyte: add deionized water into a beaker, add 1 mol / L KOH, and stir to dissolve for electrolysis test;

[0123] In step S2, the electrolyte and NiFe-LDH electrode were stacked into an electrolytic cell, which was then placed in an electrochemical workstation for electrode polarization and stability testing. Cyclic voltammetry was first performed, with a scan rate of 100 mV / s and a potential of 1-2 V for 100 cycles to stabilize the electrode.

[0124] S3, the intermittent potential reduction method was used for constant current scanning. First, the working current density was 1.0 A / cm 2 The reaction mixture was run continuously for 1 h at a reduction potential of 0.77 V, and then reduced at a reduction potential of 0.77 V for 15 min, and this cycle was repeated 15 times.

[0125] That is, the same as Example 6, except that the reduction time at a reduction potential of 0.77 V is increased from 5 min to 15 min.

[0126] Example 8

[0127] A method for improving the life of an AEM water electrolysis hydrogen evolution catalyst is prepared according to the following steps:

[0128] S1, prepare functionalized electrolyte: add deionized water into a beaker, add 1 mol / L KOH, and stir to dissolve for electrolysis test;

[0129] In step S2, the electrolyte and NiFe-LDH electrode were stacked into an electrolytic cell, which was then placed in an electrochemical workstation for electrode polarization and stability testing. Cyclic voltammetry was first performed, with a scan rate of 100 mV / s and a potential of 1-2 V for 100 cycles to stabilize the electrode.

[0130] S3, the intermittent potential reduction method was used for constant current scanning. First, the working current density was 1.0 A / cm 2 The reaction was continued for 1 h at a reduction potential of 1.1 V, followed by reduction for 5 min, and this cycle was repeated 15 times.

[0131] That is, the same as Example 6, except that the reduction potential is adjusted from 0.77V to 1.1V.

[0132] Example 9

[0133] A method for improving the life of an AEM water electrolysis hydrogen evolution catalyst is prepared according to the following steps:

[0134] S1, prepare functionalized electrolyte: add deionized water into a beaker, add 1mol / L KOH, 20mmol / L K3PO4 and 5mmol / L LEDDHA-K, stir and dissolve, and prepare for electrolysis test;

[0135] S2, prepare anionic membrane fragments and dissolve them in ethanol to prepare a 5% membrane solution;

[0136] S3, the membrane solution was sprayed on the surface of the FeNi-LDH catalyst electrode with a size of 10 cm*10 cm and dried in an oven at 60°C for 2 h. The membrane dry basis loading was controlled at 0.6 mg / cm 2 ;

[0137] In step S4, the electrolyte and NiFe-LDH electrode were stacked into an electrolytic cell and placed in an electrochemical workstation for electrode polarization and stability testing. Cyclic voltammetry was first performed at a scan rate of 100 mV / s and a potential of 1-2 V for 100 cycles to stabilize the electrode.

[0138] S5, the intermittent potential reduction method was used for constant current scanning. First, the working current density was 1.0 A / cm 2 The reaction mixture was run continuously for 1 h at a reduction potential of 0.77 V, and then reduced at a reduction potential of 0.77 V for 5 min, and this cycle was repeated 100 times.

[0139] Comparative Example 1

[0140] S1, prepare functionalized electrolyte: add deionized water into a beaker, add 1 mol / L KOH, and stir to dissolve for electrolysis test;

[0141] In step S2, the electrolyte and NiFe-LDH electrode were stacked into an electrolytic cell, which was then placed in an electrochemical workstation for electrode polarization and stability testing. Cyclic voltammetry was first performed, with a scan rate of 100 mV / s and a potential of 1-2 V for 100 cycles to stabilize the electrode.

[0142] S3, using the constant current method, at a working current density of 1.0A / cm 2 Run continuously for 100 hours.

[0143] It can be seen from the stability test data of the electrochemical workstation that after 210 minutes of constant current testing, the potential of Example 1 increased by 0.111 V, the potential of Example 2 increased by 0.031 V, the potential of Example 3 increased by 0.082 V, and the potential of Comparative Example 1 increased by 0.152 V, indicating that the working potential of the catalyst using the intermittent potential reduction method has a smaller increase, a lower performance attenuation rate, and a longer service life.

[0144] Depend on Figure 2 It can be seen that the use of functionalized electrolyte can make the electrolysis process more stable. The potential of Example 1 increased by 61 mV, the potential of Example 2 increased by 57 mV, and the potential of Comparative Example 1 increased by 94 mV.

[0145] Depend on Figure 3 It can be seen that coating the protective layer on the catalyst electrode can make the electrolysis process more stable. The potential of Example 3 increased by 55mV, the potential of Example 4 increased by 46mV, the potential of Example 5 increased by 33mV, and the potential of Comparative Example 1 increased by 94mV. From Examples 3 and 5, it can be seen that as the dry basis loading of the membrane increases, the membrane protective layer is too thick, the initial performance will become worse, but the stability will be better. For example, in Example 5, the dry basis loading of the electrode membrane is 1.0mg / cm 2 When the initial potential is 1.892V, the end potential is 1.925V, and the potential increases by 33mV. In Example 3, the dry basis loading of the electrode membrane is 0.2mg / cm 2 When the initial potential is 1.876V, the end potential is 1.931V, and the potential increases by 55mV.

[0146] Depend on Figure 4 It can be seen that after 15 hours of continuous electrolysis, the potential of Comparative Example 1 increased by 94 mV, Example 6 increased by 56 mV, Example 7 increased by 25 mV, and Example 8 increased by 35 mV. It can be seen that the potential increase after electrolysis using the intermittent potential reduction method is lower than that of Comparative Example 1, which can improve the service life of the catalyst.

[0147] Depend on Figure 5As can be seen, after 100 hours of electrolysis, the potential of Example 9 increased by only 34 mV, with a decay rate of 0.34 mV / h, while in Comparative Example 1, the potential increased by 230 mV, with a decay rate of 2.3 mV / h. This indicates that the simultaneous use of a functionalized electrolyte, a membrane protective layer on the electrode surface, and intermittent potential reduction significantly extends the service life of the catalyst and anion membrane, significantly improving the operational life of the entire electrolytic cell.

[0148] In summary, the present application simultaneously adopts a functionalized electrolyte, a membrane protective layer on the electrode surface, and an intermittent potential reduction method, which can greatly improve the service life of the AEM water electrolysis hydrogen and oxygen evolution catalyst and the electrolyzer, and has higher industrial applicability.

[0149] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for improving the life of an AEM electrolysis water hydrogen production and oxygen evolution catalyst, characterized in that: The following steps are involved: S1, preparation of functionalized electrolyte; S2, spraying the membrane solution on the surface of the OER catalyst to build a protective layer; S3, placing the installed electrolytic cell in a preset electrochemical testing device, and cyclically executing a constant current mode and an anodic electrochemical deposition mode.

2. The method for improving the life of the AEM electrolysis water hydrogen production and oxygen evolution catalyst according to claim 1, wherein: The step of preparing the functionalized electrolyte comprises: Add deionized water to a pre-set beaker, and add 1 mol / L KOH, 5 mmol / L-50 mmol / L K3PO4, and 1 mmol / L-10 mmol / L EDDHA-K; Stir to dissolve; Keep sealed.

3. The method for improving the life of the AEM electrolysis water hydrogen production and oxygen evolution catalyst according to claim 1, wherein The step of spraying a membrane solution on the surface of the OER catalyst to form a protective layer comprises: Preparing a membrane solution: dissolving the predetermined anionic membrane fragments in an organic solvent to obtain a membrane solution; wherein the organic solvent is one or more of ethanol, isopropanol, DMSO, NMP, and DMF; Spraying or scraping the membrane solution onto the surface of a NiFe-LDH catalyst electrode of a preset size; The NiFe-LDH catalyst electrode was placed at 60°C and dried for 2 hours, and the dry basis loading of the NiFe-LDH catalyst electrode was set at 0.2 mg / cm 2 -1.0mg / cm 2 .

4. The method for improving the life of the AEM electrolysis water hydrogen production and oxygen evolution catalyst according to claim 1, wherein The step of placing the installed electrolytic cell in a preset electrochemical testing device and cyclically executing a constant current mode and an anodic electrochemical deposition mode includes: Set the scanning frequency and scanning potential, and perform cyclic voltammetry scanning to the preset number of cycles; Et scans were performed by intermittent potentiostatic reduction method.

5. The method for improving the life of the AEM electrolysis water hydrogen production and oxygen evolution catalyst according to claim 4, wherein: The step of performing Et scanning by intermittent potential reduction method comprises: Constant current mode: Run at a preset working current density until the preset scan time; wherein the scan time is 10min-360min; Anodic electrochemical deposition mode: reduction to the preset reduction time at the preset reduction potential; The constant current mode and the anodic electrochemical deposition mode are repeatedly performed.

6. The method for improving the life of the AEM electrolysis water hydrogen production and oxygen evolution catalyst according to claim 4, characterized in that: The number of cycles is 100; the scanning frequency is 100 mV / s; the scanning potential is 1-2 V; the reduction potential is 0.4 V-1.23 V; and the reduction time is 1 min-10 min.

7. An AEM electrolyte, characterized in that Prepared by the steps described in claim 2.

8. An AEM water electrolysis hydrogen production and oxygen evolution catalyst, characterized in that The method for improving the life of the AEM water electrolysis hydrogen production and oxygen evolution catalyst according to any one of claims 1 to 6 is prepared.

9. An AEM water electrolysis hydrogen production and oxygen evolution catalyst electrode, characterized in that Prepared by the steps described in claim 3.

10. An AEM electrolysis water hydrogen production and oxygen evolution electrolyzer, characterized in that: The electrolytic solution is prepared by stacking the AEM electrolyte according to claim 7 and the AEM water electrolysis hydrogen and oxygen evolution catalyst electrode according to claim 9.

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