In-situ electrodeposition of nickel to enhance NiMoP x O y Method and application of self-supporting nickel-based hydrogen evolution electrode catalytic activity and stability of / NF foam

Abstract

This invention relates to the field of water electrolysis and hydrogen energy utilization technology, and provides an in-situ electrodeposition method for improving NiMoP. x O y A method for studying the catalytic activity and stability of a self-supporting nickel-based hydrogen evolution electrode (NMOP). First, NiMoP... x O y The / NF self-supporting foam nickel-based electrode is prepared by immersing it in a nickel salt solution for a certain period of time, drying it, and then immersing it in a sodium sulfate solution for electrodeposition reduction reaction. This invention provides a simple and convenient method for adjusting the amount of metallic nickel deposited, ensuring its distribution among the active component particles of the electrode. This effectively improves the adhesion of the active component and prevents its detachment, significantly enhancing the hydrogen evolution activity and stability of the hydrogen evolution electrode. At an industrial current density of 100 mA / cm², the overpotential of the modified electrode prepared by this method is reduced by approximately 20% compared to the unmodified electrode, and the charge transfer resistance is reduced by approximately 41%. After 30,000 CV cycle accelerated durability tests, the increases in overpotential and charge transfer resistance are less than 7% and 26% of those of the unmodified electrode, respectively. Therefore, this invention has promising prospects for industrial application.

Description

Technical Field

[0001] This invention belongs to the field of water electrolysis and hydrogen energy utilization technology, and particularly relates to an in-situ electrodeposition method for improving NiMoP. x O y Methods and applications for improving the catalytic activity and stability of / NF self-supporting foam nickel-based hydrogen evolution electrode. Background Technology

[0002] Hydrogen, due to its high energy density and environmental friendliness, is considered a promising approach to addressing the energy crisis. Self-supporting metal foam-based electrodes, with their three-dimensional interconnected porous structure, offer advantages such as a large electrochemical specific surface area, fully exposed active sites, and a porous structure that facilitates electrolyte permeation and hydrogen desorption while reducing bubble aggregation. Therefore, self-supporting foam-based electrodes have become a popular research material in the field of water electrolysis in recent years. However, because the interaction between the active catalytic material and the metal foam substrate in self-supporting electrodes is mostly physical deposition or weak chemical reaction, the interfacial bonding strength between the active component and the substrate is insufficient. Especially under high-current industrial conditions, the rapid generation of numerous bubbles easily causes the active catalytic component to peel off from the electrode, resulting in reduced catalytic activity and hindering its practical industrial application. Therefore, effectively improving the stability and further enhancing the activity of self-supporting metal foam-based electrodes is crucial for their industrial application in large-scale hydrogen production. Summary of the Invention

[0003] The purpose of this invention is to provide an in-situ electrodeposited nickel method to improve NiMoP x O y Methods and applications for improving the catalytic activity and stability of / NF self-supporting foam nickel-based hydrogen evolution electrode. The objective of this invention is achieved through the following technical solutions:

[0004] An in-situ electrodeposited nickel enhances NiMoP x O y The method and application of improving the catalytic activity and stability of / NF self-supporting foam nickel-based hydrogen evolution electrode are characterized by the following steps: 1) NiMoP x O y / NF self-supporting foam nickel-based electrode is immersed in nickel salt solution for a certain period of time and then dried; 2) The self-supporting foam nickel-based electrode after the previous step of impregnation with nickel salt is immersed in sodium sulfate solution to carry out an electroreduction reaction, thereby obtaining in-situ electrodeposited nickel NiMoP. x O y / NF self-supporting foam nickel-based hydrogen evolution electrode.

[0005] Preferably, the nickel salt solution in step 1) is an aqueous solution of one or a mixture of nickel sulfate hexahydrate, nickel chloride hexahydrate, and nickel nitrate hexahydrate.

[0006] Preferably, the nickel ion concentration of the nickel salt solution in step 1) is 0.5-5 mol / L.

[0007] Preferably, the immersion time in step 1) is 1-300 minutes.

[0008] Preferably, the drying temperature in step 1) is 25–75°C, and the drying time is 3–12 hours.

[0009] Preferably, the concentration of the sodium sulfate solution in step 2) is 0.5-3 mol / L.

[0010] Preferably, the current density of the electroreduction in step 2) is 1-100 mA / cm². 2 .

[0011] Preferably, the electroreduction time in step 2) is 1-2000 seconds.

[0012] The present invention has the following beneficial effects:

[0013] (1) NiMoP x O y The amount of metallic nickel deposited in the / NF self-supporting foam nickel electrode is simple and convenient to adjust. This invention uses nickel salts pre-adsorbed in the self-supporting foam nickel electrode as the nickel source. By adjusting the nickel salt concentration and immersion time of the impregnation solution, the amount of electrodeposited nickel can be precisely controlled.

[0014] (2) NiMoP x O y In the / NF self-supporting nickel foam electrode, the pre-adsorbed nickel salt is a solid. During the electrochemical reduction process, the nickel salt is dissolved and reduced simultaneously. Therefore, the in-situ electrodeposited metallic nickel is mainly distributed in the active component (NiMoP) of the self-supporting nickel foam electrode. x O y The particles not only effectively improve the adhesion of the active components and prevent them from falling off, but also effectively prevent deposited metallic nickel from covering the surface of the self-supporting foam nickel electrode and affecting the catalytic performance of the active components.

[0015] (3) NiMoP prepared by in-situ electrodeposition of nickel using the method of the present invention x O y The hydrogen evolution activity and stability of the / NF (nickel foam) self-supporting nickel foam-based hydrogen evolution electrode are greatly improved: at an industrial current density of 100 mA / cm², the overpotential of the modified electrode prepared by the method of this invention is reduced by about 20% compared with the unmodified electrode. In addition, after 30,000 CV cycle accelerated durability tests, its overpotential only increased by 2 mV, less than 7% of that of the unmodified electrode (29 mV), exhibiting excellent hydrogen evolution stability. Attached Figure Description

[0016] Figure 1 Ni / NiMoP prepared in Examples 1-4 x O y / NF hydrogen evolution electrode and unmodified NiMoP prepared in Comparative Example 1 x O y Comparison of polarization curves of the / NF hydrogen evolution electrode;

[0017] Figure 2 Ni / NiMoP prepared in Examples 1-4 x O y / NF hydrogen evolution electrode and unmodified NiMoP prepared in Comparative Example 1 x O y Comparison of Nyquist curves for the / NF hydrogen evolution electrode;

[0018] Figure 3 To accelerate durability testing, Ni / NiMoP prepared in Examples 1-4 x O y / NF hydrogen evolution electrode and unmodified NiMoP prepared in Comparative Example 1 x O y Comparison of polarization curves of the / NF hydrogen evolution electrode;

[0019] Figure 4 To accelerate durability testing, Ni / NiMoP prepared in Examples 1-4 x O y / NF hydrogen evolution electrode and unmodified NiMoP prepared in Comparative Example 1 x O y Comparison of Nyquist curves for the / NF hydrogen evolution electrode; Detailed Implementation

[0020] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0021] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0022] The self-supporting metal foam-based NiMoP involved in the specific embodiments of the present invention x O yThe / NF hydrogen evolution electrode can be prepared by referring to the preparation method of Comparative Example 1. Changes in the preparation conditions of this material do not affect the scope of this invention.

[0023] The raw materials and reagents involved in the specific embodiments of this invention are all commercially available products.

[0024] Unless otherwise specified, the room temperature and room temperature mentioned in the specific embodiments of this invention refer to 20-30℃.

[0025] Example 1

[0026] An in-situ electrodeposited nickel enhances NiMoP x O y The steps of the method for improving the catalytic activity and stability of the / NF self-supporting foam nickel-based hydrogen evolution electrode include:

[0027] Step 1: Add nickel sulfate hexahydrate to ultrapure water to prepare an impregnation solution with a nickel ion concentration of 0.5 mol / L. Then, apply the self-supporting metal foam-based NiMoP... x O y The / NF hydrogen evolution electrode was immersed in the immersion solution for 300 min. The electrode was then removed and quickly but gently rinsed with deionized water to remove any loose nickel salt solution adhering to the surface. After that, it was placed in a drying oven at 60°C for 5 h to dry.

[0028] Step 2: Place the dried electrode as the working electrode in the electrodeposition solution (2 M Na2SO4 solution), with the carbon rod electrode as the counter electrode. Apply current to the working electrode using the constant current mode of the electrochemical workstation, setting the current density to 50 mA / cm², and perform electrodeposition for 500 s. This yields a self-supporting metal foam-based hydrogen evolution electrode with enhanced hydrogen evolution stability and activity, i.e., Ni / NiMoP x O y / NF-Experimental Example 1 Hydrogen Evolution Electrode.

[0029] Example 2

[0030] An in-situ electrodeposited nickel enhances NiMoP x O y The steps of the method for improving the catalytic activity and stability of the / NF self-supporting foam nickel-based hydrogen evolution electrode include:

[0031] Step 1: Add nickel sulfate hexahydrate, nickel nitrate hexahydrate, and nickel chloride hexahydrate to ultrapure water to prepare an impregnation solution with a nickel ion concentration of 2 mol / L. Then, apply the self-supporting metal foam-based NiMoP... x O y The / NF hydrogen evolution electrode was immersed in the immersion solution for 180 min. The electrode was then removed and quickly but gently rinsed with deionized water to remove any loose nickel salt solution adhering to the surface. After that, it was placed in a drying oven at 45°C for 8 h to dry.

[0032] Step 2: Place the dried electrode as the working electrode in the electrodeposition solution (0.5 M Na2SO4 solution), with the carbon rod electrode as the counter electrode. Apply current to the working electrode using the constant current mode of the electrochemical workstation, setting the current density to 1 mA / cm², and perform electrodeposition for 2000 s. This yields a self-supporting metal foam-based hydrogen evolution electrode with enhanced hydrogen evolution stability and activity, i.e., Ni / NiMoP. x O y / NF-Experimental Example 2 Hydrogen Evolution Electrode.

[0033] Example 3

[0034] An in-situ electrodeposited nickel enhances NiMoP x O y The steps of the method for improving the catalytic activity and stability of the / NF self-supporting foam nickel-based hydrogen evolution electrode include:

[0035] Step 1: Add nickel sulfate hexahydrate and nickel chloride hexahydrate to ultrapure water to prepare an impregnation solution with a nickel ion concentration of 3.5 mol / L. Then, apply the self-supporting metal foam-based NiMoP... x O y The / NF hydrogen evolution electrode was immersed in the immersion solution for 60 minutes. The electrode was then removed and quickly but gently rinsed with deionized water to remove any loose nickel salt solution adhering to the surface. After that, it was placed in a drying oven at 75°C for 3 hours to dry.

[0036] Step 2: Place the dried electrode as the working electrode in the electrodeposition solution (3 M Na2SO4 solution), with the carbon rod electrode as the counter electrode. Apply current to the working electrode using the constant current mode of the electrochemical workstation, setting the current density to 35 mA / cm², and perform electrodeposition for 1000 s. This yields a self-supporting metal foam-based hydrogen evolution electrode with enhanced hydrogen evolution stability and activity, i.e., Ni / NiMoP. x O y / NF-Experimental Example 3 Hydrogen Evolution Electrode.

[0037] Example 4

[0038] An in-situ electrodeposited nickel enhances NiMoP x O y The steps of the method for improving the catalytic activity and stability of the / NF self-supporting foam nickel-based hydrogen evolution electrode include:

[0039] Step 1: Add nickel nitrate hexahydrate and nickel chloride hexahydrate to ultrapure water to prepare an impregnation solution with a nickel ion concentration of 5 mol / L. Then, apply the self-supporting metal foam-based NiMoP... x O yThe / NF hydrogen evolution electrode was immersed in the immersion solution for 1 minute, then the electrode was removed and quickly but gently rinsed with deionized water to remove the loose nickel salt solution adhering to the surface. After that, it was placed in a room temperature environment of 25°C for 12 hours to dry.

[0040] Step 2: Place the dried electrode as the working electrode in the electrodeposition solution (1.5 M Na2SO4 solution), with the carbon rod electrode as the counter electrode. Apply current to the working electrode using the constant current mode of the electrochemical workstation, setting the current density to 100 mA / cm² and performing electrodeposition for 10 s. This yields a self-supporting metal foam-based hydrogen evolution electrode with enhanced hydrogen evolution stability and activity, i.e., Ni / NiMoP. x O y / NF-Experimental Example 4 Hydrogen Evolution Electrode.

[0041] Comparative Example 1

[0042] Step 1: After cutting the nickel foam, clean it by ultrasonic cleaning with acetone for 15 minutes, ultrasonic cleaning with 3M hydrochloric acid for 30 minutes, ultrasonic cleaning with ethanol for 10 minutes, and finally cleaning with deionized water for 15 minutes. Dry it in a 65℃ oven for later use.

[0043] Step 2: Dissolve 3.2 mmol ammonium molybdate tetrahydrate and 12.8 mmol nickel nitrate hexahydrate in 40 mL of water, stir for 30 min, and then react with nickel foam in a hydrothermal reaction at 150 °C for 7 h. After washing and drying, obtain a NiMoO4 / NF hydrogen evolution electrode. Use 2 g of sodium hypophosphite as a phosphorus source, and heat to 300 °C at 3 °C / min in a N2 atmosphere and hold for 180 min to obtain a self-supporting metal foam-based NiMoP electrode. x O y / NF hydrogen evolution electrode.

[0044] Electrochemical testing and electrochemical analysis:

[0045] A classic three-electrode system was used, with the sample electrode as the working electrode, a platinum mesh electrode as the counter electrode, and mercury / mercury oxide as the reference electrode. A 1 mol / L KOH solution was used as the electrolyte. The electrochemical performance and accelerated durability of the electrodes were tested using the standard three-electrode system.

[0046] Figure 1 The Ni / NiMoP prepared in Examples 1-4 x O y / NF hydrogen evolution electrode and unmodified NiMoP prepared in Comparative Example 1 x O y A comparison of the polarization curves of the / NF hydrogen evolution electrodes shows that the hydrogen evolution electrode prepared in Comparative Example 1 exhibits better polarization at -100 mA / cm². 2The overpotential of the experimental example was 315mV, while that of Experimental Example 1 was 289mV, Experimental Example 2 was 270mV, Experimental Example 3 was 255mV, and Experimental Example 4 was 275mV, all of which were lower than that of Comparative Example 1. Among them, the overpotential of Experimental Example 3 was reduced by about 20% compared with Comparative Example 1, which also shows that the HER performance of the hydrogen evolution electrode was significantly improved by electrodepositing nickel. Figure 2 The Ni / NiMoP prepared in Examples 1-4 x O y / NF hydrogen evolution electrode and unmodified NiMoP prepared in Comparative Example 1 x O y The Nyquist curves of the / NF hydrogen evolution electrode are compared. The graph shows that the charge transfer resistance of Comparative Example 1 is 14.37 Ω, while that of Experimental Example 1 is 13.23 Ω, Experimental Example 2 is 10.98 Ω, Experimental Example 3 is 8.47 Ω, and Experimental Example 4 is 11.93 Ω. The charge transfer resistance of Experimental Example 3 is approximately 41% lower than that of Comparative Example 1, indicating that electrodeposition of nickel significantly improves the electron transfer rate of the hydrogen evolution electrode. Therefore, from... Figure 1 and Figure 2 It can be seen that this method effectively improves NiMoP x O y / NF self-supporting foam nickel-based hydrogen evolution electrode catalytic activity.

[0047] Figure 3 The Ni / NiMoP prepared in Examples 1-4 after accelerated durability testing x O y / NF hydrogen evolution electrode and unmodified NiMoP prepared in Comparative Example 1 x O y A comparison of the polarization curves of the / NF hydrogen evolution electrodes shows that the hydrogen evolution electrode prepared in Comparative Example 1 exhibits better polarization at -100 mA / cm². 2 The overpotential was 344 mV, with an increase of 29 mV. The increases of Experimental Example 1, Experimental Example 2, Experimental Example 3, and Experimental Example 4 were 14 mV, 14 mV, 2 mV, and 17 mV, respectively, all lower than Comparative Example 1. Among them, the increase of Experimental Example 3 was less than 7% of that of Comparative Example 1. This also shows that nickel electrodeposition significantly improves the HER stability of the hydrogen evolution electrode. Figure 4 The Ni / NiMoP prepared in Examples 1-4 after accelerated durability testing x O y / NF hydrogen evolution electrode and unmodified NiMoP prepared in Comparative Example 1 x O yThe Nyquist curves of the / NF hydrogen evolution electrode are compared. The graph shows that the charge transfer resistance of Comparative Example 1 is 15.69 Ω, with an increase of 1.32 Ω. The increases in Experimental Examples 1, 2, 3, and 4 are 0.5 Ω, 0.45 Ω, 0.34 Ω, and 0.48 Ω, respectively, all lower than Comparative Example 1. In Experimental Example 3, the increase in charge transfer resistance is less than 26% of that of Comparative Example 1. This indicates that nickel electrodeposition significantly improves the structural stability and conductivity retention of the hydrogen evolution electrode. Therefore, from... Figure 3 and Figure 4 It can be seen that this method effectively improves NiMoP x O y / NF self-supporting foam nickel-based hydrogen evolution electrode catalytic stability.

[0048] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An in-situ electrodeposition method for improving NiMoP x O y The method and application of improving the catalytic activity and stability of / NF self-supporting foam nickel-based hydrogen evolution electrode are characterized by... Includes the following steps: a) NiMoP x O y / NF self-supporting foam nickel-based electrode is immersed in nickel salt solution for a certain period of time and then dried; b) the self-supporting foam nickel-based electrode after the previous step of impregnation with nickel salt is immersed in sodium sulfate solution to carry out an electroreduction reaction, thereby obtaining in-situ electrodeposited nickel NiMoP. x O y / NF self-supporting foam nickel-based hydrogen evolution electrode.

2. As described in claim 1, characterized in that, The nickel salt solution is an aqueous solution of one or a mixture of nickel sulfate hexahydrate, nickel chloride hexahydrate, and nickel nitrate hexahydrate.

3. As described in claims 1 and 2, characterized in that, The nickel ion concentration in the nickel salt solution is 0.5-5 mol / L.

4. As described in claim 1, characterized in that, The soaking time is 1-300 minutes.

5. As described in claim 1, characterized in that, The drying temperature is 25–75℃, and the drying time is 3–12 hours.

6. As described in claim 1, characterized in that, The concentration of sodium sulfate solution is 0.5-3 mol / L.

7. As described in claim 1, characterized in that, The current density for electroreduction is 1-100 mA / cm²; the electroreduction time is 10-2000 seconds.

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