Water-ripple-shaped multi-metal oxysulfide self-supporting electrode and preparation method and application of water-ripple-shaped multi-metal oxysulfide self-supporting electrode

Abstract

The invention belongs to the technical field of electro-catalytic materials, and discloses a water-corrugation-shaped polyoxosulfide self-supporting electrode and a preparation method and application of the water-corrugation-shaped polyoxosulfide self-supporting electrode. Foamed nickel is used as a substrate of a self-supporting electrode, after the foamed nickel is pretreated, the pretreated foamed nickel is immersed in a precursor solution containing potassium ferricyanide, soluble vanadium salt and soluble cobalt salt, nickel on the surface of the foamed nickel is etched into nickel ions through room-temperature ultrasound, the nickel ions are released into the precursor solution, and the self-supporting electrode is obtained. A multi-metal cation precursor solution is obtained; the method comprises the following steps: adding a sulfur source into a precursor solution of multi-metal ions under an ultrasonic condition, so that ferric ions, nickel ions and cobalt ions in the precursor solution of the multi-metal ions react with the sulfur source to form a multi-metal sulfide, and meanwhile, doping oxygen ions combined with vanadium ions into the multi-metal sulfide to generate a precursor self-supporting electrode; and performing Joule heating on the precursor self-supporting electrode to obtain the multi-metal oxysulfide self-supporting electrode.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic materials, and in particular relates to a water-corrugated polymetallic oxysulfide self-supporting electrode and a preparation method and application thereof. Background Art

[0002] Electrocatalytic oxygen evolution reaction is one of the key reaction processes in new energy technologies such as water electrolysis to produce hydrogen and metal-air batteries. Its full name is Oxygen Evolution Reaction, or OER for short. However, due to the high overpotential and complex reaction pathway of the OER reaction, the selection and optimization of electrocatalysts are key to improving the efficiency of the OER. In recent years, transition metal sulfides have become a hot research material due to their rich reactive sites and excellent electrochemical properties.

[0003] Metallic Ni3S2 is a typical representative of transition metal sulfur compounds. There are abundant Ni-S and Ni-Ni bonds in its structure. It has good adsorption energy for oxygen intermediates O* and OH* and is an OER electrocatalyst with great application prospects. However, due to the high rate-determining step reaction energy barrier of Ni3S2, its activity has not reached the expected level, which greatly limits the OER kinetics. In addition, transition metal sulfides are exposed to a strong oxidizing environment during the electrocatalytic oxygen evolution process, and the sulfur elements on their surface are easily oxidized to form oxides or other unstable compounds, thereby causing the material to self-oxidize. This reconstruction of structure and composition not only reduces the electrocatalytic activity of the material, but also significantly affects the long-term stability and service life of the material.

[0004] The preparation of self-supporting materials of transition metal sulfides is usually carried out by high temperature and high pressure hydrothermal method, solvothermal method, electrochemical deposition method or solid phase method. However, although these methods have optimized the electrocatalytic performance of the materials to a certain extent, there is still the problem of self-oxidation of metal sulfide materials; and the preparation process is relatively complicated, highly dependent on equipment, and relatively high energy consumption. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a water-corrugated polymetallic oxysulfide self-supporting electrode and a preparation method and application thereof.

[0006] The present invention utilizes the acidity of the aqueous solution of soluble vanadium salt to promote potassium ferrocyanide to generate trivalent iron ions in the acidic solution; at the same time, the foamed nickel is in the acidic solution, Fe 3+and ultrasound to slowly release nickel ions; in addition, a sulfur source is added to a solution in which trivalent iron ions, nickel ions, vanadium ions and cobalt ions are uniformly present, and polymetallic sulfides are formed under ultrasonic reaction. The oxygen affinity of vanadium ions is used to dope oxygen ions in polymetallic sulfides, promote the formation of SO bonds, and obtain a precursor self-supporting electrode; under Joule heating conditions, a crystalline polymetallic oxysulfide self-supporting electrode is formed. Through the synergistic effect of different metal elements, the electrochemical reaction sites are increased, and the oxygen evolution reaction efficiency of the electrode material is improved; the introduction of SO bonds effectively inhibits the self-oxidation phenomenon of the material and enhances the chemical stability of the material, thereby achieving excellent electrocatalytic performance at high OER overpotentials.

[0007] The first object of the present invention is to provide a method for preparing a water-corrugated polymetallic oxysulfide self-supporting electrode, comprising the following steps:

[0008] Step 1: Dissolve potassium ferrocyanide, soluble vanadium salt and soluble cobalt salt in water, stir evenly, and obtain a precursor solution.

[0009] It should be noted that when soluble vanadium salts are dissolved in water, hydrochloric acid and hypovanadic acid are generated, making the precursor solution acidic; at the same time, potassium ferrocyanide is decomposed by acid in an acidic environment to generate trivalent iron ions and cyanide ions. Placing nickel foam in the precursor solution helps to etch the metal nickel on the surface of nickel foam into nickel ions.

[0010] Preferably, the molar ratio of the potassium ferrocyanide, the soluble vanadium salt and the soluble cobalt salt is 1.5-2:0.3-0.5:0.3-0.5.

[0011] Preferably, the molar ratio of the potassium ferrocyanide to the sulfur source is 1.5-2:3-5.

[0012] Preferably, the soluble vanadium salt is vanadium chloride.

[0013] Preferably, the soluble cobalt salt is one of cobalt chloride and cobalt nitrate.

[0014] Step 2: Use nickel foam as the substrate of the self-supporting electrode, pretreat the nickel foam, immerse the pretreated nickel foam in a precursor solution, and perform ultrasonic reaction at room temperature to etch the nickel on the surface of the nickel foam into nickel ions and release them into the precursor solution to obtain a multi-metal cation precursor solution.

[0015] It should be noted that in order to enhance the activity of the nickel foam surface and ensure that the subsequent reaction process can be carried out effectively; before the nickel foam reacts with the precursor solution, the present invention performs corresponding pretreatment on the nickel foam to improve the contact efficiency between the precursor solution and the nickel foam, ensure the uniform growth of oxysulfide on the surface of the nickel foam, thereby improving the structural stability and conductivity of the polymetallic oxysulfide self-supporting electrode. Preferably, the pretreatment includes: placing the nickel foam in an acetone solution and a hydrochloric acid solution for treatment in turn, and then washing it alternately with ethanol and water. The oxides and impurities on the surface of the nickel foam can be removed by treating with an acetone organic solvent and a hydrochloric acid solution, and then the surface is ensured to be free of residual chemicals by alternating washing with ethanol and purified water, thereby providing a clean and uniform effective reaction area to ensure the efficient progress of the subsequent reaction process.

[0016] The specific operation of the pretreatment of the present invention is: immersing the nickel foam in an acetone solution for ultrasonic cleaning for 5 minutes to 20 minutes, then transferring the nickel foam cleaned with acetone to 2 mol / L to 4 mol / L hydrochloric acid for ultrasonic cleaning for 5 minutes to 20 minutes, then washing the nickel foam cleaned with hydrochloric acid alternately with ethanol and ultrapure water for 2 to 3 times, and finally vacuum drying the nickel foam cleaned with ethanol and ultrapure water at 25 to 35 degrees Celsius for 10 hours to 14 hours to obtain the pretreated nickel foam.

[0017] It should also be noted that the pretreated nickel foam is immersed in a precursor solution and subjected to ultrasonic reaction at room temperature. Under the combined action of the trivalent iron ions, vanadium ions, acidic environment and ultrasound provided by the precursor solution, the nickel on the surface of the nickel foam is oxidized into nickel ions and released into the precursor solution; at the same time, the cyanide ions in the precursor solution combine with the nickel ions to form a soluble complex, which further promotes the release of nickel ions and the etching of the nickel foam.

[0018] In addition, ultrasonic etching also promotes the release of nickel ions on the surface of nickel foam, ensuring the structural consistency of the material. Preferably, the ultrasonic time in the process of preparing the multi-metal cation precursor solution is 1h to 2h, and the ultrasonic power is 150W to 200W.

[0019] Step 3: Add a sulfur source to the polymetallic cation precursor solution, and under ultrasonic conditions, allow the trivalent iron ions, nickel ions and cobalt ions in the polymetallic cation precursor solution to react with the sulfur source to form polymetallic sulfides. At the same time, oxygen ions combined with vanadium ions are doped into the polymetallic sulfides to obtain a precursor self-supporting electrode.

[0020] It should be noted that in the reaction process between the metal cations in the multi-metal cation precursor solution and the sulfur source, the vanadium ions have a strong affinity for oxygen in the aqueous solution and are more likely to attract oxygen ions, while their affinity for sulfur is weak and it is not easy to combine with S. Therefore, in the process of the reaction between the multi-metal cation precursor solution and the sulfur source, oxygen ions will be doped into the sulfide, promoting the formation of SO bonds to form oxysulfides. Oxysulfides contain hydrated O-2p orbitals and S-3p orbitals, which effectively inhibit the self-oxidation of the material and the irreversible reconstruction of the metal sulfide, extending the life of the sulfide, thereby improving the chemical stability of the material.

[0021] In the process of preparing the precursor self-supporting electrode, the present invention accelerates the interaction between molecules in the multi-metal cation precursor solution through ultrasound, thereby promoting the reaction speed and efficiency, and increasing the contact opportunity and reaction rate between the reactants. Preferably, the ultrasound time in the process of preparing the precursor self-supporting electrode is 10h to 12h, and the ultrasound power is 150W to 200W.

[0022] Preferably, the sulfur source is one of ammonium sulfide, thioacetamide, thiourea and sodium sulfide.

[0023] Step 4: Joule heating the precursor self-supporting electrode to obtain a polymetallic oxysulfide self-supporting electrode.

[0024] It should be noted that before the precursor self-supporting electrode is subjected to Joule heating, it needs to be washed alternately with water three times and alcohol three times, and then vacuum dried at room temperature for 1h to 2h. The residual solvent and unreacted substances on the surface of the precursor self-supporting electrode are removed by washing with water and organic solvents; through sufficient washing and drying, the high purity and consistency of the precursor self-supporting electrode are ensured, and the adverse effects of impurities on the electrochemical performance are reduced.

[0025] The Joule heating reaction can improve the crystallinity of the precursor self-supporting electrode, further optimize its structure and performance, and make the polymetallic oxysulfide on the surface of the precursor self-supporting electrode denser and more stable in structure; it not only inhibits the self-oxidation phenomenon of the polymetallic oxysulfide self-supporting electrode, but also significantly improves the conductivity of the polymetallic oxysulfide self-supporting electrode and the activity and stability of electrocatalytic oxygen evolution. In addition, the Joule heating temperature plays a key role in the formation of the crystal structure of the polymetallic oxysulfide self-supporting electrode. Too low a temperature is not conducive to the enhancement of the crystallinity of the polymetallic oxysulfide, and too high a temperature will reduce the toughness of the nickel foam and collapse the skeleton. Preferably, the Joule heating temperature of the present invention is 450°C to 500°C, and the Joule heating time is 15s to 30s.

[0026] The second object of the present invention is to provide a polymetallic oxysulfide self-supporting electrode prepared by the above preparation method.

[0027] The third object of the present invention is to provide the use of the above-mentioned polymetallic oxysulfide self-supporting electrode in electrocatalytic oxygen evolution.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention places the pretreated nickel foam in a precursor solution through room temperature ultrasonic reaction, and under the joint action of trivalent iron ions, vanadium ions and acidic environment provided by the precursor solution, nickel on the surface of the nickel foam undergoes an oxidation-reduction reaction, is etched into nickel ions and released into the solution; at the same time, under the promotion of the ultrasonic reaction, cyanide ions in the precursor solution combine with nickel ions to form a soluble complex, which further promotes the release of nickel ions and the etching of the nickel foam.

[0030] The present invention adds a sulfur source to a polymetallic cation precursor solution through room temperature ultrasonic reaction. These metal cations can work together with the sulfur source during the sulfurization process to generate polymetallic oxysulfides with a SO bond structure on the surface of nickel foam to obtain a precursor self-supporting electrode; the precursor self-supporting electrode is subjected to Joule heating reaction to obtain a polymetallic oxysulfide self-supporting electrode. The present invention modifies transition metal sulfides by introducing SO bonds to obtain a polymetallic oxysulfide self-supporting electrode of polymetallic oxysulfides. On the one hand, the SO bond can enhance the material's anti-self-oxidation performance, inhibit the material's self-oxidation phenomenon under high OER overpotential, and prevent irreversible reconstruction of the structure under high potential; on the other hand, the SO bond regulates the material's crystal structure and electronic structure, improves the material's electrochemical activity, and thus effectively improves the performance of electrocatalytic oxygen evolution.

[0031] The present invention introduces multiple metal elements such as vanadium, cobalt, iron and nickel. The synergistic effect of different metal elements increases the active sites of electrochemical reactions and improves the oxygen evolution reaction efficiency of electrode materials. The introduction of SO bonds effectively inhibits the self-oxidation of materials and enhances the chemical stability of materials, thereby achieving excellent electrocatalytic performance under high OER overpotentials. The present invention forms a water-rippled morphology by in-situ etching on the surface of nickel foam, which can provide more active reaction sites on the one hand. On the other hand, the in-situ generated "integrated" self-supporting electrode material with a "flesh-and-bone" structure has fast electron transmission capability and strong mechanical stability, which can increase the life of the self-supporting electrode. The polymetallic oxysulfide self-supporting electrode provided by the present invention can be used as an excellent electrocatalytic oxygen production electrode at 200mA / cm 2 At a current density of 500 mA / cm, the overpotential can be as low as 330 mV. 2 At a current density of 2.5 Å, the overpotential can be as low as 368 mV.

[0032] The present invention prepares a polymetallic oxysulfide self-supporting electrode through an ultrasound-assisted room temperature corrosion strategy and Joule heating technology. The ultrafast heating rate during the Joule heating process can accelerate the diffusion between atoms, realize the rapid growth of the catalytic layer of the polymetallic oxysulfide on the surface of the metal substrate, and further improve the crystallinity of the polymetallic oxysulfide self-supporting electrode, thereby improving the structural stability of the self-supporting electrode material.

[0033] The invention has the characteristics of low cost, short reaction cycle, simple preparation process, stable product quality, uniform material surface morphology and strong repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the XRD pattern of the polymetallic oxysulfide self-supporting electrode prepared in Example 1 of the present invention.

[0035] Figure 2 This is the XRD spectrum of the polymetallic oxysulfide self-supporting electrode prepared in Comparative Example 1 of the present invention.

[0036] Figure 3 This is the XPS spectrum of the polymetallic oxysulfide self-supporting electrode S2p prepared in Example 1 of the present invention.

[0037] Figure 4 This is a SEM photograph of the polymetallic oxysulfide self-supporting electrode prepared in Example 1 of the present invention; wherein a is a SEM photograph at 2 μm, and b is a SEM photograph at 500 nm.

[0038] Figure 5 This is a SEM photograph of the polymetallic oxysulfide self-supporting electrode prepared in Comparative Example 1 of the present invention.

[0039] Figure 6 OER performance diagram of the polymetallic oxysulfide self-supporting electrode prepared in Example 1 of the present invention DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments and drawings.

[0041] In the description of the present invention, unless otherwise specified, all reagents used are commercially available and all methods used are conventional techniques in the art.

[0042] Example 1

[0043] This embodiment provides a method for preparing a water-corrugated polymetallic oxysulfide self-supporting electrode.

[0044] Step 1: Dissolve 32.9 g of potassium ferrocyanide, 3.93 g of vanadium chloride and 3.25 g of cobalt chloride in 50 mL of ultrapure water and stir for 30 min to obtain a precursor solution.

[0045] Step 2: Use nickel foam as the substrate of the self-supporting electrode, pretreat the nickel foam, immerse the pretreated nickel foam in a precursor solution, and perform ultrasonic reaction at room temperature so that the nickel on the surface of the nickel foam is etched into nickel ions and released into the precursor solution to obtain a uniform multi-metal cation precursor solution.

[0046] 2.1) Immerse 1 cm×5 cm nickel foam in acetone solution for ultrasonic cleaning for 10 min, then transfer the nickel foam after acetone cleaning to 2 mol / L hydrochloric acid solution for ultrasonic cleaning for 10 min, then rinse the nickel foam after hydrochloric acid solution with ethanol and ultrapure water alternately for 3 times, and finally vacuum dry at 35°C for 10 h to obtain pretreated nickel foam.

[0047] 2.2) Immersing the pretreated nickel foam into the precursor solution, ultrasonically reacting at room temperature, and immersing the foam under ultrasonication at a power of 200 W for 2 h to obtain a multi-metal cation precursor solution.

[0048] Step 3: Add 30 mL of 3 mol / L ammonium sulfide solution to the multi-metal cation precursor solution, and under ultrasonic conditions, the ultrasonic power is 200 W and the ultrasonic time is 12 h to obtain a precursor self-supporting electrode.

[0049] Step 4: Take out the precursor self-supporting electrode, wash it with water three times and with alcohol three times alternately, and dry it at room temperature for 2 hours. Place the dried nickel foam in a Joule heating reaction device and react it at 450°C for 30 seconds to obtain a polymetallic oxysulfide self-supporting electrode.

[0050] Example 2

[0051] This embodiment provides a method for preparing a water-corrugated polymetallic oxysulfide self-supporting electrode.

[0052] Step 1: Dissolve 29.6 g of potassium ferrocyanide, 3.15 g of vanadium chloride and 2.6 g of cobalt nitrate in 50 mL of ultrapure water and stir for 30 min to obtain a precursor solution.

[0053] Step 2: Use nickel foam as the substrate of the self-supporting electrode, pretreat the nickel foam, immerse the pretreated nickel foam in a precursor solution, and perform ultrasonic reaction at room temperature so that the nickel on the surface of the nickel foam is etched into nickel ions and released into the precursor solution to obtain a uniform multi-metal cation precursor solution.

[0054] 2.1) Immerse 1 cm×5 cm nickel foam in acetone solution for ultrasonic cleaning for 10 min, then transfer the nickel foam after acetone cleaning to 2 mol / L hydrochloric acid solution for ultrasonic cleaning for 10 min, then rinse the nickel foam after hydrochloric acid solution with ethanol and ultrapure water alternately for 3 times, and finally vacuum dry at 35°C for 10 h to obtain pretreated nickel foam.

[0055] 2.2) The pretreated nickel foam is immersed in the precursor solution, subjected to ultrasonic reaction at room temperature, and immersed in ultrasound at a power of 150 W for 2 h to obtain a multi-metal cation precursor solution.

[0056] Step 3: Add 30 mL of 3 mol / L thiourea solution to the multi-metal cation precursor solution, and under ultrasonic conditions, the ultrasonic power is 150 W and the ultrasonic time is 12 h to obtain a precursor self-supporting electrode.

[0057] Step 4: Take out the precursor self-supporting electrode, wash it with water three times and with alcohol three times alternately, and dry it at room temperature for 2 hours. Place the dried nickel foam in a Joule heating reaction device and react it at 450°C for 30 seconds to obtain a polymetallic oxysulfide self-supporting electrode.

[0058] Example 3

[0059] This embodiment provides a method for preparing a water-corrugated polymetallic oxysulfide self-supporting electrode.

[0060] Step 1: Dissolve 24.7 g of potassium ferrocyanide, 2.36 g of vanadium chloride and 1.95 g of cobalt chloride in 50 mL of ultrapure water and stir for 30 min to obtain a precursor solution.

[0061] Step 2: Use nickel foam as the substrate of the self-supporting electrode, pretreat the nickel foam, immerse the pretreated nickel foam in a precursor solution, and perform ultrasonic reaction at room temperature to etch the nickel on the surface of the nickel foam into nickel ions and release them into the precursor solution to obtain a multi-metal cation precursor solution.

[0062] 2.1) Immerse 1 cm×5 cm nickel foam in acetone solution for ultrasonic cleaning for 10 min, then transfer the nickel foam after acetone cleaning to 2 mol / L hydrochloric acid solution for ultrasonic cleaning for 10 min, then rinse the nickel foam after hydrochloric acid solution with ethanol and ultrapure water alternately for 3 times, and finally vacuum dry at 35°C for 10 h to obtain pretreated nickel foam.

[0063] 2.2) The pretreated nickel foam is immersed in the precursor solution, subjected to ultrasonic reaction at room temperature, and immersed in ultrasound at a power of 150 W for 2 h to obtain a multi-metal cation precursor solution.

[0064] Step 3: Add 30 mL of 3 mol / L thioacetamide solution to the multi-metal cation precursor solution, and under ultrasonic conditions, the ultrasonic power is 200 W and the ultrasonic time is 12 h to obtain a precursor self-supporting electrode.

[0065] Step 4: Take out the precursor self-supporting electrode, wash it with water three times and with alcohol three times alternately, and dry it at room temperature for 2 hours. Place the dried nickel foam in a Joule heating reaction device and react it at 450°C for 30 seconds to obtain a polymetallic oxysulfide self-supporting electrode.

[0066] Example 4

[0067] This embodiment provides a method for preparing a water-corrugated polymetallic oxysulfide self-supporting electrode.

[0068] Step 1: Dissolve 32.9 g of potassium ferrocyanide, 3.93 g of vanadium chloride and 3.25 g of cobalt chloride in 50 mL of ultrapure water and stir for 30 min to obtain a precursor solution.

[0069] Step 2: Use nickel foam as the substrate of the self-supporting electrode, pretreat the nickel foam, immerse the pretreated nickel foam in a precursor solution, and perform ultrasonic reaction at room temperature so that the nickel on the surface of the nickel foam is etched into nickel ions and released into the precursor solution to obtain a uniform multi-metal cation precursor solution.

[0070] 2.1) Immerse 1 cm×5 cm nickel foam in acetone solution for ultrasonic cleaning for 10 min, then transfer the nickel foam after acetone cleaning to 2 mol / L hydrochloric acid solution for ultrasonic cleaning for 10 min, then rinse the nickel foam after hydrochloric acid solution with ethanol and ultrapure water alternately for 3 times, and finally vacuum dry at 35°C for 10 h to obtain pretreated nickel foam.

[0071] 2.2) The pretreated nickel foam is immersed in the precursor solution, subjected to ultrasonic reaction at room temperature, and immersed in ultrasound at a power of 180 W for 1 h to obtain a multi-metal cation precursor solution.

[0072] Step 3: Add 30 mL of 3 mol / L ammonium sulfide solution to the multi-metal cation precursor solution, and under ultrasonic conditions, the ultrasonic power is 180 W and the ultrasonic time is 10 h to obtain a precursor self-supporting electrode.

[0073] Step 4: Take out the precursor self-supporting electrode, wash it with water three times and alcohol three times alternately, dry it at room temperature for 2 hours, place the dried nickel foam in a Joule heating reaction device, and react it at 500°C for 15 seconds to obtain a polymetallic oxysulfide self-supporting electrode.

[0074] Comparative Example 1

[0075] This comparative example provides a method for preparing a water-corrugated polymetallic oxysulfide self-supporting electrode.

[0076] Step 1: Dissolve 32.9 g of potassium ferrocyanide, 3.93 g of vanadium chloride and 3.25 g of cobalt chloride in 50 mL of ultrapure water and stir for 30 min to obtain a precursor solution.

[0077] Step 2: Use nickel foam as the substrate of the self-supporting electrode, pretreat the nickel foam, immerse the pretreated nickel foam in a precursor solution, and perform ultrasonic reaction at room temperature so that the nickel on the surface of the nickel foam is etched into nickel ions and released into the precursor solution to obtain a uniform multi-metal cation precursor solution.

[0078] 2.1) Immerse 1 cm×5 cm nickel foam in acetone solution for ultrasonic cleaning for 10 min, then transfer the nickel foam after acetone cleaning to 2 mol / L hydrochloric acid solution for ultrasonic cleaning for 10 min, then rinse the nickel foam after hydrochloric acid solution with ethanol and ultrapure water alternately for 3 times, and finally vacuum dry at 35°C for 10 h to obtain pretreated nickel foam.

[0079] 2.2) Immersing the pretreated nickel foam into the precursor solution, ultrasonically reacting at room temperature, and immersing the foam under ultrasonication at a power of 200 W for 2 h to obtain a multi-metal cation precursor solution.

[0080] Step 3: Add 30 mL of 3 mol / L ammonium sulfide solution to the multi-metal cation precursor solution, and under ultrasonic conditions, the ultrasonic power is 200 W and the ultrasonic time is 12 h to obtain a precursor self-supporting electrode.

[0081] Step 4: Take out the precursor self-supporting electrode, wash it with water three times and alcohol three times alternately, and dry it at room temperature for 2 hours to obtain a polymetallic oxysulfide self-supporting electrode.

[0082] The difference between this comparative example and Example 1 is:

[0083] This comparative example does not use Joule heating.

[0084] In Examples 1 to 4 of the present invention, polymetallic oxysulfide self-supporting electrodes containing SO bonds and having a water-rippled surface morphology are prepared. The following is a study using the polymetallic oxysulfide self-supporting electrodes prepared in Example 1 and Comparative Example 1 as examples. The specific research methods and results are as follows:

[0085] Experimental testing

[0086] Figure 1 This is the XRD pattern of the polymetallic oxysulfide self-supporting electrode prepared in Example 1. Figure 1From the XRD diagram, it can be seen that in addition to the diffraction peak of the metal substrate Ni, the diffraction peaks of Ni3S2 and Co3S4 are observed in the polymetallic oxysulfide self-supporting electrode prepared in the present invention, which shows that the polymetallic oxysulfide self-supporting electrode prepared in Example 1 has a crystalline structure and high crystallinity.

[0087] Figure 2 This is the XRD pattern of the polymetallic oxysulfide self-supporting electrode prepared in Comparative Example 1. Figure 2 Only the diffraction peak of the metal substrate Ni can be observed, and no other diffraction peaks appear. This indicates that when Joule heating is not used, the polymetallic oxysulfide self-supporting electrode prepared in Comparative Example 1 is in an amorphous state and has a very low crystallinity.

[0088] Figure 3 This is the S2p XPS spectrum of the polymetallic oxysulfide self-supporting electrode prepared in Example 1. Figure 3 It can be seen that the polymetallic oxysulfide self-supporting electrode prepared by the present invention has SO bonds in addition to metal-sulfur bonds, which indicates that SO bonds are successfully introduced into the polymetallic oxysulfide self-supporting electrode prepared by the present invention.

[0089] Figure 4 This is a SEM photo of the polymetallic oxysulfide self-supporting electrode prepared in Example 1; wherein a is a SEM photo at 2 μm, and b is a SEM photo at 500 nm. Figure 4 It can be seen that the surface of the polymetallic oxysulfide self-supporting electrode prepared in the present invention is rough and wavy, which is conducive to the contact between the self-supporting electrode and the electrolyte and the release of bubbles in the self-supporting electrode, and can enhance the mass transfer of the self-supporting electrode.

[0090] Figure 5 This is a SEM photo of the polymetallic oxysulfide self-supporting electrode prepared in Comparative Example 1. Figure 5 As shown, the surface of the self-supporting electrode prepared in Comparative Example 1 is in the shape of water ripples formed by continuous nanosheets.

[0091] Figure 6 This is the OER performance diagram of the polymetallic oxysulfide self-supporting electrode prepared in Example 1. Figure 6 It can be seen from the OER diagram that in 1M KOH electrolyte and under the test conditions of a scan rate of 2mV / s, the polymetallic oxysulfide self-supporting electrode prepared by the present invention has a current density of more than 100mA / cm 2 It has excellent oxygen evolution activity at high current density. 2 At a current density of 500 mA / cm, the overpotential can be as low as 330 mV. 2 At a current density of 2.5 Å, the overpotential can be as low as 368 mV.

[0092] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes a preferred embodiment. Although the preferred embodiments of the present invention have been described, once those skilled in the art know the basic creative concept, they can make other changes and modifications to these embodiments, and these changes and modifications all fall within the scope of the present invention.

[0093] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. If these modifications and variations of the present invention fall within the scope of the equivalent technology of the present invention, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a water-corrugated polymetallic oxysulfide self-supporting electrode, characterized in that: The following steps are involved: Dissolving potassium ferrocyanide, soluble vanadium salt and soluble cobalt salt in water, stirring evenly, to obtain a precursor solution; Using nickel foam as a substrate of a self-supporting electrode, the nickel foam is pretreated, and then immersed in a precursor solution, and subjected to ultrasonic reaction at room temperature, so that nickel on the surface of the nickel foam is etched into nickel ions and released into the precursor solution, thereby obtaining a multi-metal cation precursor solution; A sulfur source is added to a polymetallic cation precursor solution, and under ultrasonic conditions, trivalent iron ions, nickel ions and cobalt ions in the polymetallic cation precursor solution react with the sulfur source to form polymetallic sulfides, and oxygen ions combined with vanadium ions are doped into the polymetallic sulfides to obtain a precursor self-supporting electrode; The precursor self-supporting electrode is subjected to Joule heating to obtain a polymetallic oxysulfide self-supporting electrode.

2. The method for preparing a polymetallic oxysulfide self-supporting electrode according to claim 1, characterized in that: The molar ratio of the potassium ferrocyanide, the soluble vanadium salt and the soluble cobalt salt is 1.5-2:0.3-0.5:0.3-0.

5.

3. The method for preparing a polymetallic oxysulfide self-supporting electrode according to claim 1, characterized in that: The molar ratio of the potassium ferrocyanide to the sulfur source is 1.5-2:3-5.

4. The method for preparing a polymetallic oxysulfide self-supporting electrode according to claim 1, characterized in that: The ultrasonic time during the preparation of the multi-metal cation precursor solution is 1 hour to 2 hours, and the ultrasonic power is 150W to 200W.

5. The method for preparing a polymetallic oxysulfide self-supporting electrode according to claim 1, characterized in that: The ultrasonic time in the process of preparing the precursor self-supporting electrode is 10h to 12h, and the ultrasonic power is 150W to 200W.

6. The method for preparing a polymetallic oxysulfide self-supporting electrode according to claim 1, characterized in that: The Joule heating temperature is 450° C. to 500° C., and the Joule heating time is 15 s to 30 s.

7. The method for preparing a polymetallic oxysulfide self-supporting electrode according to claim 1, characterized in that: The soluble vanadium salt is vanadium chloride; the soluble cobalt salt is one of cobalt chloride and cobalt nitrate.

8. The method for preparing a polymetallic oxysulfide self-supporting electrode according to claim 1, characterized in that: The sulfur source is one of ammonium sulfide, thioacetamide, thiourea and sodium sulfide.

9. A polymetallic oxysulfide self-supporting electrode prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the polymetallic oxysulfide self-supporting electrode according to claim 9 in electrocatalytic oxygen evolution.

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