A water-rugate polymetallo-oxysulfide self-supporting electrode and a preparation method and application thereof

Abstract

The application belongs to the technical field of electrocatalytic materials, and discloses a water ripple-shaped multimetal oxysulfide self-supporting electrode and a preparation method and application thereof. The application takes foamed nickel as the base of the self-supporting electrode, immerses the pretreated foamed nickel in a precursor solution containing potassium ferricyanide, soluble vanadium salt and soluble cobalt salt, etches the nickel on the surface of the foamed nickel into nickel ions through room temperature ultrasonic and releases the nickel ions into the precursor solution to obtain a multimetal cation precursor solution; under ultrasonic conditions, adds a sulfur source into the multimetal cation precursor solution to make the trivalent iron ions, nickel ions and cobalt ions in the multimetal cation precursor solution react with the sulfur source to form a multimetal sulfide, and at the same time, the oxygen ions combined with the vanadium ions are doped in the multimetal sulfide to generate a precursor self-supporting electrode; and performs joule heating on the precursor self-supporting electrode to obtain a multimetal oxysulfide self-supporting electrode.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrocatalytic materials, and particularly relates to a water ripple-shaped multimetal oxysulfide self-supporting electrode and a preparation method and application thereof. BACKGROUND

[0002] Electrocatalytic oxygen evolution reaction is one of the key reaction processes of new energy technologies such as hydrogen production by water electrolysis and metal-air batteries, and its full name in English is Oxygen Evolution Reaction (OER) and its abbreviation in English is OER. However, due to the high overpotential and complex reaction path of the OER reaction, the selection and optimization of electrocatalysts become the key to improving the OER efficiency. In recent years, transition metal sulfides have become a hot research material due to their rich reaction active sites and excellent electrochemical performance.

[0003] Metallic Ni3S2 is a typical representative of transition metal sulfides, and there are rich Ni-S and Ni-Ni bonds in its structure, which have good adsorption energy for oxygen intermediates O* and OH*, and it is an OER electrocatalyst with great application prospect. However, due to the high rate-determining reaction energy barrier of Ni3S2, its activity has not reached the expected level, which has greatly limited the OER kinetics. In addition, transition metal sulfides are exposed to a strong oxidative environment during the electrocatalytic oxygen evolution process, and the sulfur element on the surface is easily oxidized to form oxides or other unstable compounds, thereby causing the material to be self-oxidized. 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 usually adopts high-temperature and high-pressure hydrothermal method, solvothermal method, electrochemical deposition method or solid phase method. However, although these methods optimize the electrocatalytic performance of the material to a certain extent, there is still the problem of self-oxidation of the metal sulfide material; and the preparation process is relatively complex, has strong dependence on equipment and relatively high energy consumption. SUMMARY

[0005] In order to solve the above technical problems, the application provides a water ripple-shaped multimetal oxysulfide self-supporting electrode and a preparation method and application thereof.

[0006] The application utilizes the fact that the aqueous solution of soluble vanadium salt is acidic, which promotes the generation of ferric ions in the acidic solution; at the same time, the foamed nickel is in the acidic solution, Fe 3+The nickel ions are released slowly under the combined action of the ultrasound; in addition, in the solution in which the ferric ions, the nickel ions, the vanadium ions and the cobalt ions are uniformly present, a sulfur source is added, and under the ultrasonic reaction, the multi-metal sulfide is formed, and the oxygen ions are doped in the multi-metal sulfide by using the oxygen affinity of the vanadium ions, so that the generation of S-O bonds is promoted, and the precursor self-supporting electrode is obtained; under the condition of joule heating, the crystalline multi-metal 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 the S-O bond effectively inhibits the self-oxidation of the material, and the chemical stability of the material is enhanced, so that excellent electrocatalytic performance is realized under high OER overpotential.

[0007] The first object of the present application is to provide a preparation method of a water ripple-shaped multi-metal oxysulfide self-supporting electrode, comprising the following steps:

[0008] Step 1, dissolving potassium ferricyanide, a soluble vanadium salt and a soluble cobalt salt in water, stirring uniformly to obtain a precursor solution.

[0009] It should be noted that after the soluble vanadium salt is dissolved in water, hydrochloric acid and vanadous acid are generated, so that the precursor solution is acidic; at the same time, the potassium ferricyanide is decomposed by the acid in the acidic environment to generate ferric ions and cyanide ions. Placing the foamed nickel in the precursor solution helps to etch the metal nickel on the surface of the foamed nickel into nickel ions.

[0010] Preferably, the molar ratio of the potassium ferricyanide, 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 ferricyanide and 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, taking foamed nickel as the substrate of the self-supporting electrode, the foamed nickel is pretreated, then the pretreated foamed nickel is immersed in the precursor solution, and ultrasonic reaction is carried out at room temperature, so that the nickel on the surface of the foamed nickel is etched into nickel ions and released into the precursor solution, and a multi-metal cation precursor solution is obtained.

[0015] It should be noted that in order to enhance the activity of the surface of the foamed nickel, ensure that the subsequent reaction process can be effectively carried out; before the foamed nickel and the precursor solution are reacted, the foamed nickel is pretreated in the application, so as to improve the contact efficiency of the precursor solution and the foamed nickel, ensure the uniform growth of the oxysulfide on the surface of the foamed nickel, and thus improve the structural stability and conductivity of the self-supporting electrode of the multi-metal oxysulfide. Preferably, the pretreatment comprises: sequentially placing the foamed nickel in an acetone solution and a hydrochloric acid solution for treatment, and then alternately washing with ethanol and water. The treatment with the acetone organic solvent and the hydrochloric acid solution can remove the oxides and impurities on the surface of the foamed nickel, and the subsequent alternating washing with ethanol and purified water can ensure that there is no residual chemical substances on the surface, so as to provide a clean and uniform effective reaction area, and ensure the efficient performance of the subsequent reaction process.

[0016] The specific operation of the pretreatment in the application is as follows: the foamed nickel is immersed in an acetone solution for ultrasonic cleaning for 5-20 min, then the foamed nickel cleaned with acetone is transferred to a 2-4 mol / L hydrochloric acid solution for ultrasonic cleaning for 5-20 min, then the foamed nickel cleaned with the hydrochloric acid is alternately washed with ethanol and ultrapure water for 2-3 times, and finally the foamed nickel washed with ethanol and ultrapure water is vacuum dried at 25-35°C for 10-14 h to obtain the pretreated foamed nickel.

[0017] It should be further noted that the pretreated foamed nickel is immersed in the precursor solution, and ultrasonic reaction is carried out at room temperature. Under the combined action of the trivalent iron ions, vanadium ions, acidic environment and ultrasonic provided by the precursor solution, the nickel on the surface of the foamed nickel 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 foamed nickel.

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

[0019] Step 3, adding a sulfur source to the multi-metal cation precursor solution under ultrasonic conditions, so that the trivalent iron ions, nickel ions and cobalt ions in the multi-metal cation precursor solution react with the sulfur source to form a multi-metal sulfide, and the oxygen ions combined with the vanadium ions are doped in the multi-metal sulfide to obtain a precursor self-supporting electrode.

[0020] It should be noted that in the process of reaction of metal cations in the multi-metal cation precursor solution and the sulfur source, vanadium ions have strong oxygen affinity in aqueous solution and are more likely to attract oxygen ions, and have weak sulfur affinity and are not easy to combine with S. Therefore, in the process of reaction of the multi-metal cation precursor solution and the sulfur source, oxygen ions will be doped in the sulfide to promote the formation of S-O bond and form an oxysulfide. The oxysulfide contains hydrated O-2p orbitals and S-3p orbitals, effectively inhibiting the self-oxidation of the material and effectively inhibiting the irreversible reconstruction of the metal sulfide, prolonging the service life of the sulfide, and thus improving the chemical stability of the material.

[0021] In the preparation of the precursor self-supporting electrode, the present application accelerates the intermolecular interaction in the multi-metal cation precursor solution by ultrasonic action, thereby promoting the reaction speed and efficiency and improving the contact opportunity and reaction rate between reactants. Preferably, the ultrasonic time during the preparation of the precursor self-supporting electrode is 10h-12h, and the ultrasonic power is 150W-200W.

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

[0023] Step 4, the precursor self-supporting electrode is subjected to joule heating to obtain a multi-metal 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 with water for 3 times and washed with alcohol for 3 times alternately, and then vacuum dried at room temperature for 1h-2h. By washing with water and organic solvent, the residual solvent and unreacted substances on the surface of the precursor self-supporting electrode are removed; by 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, make the multi-metal oxysulfide on the surface of the precursor self-supporting electrode more dense and the structure more stable; not only inhibit the self-oxidation of the multi-metal oxysulfide self-supporting electrode, but also significantly improve the conductivity and electrocatalytic oxygen evolution activity and stability of the multi-metal oxysulfide self-supporting electrode. In addition, the temperature of joule heating plays a key role in the formation of the crystal structure of the multi-metal oxysulfide self-supporting electrode, and too low temperature is not conducive to the improvement of the crystallinity of the multi-metal oxysulfide, and too high temperature will reduce the toughness of the foamed nickel and collapse the skeleton. Preferably, the temperature of joule heating is 450℃-500℃, and the time of joule heating is 15s-30s.

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

[0027] A third object of the present application is to provide the use of the above-mentioned multi-metal oxysulfide self-supporting electrode in electrocatalytic oxygen evolution.

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

[0029] In the present application, the pre-processed foam nickel is placed in the precursor solution through room-temperature ultrasonic reaction, and under the combined action of the trivalent iron ions, vanadium ions and acidic environment provided by the precursor solution, the nickel on the surface of the foam nickel is subjected to redox reaction and etched into nickel ions and released into the solution; at the same time, under the promotion of ultrasonic reaction, the cyanide ions in the precursor solution combine with the nickel ions to form a soluble complex, further promoting the release of nickel ions and the etching of the foam nickel.

[0030] In the present application, sulfur source is added to the multi-metal cation precursor solution through room-temperature ultrasonic reaction, and these metal cations can jointly act with the sulfur source in the sulfuration process to generate multi-metal oxysulfide with S-O bond structure on the surface of the foam nickel to obtain a precursor self-supporting electrode; the precursor self-supporting electrode is subjected to a joule heating reaction to obtain a multi-metal oxysulfide self-supporting electrode. In the present application, the transition metal sulfide is modified by introducing S-O bond to obtain a multi-metal oxysulfide self-supporting electrode of multi-metal oxysulfide, which can enhance the anti-self-oxidation performance of the material on the one hand, inhibit the self-oxidation phenomenon of the material under high OER overpotential, and prevent the irreversible reconstruction of the structure under high potential; on the other hand, the S-O bond regulates the crystal structure and electronic structure of the material, thereby improving the electrochemical activity of the material and effectively improving the performance of electrocatalytic oxygen evolution.

[0031] In the present application, the introduction of vanadium, cobalt, iron and nickel multi-metal elements increases the electrochemical reaction active sites through the synergistic action of different metal elements, thereby improving the oxygen evolution reaction efficiency of the electrode material; the introduction of S-O bond effectively inhibits the self-oxidation phenomenon of the material and enhances the chemical stability of the material, thereby achieving excellent electrocatalytic performance under high OER overpotential; in the present application, in-situ etching occurs on the surface of the foam nickel to form a water ripple-like morphology, which can provide more reaction active sites on the one hand; on the other hand, the in-situ generated "one-piece" self-supporting electrode material with "bone-meat connection" structure has fast electron transmission capacity and strong mechanical stability, which can improve the service life of the self-supporting electrode. The multi-metal oxysulfide self-supporting electrode provided in the present application can be used as an excellent electrocatalytic oxygen evolution electrode, and its overpotential can be as low as 330mV under a current density of 200mA / cm 2 , and its overpotential can be as low as 368mV under a current density of 500mA / cm 2 .

[0032] The self-supporting electrode of the multi-metal oxysulfide prepared by the ultrasonic-assisted room temperature corrosion strategy and the Joule heating technology can accelerate interatomic diffusion in the process of Joule heating, realize rapid growth of the catalytic layer of the multi-metal oxysulfide on the surface of the metal substrate, and further improve the crystallinity of the self-supporting electrode of the multi-metal oxysulfide, so that the structural stability of the self-supporting electrode material is improved.

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

[0034] Figure 1 The XRD pattern of the self-supporting electrode of the multi-metal oxysulfide prepared in Example 1 of the application.

[0035] Figure 2 The XRD pattern of the self-supporting electrode of the multi-metal oxysulfide prepared in Comparative Example 1 of the application.

[0036] Figure 3 The XPS pattern of S2p of the self-supporting electrode of the multi-metal oxysulfide prepared in Example 1 of the application.

[0037] Figure 4 The SEM photos of the self-supporting electrode of the multi-metal oxysulfide prepared in Example 1 of the application; wherein a is the SEM photo under 2 μm, and b is the SEM photo under 500 nm.

[0038] Figure 5 The SEM photo of the self-supporting electrode of the multi-metal oxysulfide prepared in Comparative Example 1 of the application.

[0039] Figure 6 The OER performance graph of the self-supporting electrode of the multi-metal oxysulfide prepared in Example 1 of the application. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solutions of the application and implement the same, the application will be further described below in conjunction with specific embodiments and drawings.

[0041] In the description of the application, if not specially stated, the reagents used are commercially available, and the methods used are conventional techniques in the art.

[0042] Example 1

[0043] The embodiment provides a preparation method of a water-wavy multi-metal oxysulfide self-supporting electrode.

[0044] Step 1, 32.9 g of potassium ferricyanide, 3.93 g of vanadium chloride and 3.25 g of cobalt chloride were dissolved in 50 mL of ultrapure water, stirred for 30 min to obtain a precursor solution.

[0045] Step 2, the foam nickel was used as the substrate of the self-supporting electrode, the pretreated foam nickel was immersed in the precursor solution, and the room temperature ultrasonic reaction was carried out, so that the nickel on the surface of the foam nickel was etched into nickel ions and released into the precursor solution, and a uniform multi-metal cation precursor solution was obtained.

[0046] 2.1) The 1 cm x 5 cm foam nickel was immersed in an acetone solution and ultrasonically cleaned for 10 min, then the acetone cleaned foam nickel was transferred to a 2 mol / L hydrochloric acid solution and ultrasonically cleaned for 10 min, then the hydrochloric acid solution cleaned foam nickel was washed with ethanol and ultrapure water alternately for 3 times, and finally vacuum dried at 35°C for 10h, to obtain the pretreated foam nickel.

[0047] 2.2) The pretreated foam nickel was immersed in the precursor solution, and the room temperature ultrasonic reaction was carried out, and the immersion ultrasonic was carried out at 200 W power for 2h, to obtain a multi-metal cation precursor solution.

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

[0049] Step 4, the precursor self-supporting electrode was taken out, washed with water and alcohol alternately for 3 times, and dried at room temperature for 2h, then the dried foam nickel was placed in a joule heating reaction device and reacted at 450°C for 30s, to obtain a multi-metal oxide sulfide self-supporting electrode.

[0050] Example 2

[0051] The embodiment provides a preparation method of a water-wavy multi-metal oxide sulfide self-supporting electrode.

[0052] Step 1, 29.6 g of potassium ferricyanide, 3.15 g of vanadium chloride and 2.6 g of cobalt nitrate were dissolved in 50 mL of ultrapure water, stirred for 30 min to obtain a precursor solution.

[0053] Step 2, the foam nickel was used as the substrate of the self-supporting electrode, the pretreated foam nickel was immersed in the precursor solution, and the room temperature ultrasonic reaction was carried out, so that the nickel on the surface of the foam nickel was etched into nickel ions and released into the precursor solution, and a uniform multi-metal cation precursor solution was obtained.

[0054] 2.1) 1 cm x 5 cm of the nickel foam was immersed in an acetone solution and ultrasonically cleaned for 10 min, then the nickel foam cleaned by acetone was transferred to a 2 mol / L hydrochloric acid solution and ultrasonically cleaned for 10 min, then the nickel foam cleaned by the hydrochloric acid solution was washed by ethanol and ultrapure water alternately for 3 times, and finally vacuum dried at 35°C for 10 h to obtain the pretreated nickel foam.

[0055] 2.2) The pretreated nickel foam was immersed in the precursor solution, and ultrasonically reacted at room temperature for 2 h under the power of 150 W to obtain a multi-metal cation precursor solution.

[0056] Step 3, 30 mL of a thiourea solution with a concentration of 3 mol / L was added to the multi-metal cation precursor solution, and the power of the ultrasonic was 150 W, and the ultrasonic time was 12 h to obtain a precursor self-supporting electrode.

[0057] Step 4, the precursor self-supporting electrode was taken out, washed alternately by water and alcohol for 3 times, and dried at room temperature for 2 h, and then the dried nickel foam was placed in a joule heating reaction device and reacted at 450°C for 30 s to obtain a multi-metal oxysulfide self-supporting electrode.

[0058] Example 3

[0059] The embodiment provides a preparation method of a water-wavy multi-metal oxysulfide self-supporting electrode.

[0060] Step 1, 24.7 g of potassium ferricyanide, 2.36 g of vanadium chloride and 1.95 g of cobalt chloride were dissolved in 50 mL of ultrapure water, and stirred for 30 min to obtain a precursor solution.

[0061] Step 2, the nickel foam was pretreated, and then the pretreated nickel foam was immersed in the precursor solution and ultrasonically reacted at room temperature, so that the nickel on the surface of the nickel foam was etched into nickel ions and released into the precursor solution to obtain a multi-metal cation precursor solution.

[0062] 2.1) 1 cm x 5 cm of the nickel foam was immersed in an acetone solution and ultrasonically cleaned for 10 min, then the nickel foam cleaned by acetone was transferred to a 2 mol / L hydrochloric acid solution and ultrasonically cleaned for 10 min, then the nickel foam cleaned by the hydrochloric acid solution was washed by ethanol and ultrapure water alternately for 3 times, and finally vacuum dried at 35°C for 10 h to obtain the pretreated nickel foam.

[0063] 2.2) The pretreated nickel foam was immersed in the precursor solution, and ultrasonically reacted at room temperature for 2 h under the power of 150 W to obtain a multi-metal cation precursor solution.

[0064] Step 3, 30 mL of thiourea solution with a concentration of 3 mol / L was added to the multi-metal cation precursor solution, and the precursor self-supporting electrode was obtained under ultrasonic conditions with a power of 200 W and a time of 12 h.

[0065] Step 4, the precursor self-supporting electrode was taken out and cleaned alternately by water washing and alcohol washing for 3 times, and then dried at room temperature for 2 h. The dried nickel foam was placed in a joule heating reaction device and reacted at 450℃ for 30 s to obtain a multi-metal oxysulfide self-supporting electrode.

[0066] Example 4

[0067] The embodiment provides a preparation method of a water-wavy multi-metal oxysulfide self-supporting electrode.

[0068] Step 1, 32.9 g of potassium ferricyanide, 3.93 g of vanadium chloride and 3.25 g of cobalt chloride were dissolved in 50 mL of ultrapure water, and stirred for 30 min to obtain a precursor solution.

[0069] Step 2, the nickel foam was pretreated, and then the pretreated nickel foam was immersed in the precursor solution and reacted at room temperature under ultrasonic conditions, so that the nickel on the surface of the nickel foam was etched into nickel ions and released into the precursor solution to obtain a uniform multi-metal cation precursor solution.

[0070] 2.1) The 1 cm x 5 cm nickel foam was immersed in an acetone solution and ultrasonically cleaned for 10 min, then the nickel foam cleaned with acetone was transferred to a 2 mol / L hydrochloric acid solution and ultrasonically cleaned for 10 min, then the nickel foam cleaned with the hydrochloric acid solution was washed with ethanol and ultrapure water alternately for 3 times, and finally vacuum dried at 35℃ for 10 h to obtain the pretreated nickel foam.

[0071] 2.2) The pretreated nickel foam was immersed in the precursor solution and reacted at room temperature under ultrasonic conditions for 1 h at a power of 180 W to obtain a multi-metal cation precursor solution.

[0072] Step 3, 30 mL of thiourea solution with a concentration of 3 mol / L was added to the multi-metal cation precursor solution, and the precursor self-supporting electrode was obtained under ultrasonic conditions with a power of 200 W and a time of 12 h.

[0073] Step 4, the precursor self-supporting electrode was taken out and cleaned alternately by water washing and alcohol washing for 3 times, and then dried at room temperature for 2 h. The dried nickel foam was placed in a joule heating reaction device and reacted at 450℃ for 30 s to obtain a multi-metal oxysulfide self-supporting electrode.

[0074] Comparative Example 1

[0075] The comparative example provides a preparation method of a water-wavy multi-metal oxysulfide self-supporting electrode.

[0076] Step 1, 32.9 g of potassium ferricyanide, 3.93 g of vanadium chloride and 3.25 g of cobalt chloride were dissolved in 50 mL of ultrapure water, stirred for 30 min to obtain a precursor solution.

[0077] Step 2, taking the foamed nickel as the substrate of the self-supporting electrode, the foamed nickel was pretreated, then the pretreated foamed nickel was immersed in the precursor solution, and the nickel on the surface of the foamed nickel was etched into nickel ions and released into the precursor solution under ultrasonic reaction at room temperature, to obtain a uniform multi-metal cation precursor solution.

[0078] 2.1) The 1 cm x 5 cm foamed nickel was immersed in an acetone solution and ultrasonically cleaned for 10 min, then the foamed nickel cleaned with acetone was transferred to a 2 mol / L hydrochloric acid solution and ultrasonically cleaned for 10 min, then the foamed nickel cleaned with the hydrochloric acid solution was washed with ethanol and ultrapure water alternately for 3 times, and finally vacuum dried at 35°C for 10 h to obtain the pretreated foamed nickel.

[0079] 2.2) The pretreated foamed nickel was immersed in the precursor solution and ultrasonically reacted at room temperature, and the foamed nickel was immersed and ultrasonically reacted for 2 h under a power of 200 W to obtain a multi-metal cation precursor solution.

[0080] Step 3, 30 mL of ammonium sulfide solution with a concentration of 3 mol / L was added to the multi-metal cation precursor solution, and the precursor self-supporting electrode was obtained under ultrasonic conditions, with an ultrasonic power of 200 W and an ultrasonic time of 12 h.

[0081] Step 4, the precursor self-supporting electrode was taken out, washed alternately with water and alcohol for 3 times, and dried at room temperature for 2 h to obtain a multi-metal oxysulfide self-supporting electrode.

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

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

[0084] Examples 1-4 of the present application all prepare a multi-metal oxysulfide self-supporting electrode containing S-O bonds and having a water-wavy surface morphology. The multi-metal oxysulfide self-supporting electrode prepared in example 1 and comparative example 1 is taken as an example for research, and the specific research method and results are shown as follows:

[0085] Experimental test

[0086] Figure 1 The XRD pattern of the multi-metal oxysulfide self-supporting electrode prepared in example 1. From the XRD pattern, it can be seen that the prepared multi-metal oxysulfide self-supporting electrode has a strong diffraction peak at 2θ=26.5°, which is the characteristic peak of the multi-metal oxysulfide self-supporting electrode. Figure 1The XRD diagram of the prepared multi-metal oxysulfide self-supporting electrode of the application can be known that, in addition to the diffraction peak of the metal base Ni, the diffraction peaks of Ni3S2 and Co3S4 are observed. It is shown that the multi-metal oxysulfide self-supporting electrode prepared in Example 1 is a crystalline structure with high crystallinity.

[0087] Figure 2 The XRD diagram of the multi-metal oxysulfide self-supporting electrode prepared in Comparative Example 1. Figure 2 Only the diffraction peak of the metal base Ni can be observed, and no other diffraction peak is observed. It is shown that the multi-metal oxysulfide self-supporting electrode prepared in Comparative Example 1 is in an amorphous state, and the crystallinity is very low.

[0088] Figure 3 The S2p XPS diagram of the multi-metal oxysulfide self-supporting electrode prepared in Example 1. Figure 3 It can be known that, in addition to the metal-sulfur bond, the S-O bond exists in the multi-metal oxysulfide self-supporting electrode prepared in the application; it is shown that the S-O bond is successfully introduced in the multi-metal oxysulfide self-supporting electrode prepared in the application.

[0089] Figure 4 The SEM photos of the multi-metal oxysulfide self-supporting electrode prepared in Example 1; wherein, a is the SEM photo under 2 μm, and b is the SEM photo under 500 nm. According to Figure 4 It can be known that the surface roughness of the multi-metal oxysulfide self-supporting electrode prepared in the application is in a water ripple shape, which is beneficial to the contact of the self-supporting electrode with the electrolyte and the release of the bubbles in the self-supporting electrode, and can enhance the mass transfer of the self-supporting electrode.

[0090] Figure 5 The SEM photo of the multi-metal oxysulfide self-supporting electrode prepared in Comparative Example 1. As Figure 5 shown, the surface of the self-supporting electrode prepared in Comparative Example 1 is in a water ripple shape connected by continuous nanosheets.

[0091] Figure 6 The OER performance diagram of the multi-metal oxysulfide self-supporting electrode prepared in Example 1. According to Figure 6 the OER diagram, under the test conditions that the KOH electrolyte is 1M, and the scanning speed is 2 mV / s, the multi-metal oxysulfide self-supporting electrode prepared in the application has excellent oxygen evolution activity under the large current density of more than 100 mA / cm 2 . Among them, under the current density of 200 mA / cm 2 , the overpotential can be as low as 330 mV, and under the current density of 500 mA / cm 2 , the overpotential can be as low as 368 mV.

[0092] It should be noted that in the present application, when a numerical range is involved, both the two end points of each numerical range and any number between the two end points can be selected. Since the same method and example are used, in order to prevent repetition, the present application describes the preferred embodiments. Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic inventive concept, and these changes and modifications all fall within the scope of the present application.

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

Claims

1. A method for preparing a water-ripple-shaped multimetallic oxysulfide self-supporting electrode, characterized in that, Includes the following steps: Potassium ferricyanide, soluble vanadium salt, and soluble cobalt salt are dissolved in water and stirred until homogeneous to obtain a precursor solution. The aqueous solution of the soluble vanadium salt is acidic. Using nickel foam as the substrate of the self-supporting electrode, the nickel foam is pretreated and then immersed in a precursor solution. The pretreated nickel foam is ultrasonically reacted at room temperature to etch nickel on the surface of the nickel foam into nickel ions and release them into the precursor solution, thus obtaining a multi-metal cation precursor solution. Sulfur source is added to a polymetallic cation precursor solution. Under ultrasonic conditions, the ferric ions, nickel ions and cobalt ions in the polymetallic cation precursor solution react with the sulfur source to form polymetallic sulfides. At the same time, oxygen ions bound by vanadium ions are doped into the polymetallic sulfides to obtain a precursor self-supporting electrode. By subjecting the precursor self-supporting electrode to Joule heating, a polymetallic oxysulfide self-supporting electrode is obtained.

2. 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 polymetallic cation precursor solution is 1h to 2h, and the ultrasonic power is 150W to 200W.

3. 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 precursor self-supporting electrode is 10h~12h, and the ultrasonic power is 150W~200W.

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

5. 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.

6. 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.

7. A polymetallic oxysulfide self-supporting electrode prepared by the preparation method according to any one of claims 1 to 6.

8. The application of a polymetallic oxysulfide self-supporting electrode according to claim 7 in electrocatalytic oxygen evolution.

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