A self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst and its preparation method and application

Abstract

The present invention relates to a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, a preparation method, and an application thereof. The preparation method comprises: step 1, preparing a self-supporting ultrathin cobalt-based nanosheet precursor by a thermal synthesis method; step 2, using the self-supporting ultrathin cobalt-based nanosheet precursor as a working electrode and preparing a self-supporting ultrathin cobalt oxyhydroxide nanosheet by an anodic oxidation method; and step 3, using the self-supporting ultrathin cobalt oxyhydroxide nanosheet as a working electrode to prepare a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, wherein the electrolyte is an aqueous solution containing hydrated ruthenium trichloride. The self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst and preparation method provided by the present invention overcome the problems of low efficiency, high cost, low catalytic activity, poor stability, and difficulty in industrial production.

Description

Technical Field

[0001] The present invention relates to the field of materials and energy technology, and in particular to a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, a preparation method and an application thereof. Background Art

[0002] Finding green, clean energy is one of the key approaches to alleviating the global energy crisis and meeting the demand for renewable energy. Hydrogen is considered an ideal candidate for a new energy source due to its carbon-free nature, high energy density, and renewability. Among various hydrogen production methods, water electrolysis is an effective solution for obtaining clean, high-energy-density hydrogen. Water electrolysis can utilize intermittent solar and wind energy as a starting energy source to produce high-purity hydrogen for use in industrial applications such as fuel cells. However, the two half-reactions of water electrolysis—the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode—are sluggish in electrochemical kinetics, resulting in high energy consumption in practical water electrolysis. Therefore, to lower the catalytic reaction energy barrier and increase the reaction rate, the development of efficient bifunctional catalysts for water electrolysis is necessary. To date, noble metal-based materials, such as platinum, iridium, and ruthenium, have been considered state-of-the-art electrocatalysts for the HER and OER due to their high intrinsic catalytic activity. However, their high price, scarcity, and poor durability have severely hindered their large-scale industrial application. Due to the constraints of precious metal resources, there is an urgent need to develop electrolytic water splitting catalysts with high HER and OER activity that can replace precious metal-based electrocatalysts. However, the selection and design of catalyst materials are difficult problems faced by the field of electrocatalysis. The rational design and preparation of low-cost, high-efficiency dual-functional electrolytic water catalyst materials is full of challenges. Among them, transition metal hydroxides, especially two-dimensional layered co-oxyhydroxide (CoOOH) nanosheets, have attracted widespread attention due to their abundant resources, low cost, high activity at the edge sites, and good catalytic performance in water electrolysis in alkaline media. However, since these two-dimensional nanosheet materials usually tend to stack together, the number of edge active sites is limited, which greatly reduces their catalytic activity; in addition, the voltage required for hydrogen evolution and oxygen evolution reactions of cobalt-based catalysts in practical applications is still relatively high. The above problems will limit the large-scale production and commercial development of such materials in water electrolysis.

[0003] Therefore, how to design and prepare cobalt-based electrocatalyst materials that are highly active, stable, cheap and readily available remains a challenge. Summary of the Invention

[0004] To address the above-mentioned problems in the prior art, the present invention provides a method for preparing a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] One embodiment of the present invention provides a method for preparing a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, the preparation method comprising:

[0006] Step 1: preparing a self-supporting ultrathin cobalt-based nanosheet precursor by a thermal synthesis method;

[0007] Step 2: Using the self-supporting ultra-thin cobalt-based nanosheet precursor as a working electrode, a self-supporting ultra-thin cobalt oxyhydroxide nanosheet is prepared by an anodic oxidation method;

[0008] Step 3: Using the self-supporting ultrathin cobalt oxyhydroxide nanosheets as working electrodes to prepare a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, wherein the electrolyte is an aqueous solution containing hydrated ruthenium trichloride.

[0009] In one embodiment of the present invention, step 1 includes:

[0010] Step 1.1. First, ultrasonically clean the nickel foam with acetone and dilute hydrochloric acid solution, respectively, and then ultrasonically clean it with deionized water and ethanol. After washing, the nickel foam is dried under a vacuum environment to obtain pretreated nickel foam. Cobalt nitrate hexahydrate and hexamethylenetetramine are dissolved in a mixed solvent consisting of deionized water and ethanol, and the mixture is thoroughly stirred to obtain a mixed solution.

[0011] Step 1.2: Immerse the pretreated nickel foam in the mixed solution and place it in a constant temperature oven for reaction. After the reaction is completed, wash it with deionized water and ethanol respectively, and then place it in a drying oven to dry, thereby obtaining a self-supporting ultrathin cobalt-based nanosheet precursor.

[0012] In one embodiment of the present invention, step 1.1 includes:

[0013] First, the nickel foam is ultrasonically washed with acetone and 6 mol dilute hydrochloric acid solution for 30 minutes, respectively, and then ultrasonically cleaned with deionized water and ethanol for 15 minutes. After washing, the nickel foam is vacuum dried at 60°C for 8 hours to obtain pretreated nickel foam; 5 to 100 mmol of cobalt nitrate hexahydrate and 5 to 100 mmol of hexamethylenetetramine are dissolved in a mixed solvent consisting of 30 to 300 mL of deionized water and 5 to 100 mL of ethanol, and the mixture is fully stirred to obtain a mixed solution.

[0014] In one embodiment of the present invention, step 1.2 includes:

[0015] The pretreated nickel foam was immersed in the mixed solution and placed in a constant temperature oven at 90°C to react for 6 to 12 hours. After the reaction, it was washed with deionized water and ethanol respectively, and then placed in a drying oven at 60°C to dry to obtain a self-supporting ultra-thin cobalt-based nanosheet precursor.

[0016] In one embodiment of the present invention, step 2 includes:

[0017] A saturated calomel electrode was used as the reference electrode, a graphite rod was used as the counter electrode, a 1M potassium hydroxide solution was used as the electrolyte, and a self-supporting ultrathin cobalt-based nanosheet precursor was used as the working electrode. Cyclic voltammetry scanning was performed using a three-electrode electrochemical deposition method while stirring with a magnetic stirrer. After the cycle reaction was completed, the obtained product was washed with deionized water and then dried under a vacuum environment to obtain self-supporting ultrathin cobalt oxyhydroxide nanosheets.

[0018] In one embodiment of the present invention, step 2 specifically includes:

[0019] A saturated calomel electrode was used as the reference electrode, a graphite rod was used as the counter electrode, and the electrolyte was 1 M potassium hydroxide solution. The self-supporting ultrathin cobalt-based nanosheet precursor was used as the working electrode. A three-electrode electrochemical deposition method was used to perform cyclic voltammetry scans in the voltage range of 0.3-0.7 V at a scan rate of 5 mV s –1 , and circulate 500 to 2000 times while stirring with a magnetic stirrer. After the cyclic reaction, the obtained product is washed with deionized water and then vacuum dried at 60°C to obtain self-supporting ultra-thin cobalt oxyhydroxide nanosheets.

[0020] In one embodiment of the present invention, step 3 includes:

[0021] A saturated calomel electrode was used as the reference electrode, a platinum sheet was used as the counter electrode, and a self-supporting ultrathin cobalt oxyhydroxide nanosheet was used as the working electrode. The electrolyte was an aqueous solution containing hydrated ruthenium trichloride. Cyclic voltammetry scanning was performed using an electrochemical deposition method with a three-electrode system. After the reaction, the obtained product was rinsed with deionized water and then dried under a vacuum environment to obtain a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst.

[0022] In one embodiment of the present invention, step 3 specifically includes:

[0023] A saturated calomel electrode was used as the reference electrode, a platinum sheet was used as the counter electrode, and a self-supporting ultrathin cobalt oxyhydroxide nanosheet was used as the working electrode. The electrolyte was a 15-100 mL aqueous solution containing 8-50 mg of hydrated ruthenium trichloride. Cyclic voltammetry was performed in the voltage range of -0.5 to 0.4 V using a three-electrode electrochemical deposition method at a scan rate of 20 mV s –1 The scanning number was 20 circles. After the reaction, the obtained product was rinsed with deionized water and then vacuum dried at a temperature of 60°C to obtain a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst.

[0024] One embodiment of the present invention further provides a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, wherein the self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst is prepared using the preparation method described in any of the above embodiments.

[0025] One embodiment of the present invention further provides an application of a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst obtained by the preparation method described in any of the above embodiments in hydrogen and oxygen evolution reactions and total water splitting.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst and preparation method provided by the present invention overcome the problems of low efficiency, high cost, low catalytic activity, poor stability, and difficulty in industrial production. The self-supporting ruthenium / cobalt oxyhydroxide composite material prepared by the present invention not only has strong conductivity, numerous active sites, and excellent electrocatalytic performance, but also has a simple preparation process, low cost, and can be produced on a large scale, representing a new low-cost, high-efficiency preparation method.

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 1 is a schematic flow chart of a method for preparing a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst provided in an embodiment of the present invention;

[0030] Figure 2 This is a scanning electron microscope image of the Ru / CoOOH@NF composite material prepared in Example 2 of the present invention;

[0031] Figure 3 This is a transmission electron microscopy image of the Ru / CoOOH@NF composite material prepared in Example 2 of the present invention;

[0032] Figure 4 This is an X-ray diffraction spectrum analysis diagram of the Ru / CoOOH@NF composite material prepared in Example 2 of the present invention;

[0033] Figure 5 This is a Fourier transform infrared spectrum of the Ru / CoOOH@NF composite material prepared in Example 2 of the present invention;

[0034] Figure 6 This is a linear sweep voltammogram of the HER of the Ru / CoOOH@NF composite material prepared in Example 2 of the present invention in a 1.0 mol / L potassium hydroxide electrolyte at a scan rate of 5 mV / s;

[0035] Figure 7This is a linear sweep voltammogram of the OER of the Ru / CoOOH@NF composite material prepared in Example 2 of the present invention in a 1.0 mol / L potassium hydroxide electrolyte at a scan rate of 5 mV / s;

[0036] Figure 8 Schematic diagram of a full hydrolysis test of the Ru / CoOOH@NF composite material prepared in Example 2 of the present invention in a 1.0 mol / L potassium hydroxide electrolyte at a scan rate of 5 mV / s;

[0037] Figure 9 This is a scanning electron microscope image of the Ru / CoOOH@NF composite material prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0038] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0039] Example 1

[0040] In order to overcome the problems of low efficiency, high cost, low catalytic activity, poor stability and difficulty in industrial production, the present invention provides a method for preparing a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, see Figure 1 , Figure 1 : This is a flow chart of a method for preparing a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst provided in an embodiment of the present invention. The method for preparing a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst provided by the present invention comprises:

[0041] Step 1: preparing a self-supporting ultrathin cobalt-based nanosheet precursor by a thermal synthesis method;

[0042] Step 2: Using the self-supporting ultra-thin cobalt-based nanosheet precursor as a working electrode, a self-supporting ultra-thin cobalt oxyhydroxide nanosheet is prepared by an anodic oxidation method;

[0043] Step 3: Using the self-supporting ultrathin cobalt oxyhydroxide nanosheets as working electrodes to prepare a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, wherein the electrolyte is an aqueous solution containing hydrated ruthenium trichloride.

[0044] The present invention combines Ru with the transition metal Co to create a nanocluster-nanosheet structure that not only exhibits stable mechanical coupling but also combines high conductivity and rapid electron transport. Ru is a more economical and practical alternative to Pt, making it a promising alternative. Furthermore, Ru effectively inhibits the stacking of layered CoOOH nanosheets, fully exposing the catalyst's active sites. The synergistic effect with the CoOOH nanosheets achieves high electrocatalytic efficiency.

[0045] In a specific embodiment, step 1 may specifically include:

[0046] Step 1.1. First, ultrasonically clean the nickel foam with acetone and dilute hydrochloric acid solution, respectively, and then ultrasonically clean it with deionized water and ethanol. After washing, the nickel foam is dried under a vacuum environment to obtain pretreated nickel foam; cobalt nitrate hexahydrate and hexamethylenetetramine are dissolved in a mixed solvent consisting of deionized water and ethanol, and the mixture is thoroughly stirred to obtain a mixed solution.

[0047] Specifically, first, the nickel foam (for example, about 4×5 cm) is ultrasonically washed with acetone and 6 mol dilute hydrochloric acid solution for 30 minutes, respectively, and then further ultrasonically cleaned with deionized water and ethanol for 15 minutes. After washing, the nickel foam is vacuum-dried at 60° C. for 8 hours for standby use to obtain the pretreated nickel foam; 5 to 100 mmol of cobalt nitrate hexahydrate Co(NO3)2·6H2O and 5 to 100 mmol of hexamethylenetetramine (urotropine) are dissolved in a mixed solvent consisting of 30 to 300 mL of deionized water and 5 to 100 mL of ethanol, and the mixture is fully stirred to obtain a mixed solution.

[0048] Step 1.2: Immerse the pretreated nickel foam in the mixed solution and place it in a constant temperature oven for reaction. After the reaction is completed, wash it with deionized water and ethanol respectively, and then place it in a drying oven to dry, thereby obtaining a self-supporting ultrathin cobalt-based nanosheet precursor.

[0049] Specifically, the pretreated nickel foam is immersed in the mixed solution and placed in a constant temperature oven at 90°C to react for 6 to 12 hours. After the reaction is completed, it is taken out, washed with deionized water and ethanol respectively, and then placed in a drying oven at 60°C to obtain a self-supporting ultra-thin cobalt-based nanosheet precursor, namely Co-LDH@NF.

[0050] In a specific embodiment, step 2 may specifically include:

[0051] A saturated calomel electrode was used as the reference electrode, a graphite rod was used as the counter electrode, and the electrolyte was 1M potassium hydroxide solution. The self-supporting ultrathin cobalt-based nanosheet precursor was used as the working electrode. Cyclic voltammetry scanning was performed using a three-electrode electrochemical deposition method while stirring with a magnetic stirrer. After the cycle reaction, the obtained product was washed with deionized water and then dried under a vacuum environment to obtain self-supporting ultrathin cobalt oxyhydroxide nanosheets, namely CoOOH@NF.

[0052] Specifically, a saturated calomel electrode (SCE) was used as the reference electrode, a graphite rod was used as the counter electrode, the electrolyte was 1 M potassium hydroxide solution (70 mL), and the self-supporting ultrathin cobalt-based nanosheet precursor (Co LDH@NF) was used as the working electrode. A three-electrode electrochemical deposition method was used, and cyclic voltammetry was performed in the voltage range of 0.3 to 0.7 V at a scan rate of 5 mVS. –1 , and circulate 500 to 2000 times. The entire cyclic reaction is carried out at room temperature and stirred with a magnetic stirrer. After the cyclic reaction, the obtained product is washed with deionized water and then vacuum dried at 60°C to obtain self-supporting ultra-thin cobalt oxyhydroxide nanosheets.

[0053] In a specific embodiment, step 3 may specifically include:

[0054] A saturated calomel electrode was used as the reference electrode, a platinum sheet was used as the counter electrode, and a self-supporting ultrathin cobalt oxyhydroxide nanosheet (CoOOH@NF) was used as the working electrode. The electrolyte was an aqueous solution containing hydrated ruthenium trichloride. Cyclic voltammetry scanning was performed using a three-electrode electrochemical deposition method. After the reaction, the obtained product was rinsed with deionized water and then dried under a vacuum environment to obtain a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, namely Ru / CoOOH@NF composite material.

[0055] Specifically, a saturated calomel electrode (SCE) was used as a reference electrode, a platinum sheet was used as a counter electrode, and a self-supporting ultrathin cobalt oxyhydroxide nanosheet was used as a working electrode. The electrolyte was a 15-100 mL aqueous solution containing 8-50 mg of hydrated ruthenium trichloride (RuCl3·H2O). A three-electrode electrochemical deposition method was used, and cyclic voltammetry was performed in the voltage range of -0.5 to 0.4 V at a scan rate of 20 mV s –1 The scanning number was 20 circles. After the reaction, the obtained product was rinsed with deionized water and then vacuum dried at a temperature of 60°C to obtain a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst.

[0056] In the Ru / CoOOH@NF composite prepared in this invention, ruthenium clusters are uniformly dispersed on the CoOOH nanosheets, forming a strong interfacial coupling with the cobalt oxyhydroxide, activating a large number of active sites. The Ru / CoOOH@NF composite prepared in this invention exhibits a relatively stable layered structure and a large specific surface area. The porous nickel foam substrate provides a rich three-dimensional network and high conductivity. Furthermore, the ultrathin CoOOH nanosheets are in situ grown on the nickel foam surface. This seamless contact enables faster charge transfer and, to a certain extent, prevents catalyst shedding. The layered structure of CoOOH also provides a rich specific surface area and active sites. Furthermore, these layered transition metal oxyhydroxides typically have a well-defined atomic structure and high activity at edge sites, demonstrating excellent catalytic performance for water splitting in alkaline media. Studies have shown that cobalt-based compounds often undergo surface self-reconstruction during the oxygen evolution reaction (OER), converting in situ to the true OER catalytically active cobalt oxyhydroxide at the OER potential. This unique material offers a richer and more tunable range of active sites when used as an electrocatalyst. Based on this, the present invention uses CoOOH as a precursor, and the prepared Ru / CoOOH@NF composite material can show excellent electrocatalytic performance when used as a bifunctional electrocatalyst for hydrogen and oxygen evolution reactions.

[0057] The present invention uses a two-step electrochemical deposition method to stably obtain uniform and small-sized Ru nanoclusters / nanoparticles. A large number of experiments and theoretical calculations have proved that precious metals have adsorption / desorption free energies closer to zero for the HER reaction intermediate *H, which is very beneficial for optimizing the intrinsic *H adsorption energy of CoOOH. Therefore, the introduction of Ru nanoclusters can effectively activate the surface of CoOOH nanosheets and form more abundant HER active sites. At the same time, the self-supporting 3D nickel foam is used as a matrix to support Ru / CoOOH nanosheets without any polymer binder, which can effectively inhibit the accumulation of nanosheets, thereby facilitating the exposure of the OER active sites of CoOOH itself and promoting the kinetics and durability of the entire catalytic reaction. In addition, even if a higher concentration of ruthenium electroplating solution is used, the target product obtained still has a stable and uniform structure and retains the layered structure of the nanosheets. This further illustrates that the process used in the present invention is simple and stable and can be adjusted according to different requirements.

[0058] The Ru / CoOOH@NF composite material of the present invention undergoes oxidation of the precursor at a voltage range of 0.5 to 1.0 V. The resulting cobalt oxyhydroxide nanosheet structure maintains good mechanical coupling with ruthenium, exhibiting balanced hydrogen and oxygen evolution performance. The wide preparation voltage range provided by the present invention provides more adjustable finite element options, while still maintaining high water electrolysis catalytic efficiency.

[0059] Example 2

[0060] This example provides a method for preparing a bifunctional self-supporting ruthenium / cobalt oxyhydroxide composite electrocatalyst for full water splitting, whose chemical formula is Ru / CoOOH@NF. The specific preparation process is as follows:

[0061] Step 1: Prepare a free-standing ultrathin cobalt-based nanosheet precursor (Co-LDH@NF) using a thermal synthesis method: First, a piece of nickel foam (approximately 4×5 cm) was ultrasonically cleaned with acetone and a 6 mol dilute hydrochloric acid solution for 30 minutes, followed by further ultrasonic cleaning with deionized water and ethanol for 15 minutes. After washing, it was vacuum-dried at 60°C for 8 hours before use. 45 mmol of cobalt nitrate hexahydrate (Co(NO₃)₂·6H₂O) and 35 mmol of hexamethylenetetramine (urotropine) were dissolved in a mixture of 150 mL of deionized water and 50 mL of ethanol and stirred thoroughly to obtain a mixed solution. The pretreated nickel foam was immersed in the mixed solution and placed in a 90°C oven for 6 hours. After the reaction, it was removed, washed with deionized water and ethanol, and then dried in a 60°C drying oven. The resulting product is Co-LDH@NF.

[0062] Step 2: Prepare self-supporting ultrathin cobalt oxyhydroxide nanosheets (CoOOH@NF) by anodic oxidation: A three-electrode electrochemical deposition method was used, with a saturated calomel electrode (SCE) as the reference electrode, a graphite rod as the counter electrode, and a 1 M KOH solution (70 mL) as the electrolyte. Using the Co-LDH@NF obtained in step 1 as the working electrode, cyclic voltammetry was performed in the voltage range of 0.3 to 0.7 V at a scan rate of 5 mV s –1 The reaction mixture was then cycled for 1000 cycles. The entire process was carried out at room temperature and stirred with a magnet. After the cycle was complete, the mixture was removed and washed with deionized water, and then dried under vacuum at 60°C to obtain the CoOOH@NF intermediate.

[0063] Step 3. Preparation of a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst (Ru / CoOOH@NF): A three-electrode electrochemical deposition method was used, with a saturated calomel electrode (SCE) as the reference electrode and a platinum sheet as the counter electrode. The CoOOH@NF obtained in Step 2 was used as the working electrode, and the electrolyte was a 30 mL aqueous solution containing 16 mg of RuCl3·H2O. Cyclic voltammetry was performed in the voltage range of –0.5 to 0.4 V at a scan rate of 20 mV s –1 The scanning number was 20. The obtained Ru / CoOOH@NF was then taken out and rinsed with deionized water, and dried in vacuum at 60°C to obtain the Ru / CoOOH@NF composite material.

[0064] The scanning electron microscope (SEM) image of the composite material prepared in this embodiment is as follows: Figure 2 As shown in FIG, it can be observed that CoOOH nanosheets are evenly covered on the surface of nickel foam, and Ru metal is evenly distributed on the surface of nanosheets in the form of clusters, indicating that the electrochemical deposition process in this preparation method can introduce Ru into the system while retaining the stable structure of CoOOH nanosheets. In order to further observe the existence form of Ru, the material of this example can be observed under a transmission electron microscope (TEM) to have extremely small Ru nanostructures, such as Figure 3 As shown in the figure, Ru nanoclusters are evenly distributed on the nanosheets, with an average particle size of less than 10 nm. In addition, the material obtained in Example 1 was characterized by XRD, FTIR and other phase characteristics, and the results are shown in the figure. Figure 4 and 5 As shown in the figure, due to the strong peak of the substrate nickel foam, the characteristic peak of CoOOH is almost indistinguishable. On the other hand, it is also due to the low crystallinity of CoOOH. However, the peak belonging to Ru at around 38° can be identified, indicating that Ru exists in the form of metal nanoclusters. Furthermore, the Fourier transform infrared spectroscopy of the example sample can clearly see the characteristic vibration peaks belonging to CoOOH, which are located at 573cm –1 and 1569cm –1 , of which 3434cm –1 The peak at is attributed to water (-OH), which is the result of the presence of moisture in the air.

[0065] In a specific embodiment, when the Ru / CoOOH@NF composite material prepared by the present invention is used as a bifunctional catalyst, the specific steps are as follows: the prepared Ru / CoOOH@NF composite material is clamped on a platinum electrode clamp and directly used as a working electrode, a calomel electrode is used as a reference electrode, and a carbon rod is used as a counter electrode. The electrochemical performance of HER and OER is tested in a 1.0M KOH solution at room temperature and pressure. When used for full water splitting, the Ru / CoOOH@NF composite material is directly used as the cathode and anode, respectively, and its full water splitting performance is tested in a saturated 1.0M KOH solution. The test results are as follows Figure 6-Figure 8 As shown, in 1.0M KOH alkaline solution, the material in this embodiment has a –1 At a current density of 1.5 volts, the overpotential of the HER reaction for water electrolysis is only 36 mV, and the overpotential of the OER reaction is 264 mV, which are excellent among products of the same type. When used in a full water decomposition electrolyzer, an ultra-low water decomposition voltage of 1.54 V can be achieved, which reveals that the Ru / CoOOH@NF composite material prepared by the present invention can maintain a high water electrolysis efficiency while using a low content of precious metals.

[0066] The advantages of the present invention are: (1) in the prepared Ru / CoOOH@NF composite material, metallic ruthenium clusters are uniformly dispersed on the CoOOH nanosheets, forming a strong interfacial coupling effect with the cobalt oxyhydroxide, activating a large number of active sites; (2) the Ru / CoOOH@NF composite material has a relatively stable layered structure and a large specific surface area, which enables it to maintain high catalytic activity, excellent stability and excellent conductivity in electrocatalytic applications; (3) the Ru / CoOOH@NF composite material in this embodiment shows excellent electrocatalytic properties when used as a bifunctional electrocatalyst for hydrogen and oxygen evolution reactions (HER overpotential: η in 1.0 M KOH solution: 10 mA cm -2 =36mV, OER overpotential: η 10 mA cm -2 =264mV) and showed efficient full water splitting ability (in 1.0M KOH solution, η 10 mA cm -2 =1.54V).

[0067] Example 3

[0068] This embodiment provides a preparation method and application of a self-supporting ruthenium / cobalt composite material Ru / CoOOH@NF (Ru / CoOOH@NF-1). The specific preparation process is as follows:

[0069] Step 1: Preparation of a self-supporting ultrathin cobalt-based nanosheet precursor (Co-LDH@NF): Nickel foam (approximately 4 × 5 cm) was ultrasonically cleaned with acetone and a 6 mol dilute hydrochloric acid solution for 30 minutes, followed by further ultrasonic cleaning with deionized water and ethanol for 15 minutes. After washing, it was vacuum-dried at 60°C for 8 hours. 45 mmol of cobalt nitrate hexahydrate (Co(NO₃)₂·6H₂O) and 35 mmol of hexamethylenetetramine (urotropine) were dissolved in a mixture of 150 mL of deionized water and 50 mL of ethanol and stirred thoroughly to obtain a mixed solution. The pretreated nickel foam was immersed in the above solution and placed in a 90°C constant temperature oven for 6 hours. After the reaction, it was removed, washed with deionized water and ethanol, and then dried in a 60°C drying oven. The resulting product is Co-LDH@NF.

[0070] Step 2: Prepare self-supporting ultrathin cobalt oxyhydroxide nanosheets (CoOOH@NF) by electrochemical deposition: In a three-electrode system, electrochemical deposition was used, with a saturated calomel electrode (SCE) as the reference electrode, a graphite rod as the counter electrode, and a 1 M KOH solution (70 mL) as the electrolyte. The Co-LDH@NF obtained in step 1 was used as the working electrode, and cyclic voltammetry was performed in the voltage range of 0.3 to 0.7 V at a scan rate of 5 mV s–1 The reaction mixture was then cycled 1000 times. The entire process was carried out at room temperature and stirred with a magnet. After the cycle was complete, the mixture was removed and washed with deionized water, and then dried under vacuum at 60°C to obtain the CoOOH@NF intermediate.

[0071] Step 3. Preparation of a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst (Ru / CoOOH@NF): A three-electrode electrochemical deposition method was used, with a saturated calomel electrode (SCE) as the reference electrode and a platinum sheet as the counter electrode. The CoOOH@NF obtained in Step 2 was used as the working electrode, and the electrolyte was a 30 mL aqueous solution containing 8 mg of RuCl3·H2O. Cyclic voltammetry was performed in the voltage range of –0.5 to 0.4 V at a scan rate of 20 mV s –1 , the number of scanning circles is 20. The obtained Ru / CoOOH@NF was then taken out and rinsed with deionized water, and vacuum dried at 60°C to obtain a Ru / CoOOH@NF composite material. The material in this example reduced the amount of Ru and was characterized by SEM. Figure 9 As shown, the CoOOH nanosheets in this embodiment still maintain a stable structure, and no obvious Ru clusters are observed under the observation magnification of SEM. This is because the initial amount of Ru is reduced, and Ru is not easy to form obvious clusters during the deposition process.

[0072] In one specific embodiment, the Ru / CoOOH@NF composite prepared according to the present invention was used as a bifunctional catalyst by sandwiching the prepared Ru / CoOOH@NF composite between a platinum electrode holder as the working electrode, using a calomel electrode as the reference electrode, and a carbon rod as the counter electrode. The electrochemical performance of the composite for HER and OER was tested in a 1.0 M KOH solution at room temperature and pressure. For water splitting, the Ru / CoOOH@NF composite was used directly as the cathode and anode, respectively, and its water splitting performance was tested in a saturated 1.0 M KOH solution.

[0073] The Ru / CoOOH@NF-1 composite material of this embodiment showed excellent electrocatalytic properties when used as an electrocatalyst for hydrogen and oxygen evolution reactions (HER overpotential: η in 1.0 M KOH solution). 10 mA cm -2 =76mV, OER overpotential: η 10 mAcm -2 =300mV). The electrochemical deposition method used in this embodiment can stably obtain uniform and small-sized Ru nanoclusters / nanoparticles. Moreover, the addition of a small amount of ruthenium activates more active sites on the CoOOH nanosheets, giving the composite material advantages such as good mechanical stability, strong conductivity, and excellent electrocatalytic performance.

[0074] Example 4

[0075] This embodiment provides a preparation method and application of a self-supporting ruthenium / cobalt composite material Ru / CoOOH@NF (Ru / CoOOH@NF-2). The specific preparation process is as follows:

[0076] Step 1: Preparation of self-supporting ultrathin cobalt-based nanosheet precursor (Co-LDH@NF): Nickel foam (approximately 4×5 cm) was ultrasonically cleaned with acetone and 6 mol dilute hydrochloric acid solution for 30 minutes, respectively. It was further ultrasonically cleaned with deionized water and ethanol for 15 minutes. After washing, it was vacuum-dried at 60°C for 8 hours before use. 45 mmol of cobalt nitrate hexahydrate (Co(NO3)2·6H2O) and 35 mmol of hexamethylenetetramine (urotropine) were weighed and dissolved in a mixed solvent of 150 mL of deionized water and 50 mL of ethanol, and stirred thoroughly. The pretreated nickel foam was immersed in the above solution and placed in a constant temperature oven at 90°C for 6 hours. After the reaction, it was removed, washed with deionized water and ethanol, and dried to obtain the product, Co-LDH@NF.

[0077] Step 2: Prepare self-supporting ultrathin cobalt oxyhydroxide nanosheets (CoOOH@NF) by electrochemical deposition: In a three-electrode system, electrochemical deposition was used, with a saturated calomel electrode (SCE) as the reference electrode, a graphite rod as the counter electrode, and a 1 M KOH solution (70 mL) as the electrolyte. The Co-LDH@NF obtained in step 1 was used as the working electrode, and cyclic voltammetry was performed in the voltage range of 0.3 to 0.7 V at a scan rate of 5 mV s –1 , and cycled 1000 times. The entire process was carried out at room temperature and stirred with a magnet. After the cycle was completed, the product was taken out and washed with deionized water, and then vacuum-dried at 60°C to obtain the CoOOH@NF intermediate.

[0078] Step 3. Preparation of a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst (Ru / CoOOH@NF): A three-electrode electrochemical deposition method was used, with a saturated calomel electrode (SCE) as the reference electrode and a platinum sheet as the counter electrode. The CoOOH@NF obtained in Step 2 was used as the working electrode, and the electrolyte was a 30 mL aqueous solution containing 32 mg of RuCl3·H2O. Cyclic voltammetry was performed in the voltage range of –0.5 to 0.4 V at a scan rate of 20 mV s –1 The scanning cycle was 20 and the electrodeposition time was 30 minutes. The obtained Ru / CoOOH@NF was then taken out and rinsed with deionized water, and vacuum dried at 60°C to obtain the Ru / CoOOH@NF composite material.

[0079] In one specific embodiment, the Ru / CoOOH@NF composite prepared according to the present invention was used as a bifunctional catalyst by sandwiching the prepared Ru / CoOOH@NF composite between a platinum electrode holder as the working electrode, using a calomel electrode as the reference electrode, and a carbon rod as the counter electrode. The electrochemical performance of the composite for HER and OER was tested in a 1.0 M KOH solution at room temperature and pressure. For water splitting, the Ru / CoOOH@NF composite was used directly as the cathode and anode, respectively, and its water splitting performance was tested in a saturated 1.0 M KOH solution.

[0080] The Ru / CoOOH@NF-2 composite material in this embodiment showed excellent electrocatalytic performance when used as an electrocatalyst for hydrogen and oxygen evolution reactions (HER overpotential: η in 1.0 M KOH solution). 10 mA cm -2 =48mV, OER overpotential: η 10 mA cm -2 =308mV). Due to the increased ruthenium content, the composite electrocatalyst in this embodiment activates more active sites, significantly improving hydrogen evolution reaction performance and achieving even better water electrolysis catalytic performance. Furthermore, even when a high ruthenium content electroplating solution is used, the resulting target product still has a stable and uniform structure, preserving the layered structure of the nanosheets. This further demonstrates that the process used in the present invention is simple and stable, and can be adjusted to meet different requirements.

[0081] Example 5

[0082] This embodiment provides a preparation method and application of a self-supporting ruthenium / cobalt composite material Ru / CoOOH@NF (Ru / CoOOH@NF-3). The specific preparation process is as follows:

[0083] Step 1: Preparation of self-supporting ultrathin cobalt-based nanosheet precursor (Co-LDH@NF): Nickel foam (approximately 4×5 cm) was ultrasonically cleaned with acetone and 6 mol dilute hydrochloric acid solution for 30 minutes, respectively. It was further ultrasonically cleaned with deionized water and ethanol for 15 minutes. After washing, it was vacuum-dried at 60°C for 8 hours. 45 mmol of cobalt nitrate hexahydrate (Co(NO3)2·6H2O) and 35 mmol of hexamethylenetetramine (urotropine) were weighed and dissolved in a mixed solvent of 150 mL of deionized water and 50 mL of ethanol, and stirred thoroughly. The pretreated nickel foam was immersed in the above solution and placed in a constant temperature oven at 90°C for 6 hours. After the reaction, it was washed with deionized water and ethanol, respectively, and dried to obtain the product, Co-LDH@NF.

[0084] Step 2: Prepare self-supporting ultrathin cobalt oxyhydroxide nanosheets (CoOOH@NF) by electrochemical deposition: In a three-electrode system, a saturated calomel electrode (SCE) was used as the reference electrode, a graphite rod was used as the counter electrode, and the electrolyte was 1 M KOH solution (70 mL). The Co-LDH@NF obtained in step 1 was used as the working electrode, and cyclic voltammetry was performed in the voltage range of 0-0.5 V at a scan rate of 5 mV s –1 After the reaction, the nickel foam was removed and washed with deionized water, and then dried under vacuum at 60°C to obtain the CoOOH@NF intermediate.

[0085] Step 3. Preparation of a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst (Ru / CoOOH@NF): A three-electrode electrochemical deposition method was used, with a saturated calomel electrode (SCE) as the reference electrode and a platinum sheet as the counter electrode. The CoOOH@NF obtained in Step 2 was used as the working electrode, and the electrolyte was a 30 mL aqueous solution containing 16 mg of RuCl3·H2O. Cyclic voltammetry was performed in the voltage range of –0.5 to 0.4 V at a scan rate of 20 mV s –1 The scanning cycle was 20 and the electrodeposition time was 30 minutes. The obtained Ru / CoOOH@NF was then taken out and rinsed with deionized water, and vacuum dried at 60°C to obtain the Ru / CoOOH@NF composite material.

[0086] The Ru / CoOOH@NF composite prepared by the present invention is used as a bifunctional catalyst in the following specific steps: the Ru / CoOOH@NF composite is clamped between a platinum electrode holder and used directly as the working electrode, a calomel electrode is used as the reference electrode, and a carbon rod is used as the counter electrode. The electrochemical performance of the Ru / CoOOH@NF composite for the HER and OER reactions is tested in a 1.0M KOH solution at room temperature and pressure. For water splitting, the Ru / CoOOH@NF composite is used directly as the cathode and anode, respectively, and its water splitting performance is tested in a saturated 1.0M KOH solution.

[0087] The Ru / CoOOH@NF-3 composite material in this embodiment has a hydrogen evolution reaction (HER) overpotential of η in a 1.0 M KOH solution: 10 mA cm -2 =54mV, oxygen evolution reaction (OER) overpotential: η 10 mA cm -2 =287mV, showing excellent hydrogen and oxygen evolution performance. In addition, a stable cobalt nanosheet structure can still be obtained in the voltage range of 0-0.5V, which further demonstrates the strong process adjustability of the present invention and the excellent mechanical stability of the product.

[0088] Example 6

[0089] This embodiment provides a preparation method and application of a self-supporting ruthenium / cobalt composite material Ru / CoOOH@NF (Ru / CoOOH@NF-4). The specific preparation process is as follows:

[0090] Step 1: Preparation of a self-supporting ultrathin cobalt-based nanosheet precursor (Co-LDH@NF): Nickel foam (approximately 4 × 5 cm) was ultrasonically cleaned with acetone and a 6 mol dilute hydrochloric acid solution for 30 minutes, followed by further ultrasonic cleaning with deionized water and ethanol for 15 minutes. After washing, it was vacuum-dried at 60°C for 8 hours. 90 mmol of cobalt nitrate hexahydrate (Co(NO₃)₂·6H₂O) and 35 mmol of hexamethylenetetramine (urotropine) were dissolved in a mixture of 150 mL of deionized water and 50 mL of ethanol and stirred thoroughly to obtain a mixed solution. The pretreated nickel foam was immersed in the above solution and placed in a 90°C constant temperature oven for 6 hours. After the reaction, it was removed, washed with deionized water and ethanol, and then dried in a 60°C drying oven. The resulting product is Co-LDH@NF.

[0091] Step 2: Prepare self-supporting ultrathin cobalt oxyhydroxide nanosheets (CoOOH@NF) by electrochemical deposition: In a three-electrode system, a saturated calomel electrode (SCE) was used as the reference electrode, a graphite rod was used as the counter electrode, and the electrolyte was 1 M KOH solution (70 mL). The Co-LDH@NF obtained in step 1 was used as the working electrode, and cyclic voltammetry was performed in the voltage range of 0.3 to 0.7 V at a scan rate of 5 mV s –1 After the reaction, the nickel foam was removed and washed with deionized water, and then dried under vacuum at 60°C to obtain the CoOOH@NF intermediate.

[0092] Step 3. Preparation of a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst (Ru / CoOOH@NF): A three-electrode electrochemical deposition method was used, with a saturated calomel electrode (SCE) as the reference electrode and a platinum sheet as the counter electrode. The CoOOH@NF obtained in Step 2 was used as the working electrode, and the electrolyte was a 30 mL aqueous solution containing 16 mg of RuCl3·H2O. Cyclic voltammetry was performed in the voltage range of –0.5 to 0.4 V at a scan rate of 20 mV s –1 The scanning cycle was 20. The Ru / CoOOH@NF was then removed and rinsed with deionized water, and dried in a vacuum at 60°C. This yielded the Ru / CoOOH@NF composite material.

[0093] The Ru / CoOOH@NF composite prepared by the present invention is used as a bifunctional catalyst in the following specific steps: the Ru / CoOOH@NF composite is clamped between a platinum electrode holder and used directly as the working electrode, a calomel electrode is used as the reference electrode, and a carbon rod is used as the counter electrode. The electrochemical performance of the Ru / CoOOH@NF composite for the HER and OER reactions is tested in a 1.0M KOH solution at room temperature and pressure. For water splitting, the Ru / CoOOH@NF composite is used directly as the cathode and anode, respectively, and its water splitting performance is tested in a saturated 1.0M KOH solution.

[0094] The Ru / CoOOH@NF-3 composite material in this embodiment undergoes oxidation reaction on the precursor in the voltage range of 0.5-1.0 V. The obtained cobalt oxyhydroxide nanosheet structure still has good mechanical coupling with ruthenium. In 1.0 M KOH solution, the hydrogen evolution reaction HER overpotential is: η 10 mA cm -2 =62mV, oxygen evolution reaction (OER) overpotential: η 10 mA cm -2 =292mV, showing balanced hydrogen and oxygen evolution performance. This example shows that the wide preparation voltage range provided by this patent provides more adjustable space for the product, and the obtained product still has high water electrolysis catalytic efficiency.

[0095] An embodiment of the present invention further provides a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, which is prepared using the preparation method of any of the above embodiments.

[0096] The embodiments of the present invention also provide the use of the prepared self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst in hydrogen and oxygen evolution reactions and overall water decomposition.

[0097] As for the embodiments of the self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst and its application, since they are basically similar to the embodiments of the preparation method, the description is relatively simple, and the relevant parts can be referred to the partial description of the embodiments of the preparation method.

[0098] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0099] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0100] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art can understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0101] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For those skilled in the art of the present invention, any modifications made without departing from the concept of the present invention should be deemed to fall within the scope of protection of the present invention.

Claims

1. A method for preparing a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, characterized in that: The preparation method comprises: Step 1: preparing a self-supporting ultrathin cobalt-based nanosheet precursor by a thermal synthesis method; Step 2: Using the self-supporting ultra-thin cobalt-based nanosheet precursor as a working electrode, a self-supporting ultra-thin cobalt oxyhydroxide nanosheet is prepared by an anodic oxidation method; Step 3: Using the self-supporting ultrathin cobalt oxyhydroxide nanosheets as working electrodes to prepare a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, wherein the electrolyte is an aqueous solution containing hydrated ruthenium trichloride.

2. The method for preparing the self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst according to claim 1, characterized in that: The step 1 comprises: Step 1.

1. First, ultrasonically clean the nickel foam with acetone and dilute hydrochloric acid solution, respectively, and then ultrasonically clean it with deionized water and ethanol. After washing, the nickel foam is dried under a vacuum environment to obtain pretreated nickel foam. Cobalt nitrate hexahydrate and hexamethylenetetramine are dissolved in a mixed solvent consisting of deionized water and ethanol, and the mixture is thoroughly stirred to obtain a mixed solution. Step 1.2: Immerse the pretreated nickel foam in the mixed solution and place it in a constant temperature oven for reaction. After the reaction is completed, wash it with deionized water and ethanol respectively, and then place it in a drying oven to dry, thereby obtaining a self-supporting ultrathin cobalt-based nanosheet precursor.

3. The method for preparing the self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst according to claim 2, characterized in that: The step 1.1 includes: First, the nickel foam is ultrasonically washed with acetone and 6 mol dilute hydrochloric acid solution for 30 minutes, respectively, and then ultrasonically cleaned with deionized water and ethanol for 15 minutes. After washing, the nickel foam is vacuum dried at 60°C for 8 hours to obtain pretreated nickel foam; 5 to 100 mmol of cobalt nitrate hexahydrate and 5 to 100 mmol of hexamethylenetetramine are dissolved in a mixed solvent consisting of 30 to 300 mL of deionized water and 5 to 100 mL of ethanol, and the mixture is fully stirred to obtain a mixed solution.

4. The method for preparing the self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst according to claim 2, characterized in that: The step 1.2 includes: The pretreated nickel foam was immersed in the mixed solution and placed in a constant temperature oven at 90°C to react for 6 to 12 hours. After the reaction, it was washed with deionized water and ethanol respectively, and then placed in a drying oven at 60°C to dry to obtain a self-supporting ultra-thin cobalt-based nanosheet precursor.

5. The method for preparing the self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst according to claim 1, characterized in that: The step 2 includes: A saturated calomel electrode was used as the reference electrode, a graphite rod was used as the counter electrode, a 1M potassium hydroxide solution was used as the electrolyte, and a self-supporting ultrathin cobalt-based nanosheet precursor was used as the working electrode. Cyclic voltammetry scanning was performed using a three-electrode electrochemical deposition method while stirring with a magnetic stirrer. After the cycle reaction was completed, the obtained product was washed with deionized water and then dried under a vacuum environment to obtain self-supporting ultrathin cobalt oxyhydroxide nanosheets.

6. The method for preparing the self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst according to claim 5, characterized in that: The step 2 specifically includes: A saturated calomel electrode was used as the reference electrode, a graphite rod was used as the counter electrode, and the electrolyte was 1 M potassium hydroxide solution. The self-supporting ultrathin cobalt-based nanosheet precursor was used as the working electrode. A three-electrode electrochemical deposition method was used to perform cyclic voltammetry scans in the voltage range of 0.3-0.7 V at a scan rate of 5 mV s -1 , and circulate 500 to 2000 times while stirring with a magnetic stirrer. After the cyclic reaction, the obtained product is washed with deionized water and then vacuum dried at 60°C to obtain self-supporting ultra-thin cobalt oxyhydroxide nanosheets.

7. The method for preparing the self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst according to claim 1, characterized in that: The step 3 includes: A saturated calomel electrode was used as the reference electrode, a platinum sheet was used as the counter electrode, and a self-supporting ultrathin cobalt oxyhydroxide nanosheet was used as the working electrode. The electrolyte was an aqueous solution containing hydrated ruthenium trichloride. Cyclic voltammetry scanning was performed using an electrochemical deposition method with a three-electrode system. After the reaction, the obtained product was rinsed with deionized water and then dried under a vacuum environment to obtain a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst.

8. The method for preparing the self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst according to claim 7, characterized in that: The step 3 specifically includes: A saturated calomel electrode was used as the reference electrode, a platinum sheet was used as the counter electrode, and a self-supporting ultrathin cobalt oxyhydroxide nanosheet was used as the working electrode. The electrolyte was a 15-100 mL aqueous solution containing 8-50 mg of hydrated ruthenium trichloride. Cyclic voltammetry was performed in the voltage range of -0.5 to 0.4 V using a three-electrode electrochemical deposition method at a scan rate of 20 mV s -1 The scanning number was 20 circles. After the reaction, the obtained product was rinsed with deionized water and then vacuum dried at a temperature of 60°C to obtain a self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst.

9. A self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst, characterized in that: The self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst is prepared using the preparation method according to any one of claims 1 to 8.

10. Use of the self-supporting ruthenium / cobalt oxyhydroxide electrocatalyst obtained by the preparation method according to any one of claims 1 to 8 in hydrogen and oxygen evolution reactions or total water decomposition reactions.

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