A ruthenium-nickel based bifunctional self-supporting electrode, its preparation method and application

Abstract

This invention discloses a ruthenium-nickel-based bifunctional self-supporting electrode, its preparation method, and its applications. The method includes preparing a deposition electrolyte using nickel chloride hexahydrate, ruthenium chloride, terephthalic acid, and triethylamine hydrochloride as solutes and N-dimethylformamide as a solvent; immersing pretreated nickel foam in the electrolyte as the working electrode, using a platinum mesh as the counter electrode and an Ag / AgCl electrode as the reference electrode, and applying a current of -10mA to -20mA for deposition; after electrodeposition, washing the loaded nickel foam with DMF, ultrapure water, and ethanol, and then vacuum drying to obtain the ruthenium-nickel-based bifunctional self-supporting electrode. The ruthenium-nickel-based self-supporting bifunctional electrocatalyst provided by this invention can be used for water splitting reactions, exhibiting both good HER and OER activities, and can achieve high hydrogen evolution and oxygen evolution current densities at relatively low overpotentials.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation, specifically relating to a ruthenium-nickel based bifunctional self-supporting electrode, its preparation method, and its application. Background Technology

[0002] Water electrolysis is an efficient and sustainable method for obtaining high-purity hydrogen from abundant water resources. Designing a stable and efficient bifunctional catalyst for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is crucial for the development of hydrogen production technology. Currently, noble metal catalysts (such as Pt and RuO2) exhibit the best catalytic performance in water electrolysis. However, the high cost and poor stability of noble metals severely restrict their industrial production and application. Therefore, reducing cost and improving durability are the focus of this catalyst research. Ruthenium (Ru), due to its Pt-like electronic structure and relatively low price, is considered the most promising active material among noble metals. Therefore, introducing Ru dopants into transition metal nickel-based compounds is significant for the design, development, and performance optimization of self-supporting electrode materials. However, current research focuses more on developing monofunctional catalysts for HER or OER, requiring the design of two different types of catalysts in practical applications, increasing the complexity of water electrolysis equipment. For example, Chinese patent document (application number 202210267431.9) discloses a foamed nickel-supported Ru-NiO hydrogen evolution reaction catalyst and its preparation method. It uses nickel nitrate hexahydrate as the nickel source, urea and ammonium fluoride as structure directing agents, and water as the solvent. The support is immersed in the solution for a hydrothermal reaction to generate nickel hydroxide on the surface of the foamed nickel. Then, ruthenium is electrodeposited in an aqueous ruthenium trichloride solution to load ruthenium onto the surface of the nickel hydroxide. Finally, calcination converts the nickel hydroxide into nickel oxide. However, due to the limited exposure of active sites, the catalytic performance is poor. A few studies have shown excellent bifunctional electrocatalysis for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). For example, the successful assembly of a solar-driven alkaline electrolyzer in the paper "Inter-doped ruthenium–nickel oxide heterostructure nanosheets with dual active centers for electrochemical- / solar-driven overall water splitting" provides more active sites for the application of (Ru-Ni)Ox electrocatalysts, but it cannot catalyze at high current densities, limiting its industrial application. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a ruthenium nickel-based bifunctional self-supporting electrode, its preparation method and application, wherein the electrode provided has both good HER activity and OER activity.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] This invention provides a method for fabricating a ruthenium-nickel-based bifunctional self-supporting electrode, comprising the following steps:

[0006] Preparation of deposition electrolyte: The deposition electrolyte was prepared using N,N-dimethylformamide (DMF) as solvent and nickel chloride hexahydrate, ruthenium chloride, terephthalic acid and triethylamine hydrochloride as solutes.

[0007] To improve the convenience and efficiency of electrolyte preparation, the preferred method for preparing the deposition electrolyte includes the following steps: first, dissolve nickel chloride hexahydrate, ruthenium chloride, terephthalic acid, and triethylamine hydrochloride in N,N-dimethylformamide (dissolution can be accelerated by agitation, such as stirring or ultrasonic treatment), to obtain a mixed solution; then, mix the mixed solution with a ruthenium chloride DMF solution until homogeneous to obtain the deposition electrolyte.

[0008] The calculated molar ratio of Ni to Ru in the deposition electrolyte is 1:0.0025–0.007, the concentration of terephthalic acid is approximately 0.1–0.3 mol / L, the concentration of triethylamine hydrochloride is approximately 0.008–0.015 mol / L, and the concentration of nickel chloride hexahydrate is 0.1–0.4 mol / L.

[0009] Electrodeposition: The nickel foam with the oxide layer removed from the surface is immersed in the electrolyte as the working electrode, a platinum mesh is used as the counter electrode, and an Ag / AgCl electrode is used as the reference electrode. A current of -10mA to -20mA is applied to deposit the nickel foam for 58 to 62 minutes (preferably 60 minutes) to obtain loaded nickel foam.

[0010] After electrodeposition, the loaded nickel foam was washed with DMF, ultrapure water and ethanol, and then dried under vacuum to obtain a ruthenium-nickel based bifunctional self-supporting electrode.

[0011] This invention is based on a three-electrode deposition method, combined with the control of the Ni / Ru molar ratio and the concentration of triethylamine hydrochloride in the electrolyte, to prepare a ruthenium-nickel-based bifunctional self-supporting electrode that has both good HER and OER activities, and can achieve a large hydrogen evolution and oxygen evolution current density at a low overpotential.

[0012] As a preferred embodiment of the preparation method described in this invention, the method for removing the oxide layer from the surface of the nickel foam includes immersing the nickel foam in a solution of 2-3 mol / L hydrochloric acid, ultrapure water and ethanol in sequence and sonicating for 15-20 minutes.

[0013] In a preferred embodiment of the preparation method described in this invention, the deposition current is 10–15 mA, and the molar ratio of Ni to Ru in the deposition electrolyte is 1:0.0025–0.004.

[0014] More preferably, the deposition current is 18-20 mA, and the molar ratio of Ni to Ru in the deposition electrolyte is 1:0.0045-0.0055.

[0015] Another objective of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a ruthenium-nickel-based bifunctional self-supporting electrode, which yields a ruthenium-nickel-based bifunctional self-supporting electrode (also referred to in this invention as a ruthenium-nickel-based bifunctional self-supporting catalytic material or a ruthenium-nickel-based bifunctional self-supporting catalyst).

[0016] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of a ruthenium-nickel-based bifunctional self-supporting electrode in electrochemical water desorption of hydrogen and oxygen evolution.

[0017] Beneficial effects of this invention:

[0018] (1) The ruthenium nickel-based bifunctional self-supporting catalytic material prepared by this invention has HER catalytic activity comparable to commercial Pt / C under both acidic and alkaline conditions, and its price is significantly lower than that of commercial Pt / C.

[0019] (2) The ruthenium-nickel based bifunctional self-supporting catalytic material prepared by the present invention has excellent catalytic performance and is in line with the concept of green development. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0021] Figure 1 This is an activity diagram of the ruthenium-nickel-based bifunctional self-supporting electrode HER in an embodiment of the present invention.

[0022] Figure 2 This is an activity diagram of the ruthenium-nickel based bifunctional self-supporting electrode OER in an embodiment of the present invention.

[0023] Figure 3 This is a SEM image of the morphology of the ruthenium-nickel based bifunctional self-supporting electrode 0.5RuNi / NF-20 in Example 6 of the present invention.

[0024] Figure 4 This is a comparison diagram of deposition between Example 6 and Comparative Example 2 of the present invention.

[0025] Figure 5 The HER catalytic durability curves of a ruthenium-nickel based bifunctional self-supporting electrode, tested using the CP method, are shown.

[0026] Figure 6The OER catalytic durability curves of the ruthenium-nickel based bifunctional self-supporting electrode, tested using the CP method. Detailed Implementation

[0027] To further understand the purpose, content, and advantages of this invention, specific embodiments of the invention are described in detail below. However, these embodiments are not limited to the examples described below and should be freely combined according to actual circumstances. The endpoints and values ​​of the ranges disclosed herein are not limited to the precise ranges and values. For numerical ranges, endpoint values ​​of various ranges, endpoint values ​​of various ranges and individual point values, and individual point values ​​can be combined to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0028] This invention provides a ruthenium-nickel-based bifunctional self-supporting electrode, its preparation method, and its application. The specific preparation method of the catalyst includes the following:

[0029] (1) Preparation of pretreated nickel foam: Nickel foam was sequentially immersed in 2-3 mol / L hydrochloric acid, ultrapure water and ethanol solution and sonicated for 15-20 minutes to obtain pretreated nickel foam; the size of the nickel foam was 1.0 × 2 cm. 2 ~1.0×2.5cm 2 (The dimensions used in the example are 1×2cm) 2 The nickel foam is sourced from Suzhou Shengernuo Technology Co., Ltd.

[0030] (2) Preparation of electrolyte: Nickel chloride hexahydrate (NiCl2·6H2O), terephthalic acid (PTA), and triethylamine hydrochloride (Et3NHCl) are dissolved in N,N-dimethylformamide (DMF), and then stirred until fully dissolved (a commonly used stirring method in the art can be used; in this embodiment, the solution is first stirred for 30 min, and then sonicated in an ultrasonic bath for 120 min) to obtain a DMF mixed solution. The amount of NiCl2·6H2O added is calculated to be 0.1 mol / L (molar amount of NiCl2·6H2O / DMF volume; the concentration can be from 0.1 to 0.4 mol / L). The concentration can fluctuate within the range of 0.1 mol / L and has little impact on electrode performance. In this embodiment of the invention, 0.1 mol / L is selected. The amount of terephthalic acid added is calculated as 0.1 mol / L (molar amount of terephthalic acid / volume of DMF). The concentration can fluctuate within the range of 0.1 to 0.3 mol / L and has little impact on electrode performance. In this embodiment of the invention, 0.1 mol / L is selected. The amount of triethylamine hydrochloride added is calculated as 0.01 mol / L (molar amount of triethylamine hydrochloride / volume of DMF). When the amount added is 0.008 to 0.015 mol / L, the impact on electrode performance is small.

[0031] Take 20 ml of the above DMF mixed solution and 0.3-0.7 mL of ruthenium chloride DMF solution with a concentration of 0.02 mol / L, mix them evenly to obtain the deposition electrolyte. To facilitate faster mixing, a trace amount of ultrapure water can be added before mixing, or the ruthenium chloride solution can be further diluted. In the following examples, 0.65 mL of ultrapure water was added.

[0032] (3) Preparation of ruthenium nickel-based self-supporting bifunctional electrolytic water electrolysis catalytic electrode material with ampere-level current density: The pretreated foamed nickel was immersed in the electrolyte as the working electrode, a platinum mesh was selected as the counter electrode, and an Ag / AgCl electrode was used as the reference electrode. Different currents were applied and deposited for 1 hour using the three-electrode system chronopotential method (CP) to obtain loaded foamed nickel (the platinum mesh was sourced from Shanghai Leton Industrial Co., Ltd., and the electrodeposition voltage was 1-8V, which was DC).

[0033] After electrodeposition, the loaded nickel foam is repeatedly washed with DMF, ultrapure water and ethanol, and then vacuum dried (time 4-6 hours, temperature 50-60℃) to obtain the electrode material.

[0034] (4) The prepared catalyst was subjected to electrochemical testing using a three-electrode electrolyzer to test its hydrogen desorption performance from water.

[0035] Electrochemical water splitting performance evaluation: Tested using the Donghua Electrochemical Workstation.

[0036] In the three-electrode system, the working electrode is a loaded nickel foam, the reference electrode is an Ag / AgCl electrode, and the counter electrode is a platinum mesh.

[0037] Among them, the three-electrode system studies the two half-reactions of water electrolysis, including the reduction reaction at the cathode to produce hydrogen and the oxidation reaction at the anode to produce oxygen.

[0038] The device was tested at room temperature and pressure using 1M KOH as the electrolyte.

[0039] The performance of HER / OER was tested within a suitable potential range (-1 to -3V) using the linear sweep method (LSV).

[0040] Subsequently, CV curves were continuously tested at different scan rates (-2 to -3V);

[0041] Finally, the catalyst impedance was tested using a current density of 500 / 1000 mA / cm² based on the macroscopic area of ​​the electrode. -2 As an indicator for evaluating the hydrogen evolution reaction (HER) catalytic activity of this catalyst; the current density based on the macroscopic area of ​​the electrode is 500 / 800 mA / cm². -2 This serves as an indicator for evaluating the oxygen evolution reaction (OER) catalytic activity of the catalyst.

[0042] In this embodiment of the invention, the deposition effect is sensitive to the deposition time. When the deposition time fluctuates between 58 and 62 minutes, the impact on the deposition effect is small, and the impact on performance is generally within ±2%. However, exceeding this time will have a significant impact on product performance (generally more than ±5%).

[0043] In this embodiment of the invention, when the deposition current is 18-20 mA, the product performance obtained with a Ni:Ru molar ratio of 1:0.0045-0.0055 in the deposition electrolyte is relatively superior. Compared with the electrode with pure Ni without ruthenium doping (see the preferred embodiment of the electrode NiOx / NF-15 prepared in the prior patent application No. 202411507889.2, where the preferred embodiment has the most optimized parameters), the HER activity and OER activity (for OER, a driving current of 500 / 800 mA cm⁻¹ in 1M KOH electrolyte) are significantly better. -2 The overpotentials at current densities of 530 mV and 600 mV were significantly increased. For HER, a driving current density of 500 / 1000 mA cm⁻¹ in 1 M KOH electrolyte was also significantly increased. -2 The overpotentials at current densities were below 150 mV and 160 mV, respectively; for OER, a driving current of 500 / 800 mA cm⁻¹ in 1 M KOH electrolyte was achieved. -2 The overpotentials at current densities are below 420mV and 450mV, respectively.

[0044] In embodiments of the present invention, when the molar ratio of Ni to Ru in the deposition electrolyte is 1:0.0025 to 0.004, and the deposition current is controlled at 10 to 15 mA, the obtained electrode product exhibits both good HER and OER activities. For HER, a 500 / 1000 mA cm⁻¹ driving current in a 1M KOH electrolyte is achieved. -2 The overpotentials at current densities were below 180 mV and 230 mV, respectively; for OER, a driving current of 500 / 800 mA cm⁻¹ in 1 MkOH electrolyte was achieved. -2 The overpotentials at current densities are below 450mV and 470mV, respectively.

[0045] The following detailed description is provided in conjunction with some specific embodiments and comparative examples:

[0046] Example 1:

[0047] (1) The pretreated nickel foam was immersed in an electrolyte as the working electrode. The electrolyte was a mixture of 20 mL DMF mixed solution doped with 0.65 mL ultrapure water and 0.3 mL ruthenium chloride solution (the molar ratio of Ni to Ru in the electrolyte was calculated to be 1:0.003). A platinum mesh was used as the counter electrode and an Ag / AgCl electrode was used as the reference electrode. A current of -10 mA was applied for deposition for 1 h using the three-electrode system chronopotential method (CP).

[0048] After electrodeposition, the supported nickel foam is repeatedly washed with DMF, ultrapure water and ethanol, and then vacuum dried (time 4-6h, temperature 50-60℃) to obtain the ruthenium nickel-based bifunctional self-supporting catalyst S1 (also known as 0.3RuNi / NF-10 or 0.3RuNi / NF-10mA1h).

[0049] (2) After conducting electrochemical water desorption hydrogen / oxygen evolution tests on the above catalyst, it can be seen that S1 has certain catalytic performance.

[0050] For HER, the catalyst is driven by 500 / 1000 mA cm⁻¹ in 1M KOH electrolyte. -2 The overpotentials at the current densities are 176 / 201 mV, respectively;

[0051] For OER, this catalyst drives 500 / 800 mAcm in 1M KOH electrolyte. -2 The overpotentials at the current densities are 424 / 448 mV.

[0052] Example 2:

[0053] (1) The pretreated nickel foam was immersed in an electrolyte as the working electrode. The electrolyte was a mixture of 20 mL DMF mixed solution doped with 0.65 mL ultrapure water and 0.3 mL ruthenium chloride solution (the molar ratio of Ni to Ru in the electrolyte was calculated to be 1:0.003). A platinum mesh was used as the counter electrode and an Ag / AgCl electrode was used as the reference electrode. A current of -15 mA was applied and deposited for 1 h using the three-electrode system chronopotential method (CP).

[0054] After electrodeposition, the supported nickel foam is repeatedly washed with DMF, ultrapure water and ethanol, and then vacuum dried (time 4-6h, temperature 50-60℃) to obtain catalyst S2 (also known as 0.3RuNi / NF-15 or 0.3RuNi / NF-15mA1h).

[0055] (2) After conducting electrochemical water desorption hydrogen / oxygen evolution tests on the above catalyst, it can be seen that S2 has certain catalytic performance.

[0056] For HER, the catalyst is driven by 500 / 1000 mA cm⁻¹ in 1M KOH electrolyte. -2 The overpotentials at the current densities are 165 / 197 mV, respectively;

[0057] For OER, this catalyst drives 500 / 800 mAcm in 1M KOH electrolyte. -2 The overpotentials at the current densities are 445 / 468 mV.

[0058] Example 3:

[0059] (1) The pretreated nickel foam was immersed in an electrolyte as the working electrode. The electrolyte was a mixture of 20 mL DMF mixed solution doped with 0.65 mL ultrapure water and 0.3 mL ruthenium chloride solution (the molar ratio of Ni to Ru in the electrolyte was calculated to be 1:0.003). A platinum mesh was used as the counter electrode and an Ag / AgCl electrode was used as the reference electrode.

[0060] A three-electrode system chronopotential method (CP) was used to apply a current of -20mA for 1h to deposit the nickel. After electrodeposition, the supported nickel foam was repeatedly washed with DMF, ultrapure water and ethanol. After vacuum drying (time 4-6h, temperature 50-60℃), catalyst S3 (also known as 0.3RuNi / NF-20 or 0.3RuNi / NF-20mA1h) was obtained.

[0061] (2) After conducting electrochemical water desorption hydrogen / oxygen evolution tests on the above catalyst, it can be seen that S3 has certain catalytic performance.

[0062] For HER, the catalyst is driven by 500 / 1000 mA cm⁻¹ in 1M KOH electrolyte. -2 The overpotentials at the current densities are 190 / 234 mV, respectively;

[0063] For OER, this catalyst drives 500 / 800 mAcm in 1M KOH electrolyte. -2 The overpotentials at the current densities are 459 / 490mV.

[0064] Example 4:

[0065] (1) The pretreated nickel foam was immersed in an electrolyte as the working electrode. The electrolyte was a mixture of 20 mL DMF mixed solution doped with 0.65 mL ultrapure water and 0.5 mL ruthenium chloride solution (the molar ratio of Ni to Ru in the electrolyte was calculated to be 1:0.005). A platinum mesh was used as the counter electrode and an Ag / AgCl electrode was used as the reference electrode. A current of -10 mA was applied and deposited for 1 h using the three-electrode system chronopotential method (CP).

[0066] After electrodeposition, the loaded nickel foam is repeatedly washed with DMF, ultrapure water and ethanol, and then vacuum dried (time 4-6h, temperature 50-60℃) to obtain S4 (also known as 0.5RuNi / NF-10 or 0.5RuNi / NF-10mA1h).

[0067] (2) After conducting electrochemical water desorption hydrogen / oxygen evolution tests on the above catalyst, it can be seen that S4 has certain catalytic performance.

[0068] For HER, the catalyst is driven by 500 / 1000 mA cm⁻¹ in 1M KOH electrolyte. -2The overpotentials at the current densities are 180 / 211mV.

[0069] For OER, this catalyst drives 500 / 800 mAcm in 1M KOH electrolyte. -2 The overpotentials at the current densities are 522 / 579 mV.

[0070] Example 5:

[0071] (1) The pretreated nickel foam was immersed in an electrolyte as the working electrode. The electrolyte was a mixture of 20 mL DMF mixed solution, 0.65 mL ultrapure water and 0.5 mL ruthenium chloride solution (calculated as 1:0.005 molar ratio of Ni to Ru in the electrolyte). A platinum mesh was used as the counter electrode and an Ag / AgCl electrode was used as the reference electrode. A current of -15 mA was applied and deposited for 1 h using the three-electrode system chronopotential method (CP).

[0072] After electrodeposition, the loaded nickel foam is repeatedly washed with DMF, ultrapure water and ethanol, and then vacuum dried (time 4-6h, temperature 50-60℃) to obtain S5 (also known as 0.5RuNi / NF-15 or 0.5RuNi / NF-15mA1h).

[0073] (2) After conducting electrochemical water desorption hydrogen / oxygen evolution tests on the above catalyst, it can be seen that S5 has certain catalytic performance.

[0074] For HER, the catalyst is driven by 500 / 1000 mA cm⁻¹ in 1M KOH electrolyte. -2 The overpotentials at the current densities are 120 / 165mV.

[0075] For OER, this catalyst drives 500 / 800 mAcm in 1M KOH electrolyte. -2 The overpotentials at the current densities are 500 / 549 mV.

[0076] Example 6:

[0077] (1) The pretreated nickel foam was immersed in an electrolyte as the working electrode. The electrolyte was a mixture of 20 mL DMF mixed solution, 0.65 mL ultrapure water and 0.5 mL ruthenium chloride solution (calculated as 1:0.005 molar ratio of Ni to Ru in the electrolyte). A platinum mesh was used as the counter electrode and an Ag / AgCl electrode was used as the reference electrode. A current of -20 mA was applied and deposited for 1 h using the three-electrode system chronopotential method (CP).

[0078] After electrodeposition, the supported nickel foam is repeatedly washed with DMF, ultrapure water and ethanol, and then vacuum dried (time 4-6h, temperature 50-60℃) to obtain catalyst S6 (also known as 0.5RuNi / NF-20 or 0.5RuNi / NF-20mA1h).

[0079] (2) After conducting electrochemical water desorption hydrogen / oxygen evolution tests on the above catalyst, it can be seen that S6 has certain catalytic performance.

[0080] For HER, the catalyst is driven by 500 / 1000 mA cm⁻¹ in 1M KOH electrolyte. -2 The overpotentials at the current densities are 102 / 136mV.

[0081] For OER, this catalyst drives 500 / 800 mAcm in 1M KOH electrolyte. -2 The overpotentials at the current densities are 408 / 417 mV, respectively.

[0082] Based on this embodiment, with other conditions unchanged, the deposition current was adjusted to -25mA. For HER, this catalyst was driven at 500 / 1000mA / cm in 1M KOH electrolyte. -2 The overpotentials at current densities were 186 / 260 mV; for OER, the catalyst drove 500 / 800 mA / cm² in 1 M KOH electrolyte. -2 The overpotentials at the current densities are 530 / 610 mV.

[0083] See the catalyst HER activity diagram. Figure 1 As can be seen from the figure, according to η500-HER, the catalytic performance of these catalysts is in the following order: 0.5RuNi / NF-20>0.5RuNi / NF-15>0.3RuNi / NF-10>0.3RuNi / NF-15>0.5RuNi / NF-10>0.3RuNi / NF-20>0.7RuNi / NF-20;

[0084] According to η1000-HER, the catalytic performance order is: 0.5RuNi / NF-20>0.5RuNi / NF-15>0.3RuNi / NF-10>0.3RuNi / NF-15>0.5RuNi / NF-10>0.3RuNi / NF-20>0.7RuNi / NF-20;

[0085] See catalyst OER activity diagram. Figure 2As can be seen, according to η500-OER, the catalytic performance of these catalysts is in the following order: 0.5RuNi / NF-20>0.5RuNi / NF-15>0.3RuNi / NF-10>0.3RuNi / NF-15>0.5RuNi / NF-10>0.3RuNi / NF-20>0.7RuNi / NF-20;

[0086] According to η800-OER, the catalytic performance order is: 0.5RuNi / NF-20>0.5RuNi / NF-15>0.3RuNi / NF-10>0.3RuNi / NF-15>0.5RuNi / NF-10>0.3RuNi / NF-20>0.7RuNi / NF-20.

[0087] SEM images of the morphology and structure of the bifunctional catalyst 0.5RuNi / NF-20 are shown below. Figure 3 As shown, the ruthenium-nickel-based self-supporting electrode, prepared under high deposition current, exhibits good catalytic activity when uniformly grown on the surface of NF with interlaced ultrathin nanosheets. This can be attributed to the fact that the nanoflower-like structure composed of a large number of interlaced nanosheets facilitates the full exposure of the electrode's catalytically active surface area, increases the contact area between the electrolyte and the catalyst in the catalytic reaction, and thus accelerates the overall catalytic reaction rate of the electrode.

[0088] Example 7:

[0089] (1) The pretreated nickel foam was immersed in an electrolyte as the working electrode. The electrolyte was a mixture of 20 mL DMF mixed solution, 0.65 mL ultrapure water and 0.7 mL ruthenium chloride solution (calculated as 1:0.007 molar ratio of Ni to Ru in the electrolyte). A platinum mesh was used as the counter electrode and an Ag / AgCl electrode was used as the reference electrode. A current of -20 mA was applied and deposited for 1 h using the three-electrode system chronopotential method (CP).

[0090] After electrodeposition, the loaded nickel foam is repeatedly washed with DMF, ultrapure water and ethanol, and then vacuum dried (time 4-6h, temperature 50-60℃) to obtain S7 (also known as 0.7RuNi / NF-20 or 0.7RuNi / NF-20mA1h).

[0091] (2) After conducting electrochemical water desorption hydrogen / oxygen evolution tests on the above catalyst, it can be seen that S5 has certain catalytic performance.

[0092] For HER, the catalyst is driven by 500 / 1000 mA cm⁻¹ in 1M KOH electrolyte. -2 The overpotentials at the current densities are 211 / 315mV.

[0093] For OER, this catalyst drives 500 / 800 mA cm⁻¹ in 1M KOH electrolyte. -2 The overpotentials at the current densities are 540 / 620mV.

[0094] Comparative Example 1 (the difference from Example 1 is that the amount of triethylamine hydrochloride added to the DMF mixed solution is calculated as 0.03 mol / L):

[0095] Nickel chloride hexahydrate (0.1 mol / L), terephthalic acid (0.1 mol / L), and triethylamine hydrochloride (0.03 mol / L) were dissolved in N,N-dimethylformamide, stirred, and sonicated to prepare the initial electrolyte; however, crystals precipitated after standing overnight.

[0096] Comparative Example 2 (the difference from Example 6 is that the amount of triethylamine hydrochloride added to the DMF mixed solution is 0.02 mol / L when calculated by concentration)

[0097] Nickel chloride hexahydrate (0.1 mol / L), terephthalic acid (0.1 mol / L), and triethylamine hydrochloride (0.02 mol / L) were dissolved in N,N-dimethylformamide, stirred, and sonicated to prepare the initial electrolyte.

[0098] The pretreated nickel foam was immersed in an electrolyte as the working electrode. The electrolyte was 20 mL of DMF mixed solution doped with 0.65 mL of ultrapure water and 0.5 mL of ruthenium chloride solution. A platinum mesh was used as the counter electrode and an Ag / AgCl electrode was used as the reference electrode. A current of -20 mA was applied and deposited for 1 h using the three-electrode system chronopotential method (CP).

[0099] Compared with Example 6, as Figure 4 As shown, in Comparative Example 2 (the sample on the left in the figure), the active substance grew unevenly and green substances were precipitated.

[0100] Furthermore, the durability of the 0.5RuNi / NF-20 electrode prepared in Example 6 was determined using the CP method. Specifically, at 1 mol·L⁻¹, the durability was measured. -1 In KOH solution, at 200 mA·cm -2 The chromatograms of HER and OER of the 0.5RuNi / NF-20 electrode were measured using constant current density. Figure 5 , 6 It can be seen that the 0.5RuNi / NF-20 electrode exhibits good HER and OER activity durability.

[0101] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

Claims

1. A method for the preparation of a ruthenium-nickel based bifunctional self- supporting electrode, characterized in that: Comprising, Preparation of deposition electrolyte: DMF as solvent, nickel chloride hexahydrate, ruthenium chloride, terephthalic acid and triethylamine hydrochloride as solute, to prepare deposition electrolyte; accounting for the molar ratio of Ni, Ru in the deposition electrolyte is 1:0.003~0.005, the concentration of terephthalic acid is 0.1~0.3 mol / L, the concentration of triethylamine hydrochloride is 0.008~0.015 mol / L, and the concentration of nickel chloride hexahydrate is 0.1~0.4 mol / L; Electrodeposition: the foam nickel with surface oxide layer removed is immersed in the deposition electrolyte as the working electrode, the counter electrode is selected as platinum mesh, the reference electrode is selected as Ag / AgCl electrode, and the current of-10 mA~-20 mA is applied for 58~62 min to obtain the supported foam nickel; Post-treatment: the supported foam nickel is washed with DMF, ultrapure water and ethanol, and vacuum dried to obtain the ruthenium-nickel-based bifunctional self-supporting electrode.

2. The method for preparing a ruthenium nickel based bifunctional self-supported electrode according to claim 1, characterized in that: The method for removing the oxide layer on the surface of the foam nickel comprises the following steps: immersing the foam nickel in 2~3 mol / L hydrochloric acid, ultrapure water and ethanol solution for 15~20 minutes under ultrasonic, to obtain the pretreated foam nickel.

3. The method for preparing a ruthenium nickel based bifunctional self-supported electrode according to claim 1, characterized in that: The electrodeposition time is 60 min.

4. The method for preparing a ruthenium nickel based bifunctional self-supported electrode according to claim 1, characterized in that: The deposition current is 10~15 mA, and the molar ratio of Ni, Ru in the deposition electrolyte is 1:0.003~0.

004.

5. The method for preparing a ruthenium nickel based bifunctional self- supported electrode according to claim 1, characterized in that: The deposition current is 18~20 mA, and the molar ratio of Ni, Ru in the deposition electrolyte is 1:0.0045~0.

005.

6. The method for preparing a ruthenium nickel based bifunctional self-supported electrode according to claim 1, characterized in that: The concentration of triethylamine hydrochloride in the deposition electrolyte is 0.01 mol / L.

7. A ruthenium-nickel based bifunctional self-supporting electrode, characterized in that: Prepared by the method for preparing the ruthenium-nickel-based bifunctional self-supporting electrode according to any one of claims 1~6.

8. The application of the ruthenium-nickel-based bifunctional self-supporting electrode according to claim 7 in electrochemical water decomposition.

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