Preparation method and application of Ru-based single-atom catalyst

Abstract

The present invention provides a preparation method and application of a Ru-based single-atom catalyst. The preparation method comprises the following steps: (1) mixing a tungsten salt, a ruthenium salt and a morphology regulator in a solvent to obtain a salt solution, adding nickel foam to the salt solution for hydrothermal reaction to obtain a precursor material; (2) coating the precursor material in step (1) with an organic matter to obtain a coated material; (3) annealing the coated material in step (2) to obtain the Ru-based single-atom catalyst. The Ru-based single-atom catalyst of the present invention has high stability, a simple preparation method, low preparation cost, and exhibits outstanding hydrogen evolution catalytic activity in a 1.0M KOH alkaline electrolyte. Compared with commercial Pt / C catalysts, this catalyst significantly reduces the amount of precious metals used while ensuring high activity, and has outstanding advantages and application potential.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalysis, and in particular relates to a preparation method of a Ru-based single-atom catalyst and its application. Background Art

[0002] As an abundant, green, clean, and widely applicable secondary energy source, hydrogen is of great significance for reducing greenhouse gas emissions such as carbon dioxide and achieving the "dual carbon" goals. It is a crucial component of China's future energy system. Focusing on building a clean, low-carbon, and low-cost diversified hydrogen production system is the development principle of my country's hydrogen production industry. Among the many advanced hydrogen production technologies, electrocatalytic water splitting is considered one of the most cost-effective, green, and sustainable hydrogen production methods. It can be driven by renewable energy (solar, wind, hydropower, etc.) to generate electricity, with the hydrogen evolution reaction (HER) occurring at the cathode. While traditional acidic HER can achieve efficient proton coupling reactions, it faces challenges such as limited reserves and high costs of precious metals, catalyst corrosion and dissolution, and product acid mist contamination. Alkaline HER typically uses inexpensive catalysts, has mild reaction conditions, and can be combined with other efficient anodic half-reactions (oxygen evolution / chlorine evolution) to achieve industrial-scale hydrogen production at the cathode and oxygen / chlorine production at the anode, offering a wider range of industrial applications. However, alkaline water electrolysis requires the additional cleavage of water molecules, which undoubtedly increases the HER reaction barrier, making the alkaline HER activity of the catalyst 2 to 3 orders of magnitude lower than that in an acidic environment under the same conditions. Therefore, developing efficient and low-cost catalysts to accelerate the cleavage of H-OH bonds is crucial for improving alkaline HER catalytic activity.

[0003] From a kinetic perspective, HER is more difficult to achieve in an alkaline environment. Without readily available hydrogen protons, an additional water splitting step is required to provide available hydrogen protons for the subsequent dehydrogenation step to form hydrogen. The performance of existing catalysts still has room for improvement, and the development of high-performance, low-cost alkaline hydrogen evolution catalysts is a pressing challenge.

[0004] Transition metal oxides typically possess excellent water-splitting abilities, but strong interactions between oxygen sites in transition metal oxides and cracking intermediates make hydrogen desorption extremely difficult. Based on their optimal hydrogen adsorption free energies, loading precious metals onto transition metal oxides is expected to significantly enhance the catalyst's alkaline hydrogen evolution activity. However, precious metals face challenges in their limited reserves and high cost, hindering their widespread application. Reducing their use is an important solution.

[0005] Noble metal single-atom catalysts can achieve HER catalytic performance comparable to or even exceeding that of commercial Pt / C at loadings below 10wt%, offering outstanding advantages in maximizing activity while minimizing cost. Furthermore, Ru is the cheapest platinum group metal, costing only one-third of Pt and possessing a hydrogen adsorption free energy similar to that of Pt. Therefore, the preparation of a Ru-based single-atom catalyst achieves high-performance alkaline hydrogen evolution while significantly reducing the amount of precious metals used and lowering costs.

[0006] CN113293406A discloses a nanoelectrocatalyst and synthesis method, as well as a test electrode and preparation method. After activating a carbon material, the activated carbon material is immersed in a metal salt solution to allow the metal salt to adsorb onto the carbon material. The carbon material adsorbing the metal salt is dried, and the dried carbon material is subjected to a thermal shock to form a nanometal or nanometal oxide supported on the carbon material, thereby obtaining a nanoelectrocatalyst. However, the catalyst exhibits poor hydrogen evolution activation performance in alkaline solutions. CN115161664A discloses a spinel-supported Ru-based single-atom catalyst, its preparation method, and application. This method utilizes a coprecipitation method to synthesize the catalyst. A first mixed salt solution and a first precipitant are heated and mixed in a first microchannel reactor to obtain a slurry. The slurry is then aged, impurities are removed, and then calcined to obtain a support. The support is then heated and stirred with a second mixed salt solution and a second precipitant, followed by impurities removal to obtain a first catalyst to be reduced. The first catalyst to be reduced is calcined to obtain a spinel-supported Ru-based single-atom catalyst. However, the preparation process is complex and unsuitable for large-scale production.

[0007] Therefore, how to prepare a Ru-based single-atom catalyst on a large scale and at low cost is an important research direction in this field. Summary of the Invention

[0008] The purpose of the present invention is to provide a preparation method of a Ru-based single-atom catalyst and its application.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] One of the purposes of the present invention is to provide a method for preparing a Ru-based single-atom catalyst, the preparation method comprising the following steps:

[0011] (1) mixing a tungsten salt, a ruthenium salt, and a morphology modifier in a solvent to obtain a salt solution, adding nickel foam to the salt solution for hydrothermal reaction to obtain a precursor material;

[0012] (2) coating the precursor material of step (1) with an organic substance to obtain a coated material;

[0013] (3) Annealing the coating material in step (2) to obtain the Ru-based single-atom catalyst.

[0014] In the present invention, a Ru-based single-atom catalyst is obtained through hydrothermal reaction, organic coating and annealing, wherein WO2 can spontaneously adsorb and dissociate water molecules and produce a large number of hydrogen protons, ensuring a high concentration of proton coverage at the catalytic interface; the single-atom Ru site drives proton transfer to couple into hydrogen molecule escape, thereby improving the efficient operation of the entire system to produce hydrogen.

[0015] The catalyst obtained by the present invention is in-situ grown on a nickel foam conductive carrier, and no additional binder is required, so it can be directly used as a self-supporting electrode for cathode hydrogen production. Moreover, the in-situ grown active material is tightly combined with the nickel foam carrier, which reduces contact resistance, avoids the problem of easy shedding of the active material under long-term and high-current conditions, and increases the stability of the catalyst.

[0016] The catalyst of the present invention is simple to prepare and has low cost. The atomic content of the precious metal Ru is 0.2 to 5 wt%. It exhibits outstanding hydrogen evolution catalytic activity in a 1.0 M KOH alkaline electrolyte. Compared to commercial Pt / C catalysts, this catalyst significantly reduces the amount of precious metal required while maintaining high activity, offering significant advantages and application potential.

[0017] As a preferred technical solution of the present invention, the tungsten salt in step (1) includes any one or a combination of at least two of tungsten chloride, sodium tungstate dihydrate, ammonium tungstate or ammonium metatungstate, wherein typical but non-limiting examples of the combination include: a combination of tungsten chloride and sodium tungstate dihydrate, a combination of sodium tungstate dihydrate and ammonium tungstate, or a combination of ammonium tungstate and ammonium metatungstate.

[0018] Preferably, the ruthenium salt in step (1) comprises ruthenium chloride.

[0019] Preferably, the morphology regulator in step (1) comprises polyvinyl pyrrolidone.

[0020] Preferably, the solvent in step (1) comprises anhydrous ethanol.

[0021] As a preferred technical solution of the present invention, the concentration of the tungsten salt in the salt solution in step (1) is 0.005-0.5 mol / L, wherein the concentration can be 0.005 mol / L, 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L, 0.45 mol / L or 0.5 mol / L, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] Preferably, the molar ratio of the tungsten salt and the ruthenium salt in step (1) is 1:(0.001-0.15), wherein the molar ratio can be 1:0.001, 1:0.005, 1:0.01, 1:0.05, 1:0.1 or 1.0.15, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the mass ratio of the tungsten salt and the morphology regulator in step (1) is 1:(0.005-0.5), wherein the mass ratio can be 1:0.005, 1:0.01, 1:0.02, 1:0.05, 1:0.1, 1:0.2, 1:0.3, 1:0.4 or 1:0.5, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] As a preferred technical solution of the present invention, the nickel foam described in step (1) is pretreated.

[0025] Preferably, the pretreatment includes: cleaning the nickel foam and then drying it to complete the pretreatment of the nickel foam.

[0026] Preferably, the cleaning solution comprises any one of acetone, hydrochloric acid, water or ethanol, or a combination of at least two of them, wherein typical but non-limiting examples of the combination include: a combination of acetone and hydrochloric acid, a combination of hydrochloric acid and water, or a combination of water and ethanol.

[0027] Preferably, the cleaning comprises ultrasonic cleaning.

[0028] Preferably, the cleaning time is 30 to 50 minutes, wherein the time can be 30 minutes, 32 minutes, 34 minutes, 36 minutes, 38 minutes, 40 minutes, 42 minutes, 44 minutes, 46 minutes, 48 ​​minutes or 50 minutes, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] As a preferred technical solution of the present invention, the temperature of the hydrothermal reaction in step (1) is 100-200°C, wherein the temperature can be 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the time of the hydrothermal reaction in step (1) is 6 to 24 hours, wherein the time can be 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours or 24 hours, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, the thickness of the nickel foam in step (1) is 0.1 to 1.5 mm, wherein the thickness can be 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.4 mm or 1.5 mm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the area of ​​the nickel foam in step (1) is 2 to 30 cm 2 Wherein the area may be 2 cm 2 , 5cm 2 , 10cm 2 , 15cm 2 , 20cm 2 , 25cm 2 or 30cm 2 etc., but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] As a preferred technical solution of the present invention, the organic coating in step (2) comprises: placing the precursor liquid material in a carbon source solution and stirring;

[0034] Preferably, the carbon source in the carbon source solution in step (2) comprises dopamine, PEO-PEP-PEO triblock polymer and tris(hydroxymethyl)aminomethane.

[0035] Preferably, the concentration of dopamine is 0.0005 to 0.05 mol / L, wherein the concentration can be 0.0005 mol / L, 0.001 mol / L, 0.005 mol / L, 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L or 0.05 mol / L, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the concentration of the PEO-PEP-PEO triblock polymer is 0.0005 to 0.5 mol / L, wherein the concentration may be 0.0005 mol / L, 0.001 mol / L, 0.005 mol / L, 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L or 0.5 mol / L, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the concentration of tris(hydroxymethyl)aminomethane is 0.0002 to 0.005 mol / L, wherein the concentration can be 0.0002 mol / L, 0.0005 mol / L, 0.001 mol / L, 0.0015 mol / L, 0.002 mol / L, 0.0025 mol / L, 0.003 mol / L, 0.0034 mol / L, 0.004 mol / L, 0.0045 mol / L or 0.005 mol / L, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] As a preferred technical solution of the present invention, the time for coating the organic matter in step (2) is 6 to 48 hours, wherein the time can be 6 hours, 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, 45 hours or 48 hours, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the temperature for coating the organic matter is room temperature.

[0040] Preferably, the stirring rate is 100 to 800 rpm, wherein the rate may be 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm or 800 rpm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] As a preferred technical solution of the present invention, the annealing temperature in step (3) is 550-750°C, wherein the temperature can be 550°C, 600°C, 650°C, 700°C or 750°C, etc., but is not limited to the listed values. Other values ​​not listed within this numerical range are also applicable.

[0042] Preferably, the heating rate of the annealing in step (3) is 1 to 5°C / min, wherein the heating rate can be 1°C / min, 2°C / min, 3°C / min, 4°C / min or 5°C / min, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0043] Preferably, the annealing time in step (3) is 1 to 5 hours, wherein the time can be 1 hour, 2 hours, 3 hours, 4 hours or 5 hours, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] Preferably, the annealing atmosphere in step (3) is hydrogen and argon.

[0045] Preferably, the volume fraction of hydrogen in the hydrogen and argon is 3 to 10%, wherein the volume fraction can be 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0046] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0047] (1) mixing a tungsten salt, a ruthenium salt, and a morphology modifier in a solvent to obtain a salt solution, adding nickel foam to the salt solution for a hydrothermal reaction at a temperature of 100 to 200° C. for 6 to 24 hours to obtain a precursor material;

[0048] (2) immersing the precursor material described in step (1) in a carbon source solution for coating for 6 to 48 hours to obtain a coated material;

[0049] (3) Annealing the coating material in step (2) at a temperature of 550 to 750° C. for 1 to 5 hours to obtain the Ru-based single-atom catalyst.

[0050] A second object of the present invention is to provide an application of the preparation method of the Ru-based single-atom catalyst as described in the first object, wherein the preparation method is applied in the field of electrocatalysis technology.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The Ru-based single-atom catalyst of the present invention boasts high stability, simple preparation methods, and low production costs. The noble metal Ru atomic content ranges from 0.2 to 5 wt%. It exhibits outstanding hydrogen evolution catalytic activity in a 1.0 M KOH alkaline electrolyte. Compared to commercial Pt / C catalysts, this catalyst significantly reduces the amount of noble metal required while maintaining high activity, offering significant advantages and potential for application. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is the X-ray diffraction pattern of the Ru-based single-atom catalyst prepared in Example 1-3.

[0054] Figure 2 This is a scanning electron microscope image of the Ru-based single-atom catalyst prepared in Example 1.

[0055] Figure 3 This is a transmission electron microscope image of the Ru-based single-atom catalyst prepared in Example 1.

[0056] Figure 4 This is a spherical aberration diagram of the Ru-based single-atom catalyst prepared in Example 1.

[0057] Figure 5This is the HER performance diagram of the Ru-based single-atom catalyst prepared in Examples 1-3.

[0058] Figure 6 This is a chronopotentiometry graph of the Ru-based single-atom catalyst prepared in Example 1. DETAILED DESCRIPTION

[0059] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0060] Example 1

[0061] This embodiment provides a method for preparing a Ru-based single-atom catalyst, the preparation method comprising the following steps:

[0062] (1) Weigh 0.5 g of tungsten chloride, a molar ratio of tungsten salt to ruthenium salt of 1:0.15, and 0.02 g of polyvinyl pyrrolidone, then add 50 mL of ethanol and stir for 30 min until fully dissolved to obtain a precursor solution; clean the nickel foam, and the cleaning process includes: ultrasonicating in acetone, hydrochloric acid, water, and ethanol for 10 min, and then drying to obtain a clean nickel foam carrier. Transfer the above precursor solution to a reactor, add clean nickel foam, place it in a stainless steel reactor shell, tighten the reactor lid, and react in an oven at 180°C for 24 h to obtain a precursor material grown on the nickel foam. Wash the nickel foam, place it in an oven at 60°C to dry it for use.

[0063] (2) Weigh 0.05 g of dopamine, 0.08 g of PEO-PEP-PEO triblock polymer, and 0.02 g of tris(hydroxymethyl)aminomethane, then add 120 mL of deionized water, put the precursor material into the solution and stir for 24 h to coat the organic matter to obtain a coated material.

[0064] (3) The coated material is placed in a tubular furnace and reduced at 600 °C in a mixed atmosphere of H2 / Ar (6 / 120) for 2 h to obtain a Ru-based single-atom catalyst.

[0065] Figure 1 This is the X-ray diffraction pattern of the Ru-based single-atom catalyst prepared in Example 1, which shows that in addition to the characteristic peak of the base nickel foam, the other diffraction peaks appearing in the material are attributed to WO2 (JCPDF 32-1393), and there are no diffraction characteristic peaks related to Ru species.

[0066] Figure 2 This is a scanning electron microscope image of the Ru-based single-atom catalyst prepared in Example 1, which shows that the material is uniformly loaded on the surface of the nickel foam in a nanosheet structure.

[0067] Figure 3 This is a transmission electron microscope image of the Ru-based single-atom catalyst prepared in Example 1, which only shows lattice fringes with a spacing of 0.35 nm, corresponding to the WO2(011) crystal plane.

[0068] Figure 4 This is a spherical aberration diagram of the Ru-based single-atom catalyst prepared in Example 1. Further observations show alternating light and dark atomic points, indicating that Ru atoms exist in a monodisperse form.

[0069] Figure 5 The HER performance of the Ru-based single-atom catalyst prepared in Example 1 was plotted. Data were collected using a CHI1760E electrochemical workstation. A three-electrode system was used for testing, with the Ru-based single-atom catalyst prepared above as the working electrode, an Ag / AgCl electrode as the reference electrode, a carbon rod electrode as the counter electrode, and a 1.0 M KOH solution as the electrolyte. The Ru-based single-atom catalyst prepared achieved a HER of 10 mA / cm -2 and 100mA / cm -2 The overpotentials required at current densities of 6 mV and 65 mV respectively.

[0070] Figure 6 The Ru-based single-atom catalyst prepared in Example 1 of the present invention was tested in a 1.0 M KOH solution at 10 mA / cm 2 The chronopotentiometry curve under current density showed that the activity hardly decayed after 45 h of continuous reaction, indicating that the catalyst had excellent stability.

[0071] Example 2

[0072] This embodiment provides a method for preparing a Ru-based single-atom catalyst, the preparation method comprising the following steps:

[0073] Weigh 0.25g of tungsten chloride, with a molar ratio of tungsten salt to ruthenium salt of 1:0.1, and 0.01g of polyvinyl pyrrolidone. Add 50mL of ethanol and stir for 30 minutes until fully dissolved to obtain a precursor solution. Nickel foam is ultrasonically treated in acetone, hydrochloric acid, water, and ethanol for 10 minutes, followed by drying to obtain a clean nickel foam support. The precursor solution is transferred to a reactor, and clean nickel foam is added. The reactor is placed in a stainless steel reactor shell, the lid is tightened, and the reaction is carried out in an oven at 180°C for 12 hours to obtain the precursor material grown on the nickel foam. The nickel foam is rinsed and dried in an oven at 60°C for later use. Then, weigh 0.01g of dopamine, 0.01g of PEO-PEP-PEO triblock polymer, and 0.01g of tris(hydroxymethyl)aminomethane. Add 120mL of deionized water, place the precursor material in the solution, and stir for 24 hours to achieve organic coating. Finally, it was placed in a tube furnace and reduced at 600°C in a mixed atmosphere of H2 / Ar (6 / 120) for 2 hours to obtain a Ru-based single-atom catalyst.

[0074] The X-ray diffraction pattern of the Ru-based single-atom catalyst prepared in Example 2 is as follows: Figure 1 As shown, the characteristic peaks of nickel foam support and WO2 are shown, and the electrochemical test hydrogen evolution performance is as follows Figure 5 As shown, the catalyst reaches 10mA / cm -2 and 100mA / cm -2 The corresponding overpotentials at the current density are 12mV and 114mV respectively.

[0075] Example 3

[0076] This embodiment provides a method for preparing a Ru-based single-atom catalyst, the preparation method comprising the following steps:

[0077] 0.5g of tungsten chloride and 0.02g of polyvinyl pyrrolidone were weighed, followed by the addition of 50mL of ethanol and stirring for 30 minutes until fully dissolved, to obtain a precursor solution. Nickel foam was ultrasonically treated in acetone, hydrochloric acid, water, and ethanol for 10 minutes, respectively, and then dried to obtain a clean nickel foam. The precursor solution was transferred to a reactor, and clean nickel foam was added. The reactor was placed in a stainless steel reactor shell, the lid was tightened, and the reactor was reacted in an oven at 180°C for 24 hours to obtain a tungsten oxide precursor grown on the nickel foam. The nickel foam was washed and dried in an oven at 60°C for later use. Then, 0.05g of dopamine, 0.08g of PEO-PEP-PEO triblock polymer, and 0.02g of tris(hydroxymethyl)aminomethane were weighed, followed by the addition of 120mL of deionized water. The tungsten oxide precursor was immersed in the solution and stirred for 24 hours to achieve organic coating. Finally, it was placed in a tubular furnace and reduced at 600°C in a mixed atmosphere of H2 / Ar (6 / 120) for 2 hours to obtain the catalyst.

[0078] The X-ray diffraction pattern of the catalyst prepared in Example 3 is as follows: Figure 1 As shown, it shows the characteristic peaks of nickel foam support and WO2; the electrochemical test hydrogen evolution performance is as follows Figure 5 As shown, 10mA / cm -2 and 100mA / cm -2 The corresponding overpotentials at the current density were 137 mV and 284 mV, respectively. Compared with the catalysts prepared in Examples 1 and 2, the catalyst prepared in Example 3, which did not incorporate single-atom Ru, exhibited significantly reduced alkaline hydrogen evolution performance, indicating that single-atom Ru is crucial for enhancing electrochemical hydrogen evolution activity.

[0079] Examples 4-6

[0080] The corresponding feed amounts were calculated according to the molar ratios of tungsten salt to ruthenium salt of 1:0.2, 1:0.05, and 1:0.02, respectively. Then, the steps in Example 1 were repeated to obtain the corresponding Ru-based single-atom catalysts.

[0081] Examples 7-8

[0082] The steps in Example 2 were followed, except that the organic coating time was 4 h and 48 h, respectively, to obtain the corresponding Ru-based single-atom catalysts.

[0083] The Ru-based single-atom catalysts prepared in Examples 1-8 were tested for hydrogen evolution catalytic activity. The test results are shown in Table 1. The electrochemical hydrogen evolution test was performed on a CHI1760E electrochemical workstation using a standard three-electrode system. The working electrode was a Ru-based single-atom catalyst (effective area 0.5 cm*0.5 cm), the reference electrode was an Ag / AgCl electrode, and the counter electrode was a carbon rod electrode. Linear sweep voltammetry was performed in a 1.0 M KOH electrolyte at room temperature at a scan rate of 5 mV / s. The test potential was calculated according to the equation (E RHE =E Ag / AgCl +1.02 V) for calibration against the reversible hydrogen electrode (RHE).

[0084] Table 1

[0085]

[0086]

[0087] The table above shows that, on the one hand, the introduction of Ru into the catalyst significantly improves the alkaline hydrogen evolution catalytic activity, and that varying the amount of Ru added varies the catalytic performance, reaching optimal hydrogen evolution activity at a molar ratio of tungsten salt to ruthenium salt of 1:0.15. On the other hand, carbon plays a certain reducing role during annealing, facilitating the creation of oxygen vacancies in the catalyst, thereby affecting the hydrogen evolution catalytic activity. Furthermore, carbon coating ensures the stability of the catalyst during the HER process.

[0088] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a Ru-based single-atom catalyst, characterized in that: The preparation method comprises the following steps: (1) mixing a tungsten salt, a ruthenium salt, and a morphology modifier in a solvent to obtain a salt solution, adding nickel foam to the salt solution for a hydrothermal reaction at a temperature of 100-200° C. for 6-24 hours to obtain a precursor material; The molar ratio of the tungsten salt to the ruthenium salt is 1:(0.005-0.15), and the mass ratio of the tungsten salt to the morphology modifier is 1:(0.005-0.5); (2) coating the precursor material in step (1) with an organic substance for 6 to 48 hours to obtain a coated material; The organic coating comprises: placing a precursor material in a carbon source solution and stirring, wherein the carbon source in the carbon source solution is dopamine, PEO-PEP-PEO triblock polymer and tris(hydroxymethyl)aminomethane; The concentration of dopamine is 0.0005-0.05 mol / L, the concentration of the PEO-PEP-PEO triblock polymer is 0.0005-0.5 mol / L, and the concentration of tris(hydroxymethyl)aminomethane is 0.0002-0.005 mol / L; (3) Annealing the coating material in step (2) at a temperature of 550-750° C. for 1-5 hours to obtain the Ru-based single-atom catalyst.

2. The preparation method according to claim 1, characterized in that The tungsten salt in step (1) includes any one of tungsten chloride, sodium tungstate dihydrate, ammonium tungstate or ammonium metatungstate, or a combination of at least two thereof.

3. The preparation method according to claim 1, characterized in that The ruthenium salt in step (1) includes ruthenium chloride.

4. The preparation method according to claim 1, characterized in that The morphology regulator in step (1) includes polyvinyl pyrrolidone.

5. The preparation method according to claim 1, characterized in that The solvent in step (1) includes anhydrous ethanol.

6. The preparation method according to claim 1, characterized in that The concentration of the tungsten salt in the salt solution in step (1) is 0.005-0.5 mol / L.

7. The preparation method according to claim 1, characterized in that The nickel foam described in step (1) is pretreated.

8. The preparation method according to claim 7, characterized in that The pretreatment includes: cleaning the nickel foam and then drying it to complete the pretreatment of the nickel foam.

9. The preparation method according to claim 8, characterized in that The cleaning solution includes any one of acetone, hydrochloric acid, water or ethanol, or a combination of at least two of them.

10. The preparation method according to claim 8, characterized in that The cleaning includes ultrasonic cleaning.

11. The preparation method according to claim 8, characterized in that The cleaning time is 30 to 50 minutes.

12. The preparation method according to claim 1, characterized in that The thickness of the nickel foam in step (1) is 0.1-1.5 mm.

13. The preparation method according to claim 1, characterized in that The area of ​​the nickel foam in step (1) is 2 to 30 cm 2 .

14. The preparation method according to claim 1, characterized in that The temperature for the organic coating in step (2) is room temperature.

15. The preparation method according to claim 1, characterized in that The stirring rate in step (2) is 100~800rpm.

16. The preparation method according to claim 1, characterized in that The heating rate of the annealing in step (3) is 1-5°C / min.

17. The preparation method according to claim 1, characterized in that The annealing atmosphere in step (3) is hydrogen and argon.

18. The preparation method according to claim 17, characterized in that The volume fraction of hydrogen in the hydrogen and argon gases is 3-10%.

19. Use of a Ru-based single-atom catalyst prepared by the method for preparing a Ru-based single-atom catalyst according to any one of claims 1 to 18, characterized in that: The Ru-based single-atom catalyst is applied to alkaline hydrogen evolution catalysis.

Images