Cobalt hydroxide nanosheet supported ruthenium nanocluster catalyst and method of making same

Abstract

The application provides a cobalt hydroxide nanosheet loaded ruthenium nanocluster catalyst and a preparation method thereof, and particularly relates to the technical field of nanomaterials. The preparation method comprises the following steps: A, immersing cobalt hydroxide nanosheets in a ruthenium salt solution, and taking out and drying to obtain cobalt hydroxide immersed in the ruthenium salt solution; B, using a laser to perform parallel light irradiation on the cobalt hydroxide immersed in the ruthenium salt solution to obtain the cobalt hydroxide nanosheet loaded ruthenium nanocluster catalyst. The high-temperature thermal shock generated by laser irradiation is used to induce Ru nanoclusters to be uniformly loaded on CoOOH / Co(OH)2 nanosheets from Ru salt. The induced Ru nanoclusters are used to improve the utilization rate of Ru atoms by using the instantaneous heating and ultrafast cooling characteristics of thermal shock.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials technology, and in particular to a cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst and its preparation method. Background Technology

[0002] In the process of the world's energy system transitioning to a low-carbon model, clean, high-energy-density hydrogen energy will play an increasingly important role in various industries. Water electrolysis is considered the most promising technology for efficiently producing green hydrogen using intermittent renewable energy sources. However, traditional alkaline water electrolysis suffers from low industrial density and poor durability, and due to the strong uphill reaction process, requires a battery voltage of approximately 1.8-2.0V. Charge / mass transfer in the reaction leads to high overpotentials, excessive energy consumption, and slow hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Currently, supported platinum-based catalysts exhibit excellent catalytic activity in hydrogen production, but their high cost and scarcity greatly hinder their further sustainable and practical application. Therefore, the development of economical, efficient, and stable HER / OER bifunctional catalysts is urgently needed.

[0003] Ruthenium (Ru), as the cheapest platinum-like metal, has attracted much attention due to its hydrogen bond strength being similar to that of Pt. Among a range of ruthenium-based electrocatalysts, compared to alloy and doped catalysts, supported ruthenium-based catalysts exhibit higher stability because the metal particles can interact with the support, leading to interfacial charge transfer. Furthermore, supported catalysts can achieve multifunctional combinations of components, reducing the amount of precious metals like Ru and enabling efficient and economical catalyst production. Common support forms include single atoms, nanoclusters, and nanoparticles. The catalytic performance of supported metal catalysts often depends on size, increasing as the size of the active component decreases. However, single-atom catalysts have low loading, high specific surface energy, and are prone to aggregation, limiting their catalytic activity and stability, making them unsuitable for industrial water splitting.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] One of the objectives of this invention is to provide a method for preparing a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets, in order to alleviate the technical problems of existing preparation methods, such as low single-atom loading, high specific surface energy, and easy agglomeration of catalysts, which affect the catalytic activity and stability of the catalysts and make them difficult to use in industrial water splitting.

[0006] The second objective of this invention is to provide a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets.

[0007] The third objective of this invention is to provide an application of a cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst in water electrolysis for hydrogen production.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] The first aspect of this invention provides a method for preparing a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets, comprising the following steps:

[0010] A. Cobalt hydroxide nanosheets are immersed in a ruthenium salt solution, and after being removed and dried, cobalt hydroxide impregnated with a ruthenium salt solution is obtained;

[0011] B. Using a CO2 laser, cobalt hydroxide impregnated with ruthenium salt solution is irradiated with parallel light. The laser power is 3W to 18W, the laser scanning speed is 62.5mm / s to 375mm / s, and the sampling frequency is 500PPI to 1000PPI to obtain the cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst.

[0012] Further, in step A, the concentration of the ruthenium salt solution is 0.01 mg / mL to 0.5 mg / mL, preferably 0.1 mg / mL to 0.3 mg / mL.

[0013] Preferably, in step A, the immersion time is 1 min to 30 min.

[0014] Furthermore, the wavelength of the parallel light is 10μm to 15μm, preferably 10.64μm.

[0015] Preferably, the irradiation time is 30s to 5min, and more preferably 1min to 3min.

[0016] Furthermore, in step B, the laser power is 3W to 12W, and the laser scanning speed is 62.5mm / s to 200mm / s.

[0017] Furthermore, the method for preparing the cobalt hydroxide nanosheets is as follows:

[0018] An electrodeposition solution was prepared using a cobalt source and NH4Cl. Two electrodes were subjected to constant current discharge in the electrodeposition solution with carbon cloth as the substrate. Then, the two electrodes were transferred to an ammonium sulfate solution for constant current in-situ anodic oxidation. After drying, cobalt hydroxide nanosheets were obtained.

[0019] Furthermore, the cobalt source includes cobalt nitrate.

[0020] Preferably, in the electrodeposition solution, the concentration of the cobalt source is 0.01 mol / L to 0.1 mol / L, and the concentration of NH4Cl is 0.01 mol / L to 0.1 mol / L.

[0021] Furthermore, at -1mA / cm 2 ~-3mA / cm 2The constant current discharge is performed for 30-120 minutes.

[0022] Preferably, at 1 mA / cm 2 ~3mA / cm 2 The constant current in-situ anodic oxidation is performed after charging for 30 to 120 minutes.

[0023] Furthermore, at -1.5 mA / cm 2 The constant current discharge was performed for 60 minutes.

[0024] Preferably, at 1.2 mA / cm 2 The constant current in-situ anodic oxidation was performed after charging for 60 minutes.

[0025] A second aspect of the present invention provides a cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst prepared by the aforementioned preparation method.

[0026] A third aspect of the present invention provides the application of the aforementioned cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst in water electrolysis for hydrogen production.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects:

[0028] This invention provides a method for preparing a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets. The method involves immersing cobalt hydroxide nanosheets in a ruthenium salt solution to uniformly distribute the ruthenium salt on the nanosheets. Then, high-temperature thermal shock generated by laser irradiation induces Ru nanoclusters from the Ru salt, which are then uniformly loaded onto the CoOOH / Co(OH)₂ nanosheets. The instantaneous heating and ultrafast cooling characteristics of the thermal shock induce Ru nanoclusters, thereby improving the utilization rate of Ru atoms. The dense CoOOH / Co(OH)₂ nanosheets provide more active sites, enhancing the mass transfer rate. The entire preparation process does not require a protective gas and can be carried out in an air environment, requiring less stringent equipment and site conditions, making it suitable for large-scale industrial production.

[0029] The cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst provided by this invention synergistically enhances the catalytic activity of HER and OER through Ru and CoOOH / Co(OH)2, exhibiting excellent overall water splitting performance in total water splitting, driving 10 mA / cm². 2 Alkaline water electrolysis requires only 1.52V.

[0030] The application of the cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst provided by this invention in water electrolysis for hydrogen production offers a better catalyst, reduces the cost of water electrolysis for hydrogen production, and expands the development of downstream industries. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0032] Figure 1 SEM image of the ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets obtained in Example 2;

[0033] Figure 2 This is a TEM image of the ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets obtained in Example 2;

[0034] Figure 3 The elemental distribution characterization diagram is shown for the ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets obtained in Example 2.

[0035] Figure 4 The XRD pattern of the ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets obtained in Example 2 is shown below.

[0036] Figure 5 The Raman spectrum characterization of the cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst obtained in Example 2 is shown below.

[0037] Figure 6 XPS spectra of the ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets obtained in Example 2;

[0038] Figure 7 HER and OER data graphs were obtained for Example 2 and the comparative example;

[0039] Figure 8 Tafel plots of HER and OER data were obtained for Example 2 and the comparative example;

[0040] Figure 9 The total water decomposition performance diagram provided for Experiment Example 2. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. The components of the embodiments of this invention can be arranged and designed in various different configurations.

[0042] The first aspect of this invention provides a method for preparing a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets, comprising the following steps:

[0043] A. Cobalt hydroxide nanosheets are immersed in a ruthenium salt solution, and after being removed and dried, cobalt hydroxide impregnated with a ruthenium salt solution is obtained;

[0044] B. Using a CO2 laser, cobalt hydroxide impregnated with ruthenium salt solution is irradiated with parallel light. The laser power is 3W to 18W, the laser scanning speed is 62.5mm / s to 375mm / s, and the sampling frequency is 500PPI to 1000PPI to obtain the cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst.

[0045] This invention provides a method for preparing a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets. The method involves immersing cobalt hydroxide nanosheets in a ruthenium salt solution to uniformly distribute the ruthenium salt on the nanosheets. Then, high-temperature thermal shock generated by laser irradiation induces Ru nanoclusters from the Ru salt, which are then uniformly loaded onto the CoOOH / Co(OH)₂ nanosheets. The instantaneous heating and ultrafast cooling characteristics of the thermal shock induce Ru nanoclusters, thereby improving the utilization rate of Ru atoms. The dense CoOOH / Co(OH)₂ nanosheets provide more active sites, enhancing the mass transfer rate. The entire preparation process does not require a protective gas and can be carried out in an air environment, requiring less stringent equipment and site conditions, making it suitable for large-scale industrial production.

[0046] Laser power affects the degree and speed of ruthenium nanoclusters reduction. When the laser power is below 3W, the thermal effect of the laser is insufficient to reduce Ru salt into Ru nanoclusters. When the laser power is above 18W, Ru nanoclusters will agglomerate into particles.

[0047] Typical, but not limiting, laser power can be, for example, 3W, 6W, 9W, 12W, 15W or 18W; preferred laser power can be, for example, 3W, 6W, 9W or 12W.

[0048] The scanning speed of the laser also affects the degree and efficiency of reduction. Increasing the scanning speed reduces the residence time of the laser on the sample surface, decreasing the heat provided and the diffusion effect, thus leading to a decrease in the reduction efficiency of Ru nanoclusters and incomplete reduction. Therefore, the suitable laser scanning speed is 62.5 mm / s to 375 mm / s. When the laser scanning speed is below 62.5 mm / s, the heat provided by the laser on the sample surface is excessive, causing Ru nanoclusters to agglomerate into particles; when the laser scanning speed is above 375 mm / s, the reduction efficiency of Ru nanoclusters decreases, resulting in incomplete reduction.

[0049] Typical, but not limiting, laser scanning speeds can be, for example, 62.5 mm / s, 100 mm / s, 150 mm / s, 200 mm / s, 250 mm / s, 300 mm / s, 350 mm / s, or 375 mm / s; preferred laser scanning speeds can be, for example, 62.5 mm / s, 100 mm / s, 150 mm / s, or 200 mm / s.

[0050] The sampling frequency of the laser affects the uniformity of the Ru nanoclusters; therefore, a suitable sampling frequency is 500 PPI to 1000 PPI. Typical, but not limiting, sampling frequencies can be, for example, 500 PPI, 600 PPI, 700 PPI, 800 PPI, 900 PPI, or 1000 PPI.

[0051] Further, in step A, the concentration of the ruthenium salt solution is 0.01 mg / mL to 0.5 mg / mL, preferably 0.1 mg / mL to 0.3 mg / mL.

[0052] Preferably, in step A, the immersion time is 1 min to 30 min.

[0053] On cobalt hydroxide nanosheets of the same size, the loading of ruthenium salt depends on the concentration of the ruthenium salt solution and the impregnation time. That is, for the same ruthenium salt loading, a higher ruthenium salt concentration requires a relatively shorter impregnation time, while a lower ruthenium salt concentration requires a relatively longer impregnation time.

[0054] Typical, but not limiting, concentrations of ruthenium salt solutions may be, for example, 0.01 mg / mL, 0.1 mg / mL, 0.2 mg / mL, 0.3 mg / mL, 0.4 mg / mL, or 0.5 mg / mL; and immersion times may be, for example, 1 min, 5 min, 10 min, 20 min, or 30 min.

[0055] Furthermore, the wavelength of the parallel light is 10μm to 15μm, preferably 10.64μm. The wavelength of the parallel light is the output wavelength of the laser. At a wavelength of 10μm to 15μm, the energy transfer and penetration of the laser are better suited to ruthenium ions, and the optimal suitable wavelength is 10.64μm.

[0056] Preferably, the irradiation time is 30 seconds to 5 minutes, more preferably 1 minute to 3 minutes. It should be noted that the irradiation time is determined by the size of the model area. Generally, a model area of ​​1 cm × 1 cm is selected. Under the above-mentioned laser power and scanning rate, the irradiation time is controlled within 30 seconds to 5 minutes to complete the reduction of ruthenium ions.

[0057] Furthermore, in step B, the laser power is 3W to 12W, and the laser scanning speed is 62.5mm / s to 200mm / s.

[0058] Furthermore, the method for preparing the cobalt hydroxide nanosheets is as follows:

[0059] An electrodeposition solution was prepared using a cobalt source and NH4Cl. Two electrodes were subjected to constant current discharge in the electrodeposition solution with carbon cloth as the substrate. Then, the two electrodes were transferred to an ammonium sulfate solution for constant current in-situ anodic oxidation. After drying, cobalt hydroxide nanosheets were obtained.

[0060] Furthermore, the cobalt source includes cobalt nitrate.

[0061] Preferably, in the electrodeposition solution, the concentration of the cobalt source is 0.01 mol / L to 0.1 mol / L, and the concentration of NH4Cl is 0.01 mol / L to 0.1 mol / L.

[0062] Typical, but not limiting, concentrations of the cobalt source may be, for example, 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, or 0.1 mol / L; and concentrations of NH4Cl may be, for example, 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, or 0.1 mol / L.

[0063] Furthermore, at -1mA / cm 2 ~-3mA / cm 2 The constant current discharge is performed for 30-120 minutes.

[0064] It should be noted that -1mA / cm 2 ~-3mA / cm 2 The current representation method indicates a current in the opposite direction to the constant current in-situ anodic oxidation current. Under constant current discharge, the system undergoes an electrochemical reduction reaction, and Co... 3+ The reaction produces Co(OH)2 nanosheets.

[0065] Typical, but not limiting, constant current discharge current can be -1 mA / cm. 2 -2mA / cm 2 or -3mA / cm 2 The discharge time can be 30 min, 60 min, 90 min or 120 min.

[0066] Preferably, at 1 mA / cm 2 ~3mA / cm 2 The constant current in-situ anodic oxidation is performed after charging for 30 to 120 minutes.

[0067] Constant current in-situ anodic oxidation is a process in which an oxidation reaction occurs at the anode in an ammonium sulfate solution under the action of an applied current to generate CoOOH nanosheets.

[0068] Typical, but not limiting, current for constant current in-situ anodizing can be 1 mA / cm. 2 2mA / cm 2 or 3mA / cm 2 The constant current in-situ anodizing time can be 30 min, 60 min, 90 min or 120 min.

[0069] In a preferred embodiment of the present invention, at -1.5 mA / cm 2 The constant current discharge was performed for 60 minutes.

[0070] In a preferred embodiment of the present invention, at 1.2 mA / cm 2 The constant current in-situ anodic oxidation was performed after charging for 60 minutes.

[0071] A second aspect of the present invention provides a cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst prepared by the aforementioned preparation method.

[0072] The cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst provided by this invention synergistically enhances the catalytic activity of HER and OER through Ru and CoOOH / Co(OH)2, exhibiting excellent overall water splitting performance in total water splitting, driving 10 mA / cm². 2 Alkaline water electrolysis requires only 1.52V.

[0073] A third aspect of the present invention provides the application of the aforementioned cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst in water electrolysis for hydrogen production.

[0074] The application of the cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst provided by this invention in water electrolysis for hydrogen production offers a better catalyst, reduces the cost of water electrolysis for hydrogen production, and expands the development of downstream industries.

[0075] The following detailed description of some embodiments of the present invention is provided in conjunction with examples. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0076] The cobalt hydroxide nanosheets used in the following examples and comparative examples were prepared by using Co(NO3)26H2O as the cobalt source and preparing an electrodeposition solution with a Co(NO3)26H2O concentration of 0.02M and an NH4Cl concentration of 0.1M.

[0077] Using 1cm×1cm carbon cloth as a substrate, the two electrodes are at -1.5mA / cm 2 The electrodes were discharged under current for 60 min, and then transferred to a 0.01 M (NH4)2SO4 solution at 1.2 mA / cm². 2 After in-situ anodizing for 60 minutes, the nanosheets were removed, rinsed with deionized water, and dried by blowing air to obtain cobalt hydroxide CoOOH / Co(OH)2 nanosheets.

[0078] Example 1

[0079] This embodiment provides a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets, and the preparation method is as follows:

[0080] 1. Place 10 mL of a 0.2 mg / mL RuCl3 xH2O solution (Ru group content 35.0%-42.0%, manufacturer: Aladdin) into a 50 mL beaker, then immerse the cobalt hydroxide nanosheets in the solution for 10 min, and then remove them and dry them in a forced-air oven for later use.

[0081] 2. Start the CO2 laser and laser smoke purifier. Irradiate the Ru-impregnated cobalt hydroxide with parallel light of wavelength 10.64 μm. The spot diameter is 25 μm. Adjust the focal length between the target and the lens to achieve fixed focus. The Z-axis distance is 260.7 mm. The laser power is 3 W and the scanning speed is 125 mm / s. The model area is 1 cm × 1 cm. The treatment time is 1 minute and 10 seconds. The sampling rate is 1000 PPI. After the laser treatment, stop the engraving machine and remove the catalyst to obtain the cobalt hydroxide nanosheet supported ruthenium nanocluster catalyst, abbreviated as L-Ru-CoOOH / Co(OH)2 catalyst. Here, L is the abbreviation for Laser, used to mark the preparation method of the product.

[0082] Example 2

[0083] This embodiment provides a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets. The difference from Example 1 is that the laser power used is 6W. The other raw materials and steps are the same as in Example 1, and will not be repeated here.

[0084] Example 3

[0085] This embodiment provides a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets. The difference from Example 1 is that the laser power used is 12W. The other raw materials and steps are the same as in Example 1, and will not be repeated here.

[0086] Example 4

[0087] This embodiment provides a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets. The difference from Example 1 is that the laser power used is 18W. The other raw materials and steps are the same as in Example 1, and will not be repeated here.

[0088] Example 5

[0089] This embodiment provides a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets, and the preparation method is as follows:

[0090] 1. Place 10 mL of RuCl3 xH2O solution with a concentration of 0.2 mg / mL into a 50 mL beaker, then immerse a 1 cm × 1 cm cobalt hydroxide nanosheet in the solution for 3 min, and then remove it and dry it in a forced-air oven for later use.

[0091] 2. Same as Example 2.

[0092] Example 6

[0093] This embodiment provides a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets, and the preparation method is as follows:

[0094] 1. Place 10 mL of a 0.2 mg / mL RuCl3 xH2O solution (Ru group content 35.0%-42.0%, manufacturer: Aladdin) into a 50 mL beaker, then immerse a 1 cm × 1 cm cobalt hydroxide nanosheet in the solution for 30 min, and then remove it and dry it in a forced-air oven for later use.

[0095] 2. Same as Example 2.

[0096] Example 7

[0097] This embodiment provides a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets, and the preparation method is as follows:

[0098] 1. Place 10 mL of a 0.2 mg / mL RuCl3 xH2O solution (Ru group content 35.0%-42.0%, manufacturer: Aladdin) into a 50 mL beaker, then immerse a 1 cm × 1 cm cobalt hydroxide nanosheet in the solution for 60 min, and then remove it and dry it in a forced-air oven for later use.

[0099] 2. Same as Example 2.

[0100] Example 8

[0101] This embodiment provides a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets, and the preparation method is as follows:

[0102] 1. Same as Example 1.

[0103] 2. Start the CO2 laser and laser smoke purifier. Irradiate the Ru-impregnated cobalt hydroxide with parallel light of wavelength 10.64 μm. The spot diameter is 25 μm. Adjust the focal length between the target and the lens to achieve fixed focus. The Z-axis distance is 260.7 mm. The laser power is 3 W and the scanning speed is 62.5 mm / s. The model area is 1 cm × 1 cm. The treatment time is 2 minutes and 6 seconds. The sampling rate is 500 PPI. After laser treatment, stop the engraving machine and remove the catalyst to obtain the cobalt hydroxide nanosheet supported ruthenium nanocluster catalyst, abbreviated as L-Ru-CoOOH / Co(OH)2 catalyst. Here, L is the abbreviation for Laser, used to mark the preparation method of the product.

[0104] Example 9

[0105] This embodiment provides a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets, and the preparation method is as follows:

[0106] 1. Same as Example 1.

[0107] 2. Start the CO2 laser and laser smoke purifier. Irradiate the Ru-impregnated cobalt hydroxide with parallel light of wavelength 10.64 μm. The spot diameter is 25 μm. Adjust the focal length between the target and the lens to achieve fixed focus. The Z-axis distance is 260.7 mm. The laser power is 3 W and the scanning speed is 375 mm / s. The model area is 1 cm × 1 cm. The action time is 37 seconds and the sampling rate is 1000 PPI. After the laser action, stop the engraving machine and remove the catalyst to obtain the cobalt hydroxide nanosheet supported ruthenium nanocluster catalyst, abbreviated as L-Ru-CoOOH / Co(OH)2 catalyst. Here, L is the abbreviation for Laser, used to mark the preparation method of the product.

[0108] Comparative Example 1

[0109] This comparative example provides a ruthenium catalyst supported on cobalt hydroxide nanosheets, and the preparation method is as follows:

[0110] 1. Take 10 mL of Ru nanoparticle dispersion with a concentration of 0.2 mg / mL and place it in a 50 mL beaker. Then, immerse the cobalt hydroxide nanosheets in the solution for 10 min, and then take them out and dry them in a forced-air oven for later use.

[0111] 2. The cobalt hydroxide impregnated with the Ru nanoparticle dispersion was placed in a tube furnace and annealed at 400°C for 30 minutes under an argon atmosphere, with a heating rate of 5°C / min. After annealing, the catalyst was removed to obtain a cobalt hydroxide nanosheet-supported ruthenium catalyst, abbreviated as Ru-CoOOH / Co(OH)2 catalyst.

[0112] Comparative Example 2

[0113] This comparative example provides a catalyst for hydrogen production through water electrolysis, which is a cobalt hydroxide nanosheet.

[0114] Comparative Example 3

[0115] This comparative example provides a catalyst for hydrogen production through water electrolysis, which is a commercial OER (oxygen evolution reaction) catalyst, ruthenium oxide (RuO2).

[0116] Comparative Example 4

[0117] This comparative example provides a catalyst for hydrogen production through water electrolysis, which is a commercially available HER (hydrogen evolution reaction) catalyst, Pt / C.

[0118] Comparative Example 5

[0119] This comparative example provides a catalyst for hydrogen production through water electrolysis, which is a HER catalyst Ru / C.

[0120] Characterization Example 1

[0121] The cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst obtained in Example 2 was subjected to scanning electron microscopy (SEM), and the resulting SEM images are shown below. Figure 1 and Figure 2 As shown.

[0122] from Figure 1 It can be seen that the ultrafine ruthenium nanoparticles are anchored on the CoOOH / Co(OH)2 sheet; Figure 2 It can be seen that Ru exists in the form of nanoclusters on nanosheets in the product, with most crystal planes having a spacing of 0.23 nm, corresponding to the (100) crystal plane of Ru.

[0123] Characterization Example 2

[0124] The elemental distribution characterization diagram of the ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets obtained in Example 2 is shown below. Figure 3 As shown.

[0125] from Figure 3 It can be seen that the product morphology consists of Ru nanoclusters anchored on nanosheets and uniformly distributed.

[0126] Characterization Example 3

[0127] XRD was performed on the cobalt hydroxide nanosheets supported on ruthenium nanoclusters obtained in Example 2 and the cobalt hydroxide nanosheets provided in Comparative Example 2, and the results are as follows: Figure 4 As shown.

[0128] from Figure 4 It can be seen that the ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets is L-Ru-CoOOH / Co(OH)2. Due to the thermal shock effect of the laser, the crystallinity is enhanced, and the diffraction peaks of L-Ru-CoOOH / Co(OH)2 are obvious. However, the Ru content is low, and metallic ruthenium was not detected. Therefore, Raman spectroscopy characterization was performed, and the results are as follows. Figure 5 As shown.

[0129] from Figure 5 It can be seen that it is located at 610cm -1 -630cm -1 The peak belongs to Ru-OA 1g .

[0130] XPS was performed on the cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst obtained in Example 2, and the results are as follows: Figure 6 As shown.

[0131] from Figure 6 It can be seen that the product contains Ru, Co and O elements.

[0132] Experimental Example 1

[0133] The catalysts obtained in Examples 1-9 and Comparative Examples 1-5 were subjected to three-electrode electrochemical performance tests. The synthesized composite material was used as the working electrode, the graphite rod as the counter electrode, and the saturated calomel electrode as the reference electrode. The LSV test was performed in 1M KOH solution.

[0134] The test results are shown in Table 1 below.

[0135] Table 1 Electrochemical Performance Data

[0136]

[0137]

[0138] As can be seen from Table 1, the catalysts provided in Examples 1-9 operate at a current density of 10 mA / cm². 2 At that time, the required overpotentials for HER and OER were much lower than those required for the catalysts provided in Comparative Examples 1-5. In both HER and OER, they exhibited better catalytic activity and reduced the overpotential required for the reaction.

[0139] The results obtained from Example 2 and Comparative Examples 1-4 in Table 1 are plotted as follows. Figure 7 ,from Figure 7 It can be seen that the HER (13mV@10mA / cm) of L-Ru-CoOOH / Co(OH)2 prepared by laser thermal shock is effective. 2 OER (1.51V@10mA / cm) 2 The potential is much smaller than that of Ru-CoOOH / Co(OH)2 prepared by tube furnace (76mV@10mA / cm). 2 OER (1.56V@10mA / cm) 2 Potential.

[0140] Figure 8 Tafel plots of HER and OER obtained from data in Example 2 and Comparative Examples 1-4. From... Figure 8 It can be seen that the L-Ru-CoOOH / Co(OH)2 prepared by laser thermal shock in Example 2 has the smallest Tafel slope and the best kinetic performance.

[0141] Experimental Example 2

[0142] The catalysts provided in Example 2 and Comparative Example 2, as well as the RuO2(+)||Pt / C(-) combination, were used as catalysts for a complete water splitting test.

[0143] The results were plotted. Figure 9 ,from Figure 9 It can be seen that at a current density of 10 mA / cm² 2 At that time, the L-Ru-CoOOH / Co(OH)2 provided in Example 2 required a battery voltage of only 1.52V, which is superior to the commercial RuO2||Pt / C combination.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets, characterized in that, Includes the following steps: A. Cobalt hydroxide nanosheets are immersed in a ruthenium salt solution, and after being removed and dried, cobalt hydroxide impregnated with a ruthenium salt solution is obtained; B. Using a CO2 laser, cobalt hydroxide impregnated with ruthenium salt solution is irradiated with parallel light. The laser power is 3 W to 18 W, the laser scanning speed is 62.5 mm / s to 375 mm / s, and the sampling frequency is 500 PPI to 1000 PPI to obtain the cobalt hydroxide nanosheet supported ruthenium nanocluster catalyst. The cobalt hydroxide nanosheets are CoOOH / Co(OH)2 nanosheets; The preparation method of the cobalt hydroxide nanosheets is as follows: an electrodeposition solution is prepared using a cobalt source and NH4Cl, and two electrodes are subjected to constant current discharge in the electrodeposition solution with carbon cloth as the substrate; then the two electrodes are transferred to an ammonium sulfate solution for constant current in-situ anodic oxidation, and after drying, cobalt hydroxide nanosheets are obtained.

2. The preparation method according to claim 1, characterized in that, In step A, the concentration of the ruthenium salt solution is 0.01 mg / mL to 0.5 mg / mL.

3. The preparation method according to claim 1, characterized in that, In step A, the concentration of the ruthenium salt solution is 0.1 mg / mL to 0.3 mg / mL.

4. The preparation method according to claim 1, characterized in that, In step A, the soaking time is 1 min to 30 min.

5. The preparation method according to claim 1, characterized in that, The wavelength of the parallel light is 10 μm to 15 μm.

6. The preparation method according to claim 1, characterized in that, The wavelength of the parallel light is 10.64 μm.

7. The preparation method according to claim 1, characterized in that, The irradiation time is 30 s to 5 min.

8. The preparation method according to claim 1, characterized in that, The irradiation time is 1 min to 3 min.

9. The preparation method according to claim 1, characterized in that, In step B, the laser power is 3 W to 12 W, and the laser scanning speed is 62.5 mm / s to 200 mm / s.

10. The preparation method according to claim 1, characterized in that, The cobalt source includes cobalt nitrate.

11. The preparation method according to claim 1, characterized in that, In the electrodeposition solution, the concentration of the cobalt source is 0.01 mol / L to 0.1 mol / L, and the concentration of NH4Cl is 0.01 mol / L to 0.1 mol / L.

12. The preparation method according to claim 1, characterized in that, At -1 mA / cm 2 ~-3 mA / cm 2 The constant current discharge is performed for 30-120 minutes.

13. The preparation method according to claim 1, characterized in that, At 1 mA / cm 2 ~3 mA / cm 2 The constant current in-situ anodizing is performed by charging for 30 min to 120 min.

14. The preparation method according to claim 1, characterized in that, At -1.5 mA / cm 2 The constant current discharge was performed for 60 minutes.

15. The preparation method according to claim 1, characterized in that, At 1.2 mA / cm 2 The constant current in-situ anodizing was performed after charging for 60 minutes.

16. A ruthenium nanocluster catalyst supported on cobalt hydroxide nanosheets prepared by the preparation method according to any one of claims 1-15.

17. The application of the cobalt hydroxide nanosheet-supported ruthenium nanocluster catalyst according to claim 16 in the electrolysis of water to produce hydrogen.

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