An amorphous Sr-CoOOH v Ultrathin nanosheet electrocatalysts, their preparation methods, and applications

Abstract

The application belongs to the technical field of two-dimensional nanomaterial electrocatalyst preparation, and particularly relates to an amorphous Sr-CoOOH v Ultra-thin nanosheet electrocatalyst, preparation method and application. Strontium-doped cobalt selenide nanobelt is prepared as a substrate by a hydrothermal method, and in-situ electrochemical reconstruction is generated under alkaline electrolytic water anode oxygen evolution reaction conditions. The Sr-CoOOH v The ultra-thin nanosheet can not only enhance cobalt-oxygen covalence to activate lattice oxygen, but also improve hydroxyl affinity to fill lattice oxygen due to the existence of metal cobalt vacancies, so that the catalyst exhibits excellent catalytic activity and durability in industrial application of anion exchange membrane electrolytic water hydrogen production.

Description

Technical Field

[0001] This invention belongs to the field of two-dimensional nanomaterials and hydrogen energy catalysis technology, specifically relating to an amorphous Sr-CoOOH v Ultrathin nanosheet electrocatalysts, their preparation methods, and applications. Background Technology

[0002] To overcome resource and environmental constraints and achieve sustainable development, energy structure transformation has become a crucial issue. Against this backdrop, hydrogen energy, as a clean and efficient energy source, is experiencing unprecedented development opportunities. Among various green hydrogen production technologies, anion exchange membrane electrolysis of water offers a significant cost advantage due to its use of non-precious metal catalysts, making it crucial for promoting the large-scale application of hydrogen energy. However, this technology currently faces the constraint of slow kinetics in the anode oxygen evolution reaction, which has become a bottleneck limiting its large-scale promotion. Therefore, developing economical, efficient, and environmentally friendly non-precious metal anode oxygen evolution reaction catalysts has become key to advancing the large-scale and commercial application of anion exchange membrane electrolysis of water for hydrogen production.

[0003] Currently, cobalt hydroxyoxide (CoOOH) is considered one of the most promising catalysts for the anodic oxygen evolution reaction (OER), exhibiting a relatively moderate degradation rate and tunable catalytic activity. Meanwhile, constructing metal ion vacancies, a typical symmetry-breaking structure, can effectively regulate the catalytic behavior of metal-based catalysts by altering the charge density gradient and adjusting the local atomic configuration. For example, *Nature Communications* (15, 5422, 2024) reported a method to generate La defects on the surface by reducing the metal ratio and redox treatment. La ion vacancies in LaFeO3 can reduce the electron density of surface oxygen, significantly enhancing the mobility of lattice oxygen, thereby lowering the barrier for CH4 cracking and methane oxidation to syngas. Therefore, designing and constructing CoOOH nanostructure catalysts with metal ion vacancies is of great significance for achieving efficient anion exchange membrane electrolysis for hydrogen production.

[0004] However, metal-based catalysts inevitably undergo dynamic reconstruction under the conditions of oxygen evolution reaction at the anode in water electrolysis via anion exchange membranes. This may rebuild local atomic structures, leading to the disappearance of vacancy sites. Ultimately, this makes it difficult for the constructed electrocatalyst to achieve the goals of high activity and high stability in the water electrolysis hydrogen production reaction. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides an amorphous Sr-CoOOH rich in cobalt vacancies. v Preparation methods and applications of ultrathin nanosheet electrocatalysts.

[0006] The amorphous Sr-CoOOH of the present invention v The ultrathin nanosheet electrocatalyst is rich in cobalt vacancies. The presence of metallic cobalt vacancies not only enhances the cobalt-oxygen covalent activation of lattice oxygen, but also improves the hydroxyl affinity to fill lattice oxygen, enabling the industrial application of high-performance and high-stability anion exchange membrane electrolysis for hydrogen production. This solves the problem of poor catalytic activity and durability of anode catalysts for hydrogen production by water electrolysis, which is difficult to address with existing technologies.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows.

[0008] The first aspect of this invention provides an amorphous Sr-CoOOH v The ultrathin nanosheet electrocatalyst uses Sr-doped cobalt selenide nanoribbons as a substrate. Under the conditions of oxygen evolution reaction at the anode of water electrolysis for hydrogen production, an in-situ amorphous structure rich in cobalt vacancies is formed through electrochemical oxidation reconstruction. The amorphous Sr-CoOOH... v The chemical composition of the ultrathin nanosheet electrocatalyst is Sr-CoOOH v .

[0009] This invention provides an amorphous Sr-CoOOH rich in cobalt vacancies. v Ultrathin nanosheets, amorphous Sr-CoOOH v The ultrathin nanosheet electrocatalyst is rich in cobalt vacancies. The presence of metallic cobalt vacancies can not only enhance the cobalt-oxygen covalent activation of lattice oxygen, but also improve the hydroxyl affinity to fill lattice oxygen, thus enabling the industrial application of high-performance and high-stability anion exchange membrane electrolysis for hydrogen production.

[0010] Preferably, during the reconstruction process, lattice Co is leached out, and Sr is dispersed in the amorphous structure rich in cobalt vacancies in the form of single atoms.

[0011] Preferably, Sr-doped cobalt selenide nanoribbons are prepared by a hydrothermal reaction of cobalt salt, strontium salt, and selenate in an aqueous solution of polyethylenepolyamine at a temperature of 170°C to 200°C. In this invention, the morphology of the nanoribbons is adjusted by regulating the hydrothermal reaction temperature to 170°C to 200°C; excessively high temperatures will destroy the nanoribbon morphology, while excessively low temperatures will result in insufficient dissolution of the precursor, preventing the formation of the nanoribbon structure.

[0012] Preferably, the molar ratio of the total molar amount of cobalt salt and strontium salt to the molar amount of selenate is 1:1 to 3; the molar ratio of strontium salt to cobalt salt is 0.002 to 0.01:1; in the aqueous solution of polyethylene polyamine, the volume ratio of polyethylene polyamine to water is 2:0.5 to 2; and the dosage ratio of cobalt salt to polyethylene polyamine is 246 mg to 249 mg: 26.7 mL.

[0013] Preferably, the cobalt salt is one of cobalt sulfate, cobalt chloride, cobalt acetate, cobalt nitrate, and cobalt acetylacetonate; the strontium salt is one of strontium nitrate, strontium chloride, strontium acetate, and strontium acetylacetonate; the selenate is one of potassium selenite and sodium selenite; and the polyethylenepolyamine is one of diethylenetriamine, triethylenetetraamine, and tetraethylenepentamine.

[0014] A second aspect of the present invention provides an amorphous Sr-CoOOH v The preparation method of ultrathin nanosheet electrocatalysts includes the following steps: Sr-doped cobalt selenide nanoribbons were prepared by hydrothermal reaction in an aqueous solution of polyethylenepolyamine at 170℃–200℃ using cobalt salts, strontium salts, and selenates as raw materials. These Sr-doped cobalt selenide nanoribbons were then subjected to electrochemical oxidation and reconstruction under conditions of oxygen evolution at the anode in water electrolysis for hydrogen production, resulting in an in-situ amorphous structure rich in cobalt vacancies, yielding amorphous Sr-CoOOH. v Ultrathin nanosheet electrocatalysts.

[0015] This invention prepares strontium-doped Sr-CoSe2 nanoribbons via hydrothermal synthesis, and then reconstructs the prepared Sr-CoSe2 nanoribbons under anion exchange membrane electrolysis water electrolysis for hydrogen production, thereby preparing amorphous Sr-CoOOH rich in cobalt vacancies. v Ultrathin nanosheet electrocatalysts.

[0016] Preferably, the hydrothermal reaction time is 15h to 20h.

[0017] Preferably, the oxygen evolution reaction conditions at the anolyte of water electrolysis for hydrogen production are those of alkaline water electrolysis for hydrogen production; the electrolyte for alkaline water electrolysis for hydrogen production is a potassium hydroxide solution with a concentration of 0.1 mol / L to 1 mol / L. In this invention, amorphous Sr-CoOOH is prepared by electrochemical reconstruction of Sr-CoSe2 nanoribbons using cyclic voltammetry. v Ultrathin nanosheet electrocatalysts were tested by cyclic voltammetry in a 1 mol / L potassium hydroxide electrolyte.

[0018] Preferably, the parameters for the anodic oxygen evolution reaction in water electrolysis for hydrogen production are as follows: voltage of 1.02V vs. RHE to 1.50V vs. RHE, and scan rate of 50mV / s to 100mV / s.

[0019] The preferred method for electrochemical oxidation reconstruction is as follows: Sr-doped cobalt selenide nanoribbons were dispersed in an alcoholic solution of Nafion and then coated onto an electrode surface to serve as the working electrode. The working electrode was subjected to cyclic voltammetry tests in an oxygen-saturated 1M potassium hydroxide electrolyte at scan rates of 50 mV / s to 100 mV / s for 30 to 200 cycles within a voltage range of 1.02 V vs. RHE to 1.50 V vs. RHE. In-situ reconstruction resulted in the formation of an amorphous structure rich in cobalt vacancies, yielding a cobalt-vacancy-rich amorphous Sr-CoOOH. v Nanosheets.

[0020] This invention primarily utilizes abundant and inexpensive raw materials such as cobalt, selenium, and strontium, synthesized through oxidative reconstruction under mild anodic reaction conditions in water electrolysis. Compared to traditional anodic oxygen evolution reaction catalyst processes in water electrolysis, this synthesis process is simpler, more environmentally friendly, and less expensive. It also allows for efficient design and optimization of the catalyst surface structure, demonstrating significant potential for large-scale industrial application.

[0021] A third aspect of the present invention provides an amorphous Sr-CoOOH v Application of ultrathin nanosheet electrocatalysts in industrial anion exchange membrane water electrolysis for hydrogen production.

[0022] The beneficial effects of this invention are: 1. This invention provides amorphous Sr-CoOOH rich in cobalt vacancies. v Ultrathin nanosheets, using Sr-doped cobalt selenide nanoribbons as a substrate, were reconstructed in situ into an amorphous structure rich in cobalt vacancies through electrochemical oxidation under the conditions of anion exchange membrane water electrolysis for hydrogen production and oxygen evolution at the anodic reaction. The presence of metallic cobalt vacancies not only enhances the cobalt-oxygen covalent activation of lattice oxygen, but also enriches the Sr-CoOOH structure with cobalt vacancies. v It can enhance the oxygen evolution reaction activity at the anode of water electrolysis and play a unique and significant role in industrial anion exchange membrane water splitting for hydrogen production, exhibiting excellent catalytic activity and durability.

[0023] 2. The Sr-CoOOH of the present invention, rich in cobalt vacancies v When nanosheets are used as electrocatalysts in the oxygen evolution reaction (OER) at the anodic end of anion exchange membrane (EEM) water electrolysis, the participation of Sr ions facilitates the leaching of Co lattice during reconstruction, forming an amorphous structure rich in cobalt vacancies. This structure exhibits excellent catalytic activity and durability in the OER reaction. Specifically, subsequent performance tests show that at a current density of 10 mA / cm²... 2 At that time, the amorphous Sr-CoOOH rich in cobalt vacancies v The overpotential of the nano-electrocatalyst is only 255 mV, which is 72 mV lower than that of the commercial RuO2 catalyst. Meanwhile, at an overpotential of 293 mV, the amorphous Sr-CoOOH rich in cobalt vacancies exhibits...v The current density of the nano-electrocatalyst is 25.0 times higher than that of the RuO2 catalyst, exhibiting the characteristics of an amorphous Sr-CoOOH rich in cobalt vacancies. v Nanosheet electrocatalysts exhibit excellent catalytic activity in the electrocatalytic oxygen evolution reaction.

[0024] Furthermore, in the industrial application of alkaline water electrolysis, amorphous Sr-CoOOH rich in cobalt vacancies... v Nanosheet catalyst achieves 3.3 A / cm at 2.0 V. 2 The current density is 5.3 times higher than that of commercial RuO2 catalysts. In industrial water electrolysis, the current density is 500 mA / cm². 2 After running for 1000 hours, the amorphous Sr-CoOOH rich in cobalt vacancies... v The decay rate of the nanosheet catalyst is only 0.10 mV / h, demonstrating the high cobalt vacancy content of the amorphous Sr-CoOOH. v The nanosheets exhibit excellent catalytic durability in the anion exchange membrane water electrolysis hydrogen production reaction. Therefore, the cobalt-vacancy-rich amorphous Sr-CoOOH obtained in this invention... v Nanosheet catalysts have significant development prospects in the industrial application of anion exchange membrane water electrolysis for hydrogen production. Attached Figure Description

[0025] Figure 1 The images shown are transmission electron microscope (TEM) images of the Sr-CoSe2 nanoribbons prepared in Example 1. In the images, a is a low-magnification TEM image; b is an aberration-corrected TEM image and its corresponding atomic intensity plot.

[0026] Figure 2 The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 1 v Transmission electron microscope (TEM) images of nanosheets. In the image, a is a low-magnification TEM image; b is an aberration-corrected TEM image.

[0027] Figure 3 The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 1 v Extended X-ray absorption fine structure spectrum and corresponding coordination number diagram of nanosheets. Where a is the extended X-ray absorption fine structure spectrum; b is the corresponding coordination number diagram.

[0028] Figure 4 The Sr-CoSe2 nanoribbons prepared in Example 1 and the cobalt-vacancy-rich amorphous Sr-CoOOH v Comparison of X-ray diffraction patterns of nanosheets.

[0029] Figure 5 The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 1v Linear scanning curves of nanosheets and commercial RuO2 catalyst in the oxygen evolution reaction at the anode of water electrolysis for hydrogen production via anion exchange membrane.

[0030] Figure 6 The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 2 v Linear scanning curves of nanosheets and commercial RuO2 catalyst in the oxygen evolution reaction at the anode of water electrolysis for hydrogen production via anion exchange membrane.

[0031] Figure 7 The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 3 v Linear scanning curves of commercial RuO2 nanosheet catalysts in the oxygen evolution reaction at the anode of water electrolysis for hydrogen production via anion exchange membrane.

[0032] Figure 8 The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 1 v Performance test curves of nanosheets in the process of hydrogen production by water electrolysis using anion exchange membranes.

[0033] Figure 9 The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 1 v Durability test curves of nanosheets in the process of hydrogen production by water electrolysis using anion exchange membranes. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Currently, in the development of anode electrocatalysts for anion exchange membrane water electrolysis, the method of precisely designing metal ion vacancies in dynamically reconstructed metal-based catalysts still cannot achieve high-performance applications in the industrialization of anion exchange membrane water electrolysis by regulating metal ion vacancies.

[0037] Currently, there is a lack of technology to dynamically control the metal ion vacancies formed during the anion exchange membrane water electrolysis anodic oxidation process of CoOOH catalysts. This prevents CoOOH catalyst materials from exhibiting the theoretically high activity and high stability expected in actual water electrolysis for hydrogen production. Therefore, it is urgent to develop a necessary metal ion vacancy design process based on the CoOOH formed under anion exchange membrane water electrolysis anodic oxidation conditions to address this problem, thereby developing a class of anion exchange membrane water electrolysis hydrogen production catalytic materials that combine high performance and high stability.

[0038] The technical solution of the present invention will be further described below through specific embodiments. Unless otherwise specified, the methods described in the following embodiments are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0039] Example 1 An amorphous Sr-CoOOH rich in cobalt vacancies v The preparation method of nanosheet electrocatalysts includes the following steps: Step 1, Preparation of Sr-CoSe2 nanoribbons: At room temperature, 247.1 mg of cobalt acetate, 1.62 mg of strontium acetate, and 173 mg of sodium selenite were added to a solution of diethylenetriamine and water in a volume ratio of 2:1. The ratio of cobalt acetate to diethylenetriamine was 247.1 mg: 26.7 mL. The mixture was reacted at 180 °C for 16 h, and then centrifuged, washed, and vacuum dried to obtain Sr-CoSe2 nanoribbons.

[0040] Step 2, amorphous Sr-CoOOH rich in cobalt vacancies v Preparation of nanosheets: The prepared Sr-CoSe2 nanoribbons were dispersed in an alcoholic solution of Nafion, and an appropriate amount was coated onto the electrode surface to serve as the working electrode. The working electrode was subjected to cyclic voltammetry for 40 cycles in an oxygen-saturated 1M potassium hydroxide electrolyte at a scan rate of 50 mV / s within a voltage range of 1.02 V vs. RHE to 1.50 V vs. RHE, thus reconstructing amorphous Sr-CoOOH rich in cobalt vacancies. v Nanosheets.

[0041] Example 2 An amorphous Sr-CoOOH rich in cobalt vacancies v The preparation method of the nanosheet electrocatalyst differs from that in Example 1 in the amount of cobalt acetate and strontium acetate added. Specifically, 247.8 mg of cobalt acetate and 0.97 mg of strontium acetate are added during the hydrothermal process in step 1. The specific preparation method includes the following steps:

[0042] Step 1, Preparation of Sr-CoSe2 nanoribbons: At room temperature, 247.8 mg of cobalt acetate, 0.97 mg of strontium acetate, and 173 mg of sodium selenite were added to a solution of diethylenetriamine and water in a volume ratio of 2:1. The ratio of cobalt acetate to diethylenetriamine was 247.8 mg: 26.7 mL. The mixture was reacted at 180 °C for 16 h, and then centrifuged, washed, and vacuum dried to obtain Sr-CoSe2 nanoribbons.

[0043] Step 2, amorphous Sr-CoOOH rich in cobalt vacancies v Preparation of nanosheets: The prepared Sr-CoSe2 nanoribbons were dispersed in an alcoholic solution of Nafion, and an appropriate amount was coated onto the electrode surface to serve as the working electrode. The working electrode was subjected to cyclic voltammetry for 40 cycles in an oxygen-saturated 1M potassium hydroxide electrolyte at a scan rate of 50 mV / s within a voltage range of 1.02 V vs. RHE to 1.50 V vs. RHE, thus reconstructing amorphous Sr-CoOOH rich in cobalt vacancies. v Nanosheets.

[0044] Example 3 An amorphous Sr-CoOOH rich in cobalt vacancies v The preparation method of the nanosheet electrocatalyst differs from that in Example 1 in that the amounts of cobalt acetate and strontium acetate added are different. Specifically, 248.7 mg of cobalt acetate and 0.32 mg of strontium acetate are added during the hydrothermal process in step 1.

[0045] Step 1, Preparation of Sr-CoSe2 nanoribbons: At room temperature, 248.7 mg of cobalt acetate, 0.32 mg of strontium acetate, and 173 mg of sodium selenite were added to a solution of diethylenetriamine and water in a volume ratio of 2:1. The ratio of cobalt acetate to diethylenetriamine was 248.7 mg: 26.7 mL. The mixture was reacted at 180 °C for 16 h, and then centrifuged, washed, and vacuum dried to obtain Sr-CoSe2 nanoribbons.

[0046] Step 2, amorphous Sr-CoOOH rich in cobalt vacancies v Preparation of nanosheets: The prepared Sr-CoSe2 nanoribbons were dispersed in an alcoholic solution of Nafion, and an appropriate amount was coated onto the electrode surface to serve as the working electrode. The working electrode was subjected to cyclic voltammetry for 40 cycles in an oxygen-saturated 1M potassium hydroxide electrolyte at a scan rate of 50 mV / s within a voltage range of 1.02 V vs. RHE to 1.50 V vs. RHE, thus reconstructing amorphous Sr-CoOOH rich in cobalt vacancies. v Nanosheets.

[0047] Comparative Example 1 A method for preparing an amorphous CoOOH nanosheet electrocatalyst, differing from Example 1 in that strontium acetate is not incorporated; the specific preparation method includes the following steps: Step 1, Preparation of CoSe2 nanoribbons: At room temperature, 249 mg of cobalt acetate and 173 mg of sodium selenite were added to a solution of diethylenetriamine and water in a volume ratio of 2:1. The ratio of cobalt acetate to diethylenetriamine was 249 mg: 26.7 mL. The mixture was reacted at 180 °C for 16 h, and then centrifuged, washed, and vacuum dried to obtain CoSe2 nanoribbons.

[0048] Step 2, amorphous CoOOH v Preparation of nanosheets: The prepared CoSe2 nanoribbons were dispersed in an alcoholic solution of Nafion, and an appropriate amount was coated onto the electrode surface to serve as the working electrode. The working electrode was subjected to cyclic voltammetry for 40 cycles in an oxygen-saturated 1M potassium hydroxide electrolyte at a scan rate of 50 mV / s within a voltage range of 1.02 V vs. RHE to 1.50 V vs. RHE, thus reconstructing the amorphous Sr-CoOOH. v Nanosheets.

[0049] Example 4 An amorphous Sr-CoOOH rich in cobalt vacancies v The preparation method of the nanosheet electrocatalyst differs from that in Example 1 in that the hydrothermal reaction conditions in step 1 are different; the specific preparation method includes the following steps: Step 1, Preparation of Sr-CoSe2 nanoribbons: At room temperature, 247.1 mg of cobalt acetate, 1.62 mg of strontium acetate, and 173 mg of sodium selenite were added to a solution of diethylenetriamine and water in a volume ratio of 2:1. The ratio of cobalt acetate to diethylenetriamine was 247.1 mg: 26.7 mL. The mixture was reacted at 170 °C for 20 h, and then centrifuged, washed, and vacuum dried to obtain Sr-CoSe2 nanoribbons.

[0050] Step 2, amorphous Sr-CoOOH rich in cobalt vacancies v Preparation of nanosheets: The prepared Sr-CoSe2 nanoribbons were dispersed in an alcoholic solution of Nafion, and an appropriate amount was coated onto the electrode surface to serve as the working electrode. The working electrode was subjected to cyclic voltammetry for 40 cycles in an oxygen-saturated 1M potassium hydroxide electrolyte at a scan rate of 50 mV / s within a voltage range of 1.02 V vs. RHE to 1.50 V vs. RHE, thus reconstructing amorphous Sr-CoOOH rich in cobalt vacancies. vNanosheets.

[0051] Example 5 An amorphous Sr-CoOOH rich in cobalt vacancies v The preparation method of the nanosheet electrocatalyst differs from that in Example 1 in that the hydrothermal reaction conditions in step 1 are different; the specific preparation method includes the following steps: Step 1, Preparation of Sr-CoSe2 nanoribbons: At room temperature, 247.1 mg of cobalt acetate, 1.62 mg of strontium acetate, and 173 mg of sodium selenite were added to a solution of diethylenetriamine and water in a volume ratio of 2:1. The ratio of cobalt acetate to diethylenetriamine was 247.1 mg: 26.7 mL. The mixture was reacted at 200 °C for 15 h, and then centrifuged, washed, and vacuum dried to obtain Sr-CoSe2 nanoribbons.

[0052] Step 2, amorphous Sr-CoOOH rich in cobalt vacancies v Preparation of nanosheets: The prepared Sr-CoSe2 nanoribbons were dispersed in an alcoholic solution of Nafion, and an appropriate amount was coated onto the electrode surface to serve as the working electrode. The working electrode was subjected to cyclic voltammetry for 40 cycles in an oxygen-saturated 1M potassium hydroxide electrolyte at a scan rate of 50 mV / s within a voltage range of 1.02 V vs. RHE to 1.50 V vs. RHE, thus reconstructing amorphous Sr-CoOOH rich in cobalt vacancies. v Nanosheets.

[0053] The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in the above examples v Structural testing was conducted on the nanosheets.

[0054] Test 1: Transmission electron microscopy and elemental analysis.

[0055] like Figure 1 Figure a shows a transmission electron microscope image of the Sr-CoSe2 nanoribbons prepared in Example 1. The obtained sample has a ribbon-like structure with a width between 400 nm and 500 nm. Figure 1 Figure b, an aberration-corrected transmission electron microscope image, confirms that Sr substitutes for Co atoms in the CoSe2 structure.

[0056] like Figure 2 Figure a shows the amorphous Sr-CoOOH rich in cobalt vacancies prepared in Example 1. v Transmission electron microscopy images of the nanosheets show that the obtained sample is an ultrathin nanosheet structure. For example... Figure 2 As shown in Figure b, the obtained sample consists of Sr single atoms dispersed in an amorphous CoOOH structure.

[0057] Compared with pure CoSe2 nanoribbons without Sr, the microstructure of the CoSe2 nanoribbons in Comparative Example 1 was analyzed. The results showed that the morphology of the CoSe2 nanoribbons in Comparative Example 1 was still that of an ultrathin nanoribbon.

[0058] Sr-CoSe2 nanoribbons prepared in Examples 1, 4, and 5 and amorphous Sr-CoOOH rich in cobalt vacancies. v Morphology analysis of the nanosheets showed that the morphology of the nanoribbons could be adjusted within the temperature range of 170℃ to 200℃. Specifically, at 180℃, uniformly sized and relatively dispersed ultrathin nanoribbons were obtained. Temperatures above 200℃ led to morphological damage to the nanosheets, while temperatures below 170℃ resulted in insufficient dissolution of the precursor, preventing the formation of nanosheet structures. The preferred hydrothermal reaction temperature was 180℃ ± 3℃.

[0059] Test 2: Fine structure analysis.

[0060] like Figure 3 The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 1 v Extended X-ray absorption fine structure spectra and corresponding coordination number diagrams comparing the nanosheets with standard CoOOH samples confirm that Sr-CoSe2 nanoribbons can generate Sr-CoOOH rich in Co vacancies through electrochemical oxidation reconstruction. v Ultrathin nanosheets.

[0061] Test 3: X-ray diffraction pattern analysis.

[0062] like Figure 4 The Sr-CoSe2 nanoribbons prepared in Example 1 and the amorphous Sr-CoOOH rich in cobalt vacancies v X-ray diffraction patterns of the nanosheets show that the main structure of the obtained Sr-CoSe2 nanoribbons is a cubic cobalt diselenide structure, while the reconstructed Sr-CoOOH nanoribbons are rich in cobalt vacancies. v Nanosheets have an amorphous structure.

[0063] The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Examples 1 to 3 v The nanosheets were subjected to performance testing.

[0064] Test 4: For amorphous Sr-CoOOH rich in cobalt vacancies v Performance testing and comparison of nanosheets in the oxygen evolution reaction of hydrogen production by anion exchange membrane electrolysis of water.

[0065] The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 1 vThe nanocatalyst was used as the working electrode, and its catalytic activity in the oxygen evolution reaction of anion exchange membrane electrolysis for hydrogen production was determined in oxygen-saturated 1M potassium hydroxide electrolyte. The linear scan curves obtained at a rotation speed of 1600 rpm and a scan rate of 10 mV / s are shown below. Figure 5 As shown. At a current density of 10 mA / cm². 2 At that time, the amorphous Sr-CoOOH rich in cobalt vacancies v The overpotential of the nano-electrocatalyst is only 255 mV, which is 72 mV lower than that of the commercial RuO2 catalyst. Meanwhile, at an overpotential of 293 mV, the amorphous Sr-CoOOH rich in cobalt vacancies exhibits... v The current density of the nanocatalyst is 25.0 times higher than that of the RuO2 catalyst, exhibiting an amorphous Sr-CoOOH rich in cobalt vacancies. v Nanosheets exhibit excellent anodic oxygen evolution reaction activity in water electrolysis.

[0066] The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 2 v The nanocatalysts were prepared using the same method and their catalytic performance was tested. The resulting linear sweep curves are shown below. Figure 6 As shown. At a current density of 10 mA / cm². 2 At that time, the amorphous Sr-CoOOH rich in cobalt vacancies v The overpotential of the nanocatalyst is only 274 mV, which is 53 mV lower than that of the commercial RuO2 catalyst. Meanwhile, at an overpotential of 293 mV, the amorphous Sr-CoOOH rich in cobalt vacancies exhibits... v The catalyst exhibits a 5.0-fold increase in current density compared to the RuO2 catalyst, demonstrating an amorphous Sr-CoOOH rich in cobalt vacancies. v Nanosheets exhibit excellent anodic oxygen evolution reaction activity in water electrolysis.

[0067] The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 3 v Nanosheets were prepared using the same method and their catalytic performance was tested. The resulting linear scanning curves are shown below. Figure 7 As shown. At a current density of 10 mA / cm². 2 At that time, the amorphous Sr-CoOOH rich in cobalt vacancies v The overpotential of the nanocatalyst is only 289 mV, which is 38 mV lower than that of the commercial RuO2 catalyst. Meanwhile, at an overpotential of 293 mV, the amorphous Sr-CoOOH rich in cobalt vacancies exhibits... v The current density of the nanocatalyst is 2.9 times higher than that of the RuO2 catalyst, exhibiting an amorphous Sr-CoOOH rich in cobalt vacancies. v Ultrathin nanosheets exhibit excellent anodic oxygen evolution reaction activity in water electrolysis.

[0068] Test 5: For amorphous Sr-CoOOH rich in cobalt vacancies v Performance testing and comparison of nanosheets in anion exchange membrane water electrolysis hydrogen production cell.

[0069] The cobalt-vacancy-rich amorphous Sr-CoOOH prepared in Example 1 v The nanocatalyst was used as the working electrode, and the performance of its anion exchange membrane water electrolysis hydrogen production cell was determined in 1M potassium hydroxide electrolyte. The obtained linear sweep curves are shown below. Figure 8 As shown, 3.3 A / cm is achieved at 2.0 V. 2 The current density. Furthermore, such as Figure 9 As shown, at a current density of 500 mA / cm² 2 After 1000 hours of stability testing, the amorphous Sr-CoOOH rich in cobalt vacancies... v The decay rate of the nanocatalyst is only 0.10 mV / h, exhibiting an amorphous Sr-CoOOH rich in cobalt vacancies. v Ultrathin nanosheets exhibit excellent catalytic durability during alkaline water electrolysis.

[0070] In summary, the amorphous Sr-CoOOH rich in cobalt vacancies prepared in the embodiments of the present invention... v Ultrathin nanosheets, using strontium-doped cobalt selenide nanoribbons as a substrate, were formed in situ through electrochemical oxidation reconstruction under the conditions of anion exchange membrane water electrolysis for hydrogen production and oxygen evolution at the anodic reaction. The presence of cobalt vacancies not only enhances the cobalt-oxygen covalent activation of lattice oxygen but also increases the affinity of hydroxyl groups for filling lattice oxygen. Sr-CoOOH rich in cobalt vacancies... v It can enhance the oxygen evolution reaction activity at the anode of water electrolysis and play a unique and significant role in industrial anion exchange membrane water splitting for hydrogen production, exhibiting excellent catalytic activity and durability.

[0071] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An amorphous Sr-CoOOH v Ultrathin nanosheet electrocatalyst, characterized in that, Using Sr-doped cobalt selenide nanoribbons as a substrate, an amorphous structure rich in cobalt vacancies is formed in situ through electrochemical oxidation reconstruction under alkaline water electrolysis for hydrogen production and oxygen evolution at the anodic reaction conditions; the amorphous Sr-CoOOH v The chemical composition of the ultrathin nanosheet electrocatalyst is Sr-CoOOH v ; During the reconstruction process, Co leaches out from the lattice, and Sr is dispersed in the amorphous structure rich in cobalt vacancies in the form of single atoms.

2. The amorphous Sr-CoOOH according to claim 1 v Ultrathin nanosheet electrocatalyst, characterized in that, Sr-doped cobalt selenide nanoribbons were prepared by using cobalt salt, strontium salt and selenate as raw materials and carrying out a hydrothermal reaction in an aqueous solution of polyethylene polyamine at a temperature of 170℃~200℃.

3. The amorphous Sr-CoOOH according to claim 2 v Ultrathin nanosheet electrocatalyst, characterized in that, The total molar ratio of cobalt salt and strontium salt to selenate is 1:1 to 3; the molar ratio of strontium salt to cobalt salt is 0.002 to 0.01:1; in the aqueous solution of polyethylene polyamine, the volume ratio of polyethylene polyamine to water is 2:0.5 to 2; the ratio of cobalt salt to polyethylene polyamine is 246 mg to 249 mg: 26.7 mL.

4. The amorphous Sr-CoOOH according to claim 2 v Ultrathin nanosheet electrocatalyst, characterized in that, Cobalt salts are one of cobalt sulfate, cobalt chloride, cobalt acetate, cobalt nitrate, and cobalt acetylacetonate; strontium salts are one of strontium nitrate, strontium chloride, strontium acetate, and strontium acetylacetonate; selenates are one of potassium selenite and sodium selenite; and polyethylenepolyamines are one of diethylenetriamine, triethylenetetraamine, and tetraethylenepentamine.

5. An amorphous Sr-CoOOH as described in any one of claims 1 to 4 v A method for preparing ultrathin nanosheet electrocatalysts, characterized in that, Includes the following steps: Sr-doped cobalt selenide nanoribbons were prepared by hydrothermal reaction in an aqueous solution of polyethylene polyamine at 170℃~200℃ using cobalt salt, strontium salt and selenate as raw materials. Sr-doped cobalt selenide nanoribbons were electrochemically oxidized and reconstructed under alkaline water electrolysis for hydrogen production via an anodic oxygen evolution reaction to form an in-situ amorphous structure rich in cobalt vacancies, yielding amorphous Sr-CoOOH. v Ultrathin nanosheet electrocatalysts; The parameters for the oxygen evolution reaction at the anode in alkaline water electrolysis for hydrogen production are as follows: voltage 1.02V vs. RHE ~ 1.50V vs. RHE, and scan rate 50mV / s ~ 100mV / s.

6. The amorphous Sr-CoOOH according to claim 5 v A method for preparing ultrathin nanosheet electrocatalysts, characterized in that, The hydrothermal reaction time is 15h to 20h.

7. The amorphous Sr-CoOOH according to claim 5 v A method for preparing ultrathin nanosheet electrocatalysts, characterized in that, The electrolyte for alkaline water electrolysis to produce hydrogen is a potassium hydroxide solution with a concentration of 0.1 mol / L to 1 mol / L.

8. An amorphous Sr-CoOOH as described in any one of claims 1 to 4 v Application of ultrathin nanosheet electrocatalysts in industrial anion exchange membrane water electrolysis for hydrogen production.

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