A high-entropy V-VI-VII group hydrogen evolution electrocatalyst, its preparation method and application
By preparing high-entropy V-VI-VII group BiSbTeSeI2 single crystal catalysts, the problem of achieving both active sites and conductivity in non-precious metal catalysts was solved, achieving efficient and stable electrocatalytic hydrogen evolution performance and expanding the application range of non-precious metal electrocatalysts.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NORTHWEST UNIV
- Filing Date
- 2026-03-23
- Publication Date
- 2026-06-02
AI Technical Summary
Existing non-precious metal catalysts suffer from problems such as difficulty in achieving both high active site density and conductivity, complex preparation processes, and insufficient stability. In particular, in the field of electrocatalytic hydrogen evolution, traditional layered materials struggle to achieve a balance between high crystallinity and high active sites.
High-entropy V-VI-VII group compound BiSbTeSeI2 single crystals were used as catalysts to prepare high-quality single crystals via chemical vapor transport method. Single crystal powders or nanosheets were obtained by mechanical grinding or liquid phase exfoliation, exposing abundant edge active sites, which simplified the preparation process and reduced costs.
The combination of high crystallinity and abundant edge active sites has been achieved, forming a fast electron transport channel. The catalyst exhibits excellent hydrogen evolution performance and good cycle stability in acidic electrolytes, with low overpotential and excellent kinetic performance.
Smart Images
Figure CN122128738A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the fields of electrocatalysis technology and new energy materials technology, specifically relating to a high-entropy V-VI-VII group hydrogen evolution electrocatalyst, and its application in electrocatalytic water splitting for hydrogen production. Background Technology
[0002] With the increasing depletion of fossil fuels and the growing environmental pollution they cause, the development of clean and renewable alternative energy sources has become an urgent need for the sustainable development of human society. Hydrogen, as a clean energy carrier with high energy density and water as its only combustion product, is considered a crucial component of the future energy structure. Among numerous hydrogen production technologies, water electrolysis technology driven by renewable energy sources is considered one of the most promising green hydrogen production pathways due to its zero carbon emissions and high hydrogen purity.
[0003] The hydrogen evolution reaction (HER) is a key half-reaction in water electrolysis, and its efficiency directly determines the overall energy consumption and production cost. Therefore, developing HER electrocatalysts with both high activity and high stability is crucial for promoting the large-scale application of water electrolysis for hydrogen production. Currently, platinum (Pt)-based noble metal materials (such as commercial Pt / C) are widely recognized as the most efficient HER catalysts, but their high cost and scarce resources severely limit their large-scale commercial application. Therefore, the development of non-noble metal-based high-efficiency HER catalysts has become a current research hotspot.
[0004] Among numerous non-noble metal catalyst systems, layered transition metal chalcogenides (represented by molybdenum disulfide MoS2 and tungsten disulfide WS2) have attracted widespread attention due to their unique two-dimensional layered structure, tunable electronic properties, and abundant edge unsaturated atomic sites. Numerous studies have shown that the catalytic active centers of MoS2 are mainly located at the edges of its layered structure, while its basal surface is chemically inert. To improve its overall catalytic performance, existing technologies typically employ the following strategies: (1) synthesizing nanostructures rich in edge sites via hydrothermal / solvothermal methods, or activating its basal surface by introducing sulfur vacancies or doping with heteroatoms; (2) combining MoS2 with highly conductive materials (such as graphene and carbon nanotubes) to construct heterostructures to improve charge transport; and (3) utilizing the higher conductivity and more active sites of the metallic phase (1T phase) MoS2 to prepare metastable catalysts through methods such as chemical exfoliation.
[0005] Despite significant progress in the research based on traditional layered materials such as MoS2, these materials still suffer from the following intrinsic limitations and technological bottlenecks: First, it is difficult to simultaneously achieve both active sites and conductivity. For traditional layered chalcogenides such as MoS2, the density of intrinsic active sites (edges) is limited, and the basal planes are typically inert. Although defect engineering can activate the basal planes, it often introduces a large amount of disordered structures, disrupting the crystallinity of the material and obstructing electron transport channels. Achieving an ideal balance between high crystallinity and high active site density is difficult. Second, modification strategies are complex and lack stability. Many high-performance modification strategies, such as heterostructure building and phase engineering, involve complex multi-step processes with low yields, making it difficult to achieve low-cost, large-scale industrial production. Furthermore, some catalysts rich in defects or metastable phases (such as 1T-MoS2) are prone to structural relaxation or phase transitions during long-term electrochemical cycling, leading to a decline in catalytic activity.
[0006] High-entropy materials have shown great potential in thermoelectrics and energy storage due to their unique "cocktail effect" (i.e., multi-principal synergistic effect), tunable electronic structure, and excellent structural stability. However, their application research in the electrocatalytic hydrogen evolution reaction (HER) field is still in its early stages, lacking targeted material design and synthesis methods. Therefore, how to move beyond the traditional binary chalcogenide system and develop a novel non-noble metal HER catalyst with high crystallinity, abundant intrinsic active sites, excellent conductivity, and simple and controllable preparation methods, especially exploring the application potential of high-entropy layered compounds in the field of electrocatalysis, remains a pressing technical challenge in this field. Summary of the Invention
[0007] This invention aims to solve the technical problems of existing non-precious metal catalysts, such as the difficulty in achieving both high active site density and conductivity, complex preparation processes, and insufficient stability. It provides a layered high-entropy V-VI-VII group hydrogen evolution electrocatalyst with high crystallinity, abundant edge active sites, and excellent conductivity, and provides a simple and low-cost preparation method for this catalyst.
[0008] The active material of the high-entropy V-VI-VII group hydrogen evolution electrocatalyst provided by this invention is BiSbTeSeI2 single crystal. Its X-ray powder diffraction pattern has characteristic peaks at diffraction angles 2θ of 11.6°±0.2°, 17.2°±0.2°, 17.8°±0.2°, 23.3°±0.2°, 27.1°±0.2° and 29.3°±0.2°, and the diffraction peak at diffraction angle 2θ of 27.1°±0.2° is the strongest peak. The particle size of the BiSbTeSeI2 single crystal is 0.5~10 μm.
[0009] Furthermore, the aforementioned BiSbTeSeI2 single crystal is either BiSbTeSeI2 single crystal powder or BiSbTeSeI2 single crystal nanosheets.
[0010] The preparation method of the high-entropy V-VI-VII group hydrogen evolution electrocatalyst of the present invention includes the following steps:
[0011] Step 1: Mix the bismuth source, antimony source, tellurium source, selenium source and iodine source evenly according to the molar ratio Bi:Sb:Te:Se:I = 0.95~1.05:0.95~1.05:0.95~1.05:0.95~1.05:1.9~2.1 to obtain the raw material mixture.
[0012] Step 2: Place the raw material mixture in a quartz tube, evacuate the inside of the quartz tube, and then seal it.
[0013] Step 3: Place the sealed quartz tube in a dual-temperature zone tube furnace to carry out a chemical vapor transport reaction. Collect the reaction products in the growth zone to obtain BiSbTeSeI2 single crystals.
[0014] Step 4: Mechanically grind or liquid-phase exfoliate the BiSbTeSeI2 single crystal to obtain a hydrogen evolution electrocatalyst with a particle size of 0.5–10 μm.
[0015] Furthermore, in step 1 above, the bismuth source is bismuth granules, the antimony source is antimony powder, the tellurium source is tellurium powder, the selenium source is selenium powder, and the iodine source is iodine granules; the purity of the bismuth source, antimony source, tellurium source, selenium source, and iodine source is not less than 99.99%.
[0016] Furthermore, in step 2 above, the vacuum degree inside the quartz tube is ≥10. -3 Pa.
[0017] Furthermore, in step 3 above, the conditions for the chemical vapor transport reaction are as follows: the temperature of the raw material zone (high-temperature zone) is set at 600–680°C, the temperature of the growth zone (low-temperature zone) is set at 500–570°C, and the reaction time is 48–72 h; after the reaction, it is cooled to room temperature at a cooling rate of 0.5–2°C / min. The mechanism of the chemical vapor transport reaction is as follows: in the high-temperature zone, Bi, Sb, Te, Se, and I2 sublimate or decompose to form gaseous species; driven by the temperature gradient, the gaseous species are transported to the low-temperature zone through diffusion and convection; in the low-temperature zone, due to the decrease in supersaturation, BiSbTeSeI2 crystallizes and precipitates, forming high-quality single crystals.
[0018] Furthermore, in step 3 above, the conditions for the chemical vapor phase transport reaction are as follows: the temperature of the raw material zone is set to 650℃, the temperature of the growth zone is set to 550℃, and the reaction time is 60 h; after the reaction is completed, the temperature is cooled to room temperature at a rate of 1℃ / min.
[0019] Furthermore, in step 4 above, the mechanical grinding is carried out in the presence of a dispersion medium, wherein the dispersion medium is anhydrous ethanol, and the grinding time is 30 to 60 minutes.
[0020] Furthermore, in step 4 above, the liquid phase exfoliation involves placing the BiSbTeSeI2 single crystal in an exfoliation solvent and subjecting it to ultrasonic treatment. The exfoliation solvent is deionized water, the ultrasonic power is 200–400 W, and the ultrasonic time is 6–8 h. After ultrasonic treatment, the resulting dispersion is centrifuged and the precipitate is collected. After washing and drying, the hydrogen evolution electrocatalyst is obtained.
[0021] This invention also provides the application of the above-mentioned high-entropy V-VI-VII group hydrogen evolution electrocatalyst in water electrolysis for hydrogen production. The specific method is as follows: the hydrogen evolution electrocatalyst is mixed with anhydrous ethanol, deionized water, and Nafion solution, and ultrasonically dispersed to obtain a catalyst slurry; the catalyst slurry is coated onto a substrate electrode, dried, and used as a working electrode for the electrocatalytic hydrogen evolution reaction in an acidic electrolyte.
[0022] The beneficial effects of this invention are as follows:
[0023] The hydrogen evolution electrocatalyst provided by this invention uses single crystals of the high-entropy V-VI-VII group ternary layered compound BiSbTeSeI2 as the active material. This material has a unique anisotropic crystal structure and a suitable electronic band structure. High-quality single crystals are prepared by chemical vapor transport method, and then obtained as single crystal powder or nanosheets by mechanical grinding or liquid phase exfoliation, fully exposing the edge active sites. The preparation method of this invention uses elemental materials, which are widely available and do not involve precious metals, resulting in low cost, simple and controllable process, and easy industrial mass production. The obtained BiSbTeSeI2 hydrogen evolution electrocatalyst has both high crystallinity and abundant edge active sites, forming a fast electron transport channel. It exhibits excellent hydrogen evolution performance and good cycle stability. Experimental data shows that this catalyst can achieve hydrogen evolution performance at -10 mA cm⁻¹. -2 At a current density of 188–255 mV, its hydrogen evolution overpotential in 0.5 M H₂SO₄ solution is 188–255 mV. This invention applies high-entropy V-VI-VII group layered compounds to the field of electrocatalytic hydrogen evolution, expanding the research scope of non-noble metal electrocatalysts and providing a novel material system for developing new and efficient HER catalysts. Attached Figure Description
[0024] Figure 1 This is an optical photograph of the BiSbTeSeI2 single crystal obtained in Example 1.
[0025] Figure 2 This is the X-ray powder diffraction pattern of the BiSbTeSeI2 single crystal obtained in Example 1.
[0026] Figure 3This is a scanning electron microscope image of the catalyst powder obtained in Example 1.
[0027] Figure 4 These are the polarization curves (a) and Tafel curves (b) of the catalyst powder obtained in Example 1.
[0028] Figure 5 This is a scanning electron microscope image of the catalyst nanosheets obtained in Example 2.
[0029] Figure 6 The figures are the polarization curves (a) and Tafel curves (b) of the catalyst nanosheets obtained in Example 2. Detailed Implementation
[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0031] Example 1
[0032] 1. Preparation of hydrogen evolution electrocatalysts
[0033] Step 1: In an argon glove box, weigh out bismuth granules (purity ≥99.99%), antimony powder (purity ≥99.99%), tellurium powder (purity ≥99.99%), selenium powder (purity ≥99.99%), and iodine granules (purity ≥99.99%), so that the molar ratio of Bi:Sb:Te:Se:I is 1:1:1:1:2, and mix them evenly to obtain the raw material mixture.
[0034] Step 2: Place the raw material mixture from Step 1 at the bottom of a quartz tube with an inner diameter of 15 mm and one end sealed. Connect the quartz tube to a vacuum system and evacuate to 10... -3 Pa, then melt and seal the material at a distance of 10-15 cm using an oxyhydrogen flame.
[0035] Step 3: Place the sealed quartz tube in a dual-temperature zone tube furnace, with the raw material end in the high-temperature zone and the empty tube end in the low-temperature zone. Set the temperature of the raw material zone (high-temperature zone) to 650℃ and the growth zone (low-temperature zone) to 550℃, with a heating rate of 5℃ / min. Maintain this temperature gradient for 60 hours to carry out the chemical vapor transport reaction. After the reaction, cool to room temperature at a rate of 1℃ / min. Remove the quartz tube and collect the grown BiSbTeSeI2 single crystals from the low-temperature zone in a fume hood. Figure 1 As shown, the obtained single crystals are needle-like or plate-like, with a size up to 4 mm, and have a smooth surface with a metallic luster, indicating that large-size, high-quality single crystals were successfully obtained through chemical vapor transport. Figure 2It can be seen that the diffraction peaks of the obtained single crystal are sharp and have high intensity, indicating that it has extremely high crystallinity. The spectrum shows characteristic diffraction peaks at diffraction angles 2θ of 11.6°, 17.2°, 17.8°, 23.3°, 27.1° and 29.3°, among which the diffraction peak at 27.1° is the strongest.
[0036] Step 4: Place 50 mg of BiSbTeSeI2 single crystals in an agate mortar, add anhydrous ethanol as a dispersion medium, and grind for 45 min to obtain catalyst powder. Figure 3 It can be seen that after mechanical grinding, the large single crystals are broken into irregular granular powders with a particle size distribution of 5 to 10 μm. These micron-sized single crystal particles fully expose the edge active sites, which is beneficial to improving the electrocatalytic hydrogen evolution performance.
[0037] 2. Electrocatalytic hydrogen evolution reaction
[0038] The obtained catalyst powder was mixed with anhydrous ethanol, deionized water, and Nafion solution at a ratio of 5 mg:500 μL:500 μL:40 μL and ultrasonically dispersed for 1 h to obtain a uniform catalyst slurry. The obtained catalyst slurry was drop-coated onto the surface of a glassy carbon electrode, and the catalyst loading on the electrode was 0.3 mg / cm³. 2 After drying at room temperature, it was used as the working electrode; using a platinum electrode as the counter electrode and an Ag / AgCl electrode as the reference electrode, electrochemical performance was tested in 0.5 M H₂SO₄ solution (scan rate 5 mV / s). Figure 4 The polarization curve in (a) shows that the catalyst operates at -10 mA cm⁻¹. -2 The overpotential at the given current density is 255 mV, indicating that it possesses good hydrogen evolution catalytic activity. From... Figure 4 As can be seen from the Tafel curve in (b), the Tafel slope of this catalyst is 73 mV dec. -1 This indicates that its hydrogen evolution reaction follows the Volmer-Heyrovsky mechanism and has good reaction kinetics.
[0039] Example 2
[0040] 1. Preparation of hydrogen evolution electrocatalysts
[0041] BiSbTeSeI2 single crystals were prepared according to the method in Example 1. 50 mg of BiSbTeSeI2 single crystals were placed in a 50 mL centrifuge tube, and 20 mL of deionized water was added. The mixture was ultrasonically exfoliated for 8 h (ultrasonic power 300 W) using an ultrasonic cleaner. After ultrasonication, the resulting dispersion was centrifuged at 3000 rpm for 10 min, and the supernatant was collected. The supernatant was then centrifuged at 10000 rpm for 15 min, and the precipitate was collected. The precipitate was washed three times with ethanol, and the washed product was vacuum dried at 60 °C for 12 h to obtain catalyst nanosheets (denoted as Ex-BiSbTeSeI2). Figure 5 As can be seen, after liquid-phase exfoliation, large single crystals are exfoliated into thin nanosheets with lateral dimensions of 1–5 μm and significantly reduced thickness. This two-dimensional nanosheet structure greatly increases the specific surface area and fully exposes the edge active sites, which is beneficial for further improving the electrocatalytic hydrogen evolution performance.
[0042] 2. Electrocatalytic hydrogen evolution reaction
[0043] The obtained Ex-BiSbTeSeI2 was subjected to an electrocatalytic hydrogen evolution reaction according to the method described in Example 1. Figure 6 The polarization curve in (a) shows that the catalyst operates at -10 mA cm⁻¹. -2 The overpotential at the given current density was 188 mV, significantly lower than the overpotential (255 mV) of the mechanically ground product in Example 1, indicating that the nanosheets obtained by liquid-phase exfoliation possess superior hydrogen evolution catalytic activity. Figure 6 As can be seen from the Tafel curve in (b), the Tafel slope of this catalyst is 53 mV dec. -1 73 mV dec lower than in Example 1 -1 This indicates that the nanosheets after liquid-phase exfoliation have faster hydrogen evolution reaction kinetics, which is due to their more complete exposure of active sites and more efficient electron transport.
Claims
1. A high-entropy V-VI-VII group hydrogen evolution electrocatalyst, characterized in that: The active material of the hydrogen evolution electrocatalyst is a single crystal of BiSbTeSeI2, whose X-ray powder diffraction pattern has characteristic peaks at diffraction angles 2θ of 11.6°±0.2°, 17.2°±0.2°, 17.8°±0.2°, 23.3°±0.2°, 27.1°±0.2° and 29.3°±0.2°, with the strongest peak at 2θ of 27.1°±0.2°. The particle size of the BiSbTeSeI2 single crystal is 0.5–10 μm.
2. The high-entropy V-VI-VII group hydrogen evolution electrocatalyst according to claim 1, characterized in that: The BiSbTeSeI2 single crystal is either BiSbTeSeI2 single crystal powder or BiSbTeSeI2 single crystal nanosheets.
3. A method for preparing the high-entropy V-VI-VII group hydrogen evolution electrocatalyst according to claim 1 or 2, characterized in that, Includes the following steps: Step 1: Mix the bismuth source, antimony source, tellurium source, selenium source and iodine source evenly according to the molar ratio Bi:Sb:Te:Se:I = 0.95~1.05:0.95~1.05:0.95~1.05:0.95~1.05:1.9~2.1 to obtain the raw material mixture; Step 2: Place the raw material mixture in a quartz tube, evacuate the inside of the quartz tube, and then seal it; Step 3: Place the sealed quartz tube in a dual-temperature zone tube furnace to carry out a chemical vapor transport reaction, collect the reaction products in the growth zone, and obtain BiSbTeSeI2 single crystals; Step 4: Mechanically grind or liquid-phase exfoliate the BiSbTeSeI2 single crystal to obtain a hydrogen evolution electrocatalyst with a particle size of 0.5–10 μm.
4. The method for preparing the high-entropy V-VI-VII group hydrogen evolution electrocatalyst according to claim 3, characterized in that: In step 1, the bismuth source is bismuth granules, the antimony source is antimony powder, the tellurium source is tellurium powder, the selenium source is selenium powder, and the iodine source is iodine granules; the purity of the bismuth source, antimony source, tellurium source, selenium source, and iodine source is not less than 99.99%.
5. The method for preparing the high-entropy V-VI-VII group hydrogen evolution electrocatalyst according to claim 3, characterized in that: In step 2, the vacuum degree inside the quartz tube is ≥10. -3 Pa.
6. The method for preparing the high-entropy V-VI-VII group hydrogen evolution electrocatalyst according to claim 3, characterized in that: In step 3, the conditions for the chemical vapor transport reaction are as follows: the temperature of the raw material zone is set to 600-680℃, the temperature of the growth zone is set to 500-570℃, and the reaction time is 48-72 hours; after the reaction is completed, the mixture is cooled to room temperature at a cooling rate of 0.5-2℃ / min.
7. The method for preparing the high-entropy V-VI-VII group hydrogen evolution electrocatalyst according to claim 6, characterized in that: In step 3, the conditions for the chemical vapor transport reaction are as follows: the temperature of the raw material zone is set to 650°C, the temperature of the growth zone is set to 550°C, and the reaction time is 60 hours; after the reaction is completed, the temperature is cooled to room temperature at a rate of 1°C / min.
8. The method for preparing the high-entropy V-VI-VII group hydrogen evolution electrocatalyst according to claim 3, characterized in that: In step 4, the mechanical grinding is carried out in the presence of a dispersion medium, which is anhydrous ethanol, and the grinding time is 30 to 60 minutes.
9. The method for preparing the high-entropy V-VI-VII group hydrogen evolution electrocatalyst according to claim 3, characterized in that: In step 4, the liquid phase exfoliation involves placing the BiSbTeSeI2 single crystal in an exfoliation solvent and subjecting it to ultrasonic treatment. The exfoliation solvent is deionized water, the ultrasonic power is 200–400 W, and the ultrasonic time is 6–8 hours. After ultrasonic treatment, the resulting dispersion is centrifuged and the precipitate is collected. After washing and drying, the hydrogen evolution electrocatalyst is obtained.
10. The application of the high-entropy V-VI-VII group hydrogen evolution electrocatalyst according to claim 1 or 2 in water electrolysis for hydrogen production.