Weyl semimetal surface modification method for improving catalytic performance
By preparing S-, Se-, or Te-substituted NbAs crystal materials through chemical vapor transport, the problem of insufficient hydrogen evolution catalytic performance of Weyl half-metal materials was solved, and the high-efficiency catalytic performance of the materials was improved.
Patent Information
- Application Number
- CN202510875117.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-27
- Publication Date
- 2025-10-28
AI Technical Summary
Existing Weyl semimetal materials suffer from instability and insufficient performance in catalytic hydrogen evolution.
Weyl semimetal materials are grown using a chemical vapor transport method. By using sheet-like niobium foil, arsenic powder, sulfur powder, selenium powder, and tellurium powder as raw materials in a high-vacuum sealed environment, and adding iodine as a transport agent, S-substituted, Se-substituted, or Te-substituted NbAs crystal materials are prepared to improve their catalytic performance.
The catalytic hydrogen evolution performance of Weyl semimetal materials was improved, and high-crystallinity and high-quality crystals were obtained, resulting in a significant improvement in catalytic performance.
Smart Images
Figure CN120838441A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of Weyl semimetal materials technology, and more specifically, to a method for surface modification of Weyl semimetals to improve catalytic performance. Background Technology
[0002] Weyl semimetals are a class of topological quantum materials with unique electronic structures, whose distinctive properties stem from the presence of Weyl nodes in their band structures. The physical basis of Weyl semimetals can be traced back to the Weyl equation proposed by mathematician Hermann Weyl in 1929, which predicted a massless Dirac fermion—the Weyl fermion. In condensed matter physics, these quasiparticles can be realized through the band structure of specific crystals. In 2015, multiple research teams observed Weyl nodes and Fermi arcs in TaAs family materials (such as TaAs and NbAs) for the first time using angle-resolved photoelectron spectroscopy (ARPES), marking the experimental verification of Weyl semimetals. These materials exhibit a series of peculiar phenomena, such as Fermi arcs, ultra-high mobility, and enormous magnetoresistance due to chiral anomalies.
[0003] Weyl semimetals, with their unique structure, offer new ideas for designing highly efficient hydrogen evolution (HER) catalysts. However, they are still in the early stages of research and face challenges such as stability and low catalytic performance in hydrogen evolution. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a method for surface modification of Weyl semimetals to improve catalytic performance, so as to improve the catalytic hydrogen evolution performance of the material.
[0005] To solve the above technical problems, according to one aspect of the present invention, a method for preparing a chalcogenide-modified Weyl semimetal material is provided, comprising: Step 1: Place sheet niobium foil and arsenic powder as raw materials inside the quartz tube, add iodine powder as a transport agent, and seal the opening of the quartz tube. Step 2: Place the quartz tube into a beaker containing dry ice and acetone solution, evacuate the quartz tube, and then seal it. Step 3: Place the sealed quartz tube into a tube furnace, heat it to 1000-1100℃ and hold it at that temperature. After the reaction is complete, NbAs crystal material is obtained. Step 4: Place the NbAs crystal material obtained in Step 3 into a quartz tube containing elemental S, Se, or Te, and then seal the quartz tube after vacuum treatment. Step 5: Place the sealed quartz tube into a tube furnace, heat it to 800-900℃ and hold it at that temperature. After the reaction is complete, obtain S-substituted, Se-substituted, or Te-substituted NbAs crystal materials.
[0006] Furthermore, in step one, the molar ratio of niobium foil: arsenic powder: iodine powder is 1.10:1.16:0.16.
[0007] Furthermore, in step one, the area of the sheet-like niobium foil is 1-2 mm. 2 .
[0008] Furthermore, in step two, the quartz tube is evacuated to a vacuum level of 4 × 10⁻⁶. -4 After Pa, seal it.
[0009] Furthermore, in step three, the temperature is increased to 1050℃ at a rate of 20℃ / min and held for 21 days.
[0010] Furthermore, in step four, the quartz tube is evacuated to a vacuum level of 4 × 10⁻⁶. -4 After Pa, seal it.
[0011] Furthermore, in step five, the temperature is increased to 850°C at a rate of 20°C / min and held for 5 minutes.
[0012] According to another aspect of the present invention, a Weyl semimetal surface-modified material with improved catalytic performance is provided by any of the above methods.
[0013] This invention selects niobium foil, arsenic powder, sulfur powder, selenium powder, and tellurium powder, which have undergone fine crushing, as raw materials. After crushing, the niobium foil will produce fewer defects and a larger specific surface area during crystal growth. In addition, a small amount of elemental iodine is added as a transport agent.
[0014] This invention employs a chemical vapor transport method for growth in a high-vacuum, closed environment, resulting in crystals with high crystallinity, good quality, and high reproducibility. Compared to pure NbAs samples, the catalytic hydrogen evolution performance of the sample is improved after the second reaction. Attached Figure Description
[0015] Figure 1 The Raman spectra of niobium arsenide with Si, Se, and Te prepared in Example 1 of this invention are shown.
[0016] Figure 2 EDS surface scan images of niobium arsenide with Si, Se, and Te oxides prepared in Example 1 of this invention.
[0017] Figure 3 This is a comparison of the HER performance of niobium arsenide prepared in Example 1 of the present invention with Si-substituted, Se-substituted, and Te-substituted niobium arsenide. Detailed Implementation
[0018] A typical embodiment of this invention provides a method for surface modification of Weyl semimetals to improve catalytic performance, wherein the chalcogen elements are S, Se, or Te. This embodiment uses niobium foil, arsenic powder, sulfur powder, selenium powder, and tellurium powder as raw materials, and iodine as a transport agent. NbAs are grown in a tube furnace and subjected to S-, Se-, and Te-modification. The main preparation method includes steps one through five.
[0019] Step 1: Place sheet niobium foil and arsenic powder as raw materials inside the quartz tube, add iodine powder as a transport agent, and seal the opening of the quartz tube.
[0020] More specifically, to prevent static electricity, niobium foil is weighed outside the glove box. First, the sheet-like niobium foil is placed into a quartz tube, then arsenic powder is added into the quartz tube, and finally, elemental iodine is added into the quartz tube as a transport agent. The opening of the quartz tube is then sealed with a vacuum flame sealing device.
[0021] The sheet-like niobium foil consists of small, cut fragments, each 1-2 mm in size. 2 .
[0022] In this step, the molar ratio of niobium foil:arsenic powder:iodine powder is 1.10:1.16:0.16.
[0023] Step two: Place the quartz tube into a beaker containing dry ice and acetone solution, evacuate the quartz tube, and then seal it.
[0024] In this step, acetone solution is placed in a beaker, and dry ice is placed in the acetone solution. The purpose of the dry ice is to lower the temperature of the quartz tube and prevent the iodine in the quartz tube from evaporating.
[0025] Connect the quartz tube to the vacuum pump and evacuate the quartz tube to a vacuum level of 4 × 10⁻⁶. -4 After Pa, the quartz tube is sealed with a methane flame torch.
[0026] Step 3: Place the sealed quartz tube into a tube furnace, heat it to 1000-1100℃ and hold it at that temperature. After the reaction is complete, NbAs crystal material is obtained.
[0027] This embodiment preferably uses a tube furnace with a diameter of 50 mm.
[0028] In this step, the temperature is raised to the reaction temperature of 1000-1100℃, for example: 1000℃, 1050℃, or 1100℃. Preferably, in a tube furnace, the temperature is raised to 1050℃ at a rate of 20℃ / min and held for 21 days. After the holding period, the reaction is stopped and cooled to room temperature. After the reaction is complete, the quartz tube is carefully opened, and the sample is removed and observed under an optical microscope to observe the grown crystals.
[0029] Step four: Place the NbAs crystal material obtained in step three into quartz tubes containing elemental S, Se, or Te, respectively, and then seal the quartz tubes after evacuating them.
[0030] Weighing of S powder, Se powder, and Te powder should be performed outside the glove box. Connect the quartz tube to the vacuum pump and evacuate to 4 × 10⁻⁶. -4 After achieving a vacuum of Pa, the quartz tube is sealed using a methane flame torch.
[0031] Step 5: Place the sealed quartz tube into a tube furnace, heat it to 800-900℃ and hold it at that temperature. After the reaction is complete, obtain S-substituted, Se-substituted, or Te-substituted NbAs crystal materials.
[0032] In this step, the temperature is raised to the reaction temperature of 800-900℃, for example, 800℃, 850℃, or 900℃. Preferably, the temperature is raised to 850℃ at a rate of 20℃ / min and held for 5 minutes, then the reaction is stopped and the temperature is allowed to cool naturally to room temperature.
[0033] In this embodiment, all key operations are performed within a glove box, thus avoiding the influence of factors such as water vapor in the air.
[0034] The technical solutions claimed in this invention will be further described below through some embodiments. However, the embodiments and comparative examples are for explaining the implementation of the present invention and do not exceed the scope of the subject matter of the present invention. The scope of protection of the present invention is not limited by the embodiments. Unless otherwise specified, the materials and reagents used in this invention can be obtained from commercially available products in the art. Example 1
[0035] First, weigh the niobium foil outside the glove box and place it at the bottom of the quartz tube. Then, put it into the glove box, add elemental arsenic into the quartz tube, and finally add elemental iodine as a transport agent. After that, put in the plug and seal the test tube opening with sealing film.
[0036] The molar ratio of niobium foil, arsenic powder, and iodine powder is 1.10:1.16:0.16. The sheet-like niobium foil consists of finely crushed small fragments, each 1 mm in size. 2 .
[0037] Place acetone solution in a beaker, then add dry ice to it, and place the quartz tube into the beaker containing the dry ice and acetone solution.
[0038] Connect the quartz tube to the vacuum pump and wait until the pressure reaches 4×10⁻⁶. -4 After achieving a vacuum of Pa, the quartz tube is sealed using a methane flame torch.
[0039] The sealed quartz tube was placed horizontally in a tube furnace and heated to 1050°C at a rate of 20°C / min. The temperature was then maintained for 21 days, after which the reaction was stopped and the tube was allowed to cool naturally to room temperature.
[0040] After the reaction is complete, the sample is removed and the grown crystals are observed under an optical microscope.
[0041] Through the above experimental steps, a sample with a size of 0.05 mm was successfully prepared. 2 Weyl semimetal niobium arsenide single crystal material.
[0042] Weigh 1 mg each of S powder, Se powder, and Te powder outside the glove box and place them into quartz tubes containing NbAs crystals.
[0043] Connect the quartz tube to the vacuum pump and wait until the pressure reaches 4×10⁻⁶. -4 After achieving a vacuum of Pa, the quartz tube is sealed using a methane flame torch.
[0044] The sealed quartz tube was placed horizontally in a tube furnace and heated to 850°C at a rate of 20°C / min. The temperature was then maintained for 5 minutes, after which the reaction was stopped and the tube was allowed to cool naturally to room temperature.
[0045] Through the above experimental steps, Weyl half-metal niobium arsenide was successfully prepared and subjected to S-, Se-, and Te-modification single-crystal materials. The EDS energy spectra of the niobium arsenide (NbAs) and S-, Se-, and Te-modified single-crystal materials prepared in this embodiment are shown below. Figure 2 As shown, various elements are uniformly distributed within the crystalline material. The Raman spectra of the NbAs single crystals prepared in this embodiment, after being treated with S, Se, and Te, are shown below. Figure 1 As shown. The NbAs prepared in this embodiment were compared with the HER performance of S-substituted, Se-substituted, and Te-substituted single-crystal materials, as shown in the figure. Figure 3 As shown, the overpotentials of S-type, Se-type, and Te-type are 190mV, 81mV, and 141mV, respectively. Compared with other materials, Se-type and Te-type have certain performance advantages in terms of overpotential. The overpotential of S-type is relatively higher than that of Se-type and Te-type, and there is still some room for improvement. Example 2
[0046] First, weigh the niobium foil outside the glove box and place it at the bottom of the quartz tube. Then, put it into the glove box, add elemental arsenic into the quartz tube, and finally add elemental iodine as a transport agent. After that, put in the plug and seal the test tube opening with sealing film.
[0047] The molar ratio of niobium foil, arsenic powder, and iodine powder is 1.10:1.16:0.16. The sheet-like tantalum foil and niobium foil are finely crushed small fragments, each 2 mm in size. 2 .
[0048] Place acetone solution in a beaker, then add dry ice to it, and place the quartz tube into the beaker containing the dry ice and acetone solution.
[0049] Connect the quartz tube to the vacuum pump and wait until the pressure reaches 4×10⁻⁶. -4 After achieving a vacuum of Pa, the quartz tube is sealed using a methane flame torch.
[0050] The sealed quartz tube was placed horizontally in a tube furnace and heated to 1000°C at a rate of 20°C / min. The temperature was then maintained for 21 days, after which the reaction was stopped and the tube was allowed to cool naturally to room temperature.
[0051] After the reaction is complete, the sample is removed and the grown crystals are observed under an optical microscope.
[0052] Through the above experimental steps, a 6mm diameter sample was successfully prepared. 2 Weyl semimetal niobium arsenide single crystal material.
[0053] Weigh 1 mg each of S powder, Se powder, and Te powder outside the glove box and place them into quartz tubes containing NbAs crystals.
[0054] Connect the quartz tube to the vacuum pump and wait until the pressure reaches 4×10⁻⁶. -4 After achieving a vacuum of Pa, the quartz tube is sealed using a methane flame torch.
[0055] The sealed quartz tube was placed horizontally in a tube furnace, and the temperature was increased to 800°C at a rate of 20°C / min. The temperature was then maintained for 5 minutes, and the reaction was stopped. The tube was then allowed to cool naturally to room temperature. Example 3
[0056] First, weigh the niobium foil outside the glove box and place it at the bottom of the quartz tube. Then, put it into the glove box, add elemental arsenic into the quartz tube, and finally add elemental iodine as a transport agent. After that, put in the plug and seal the test tube opening with sealing film.
[0057] The molar ratio of niobium foil, arsenic powder, and iodine powder is 1.10:1.16:0.16. The sheet-like tantalum foil and niobium foil are finely crushed small fragments, each 2 mm in size. 2 .
[0058] Place acetone solution in a beaker, then add dry ice to it, and place the quartz tube into the beaker containing the dry ice and acetone solution.
[0059] Connect the quartz tube to the vacuum pump and wait until the pressure reaches 4×10⁻⁶. -4 After achieving a vacuum of Pa, the quartz tube is sealed using a methane flame torch.
[0060] The sealed quartz tube was placed horizontally in a tube furnace and heated to 1100°C at a rate of 20°C / min. The temperature was then maintained for 21 days, after which the reaction was stopped and the tube was allowed to cool naturally to room temperature.
[0061] After the reaction is complete, the sample is removed and the grown crystals are observed under an optical microscope.
[0062] Through the above experimental steps, a sample with a size of 4mm was successfully prepared. 2 Weyl semimetal niobium arsenide single crystal material.
[0063] Weigh 1 mg each of S powder, Se powder, and Te powder outside the glove box and place them into quartz tubes containing NbAs crystals.
[0064] Connect the quartz tube to the vacuum pump and wait until the pressure reaches 4×10⁻⁶. -4 After achieving a vacuum of Pa, the quartz tube is sealed using a methane flame torch.
[0065] The sealed quartz tube was placed horizontally in a tube furnace and heated to 900°C at a rate of 20°C / min. The temperature was then maintained for 5 minutes, after which the reaction was stopped and the tube was allowed to cool naturally to room temperature.
[0066] Through the above experimental steps, a novel Weyl semimetal heterostructure and its hydrogen evolution performance were successfully constructed by surface modification.
Claims
1. A method for surface modification of Weyl semimetals to improve catalytic performance, characterized in that, include: Step 1: Place sheet niobium foil and arsenic powder as raw materials inside the quartz tube, add iodine powder as a transport agent, and seal the opening of the quartz tube. Step 2: Place the quartz tube into a beaker containing dry ice and acetone solution, evacuate the quartz tube, and then seal it. Step 3: Place the sealed quartz tube into a tube furnace, heat it to 1000-1100℃ and hold it at that temperature. After the reaction is complete, NbAs crystal material is obtained. Step 4: Place the NbAs crystal material obtained in Step 3 into a quartz tube containing elemental S, Se, or Te, and then seal the quartz tube after vacuum treatment. Step 5: Place the sealed quartz tube into a tube furnace, heat it to 800-900℃ and hold it at that temperature. After the reaction is complete, obtain S-substituted, Se-substituted, or Te-substituted NbAs crystal materials.
2. The method according to claim 1, characterized in that: In step one, the molar ratio of niobium foil:arsenic powder:iodine powder is 1.10:1.16:0.
16.
3. The method according to claim 2, characterized in that: In step one, the area of the sheet niobium foil is 1-2 mm. 2 .
4. The method according to claim 1 or 3, characterized in that: In step two, the quartz tube is evacuated to a vacuum level of 4 × 10⁻⁶. -4 After Pa, seal it.
5. The method according to claim 4, characterized in that: In step three, the temperature is increased to 1050℃ at a rate of 20℃ / min and held for 21 days.
6. The method according to claim 5, characterized in that: In step four, the quartz tube is evacuated to a vacuum level of 4 × 10⁻⁶. - 4 After Pa, seal it.
7. The method according to claim 1 or 6, characterized in that: In step five, the temperature is increased to 850℃ at a rate of 20℃ / min and held for 5 minutes.
8. A surface-modified Weyl semimetal material with improved catalytic performance is obtained by the method of any one of claims 1-7.