Two-dimensional beryllium alkene material and prediction method and application thereof
By screening and optimizing γ-phase two-dimensional berylliumene materials, the shortcomings of two-dimensional berylliumene materials in the field of electrochemical catalysis have been solved, and their excellent performance in the electrochemical catalytic hydrogen evolution reaction has been achieved.
Patent Information
- Application Number
- CN202511002889.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-21
- Publication Date
- 2025-10-31
AI Technical Summary
Existing technologies lack an assessment of the structural diversity and richness of two-dimensional group IIA elemental materials, especially the application research of berylliumene materials in the field of electrochemical catalysis, and there is a lack of comprehensive evaluation of their electrochemical catalytic performance.
Through theoretical prediction and experimental synthesis, γ-phase two-dimensional berylliumene materials were screened, and their electrochemical catalytic hydrogen evolution reaction performance was evaluated by using crystal structure search software and VASP simulation software for energy optimization.
The study discovered that γ-phase two-dimensional berylliumene materials exhibit excellent electrochemical catalytic performance in hydrogen evolution reaction, demonstrating broad potential for practical applications and enhancing electrochemical catalytic performance.
Smart Images
Figure CN120866941A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of new energy nanomaterials technology, and more specifically to a two-dimensional berylliumene material, its prediction method, and its application. Background Technology
[0002] Currently, the electrocatalytic hydrogen evolution reaction (HER) is a key step in hydrogen energy conversion technology. Noble metals (such as Pt) are widely used due to their excellent catalytic performance, but they are costly and resource-limited. In recent years, two-dimensional materials have become a new hotspot in HER research due to their high specific surface area and unique electronic structure. Among the two-dimensional material family, two-dimensional elemental alkenes (Xenes) exhibit excellent electrocatalytic performance. However, the bulk structures of Group IIA elements do not possess the natural layered van der Waals properties, which has led to a lack of research and application of two-dimensional Group IIA elements (such as beryllium and magnesium) materials, which are still in their initial stages. Although two two-dimensional Group IIA elemental materials and their electrochemical energy storage applications have been discovered, there is a lack of comprehensive evaluation of the structural potential energy surfaces of two-dimensional Group IIA elemental materials, that is, a lack of consideration for the structural diversity and richness of two-dimensional Group IIA elemental materials.
[0003] Meanwhile, current research on the application of two-dimensional group IIA elemental materials to the field of electrochemical catalysis is limited, and there is a lack of comprehensive comparison of formation energy and evaluation of their electrochemical catalytic HER reaction performance through simulation of Gibbs free energy and exchange current density.
[0004] By theoretically predicting various two-dimensional berylliumene crystal structures and potential synthesis schemes with different thicknesses and formation energies, and finally screening out a two-dimensional berylliumene material with excellent electrochemical catalytic hydrogen evolution reaction performance, this will be of great significance for further guiding the synthesis of two-dimensional berylliumene materials and promoting their application in the field of electrochemical catalysis. Summary of the Invention
[0005] To address the above problems, this invention provides two-dimensional berylliumene materials, their prediction methods, and applications. This invention addresses the structural diversity and electrochemical applications of two-dimensional group IIA elemental materials. Through the prediction method of this invention, a novel γ-phase two-dimensional berylliumene material was discovered, its high experimental synthesis feasibility was evaluated, and finally, its excellent electrochemical catalytic hydrogen evolution reaction performance was found, demonstrating broad practical application potential.
[0006] The first objective of this invention is to provide a two-dimensional berylliumene material, which is a γ-phase two-dimensional berylliumene material with space group P-6m2, and is composed of three planar triangular monolayers.
[0007] In a preferred embodiment of the present invention, in the two-dimensional berylliumene material, the Wyckoff position of the outermost Be atom is 1f, and the coordinates of the 1f position are (0.667, 0.333, 0.500), and the Wyckoff position of the middle layer Be atom is 2h, and the coordinates of the 2h position are (0.333, 0.667, 0.548).
[0008] The coordination number of the outermost Be atoms is 9; the coordination number of the middle Be atoms is 12.
[0009] The Be-Be bond length within the same layer is 2.18 Å.
[0010] In a preferred embodiment of the present invention, the γ-phase two-dimensional berylliumene material is obtained by exfoliating bulk beryllium material with space group P63 / mmc along the
[001] crystal orientation.
[0011] A second objective of this invention is to provide a method for predicting two-dimensional berylliumene materials, comprising the following steps: An initial two-dimensional berylliumene material structure model was obtained using crystal structure search software. Energy optimization was performed using VASP simulation software, and the optimized two-dimensional berylliumene material was obtained based on the first thermodynamic stability standard.
[0012] The optimized two-dimensional berylliumene materials were screened to obtain γ-phase two-dimensional berylliumene materials with the lowest energy and theoretical synthesability.
[0013] Using Materials Studio software, bulk beryllium material with space group P63 / mmc was cut along the three crystal orientations
[100] ,
[001] and [2-10] to construct various two-dimensional sheet-like berylliumene models.
[0014] Multiple two-dimensional sheet beryllium ene models were imported into VASP simulation software for structural optimization. Based on the first elastic stability and the first kinetic stability, optimized materials containing two-dimensional sheet beryllium ene were obtained.
[0015] Using the lowest formation energy as the criterion, various optimized materials containing two-dimensional sheet-like beryllium ene were screened to obtain γ-phase two-dimensional beryllium ene materials with crystals cut along the
[001] direction.
[0016] In a preferred embodiment of the present invention, when constructing various two-dimensional berylliumene material structure models, the first thermodynamic stability criterion is to form two-dimensional berylliumene materials with a formation energy of less than 0.8 eV / atom.
[0017] In a preferred embodiment of the present invention, during energy optimization, the kinetic energy cutoff energy is set to 600 eV, and the k-point sampling uses a Monkhorst-Pack grid with a spacing of 2π × 0.04 Å. -1 The energy convergence accuracy is 1×10⁻⁶.-5 eV, the atomic force convergence accuracy is 0.01eV / Å.
[0018] In a preferred embodiment of the present invention, the optimized two-dimensional berylliumene material is a γ-phase two-dimensional berylliumene material, a δ-phase two-dimensional berylliumene material, an ε-phase two-dimensional berylliumene material, a ζ-phase two-dimensional berylliumene material, an η-phase two-dimensional berylliumene material, a θ-phase two-dimensional berylliumene material, and an ι-phase two-dimensional berylliumene material.
[0019] In a preferred embodiment of the present invention, theoretical synthesization is determined by second thermodynamic stability, second elastic stability, second kinetic stability, and thermal stability.
[0020] In a preferred embodiment of the present invention, the criteria for the second thermodynamic stability are a formation energy of less than 0.8 eV / atom and a negative cohesive energy.
[0021] The second elastic stability is achieved in VASP by setting the labels IBRION=6 and ISIF≥3 to calculate the elastic constant.
[0022] The second criterion for dynamic stability is the absence of imaginary frequencies in the phonon spectrum.
[0023] The thermal stability of γ-phase two-dimensional berylliumene materials was determined by using energy and chemical bonds under conditions below the melting point.
[0024] In a preferred embodiment of the present invention, during structural optimization, the kinetic energy cutoff energy is set to 600 eV, and the k-point sampling uses a Monkhorst-Pack grid with a spacing of 2π × 0.04 Å. -1 The energy convergence accuracy is 1×10⁻⁶. -5 eV, the atomic force convergence accuracy is 0.01eV / Å.
[0025] The third objective of this invention is to provide the application of the above-mentioned two-dimensional berylliumene material in the electrochemical catalytic hydrogen evolution reaction, and to evaluate the catalytic performance of γ-phase two-dimensional berylliumene in the electrochemical catalytic hydrogen evolution reaction using GGA-PBE functional analysis.
[0026] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes crystal structure search software, energy optimization, and screening to obtain γ-phase two-dimensional berylliumene materials, and points out a potential method for experimentally synthesizing γ-phase two-dimensional berylliumene materials, namely, γ-phase two-dimensional berylliumene materials can be obtained by cutting the bulk material beryllium along the
[001] crystal orientation. This invention confirms the structural diversity and richness of the two-dimensional potential energy surface of group IIA elemental materials.
[0027] The γ-phase two-dimensional berylliumene material predicted by this invention has metallic conductivity, similar to bulk berylliumene. This helps to accelerate the electron transfer rate of the electrochemical catalytic process and improve the electrochemical catalytic performance, showing promising application prospects in the field of electrochemical catalytic hydrogen evolution reaction. Attached Figure Description
[0028] Figure 1 This is a schematic diagram of the formation enthalpy and structure of two-dimensional berylliumenes in the γ, δ, ε, ζ, η, θ, and ι phases.
[0029] Figure 2 The kinetic and thermal stability of γ-phase two-dimensional berylliumene are shown, where (a) is the phonon spectrum of γ-phase two-dimensional berylliumene and (b) is a snapshot of the final configuration of γ-phase two-dimensional berylliumene at different temperatures.
[0030] Figure 3 denoted as the formation energy and exfoliation energy for different crystal orientations, where (a) is the formation energy and (b) is the exfoliation energy.
[0031] Figure 4 The electrochemical catalytic performance of γ-phase two-dimensional beryllium olefins for hydrogen evolution reaction is shown, where (a) represents the Gibbs free energy Δ under different adsorption coverage. G H* (b) is the Gibbs free energy Δ G H* and the exchange current density log(i0). Detailed Implementation
[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.
[0033] Example 1 Step 1: Using the USPEX crystal structure search software, a large number of initial two-dimensional berylliumene material models were established in high throughput. Energy optimization was performed using VASP simulation software. The structure search was conducted using the first thermodynamic stability criterion (i.e., selecting two-dimensional berylliumene materials with a formation energy of less than 0.8 eV / atom). Finally, several two-dimensional berylliumene materials with lower global energy ranking on the potential energy surface were obtained, which are the optimized two-dimensional berylliumene materials.
[0034] The key parameters of the USPEX crystal structure search software are set as follows: the number of atoms in the cell is controlled to be 3, 4, 6, 8, 10 and 12 in sequence. The USPEX program is run at least twice each time to ensure convergence to the global minimum. The thickness of the two-dimensional berylliumene crystal is limited to 0~4 Å. The vacuum layer is set to 20 Å to obtain the two-dimensional berylliumene material.
[0035] Specifically, for energy optimization, the Projected Added Wave (PAW) method is used in the VASP program (version 6.3.2), and the exchange-correlation energy is based on the Perdew-Burke-Ernzerhof (PBE) functional within the framework of the Generalized Gradient Approximation (GGA). The kinetic energy cutoff of the wavefunction expansion is set to 600 eV, and k-point sampling uses a Monkhorst-Pack grid with a spacing of 2π × 0.04 Å⁻¹. The energy convergence accuracy is 1 × 10⁻⁻⁻⁶. 5 eV, with an atomic force convergence accuracy of 0.01 eV / Å. The valence electron configuration considered in the calculation is Be(2s²2p) 0 ).
[0036] like Figure 1 As shown, the optimized two-dimensional berylliumene materials are seven novel structures: γ-phase, δ-phase, ε-phase, ζ-phase, η-phase, θ-phase, and ι-phase. Among them, the γ-phase is a two-dimensional ground-state structure, exhibiting the best thermodynamic stability, and is more stable than the previously reported γ-phase, δ-phase, and sq-phase two-dimensional berylliumenes. The γ-type berylliumene has a hexagonal lattice with space group P-6m2, consisting of three planar triangular monolayers arranged in a bulk-like ABA stack. The outermost Be atoms and the middle Be atoms are located at Wyckoff positions 1f (0.667, 0.333, 0.500) and 2h (0.333, 0.667, 0.548), respectively. The coordination numbers of the outermost and middle Be atoms are 9 and 12, respectively. The Be–Be bond length within the same layer is 2.18 Å, slightly smaller than the 2.27 Å between layers. The atomic thickness of δ-type berylliumene is 3.76 Å.
[0037] Step 2: Import the γ-phase two-dimensional berylliumene material discovered in Step 1 into the VASP simulation software. Perform relevant calculations using the VASP program, and evaluate the experimental synthesis feasibility of the γ-phase based on the second thermodynamic stability, elastic stability, kinetic stability, and thermal stability criteria. Regarding energy optimization, the specific description based on thermodynamic, elastic, kinetic, and thermal stability criteria is as follows:
[0038] The second thermodynamic stability criterion is briefly described below. The thermodynamic stability of materials is usually measured using energy as a standard. Currently, common descriptors for characterizing the thermodynamic stability of two-dimensional materials include formation energy and cohesive energy. Taking two-dimensional berylliumene as an example, the mathematical expression for formation energy (or cohesive energy) is as follows: Δ E(2D_Be)= E (2D_Be) - E (Be_bulk), where, E (2D_Be) and E (Be_bulk) represents the energy of the two-dimensional beryllium ene and the bulk beryllium, respectively. Generally speaking, if the formation energy of the two-dimensional beryllium ene is less than 0.8 eV / atom and the cohesive energy is negative, it indicates the thermodynamic stability of the two-dimensional beryllium ene relative to the reference energy (bulk material precursor) and the feasibility of its experimental synthesis.
[0039] The elastic stability standard is briefly described below. A necessary condition for the thermodynamic stability of a crystalline material is that it possesses elastic stability against arbitrarily small uniform deformations. In VASP, the elastic constants can be calculated by setting the labels IBRION=6 and ISIF≥3. Specifically, six finite deformations are applied to the crystal lattice, and the elastic tensor is derived through the strain-stress relationship. For two-dimensional materials, the elastic matrix simplifies to a 3×3 form, and the corresponding six elastic constants are C0. 11 C 12 C 22 C 16 C 26 and C 66 The elastic constant C is represented using standard Voigt notation (1-xx, 2-yy, 6-xy). For two-dimensional materials, the calculated elastic constant C... 11 C 12 C 22 and C 66 The following elastic equilibrium condition should be met to ensure structural stability: C 11 C 22 -C 12 C 12 >0 and C 11 C 22 C 66 >0.
[0040] The kinetic stability criterion is briefly described below. A two-dimensional material can exist independently only if its phonon spectrum does not contain imaginary frequencies, which is considered kinetic stability. First-principles phonon spectrum calculations are performed using the open-source package PHONOPY (https: / / phonopy.github.io / phonopy / ) under the quasi-harmonic approximation combined with density functional perturbation theory (DFPT). Generally, a 3×3 supercell is sufficient for computational needs, but in some cases, a larger supercell is required to avoid the appearance of non-physical imaginary frequencies.
[0041] The thermal stability criteria are briefly described below. The thermal stability of two-dimensional materials refers to their structural stability at different temperatures. Specifically, below the melting point (400 K, 600 K, and 800 K), the thermal stability of the system can be determined by observing the changes in energy and chemical bonds over simulation time. If a large number of chemical bonds break, leading to system decomposition, the system is considered thermally unstable. To evaluate the thermal stability of the two-dimensional beryllium structure, we performed ab initio molecular dynamics simulations using the VASP program. A canonical ensemble (NVT) combined with an Andersen thermodynamic controller was used to perform molecular dynamics simulations at 400 K, 600 K, and 800 K. The time step was set to 1 fs, and the total simulation time was 10 ps. During the simulation, the two-dimensional berylliumene structure was constructed as a supercell of approximately 15 Å × 15 Å. Due to the high computational cost, the Brillouin zone integration only considered the supercell G point.
[0042] (1) The formation enthalpy of γ-phase two-dimensional berylliumene relative to bulk P63 / mmc beryllium phase is 0.306 eV / atom. This value is close to the formation enthalpy of synthesized two-dimensional elemental olefins such as tellurene (0.17 eV / atom) and silicene (approximately 0.75 eV / atom), indicating that γ-phase two-dimensional berylliumene has a high probability of being experimentally formed in terms of energy.
[0043] (2) Whether the material can maintain structural stability under small-amplitude uniform deformation is one of the necessary conditions for its experimental feasibility. Calculate the elastic constant matrix C of the γ-phase two-dimensional beryllium olefin. ij To assess its elastic stability, the results show that the elastic constant matrix C of the γ-phase two-dimensional beryllium olefin is... ij (C) 11 =183.359, C 12 =50.648, C 22 =183.359, C 66 =66.356) satisfies the Born mechanical stability criterion (C 11 C 22 -C 12 C 21 >0, C 11 C 22 C 66 >0).
[0044] (3) Evaluate its dynamic stability by calculating the phonon dispersion relation. Figure 2 (a) shows the phonon spectrum of γ-phase two-dimensional berylliumene. The absence of imaginary frequencies in the phonon spectrum indicates its good kinetic stability.
[0045] (4) The stability of the γ-phase two-dimensional berylliumene under thermal perturbation was verified by ab initio molecular dynamics simulations at different temperatures (up to 800 K). Snapshots of the final configurations at different temperatures are shown below. Figure 2 (b) shows that the Be–Be bond did not break during the entire simulation, and the atoms vibrated around the equilibrium position, indicating that the γ-phase two-dimensional beryllium ene still has good thermal stability at higher temperatures.
[0046] In summary, γ-phase two-dimensional berylliumene has high experimental feasibility and stability.
[0047] Step 3: Through structural analysis, identify potential feasible schemes for the experimental synthesis of γ-phase two-dimensional berylliumene. Further analysis revealed that the γ-phase two-dimensional beryllium ene has a similar structure to the bulk P63 / mmc Be phase. Therefore, the feasibility of obtaining the γ-phase two-dimensional beryllium ene by peeling it off from the bulk P63 / mmc Be phase along
[001] will be discussed in detail below.
[0048] (1) By cutting bulk P63 / mmc beryllium along the
[100] ,
[001] and [2-10] crystal directions and limiting its atomic thickness to within 20 Å, two-dimensional berylliumene materials with different atomic layer thicknesses were cut along the three crystal directions (
[100] ,
[001] and [2-10]) using Materials Studio software. A total of 41 two-dimensional layered berylliumene models were constructed, including 18
[100] types, 12
[001] types and 11 [2-10] types.
[0049] (2) The structures of various two-dimensional sheet beryllium ene models were then optimized by the VASP program, and their elastic stability and kinetic stability were evaluated (the calculation method is referred to the relevant content in step 2). The optimized γ-phase two-dimensional beryllium ene materials were obtained. Specifically, 32 types of γ-phase two-dimensional beryllium ene materials were confirmed to have good mechanical and kinetic stability (including 14 types
[100] , 9 types
[001] and 9 types [2-10]).
[0050] The specific parameters for structural optimization are consistent with those set in step 2 above. Specifically, the VASP program (version 6.3.2) is used with the Projected Added Wave (PAW) method, and the exchange-correlation energy is based on the Perdew-Burke-Ernzerhof (PBE) functional within the framework of the Generalized Gradient Approximation (GGA). The kinetic energy cutoff of the wavefunction expansion is set to 600 eV, and the k-point sampling uses a Monkhorst-Pack grid with a spacing of 2π × 0.04 Å⁻¹. The energy convergence accuracy is 1 × 10⁻⁻⁻⁶. 5 eV, with an atomic force convergence accuracy of 0.01 eV / Å. The valence electron configuration considered in the calculation is Be(2s²2p) 0 ).
[0051] Based on the lowest formation energy, optimized γ-phase two-dimensional berylliumene materials were screened. The formation energies of these optimized γ-phase two-dimensional berylliumene materials (32 structures) are as follows: Figure 3 As shown in (a), it can be seen that the two-dimensional berylliumene material obtained by
[001] crystal orientation cutting has the smallest formation energy, that is, its structure has the highest thermodynamic stability, indicating that it has greater experimental synthesis potential. This means that γ-phase two-dimensional berylliumene can be obtained by selectively cutting or exfoliating bulk P63 / mmc beryllium along the
[001] crystal orientation.
[0052] To further verify the experimental feasibility of obtaining γ-phase two-dimensional berylliumene by cutting or exfoliating bulk P63 / mmc beryllium, this invention also calculated the exfoliation energy, and the results are as follows: Figure 3 As shown in (b) of the figure. The results show that the exfoliation energy of the
[100] crystal orientation is 4.302~4.401 J / m² (0.269~0.274 eV / Ų), the exfoliation energy of the
[001] crystal orientation is 1.629~1.848 J / m² (0.102~0.115 eV / Ų), and the exfoliation energy of the [2-10] crystal orientation is 3.240~3.995 J / m² (0.202~0.249 eV / Ų). It can be seen that the
[001] crystal orientation has the smallest exfoliation energy. Although this value is higher than that of traditional van der Waals materials (such as graphene, BN, MoS2, phosphorene, etc., with a single-layer exfoliation energy of about 18~32 meV / Ų), it is comparable to that of the MAX phase (2.1~3.5 J / m²) and the MAB phase (such as MoAlB).
[0053] Researchers have successfully synthesized two-dimensional hexagonal beryllium and magnesium films through sonochemical or low-temperature physical exfoliation, also benefiting from the anisotropy of their crystals. Therefore, based on the method of this invention, γ-phase two-dimensional berylliumene is obtained by exfoliating bulk P63 / mmc beryllium along the
[001] direction.
[0054] The electrochemical catalytic performance of the γ-phase two-dimensional beryllium ene obtained in this invention for the hydrogen evolution reaction is evaluated below. Typically, the HER response involves two steps: 1. Adsorption step: The intermediate state (H*) is formed from the initial state (H⁺ + e⁻).
[0055] 2. Desorption step: The H* is converted to the product state (1 / 2 H2).
[0056] An ideal HER catalyst should exhibit neither too strong nor too weak adsorption of H atoms, thus its Gibbs free energy should be close to zero. According to general standards, a material possesses high-efficiency HER activity when -0.2 eV ≤ Gibbs free energy ≤ 0.2 eV.
[0057] This invention first discovered that γ-phase two-dimensional berylliumene, similar to bulk berylliumene, possesses metallic conductivity, which helps accelerate the electron transfer rate in electrochemical catalysis and improves its performance. To evaluate the electrochemical catalytic performance of γ-phase two-dimensional berylliumene in the hydrogen evolution reaction, a 3×3 supercell was constructed, considering different hydrogen atom adsorption sites and different hydrogen coverage (1 / 18, 3 / 18, 6 / 18, 9 / 18, 12 / 18, 18 / 18). Calculations showed that at low coverage (1 / 18), the optimal hydrogen adsorption site is the bridge site above the second layer of Be atoms, with an adsorption energy of -0.550 eV. For the 1 / 18 hydrogen coverage configuration, the calculated Gibbs free energy is -0.261 eV. The strong adsorption energy at low coverage hinders the desorption of H₂. As coverage increases, the interaction between H atoms and the surface weakens, leading to a gradual increase in both adsorption energy and Gibbs free energy. See [link to relevant documentation]. Figure 4 Figure (a) shows the Gibbs free energy values under different hydrogen coverage, as follows: 3 / 18: -0.087 eV, 6 / 18: 0.071 eV, 9 / 18: 0.166 eV, 12 / 18: 0.309 eV, 18 / 18: 0.428 eV. It can be seen that under medium coverage (3 / 18 and 6 / 18), the γ-phase two-dimensional berylliumene exhibits the best HER activity, with a Gibbs free energy close to zero, comparable to excellent catalysts such as platinum (0.07 eV) and two-dimensional MoS2 (~0.1 eV). At high coverage, the interaction between H atoms and the surface is too weak, causing the adsorption energy and Gibbs free energy to become positive, which is unfavorable for the reaction.
[0058] To compare the performance of γ-phase two-dimensional berylliumene with typical HER catalysts (such as Pt, two-dimensional MXene, and MoS2), this invention plotted a volcano diagram of Gibbs free energy versus exchange current density (i0), see [link to relevant documentation]. Figure 4 In the HER volcano curve, position above the curve indicates excellent catalytic performance. From Figure 4 As shown in b, the 1 / 18 coverage point is located on the left side of the volcano map, indicating excessive H adsorption. The 3 / 18 and 6 / 18 coverage points are close to the volcanic peak and, compared to Pt and Mo2CT, are significantly lower. x The fact that MoS2 is closer to the optimal position indicates that, under moderate hydrogen coverage, γ-phase two-dimensional berylliumene exhibits better HER catalytic performance and a lower theoretical overpotential. Therefore, it is expected that with a hydrogen coverage of 3 / 18 to 6 / 18, two-dimensional γ-type berylliumene will have a lower hydrogen evolution reaction overpotential than Pt, making it a highly promising HER electrocatalytic material.
[0059] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0060] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A two-dimensional berylliumene material, characterized in that, The two-dimensional berylliumene material is a γ-phase two-dimensional berylliumene material with space group P-6m2, consisting of three planar triangular monolayers.
2. The two-dimensional berylliumene material according to claim 1, characterized in that, In the two-dimensional berylliumene material, the Wyckoff position of the outermost Be atom is 1f, and the coordinates of the 1f position are (0.667, 0.333, 0.500). The Wyckoff position of the middle layer Be atom is 2h, and the coordinates of the 2h position are (0.333, 0.667, 0.548). The coordination number of the outermost Be atoms is 9; the coordination number of the middle Be atoms is 12. The Be-Be bond length within the same layer is 2.18 Å.
3. The two-dimensional berylliumene material according to claim 1, characterized in that, The γ-phase two-dimensional berylliumene material is obtained by exfoliating bulk beryllium material with space group P63 / mmc along the [001] crystal orientation.
4. A method for predicting two-dimensional berylliumene materials according to any one of claims 1 to 3, characterized in that, Includes the following steps: Using crystal structure search software, an initial two-dimensional berylliumene material structure model was obtained. Energy optimization was performed using VASP simulation software, and the optimized two-dimensional berylliumene material was obtained based on the first thermodynamic stability standard. The optimized two-dimensional berylliumene materials were screened to obtain γ-phase two-dimensional berylliumene materials with the lowest energy and theoretical synthesability; Using Materials Studio software, bulk beryllium material with space group P63 / mmc was cut along the three crystal orientations [100], [001] and [2-10] to construct various two-dimensional sheet-like berylliumene models; Multiple two-dimensional sheet berylliumene models were imported into VASP simulation software for structural optimization. Based on the first elastic stability and the first kinetic stability, multiple optimized two-dimensional sheet berylliumene materials containing three crystal orientations were obtained. Using the lowest formation energy as the criterion, various optimized two-dimensional sheet-like berylliumene materials containing three crystal orientations were screened to obtain the γ-phase two-dimensional berylliumene material with the lowest formation energy that cuts the crystal along the [001] direction.
5. The method for predicting two-dimensional berylliumene materials according to claim 4, characterized in that, When constructing various structural models of two-dimensional berylliumene materials, the first thermodynamic stability criterion is that the formation energy of two-dimensional berylliumene materials is less than 0.8 eV / atom; For energy optimization, the kinetic energy cutoff was set to 600 eV, and the k-point sampling used a Monkhorst-Pack grid with a spacing of 2π × 0.04 Å. -1 The energy convergence accuracy is 1×10⁻⁶. -5 eV, the atomic force convergence accuracy is 0.01eV / Å.
6. The method for predicting two-dimensional berylliumene materials according to claim 4, characterized in that, The optimized two-dimensional berylliumene materials are γ-phase two-dimensional berylliumene materials, δ-phase two-dimensional berylliumene materials, ε-phase two-dimensional berylliumene materials, ζ-phase two-dimensional berylliumene materials, η-phase two-dimensional berylliumene materials, θ-phase two-dimensional berylliumene materials, and ι-phase two-dimensional berylliumene materials.
7. The method for predicting two-dimensional berylliumene materials according to claim 4, characterized in that, Theoretical syntheticity is determined by the second thermodynamic stability, the second elastic stability, the second kinetic stability, and the thermal stability.
8. The method for predicting two-dimensional berylliumene materials according to claim 7, characterized in that, The second standard for thermodynamic stability is a formation energy of less than 0.8 eV / atom and a negative cohesive energy; The second elastic stability is achieved in VASP by setting the labels IBRION=6 and ISIF≥3 to calculate the elastic constant. The second criterion for dynamic stability is that there are no imaginary frequencies in the phonon spectrum; The thermal stability of γ-phase two-dimensional berylliumene materials was determined by using energy and chemical bonds under conditions below the melting point.
9. The method for predicting two-dimensional berylliumene materials according to claim 4, characterized in that, When performing structural optimization, the kinetic energy cutoff was set to 600 eV, and the k-point sampling used a Monkhorst-Pack grid with a spacing of 2π × 0.04 Å. -1 The energy convergence accuracy is 1×10⁻⁶. -5 eV, the atomic force convergence accuracy is 0.01eV / Å.
10. The application of the two-dimensional berylliumene material according to any one of claims 1 to 3 in the electrochemical catalytic hydrogen evolution reaction, characterized in that, The electrochemical catalytic performance of γ-phase two-dimensional berylliumene in the hydrogen evolution reaction was evaluated using GGA-PBE functional theory.