Method for simulating hydrogen evolution performance of Co and Fe double atoms on surface of defect-state graphene

Abstract

The invention relates to the technical field of new energy materials, in particular to a method for simulating hydrogen evolution performance of Co and Fe double-metal atoms on the surface of defect-state graphene, and aims to simulate the electronic structure performance and reaction mechanism of Co and Fe double-atom hydrogen evolution under modification of Co, Fe and N on the surface of the defect-state graphene by optimizing a modified material structure. A density functional theory of a first principle and a molecular dynamics analogue simulation method are adopted, and the relationship between the structure and hydrogen evolution performance of defect-state graphene metal diatoms and N-modified metal diatom modified materials is studied; the interaction rule between pi electrons in the carbon material under the defect and outer layer electrons of Co and Fe double atoms and Fe, Co and N three atoms is disclosed; therefore, a Co and Fe diatom and Co, Fe and N triatom-graphene two-dimensional material high-efficiency hydrogen evolution mechanism is disclosed, and a theoretical foundation is laid for developing a novel high-efficiency hydrogen evolution material.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy materials, and in particular to a method for simulating hydrogen evolution performance of Co and Fe diatoms on a defective graphene surface. Background Art

[0002] Energy crisis and environmental pollution are becoming increasingly serious, and hydrogen energy as a clean energy source has attracted much attention. The hydrogen evolution reaction is a key step in the electrolysis of water to produce hydrogen, and its efficiency depends on the activity of the catalytic material. Graphene has been widely studied due to its unique electronic structure and chemical stability, but the catalytic activity of intrinsic graphene is limited. Existing studies have shown that introducing defects on the graphene surface and loading Co, Fe bimetallic atoms or N-modified Co, Fe triatoms can significantly enhance its electrochemical activity, but its mechanism of action is still unclear. Traditional experimental methods make it difficult to analyze the structure-activity relationship between material structure and performance at the atomic level, and an efficient theoretical simulation method is urgently needed to fill this gap. Summary of the Invention

[0003] To solve the above-mentioned problems in the prior art, the present invention provides a simulation method for the hydrogen evolution performance of Co and Fe diatoms on the surface of defective graphene, aiming to reveal the interaction rules between π electrons in carbon graphene and the outer electrons of Co and Fe diatoms and N, Co, and Fe triatoms, and to reveal the mechanism of efficient electrocatalytic hydrogen evolution of CoFe-graphene and CoFe-N-graphene two-dimensional materials.

[0004] To achieve the above objectives, the present invention adopts the following specific technical solutions: The method for simulating the hydrogen evolution performance of Co and Fe diatoms on the surface of defective graphene provided by the present invention includes: S1. Using a classical periodic model to construct a double DV defect structure in a two-dimensional graphene honeycomb crystal, we optimized the crystal structure of this model, calculated the defect formation energy, and established the structure-activity relationship between material structure, stability, and electrocatalytic performance, thereby optimizing the steady-state structure of materials modified with Co and Fe bimetallic atoms on the defective graphene surface and with Co and Fe bimetallic atoms under N modification. S2. Simulate the electronic structure and reaction mechanism of hydrogen evolution of Co and Fe bimetallic atoms on defective graphene surface and Co and Fe bimetallic atoms under N modification; S3. Using first-principles density functional theory and molecular dynamics simulation methods, the relationship between the structure and hydrogen evolution performance of the material modified with Co and Fe bimetallic atoms on the defective graphene surface and Co and Fe bimetallic atoms modified with N is obtained.

[0005] Furthermore, in step S1, a material structure model of Co and Fe bimetallic atoms on the surface of defective graphene and a material structure model of Co and Fe bimetallic atoms modified with N is constructed to obtain the material steady-state structure. The specific method is: S11. Use the classical periodic model to establish a two-dimensional honeycomb crystal structure model of graphene, investigate the Co and Fe diatomic surface adsorption model under double DV defects, and construct the Co, Fe, and N atomic surface adsorption model under double DV defects to realize the functionalization of graphene surface; S12. Using the generalized gradient approximation, the steady-state structure of the crystal is optimized to obtain the changes in the bond length and bond angle structural parameters of the graphene crystal near the defect; S13, obtaining the energy change of the graphene system before and after the defect is introduced, calculating the defect formation energy, obtaining the functionalized structure of the graphene surface, and establishing a nano-defective graphene surface structure model modified with Co, Fe bimetallic atoms and N-modified Co, Fe bimetallic atoms; S14. Based on the energy minimization principle, the GGA algorithm was used to optimize the design of the stable adsorption configurations of Co, Fe diatoms and N-modified Co, Fe dimetallic atoms on the functionalized graphene substrate. S15. Calculate the influence of Co, Fe diatomic and N-modified Co, Fe diatomic surface structures and adsorption stability on defective graphene surfaces, and use the D3 algorithm to investigate the effects of Co, Fe diatomic surface structures and adsorption stability on the surface of defective graphene. The adsorption performance of defective graphene surface modified with metal diatoms is determined to determine its most stable adsorption state on the surface; The possibility of hydrogen evolution reaction on the surface of Co, Fe diatomic and N-modified materials, and the main factors affecting the surface activity of nanostructured CoFe-graphene and CoFe-N-graphene materials; S16, get The interaction mechanism of graphene two-dimensional materials with defective Co and Fe bimetallic atoms and N-modified Co and Fe bimetallic atoms is studied to establish the basic laws of the structure-activity relationship between material structure, stability and electrocatalytic performance.

[0006] Furthermore, the initial structure of the Co and Fe diatomic surface adsorption model under double DV defects is a supercell model of a graphene monolayer, which removes two pairs of adjacent carbon atoms from a 6×6×1 unit cell to form a structure with 68 carbon atoms.

[0007] Furthermore, the Co and Fe diatomic surface adsorption model under the double DV defect sets a vacuum layer thickness of 20 Å in the z direction.

[0008] Furthermore, the generalized gradient approximation in step S12 is specifically described in the form of PBE to describe the exchange-correlation functional; the exchange-correlation functional is expressed as: ; Where, represents a three-dimensional integral over the entire space, represents the exchange-correlation energy density function, represents the total spin portion of the electron density, represents the electron density with spin down, represents the gradient of the total electron density, Represents the gradient of the spin-down electron density.

[0009] Furthermore, the method for optimizing the steady-state structure of the crystal in step S12 specifically includes: using a plane wave basis set with a cutoff energy of 400 eV, and setting the convergence threshold of the total energy calculation to eV, the convergence criterion for atomic forces was set to 0.02 eV / Å; the k-points in the Brillouin zone were sampled by the Monkhorst-Pack method, and the supercell used a 3 × 3 × 1 grid centered at the gamma point.

[0010] Furthermore, in step S15 , the D3 algorithm describes the van der Waals interaction between hydrogen atoms and the material surface by using a DFT-D3 correction method; The expression of the van der Waals dispersion energy correction term in the DFT-D3 correction method is as follows: ; Where, E disp represents the correction term for van der Waals dispersion energy; Nat represents the total number of atoms in the system; i and j represent the indices of atoms; L represents the image under periodic boundary conditions; and Indicates distance The decay function of the van der Waals dispersion energy at ; Represents atoms i and j Distance under periodic boundary conditions; C 6ij 、C 8ij Represents atoms i and j The van der Waals dispersion coefficient between .

[0011] Furthermore, in step S2, the electronic structure and reaction mechanism of hydrogen evolution of Co and Fe bimetallic atoms on the defective graphene surface and Co and Fe bimetallic atoms modified with N are simulated. The specific method is as follows: S21. Characterize the bonding characteristics and local spin topology distribution of materials before and after adsorption through local electron function distribution and spin topology, and analyze the two-dimensional material structural properties of Co and Fe diatoms in the presence of defects and impurities and Co and Fe dimetallic atoms modified by N from the electronic level; S22. Through the Bader charge, charge density, charge migration, total density of states, local density of states and band structure changes, the interaction rules between π electrons in carbon graphene and the outer electrons of Co, Fe diatoms and N, Co, Fe triatoms are obtained, and the influence of Co, Fe diatoms and N, Co, Fe triatoms on the electronic structure of graphene-based two-dimensional defect materials is obtained respectively; S23. Analyze the efficient electrocatalytic activity of materials from the perspective of electronic structure and energy band theory.

[0012] Furthermore, in step S3, the first-principles density functional theory and molecular dynamics simulation method are used to obtain the relationship between the structure and hydrogen evolution performance of the material modified with Co and Fe bimetallic atoms on the defective graphene surface and the material modified with Co and Fe bimetallic atoms under N modification. The specific method is as follows: S31, using molecular dynamics method at laboratory temperature The adsorption properties on the surfaces of CoFe-Graphene and CoFeN-Graphene materials were studied to determine the most stable adsorption state on the surfaces of different two-dimensional materials; S32, judge by adsorption energy The possibility of hydrogen evolution reaction on the surface of CoFe-Graphene and CoFe-N-Graphene two-dimensional materials; S33, Experimental hydrogen evolution reaction mechanism on the surface of CoFe-Graphene and CoFeN-Graphene two-dimensional materials, using kinetic free energy analysis method to calculate energy relationship, predict and find precipitation The optimal reaction surface and active sites of the reaction, establishing the reaction mechanism; S34. Analyze the local density of states characteristics of the system's spin polarization during the reaction process.

[0013] Furthermore, in step S33, the kinetic free energy analysis method is used to calculate the kinetic Gibbs free energy, and the expression is as follows: ; Where, ΔE ZPE and ΔS represent the zero-point energy and entropy change of adsorbed hydrogen and gaseous H2 at 298.15 K, respectively; represents the difference in hydrogen adsorption energy; The calculation is as shown in the formula: ; Where, represents the total energy of the system after H adsorption, E H2 is the energy of gaseous hydrogen.

[0014] The beneficial effects of the present invention are embodied in that, by optimizing the modified two-dimensional material structure, the catalytic hydrogen evolution reaction process of Co, Fe bimetallic atoms and N, Co, Fe triatoms on the surface of defective graphene is simulated, and the relationship between the structure and electrocatalytic hydrogen evolution performance of the material modified with Co, Fe bimetallic atoms and N, Co, Fe triatoms in defective graphene is studied by using first-principles density functional theory and molecular dynamics simulation methods; the interaction law between π electrons in the carbon material under defects and the outer-shell electrons of Co, Fe bimetallic atoms and N, Co, Fe triatoms is revealed; thereby, the efficient electrocatalytic mechanism of CoFe-graphene and CoFe-N-graphene two-dimensional materials is revealed, laying a theoretical foundation for the development of new and efficient catalytic materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of a method for simulating hydrogen evolution performance of Co and Fe bimetallic atoms on defective graphene surfaces according to an embodiment of the present invention; Figure 2 Schematic diagram of the adsorption model of two atoms of Co and Fe on the graphene surface in the double DV defect and the adsorption model of three atoms of N, Co and Fe on the graphene surface in the double DV defect provided by an embodiment of the present invention; Figure 3 The graphs show the crystal bond length structure and magnetic parameters of the graphene composite material near the defect under the modification of metal atoms Co and Fe, and the parameter change data of the surface structure model of nano-defective graphene under the modification of Co and Fe under N, according to the embodiments of the present invention. Figure 4 According to the embodiment of the present invention, Schematic diagram of the most stable adsorption state on defective graphene surface modified with Co and Fe bimetallic atoms; Figure 5 According to the embodiment of the present invention, Schematic diagram of the most stable adsorption state on defective graphene surface modified with N, Co, and Fe atoms; Figure 6 The graphene crystal electronic structure model near the defect provided by the embodiment of the present invention is a localized electron function distribution diagram of the graphene surface modified with Co and Fe bimetallic atoms and the graphene surface modified with N, Co, and Fe trimetal atoms; Figure 7 3 is a Gibbs free energy distribution diagram of hydrogen evolution reaction in different systems and different active sites provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] The embodiment of the present invention provides a method for simulating the hydrogen evolution performance of Co and Fe bimetallic atoms on the surface of defective graphene. The process is as follows: Figure 1 Shown, including: S1. Using a classical periodic model to construct a double DV defect structure in a two-dimensional graphene honeycomb crystal, we optimized the crystal structure of this model, calculated the defect formation energy, and established a structure-activity relationship between material structure, stability, and electrocatalytic performance. This led to the optimization of the steady-state structure of the material modified with Co and Fe bimetallic atoms on the defective graphene surface and with Co and Fe bimetallic atoms under N modification. The details are as follows: S11. Use the classical periodic model to establish a two-dimensional honeycomb crystal structure model of graphene, investigate the Co and Fe diatomic surface adsorption model under double DV defects, and construct the Co, Fe, and N atomic surface adsorption model under double DV defects to realize the functionalization of graphene surface; The supercell model of a graphene monolayer was constructed by removing two pairs of adjacent carbon atoms from a 6×6×1 unit cell (72 carbon atoms), creating the initial graphene structure with a double DV defect model, which contains 68 carbon atoms. To prevent periodic interactions, a vacuum layer thickness of 20 Å was set in the z direction.

[0018] S12. First-principles Kohn-Sham density functional theory (DFT) is used, with the projected augmented plane wave (PAW) method used to describe the ion-electron interaction. The generalized gradient approximation (GGA) is used to describe the exchange-correlation functional using the Perdew-Burke-Ernzerhof (PBE) form. The exchange-correlation functional is expressed as: ; Where, represents a three-dimensional integral over the entire space, represents the exchange-correlation energy density function, represents the total spin portion of the electron density, represents the electron density with spin down, represents the gradient of the total electron density, represents the gradient of spin-down electron density; Optimize the steady-state structure of the crystal, focusing on the changes in the bond length and bond angle structural parameters of the graphene crystal near the defects; the optimization specifically includes: To improve the calculation accuracy, the plane wave basis set with a cutoff energy of 400 eV was used for structural optimization and electronic structure calculation, and the convergence threshold of the total energy calculation was set to eV, the convergence criterion for atomic forces was set to 0.02 eV / Å; the k-points in the Brillouin zone were sampled by the Monkhorst-Pack method, and the supercell used a 3 × 3 × 1 grid centered at the gamma point.

[0019] The adsorption model of Co and Fe atoms on the graphene surface under double DV defects is as follows: Figure 2 As shown in (a), the adsorption model of N, Co, and Fe atoms on the graphene surface in the double DV defect is as follows Figure 2 (b) The crystal bond length structure and magnetic parameters of graphene composite materials near defects modified by metal atoms Co and Fe, as well as the changes in the surface structure model parameters of nano-defective graphene modified by Co and Fe under N modification are shown in Figure 2. Figure 3 shown.

[0020] S13. Analyze the energy change of the graphene system before and after the introduction of defects, calculate the defect formation energy, obtain the functionalized structure of the graphene surface, and establish a nano-defective graphene surface structure model modified by Co, Fe bimetallic atoms and N-modified Co, Fe bimetallic atoms; the calculation formula is as follows: ; Where, E b represents the binding energy, E system represents the total energy of the entire system, E DV-C represents the total surface energy (or defect energy) of defective carbon materials, E Co Represents the energy of cobalt. E Fe Represents the energy of iron.

[0021] S14. Based on the energy minimization principle, the GGA algorithm was used to optimize the design of the steady-state adsorption configurations of Co, Fe diatoms and N-modified Co, Fe dimetallic atoms on the functionalized graphene substrate.

[0022] S15. Based on the influence of Co, Fe diatomic surface and N-modified Co, Fe diatomic surface structure and adsorption stability, the D3 algorithm was used to describe the van der Waals interaction between hydrogen atoms and the material surface through the DFT-D3 correction method proposed by Gimme. The results were analyzed at room temperature. The adsorption performance of defective graphene surface modified with metal diatoms is determined to determine its most stable adsorption state on the surface; The possibility of hydrogen evolution reaction on the surface of Co, Fe diatomic and N-modified materials is investigated, and the main factors affecting the surface activity of nanostructured CoFe-graphene and CoFe-N-graphene materials are found. The expression of the van der Waals dispersion energy correction term in the DFT-D3 correction method is as follows: ; Where, E disp represents the correction term for van der Waals dispersion energy; Nat represents the total number of atoms in the system; i and j represent the indices of atoms; L represents the image under periodic boundary conditions; and Indicates distance The decay function of the van der Waals dispersion energy at ; Represents atoms i and j Distance under periodic boundary conditions; C 6ij 、C 8ij Represents atoms i and j The van der Waals dispersion coefficient between Figure 4 and Figure 5 At room temperature In the case of Co, Fe bimetallic atoms ( Figure 4 ac) and N, Co, Fe three-atom modification ( Figure 5 df) The most stable adsorption state on the defective graphene surface.

[0023] S16, get The interaction mechanism of graphene two-dimensional materials with defective Co and Fe bimetallic atoms and N-modified Co and Fe bimetallic atoms is studied, and the basic laws of the structure-activity relationship between material structure, stability and electrocatalytic performance are established with reference to experimental laws.

[0024] S2. Simulate the electronic structure and reaction mechanism of hydrogen evolution from Co and Fe bimetallic atoms on defective graphene surfaces and under N modification. The details are as follows: S21. Characterize the bonding characteristics and local spin topology distribution of materials before and after adsorption by using local electron function (ELF) distribution and spin topology, and analyze the two-dimensional material structural properties of Co and Fe diatoms in the presence of defects and impurities and Co and Fe dimetallic atoms modified by N from the electronic level.

[0025] Figure 6 is the electronic structure model of graphene crystal near the defect, Figure 6(a) Graphene surface modified by Co and Fe bimetallic atoms. Figure 6 (b) Localized electron function distribution on the graphene surface modified with N, Co, and Fe atoms.

[0026] S22. Through Bader charge analysis, charge density, charge migration, total density of states, local density of states and band structure changes, the interaction rules between π electrons in carbon graphene and the outer electrons of Co, Fe diatoms and N, Co, Fe triatoms are obtained, and the effects of Co, Fe diatoms and N, Co, Fe triatoms on the electronic structure of graphene-based two-dimensional defect materials are obtained respectively.

[0027] S23. Analyze the efficient electrocatalytic activity of materials from the perspective of electronic structure and energy band theory.

[0028] S3. Using first-principles density functional theory and molecular dynamics simulation methods, the relationship between the structure and hydrogen evolution performance of Co and Fe bimetallic atoms on the surface of defective graphene and the material modified with Co and Fe bimetallic atoms under N modification is obtained; specifically including: S31, using molecular dynamics method at laboratory temperature The adsorption performance on the surface of CoFe-Graphene and CoFeN-Graphene materials was studied to determine the most stable adsorption state on the surfaces of different two-dimensional materials.

[0029] S32, judge H by adsorption energy * The possibility of hydrogen evolution reaction on the surface of CoFe-Graphene and CoFe-N-Graphene two-dimensional materials.

[0030] S33. Experimental study of the hydrogen evolution reaction mechanism on the surface of CoFe-Graphene and CoFeN-Graphene two-dimensional materials. Using the kinetic free energy analysis method, the kinetic Gibbs free energy was calculated, the energy distribution law was analyzed, and the optimal reaction surface and active sites were determined based on the near-zero energy analysis method, thus establishing the reaction mechanism. The Gibbs free energy distribution of hydrogen evolution reaction on different systems and different active sites is shown in the figure below. Figure 7 shown.

[0031] Gibbs free energy Δ of hydrogen evolution reaction (HER) G H As a criterion for judging the spontaneity of a reaction, its expression is as follows: ; Where, ΔE ZPE and ΔS represent the zero-point energy (ZPE) and entropy change of adsorbed hydrogen and gaseous H2 at 298.15 K (1 bar), respectively; represents the difference in hydrogen adsorption energy; The calculation is as shown in the formula: ; Where, represents the total energy of the system after H adsorption, E H2 is the energy of gaseous hydrogen.

[0032] S34. Analyze the local density of states (LDOS) characteristics of the system's spin polarization during the reaction process, and deeply explore the efficient catalytic reaction mechanism of CoFe-Graphene and CoFe-N-Graphene two-dimensional materials.

[0033] The present invention optimizes the structure of modified two-dimensional materials, simulates the catalytic hydrogen evolution reaction process of Co, Fe bimetallic atoms and N, Co, Fe triatoms on the surface of defective graphene, and adopts first-principles density functional theory and molecular dynamics simulation methods to study the relationship between the structure of the material modified with Co, Fe bimetallic atoms and N, Co, Fe triatoms in defective graphene and the electrocatalytic hydrogen evolution performance; reveals the interaction law between π electrons in the carbon material under defects and the outer-shell electrons of Co, Fe bimetallic atoms and N, Co, Fe triatoms; thereby, reveals the efficient electrocatalytic mechanism of CoFe-graphene and CoFe-N-graphene two-dimensional materials, laying a theoretical foundation for the development of new and efficient catalytic materials.

[0034] In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "center", "top", "bottom", "top", "bottom", "inside", "outside", "inner side", "outer side" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. Among them, "inside" refers to an internal or enclosed area or space. "Periphery" refers to the area surrounding a specific component or specific area.

[0035] In the description of the embodiments of the present invention, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, a feature specified as "first," "second," "third," or "fourth" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0036] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," and "assembled" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0037] In the description of the embodiments of the present invention, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0038] In describing the embodiments of the present invention, it should be understood that "-" and "~" represent a range between two values, and the range includes the endpoints. For example, "AB" represents a range greater than or equal to A and less than or equal to B. "A~B" represents a range greater than or equal to A and less than or equal to B.

[0039] In describing the embodiments of the present invention, the term "and / or" is used herein to describe a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Furthermore, the character " / " is generally used herein to indicate that the associated objects are in an "or" relationship.

[0040] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for simulating the hydrogen evolution performance of Co and Fe diatomic atoms on the surface of defective graphene, characterized in that: include: S1. Using a classical periodic model to construct a double DV defect structure in a two-dimensional graphene honeycomb crystal, we optimized the crystal structure of this model, calculated the defect formation energy, and established the structure-activity relationship between material structure, stability, and electrocatalytic performance, thereby optimizing the steady-state structure of materials modified with Co and Fe bimetallic atoms on the defective graphene surface and with Co and Fe bimetallic atoms under N modification. S2. Simulate the electronic structure and reaction mechanism of hydrogen evolution of Co and Fe bimetallic atoms on defective graphene surface and Co and Fe bimetallic atoms under N modification; S3. Using first-principles density functional theory and molecular dynamics simulation methods, the relationship between the structure and hydrogen evolution performance of the material modified with Co and Fe bimetallic atoms on the defective graphene surface and Co and Fe bimetallic atoms modified with N is obtained.

2. The method for simulating hydrogen evolution performance of Co and Fe diatomic atoms on defective graphene surface according to claim 1, wherein: In step S1, a material structure model of Co and Fe bimetallic atoms on the surface of defective graphene and a material structure model of Co and Fe bimetallic atoms modified with N is constructed to obtain the material steady-state structure. The specific method is as follows: S11. Use the classical periodic model to establish a two-dimensional honeycomb crystal structure model of graphene, investigate the Co and Fe diatomic surface adsorption model under double DV defects, and construct the Co, Fe, and N atomic surface adsorption model under double DV defects to realize the functionalization of graphene surface; S12. Using the generalized gradient approximation, the steady-state structure of the crystal is optimized to obtain the changes in the bond length and bond angle structural parameters of the graphene crystal near the defect; S13, obtaining the energy change of the graphene system before and after the defect is introduced, calculating the defect formation energy, obtaining the functionalized structure of the graphene surface, and establishing a nano-defective graphene surface structure model modified with Co, Fe bimetallic atoms and N-modified Co, Fe bimetallic atoms; S14. Based on the energy minimization principle, the GGA algorithm was used to optimize the design of the stable adsorption configurations of Co, Fe diatoms and N-modified Co, Fe dimetallic atoms on the functionalized graphene substrate. S15. Calculate the influence of Co, Fe diatomic and N-modified Co, Fe diatomic surface structures and adsorption stability on defective graphene surfaces, and use the D3 algorithm to investigate the effects of Co, Fe diatomic surface structures and adsorption stability on the surface of defective graphene. The adsorption performance of defective graphene surface modified with metal diatoms is determined to determine its most stable adsorption state on the surface; The possibility of hydrogen evolution reaction on the surface of Co, Fe diatomic and N-modified materials, and the main factors affecting the surface activity of nanostructured CoFe-graphene and CoFe-N-graphene materials; S16, get The interaction mechanism of graphene two-dimensional materials with defective Co and Fe bimetallic atoms and N-modified Co and Fe bimetallic atoms is studied to establish the basic laws of the structure-activity relationship between material structure, stability and electrocatalytic performance.

3. The method for simulating hydrogen evolution performance of Co and Fe diatomic atoms on defective graphene surface according to claim 2, wherein: The initial structure of the Co and Fe diatomic surface adsorption model under the double DV defect is a supercell model of a graphene monolayer, which is formed by removing two pairs of two adjacent carbon atoms from a 6×6×1 unit cell to form a structure with 68 carbon atoms.

4. The method for simulating hydrogen evolution performance of Co and Fe diatomic atoms on defective graphene surface according to claim 3, wherein: The Co and Fe diatomic surface adsorption model under the double DV defect is set with a vacuum layer thickness of 20 Å in the z direction.

5. The method for simulating hydrogen evolution performance of Co and Fe diatomic atoms on defective graphene surface according to claim 2, wherein: The generalized gradient approximation in step S12 is specifically described in the form of PBE to describe the exchange-correlation functional; the exchange-correlation functional is expressed as: ； Where, represents a three-dimensional integral over the entire space, represents the exchange-correlation energy density function, represents the total spin portion of the electron density, represents the electron density with spin down, represents the gradient of the total electron density, Represents the gradient of the spin-down electron density.

6. The method for simulating hydrogen evolution performance of Co and Fe diatomic atoms on defective graphene surface according to claim 2, characterized in that: The method for optimizing the steady-state structure of the crystal in step S12 specifically includes: using a plane wave basis set with a cutoff energy of 400 eV, and setting the convergence threshold of the total energy calculation to eV, the convergence criterion for atomic forces was set to 0.02 eV / Å; the k-points in the Brillouin zone were sampled by the Monkhorst-Pack method, and the supercell used a 3 × 3 × 1 grid centered at the gamma point.

7. The method for simulating hydrogen evolution performance of Co and Fe diatomic atoms on defective graphene surface according to claim 2, characterized in that: In step S15, the D3 algorithm describes the van der Waals interaction between hydrogen atoms and the material surface using the DFT-D3 correction method; The expression of the van der Waals dispersion energy correction term in the DFT-D3 correction method is as follows: ； Where Edisp is the correction term for van der Waals dispersion energy; Nat is the total number of atoms in the system; i and j are the indices of atoms; L is the image under periodic boundary conditions; and Indicates distance The decay function of the van der Waals dispersion energy at ; represents the distance between atoms i and j under periodic boundary conditions; C6ij and C8ij represent the van der Waals dispersion coefficients between atoms i and j.

8. The method for simulating hydrogen evolution performance of Co and Fe diatomic atoms on defective graphene surface according to claim 1, wherein: In step S2, the electronic structure and reaction mechanism of hydrogen evolution of Co and Fe bimetallic atoms on the defective graphene surface and Co and Fe bimetallic atoms modified with N are simulated. The specific method is as follows: S21. Characterize the bonding characteristics and local spin topology distribution of materials before and after adsorption through local electron function distribution and spin topology, and analyze the two-dimensional material structural properties of Co and Fe diatoms in the presence of defects and impurities and Co and Fe dimetallic atoms modified by N from the electronic level; S22. Through the Bader charge, charge density, charge migration, total density of states, local density of states and band structure changes, the interaction rules between π electrons in carbon graphene and the outer electrons of Co, Fe diatoms and N, Co, Fe triatoms are obtained, and the influence of Co, Fe diatoms and N, Co, Fe triatoms on the electronic structure of graphene-based two-dimensional defect materials is obtained respectively; S23. Analyze the efficient electrocatalytic activity of materials from the perspective of electronic structure and energy band theory.

9. The method for simulating hydrogen evolution performance of Co and Fe diatomic atoms on defective graphene surface according to claim 1, wherein: In step S3, first-principles density functional theory and molecular dynamics simulation methods are used to obtain the relationship between the structure and hydrogen evolution performance of the material modified with Co and Fe bimetallic atoms on the defective graphene surface and the material modified with Co and Fe bimetallic atoms under N modification. The specific method is as follows: S31, using molecular dynamics method at laboratory temperature The adsorption properties on the surfaces of CoFe-Graphene and CoFeN-Graphene materials were studied to determine the most stable adsorption state on the surfaces of different two-dimensional materials; S32, judge by adsorption energy The possibility of hydrogen evolution reaction on the surface of CoFe-Graphene and CoFe-N-Graphene two-dimensional materials; S33, Experimental hydrogen evolution reaction mechanism on the surface of CoFe-Graphene and CoFeN-Graphene two-dimensional materials, using kinetic free energy analysis method to calculate energy relationship, predict and find precipitation The optimal reaction surface and active sites of the reaction, establishing the reaction mechanism; S34. Analyze the local density of states characteristics of the system's spin polarization during the reaction process.

10. The method for simulating hydrogen evolution performance of Co and Fe diatomic atoms on defective graphene surface according to claim 9, characterized in that: In step S33, the kinetic free energy analysis method is used to calculate the kinetic Gibbs free energy, and the expression is as follows: ； Where ΔEZPE and ΔS represent the zero-point energy and entropy change of adsorbed hydrogen and gaseous H2 at 298.15 K, respectively; represents the difference in hydrogen adsorption energy; The calculation is as shown in the formula: ； Where, represents the total energy of the system after H adsorption, E H2 is the energy of gaseous hydrogen.

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