Design method of graphdiyne supported bimetallic nitrogen fixation catalyst and nitrogen fixation catalyst

Abstract

This invention discloses a design method and a nitrogen-fixing catalyst for graphdiyne-supported bimetallic nitrogen fixation. The method includes: selecting a monolayer graphdiyne supercell as a support model; constructing a bimetallic atom system on the monolayer graphdiyne supercell to form a Mo-TM@GDY configuration; the bimetallic atom system includes molybdenum atoms and transition metal atoms; screening for the Mo-TM@GDY configuration with high catalytic activity in the electrocatalytic nitrogen reduction reaction; screening for structurally stable Mo-TM@GDY configurations based on formation energy, dissolution potential, and binding energy; and screening for configurations with high catalytic selectivity in the electrocatalytic nitrogen reduction reaction to obtain the graphdiyne-supported bimetallic nitrogen-fixing catalyst. The catalyst designed in this invention can be applied to the electrochemical nitrogen reduction to ammonia synthesis reaction at room temperature and pressure, and is suitable for sustainable ammonia production processes driven by renewable electricity, possessing significant industrial application value.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a design method for a graphdiyne-supported bimetallic nitrogen-fixing catalyst and the nitrogen-fixing catalyst itself. Background Technology

[0002] Ammonia (NH3) is a key raw material for fertilizer synthesis and a hydrocarbon-free carrier, indispensable in the nitrogen cycle of human society. Traditional ammonia production relies on the Haber process, which consumes large amounts of energy and emits significant amounts of greenhouse gases (such as CO2), failing to meet the requirements of green and sustainable development. Electrochemical nitrogen reduction (NRR) can directly convert nitrogen into ammonia at ambient temperature and pressure, using water as a hydrogen source and renewable electricity as a power source, making it an ideal technological route to replace the traditional Haber process for ammonia synthesis. However, electrochemical nitrogen reduction has inherent technical bottlenecks: the NRR reaction involves multiple proton and electron transfer processes, resulting in slow reaction kinetics. Furthermore, hydrogen ions in the electrolyte readily undergo hydrogen evolution reaction (HER), creating strong competition with NRR. This leads to existing electrocatalytic nitrogen fixation catalysts generally exhibiting low catalytic activity and poor selectivity in ammonia synthesis, hindering industrial application.

[0003] The adsorption types of nitrogen on bimetallic atom catalysts include end-on and side-on adsorption. For NRR, there are five possible reaction mechanisms: Alternating mechanism: *NN(end-on)→*N-NH→*NH-NH→*NH-NH2→*NH2-NH2→*NH2+NH3→*NH3+NH3→2NH3 Remote mechanism: *NN(end-on)→*N-NH→*N-NH2→*N+NH3→*NH+NH3→*NH2+NH3→*NH3+NH3→2NH3 Enzymatic mechanism: *N-*N(side-on)→*N-*NH→*NH-*NH→*NH-*NH2→*NH2-*NH2→*NH2+NH3→*NH3+NH3→2NH3 Continuous mechanism: *N-*N(side-on)→*N-*NH→*N-*NH2→*N+NH3→*NH+NH3→*NH2+NH3→*NH3+NH3→2NH3 Mixing mechanism: *N-*N(side-on)→*N-*NH→*NH-*NH→*NH-*NH2→*NH+NH3→*NH2+NH3→*NH3+NH3→2NH3 Numerous theoretical and experimental studies have demonstrated that ideal catalysts can improve energy conversion efficiency, increase the rate of electrochemical nitrogen fixation, lower the energy barrier or confinement potential, and provide well-defined active sites. Therefore, one of the limiting factors in electrochemical nitrogen fixation is the confinement potential, which is determined by the properties of different catalysts. While single-atom catalysts (SACs) possess advantages such as high atom utilization and tunable active sites, their NRR catalytic performance is limited by the linear scaling relation (LSR), making further improvement difficult. Bimetallic atom catalysts (DACs), with their more complex and flexible active sites, offer new possibilities for breaking the linear scaling relation and optimizing intermediate adsorption structures, making them currently considered ideal electrochemical nitrogen fixation catalysts. Graphdiyne (GDY), as a novel two-dimensional layered material, possesses unique physicochemical properties and has been proven to be an excellent support for diatomic catalysts. Meanwhile, molybdenum (Mo), as a key component of nitrogenases, exhibits potential advantages in NRR catalysis. Therefore, designing graphdiyne-supported bimetallic atom catalysts holds promise for achieving breakthroughs in NRR catalytic performance. While existing technologies include research on bimetallic atom catalysts supported on two-dimensional materials, no studies have been reported on the electrocatalytic nitrogen fixation of graphdiyne-supported molybdenum-transition metal bimetallic systems, and a systematic catalyst design method and performance screening criteria are lacking. Therefore, developing a scientific and efficient design method for graphdiyne-supported molybdenum-transition metal bimetallic electrocatalytic nitrogen fixation catalysts, and screening for highly active and selective catalyst systems, is of great significance for promoting the industrial application of electrochemical ammonia synthesis technology. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a design method for a graphdiyne-supported bimetallic nitrogen-fixing catalyst and a nitrogen-fixing catalyst, thereby solving the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for designing a graphitic diyne-supported bimetallic nitrogen-fixing catalyst, the method comprising the following steps: S101. A single-layer graphitic diyne supercell was selected as the carrier model; S102. Construct a bimetallic atom system on the monolayer graphdiyne supercell to form a Mo-TM@GDY configuration; wherein the bimetallic atom system contains one molybdenum atom and one transition metal atom TM; S103. Screening out Mo-TM@GDY configurations with high catalytic activity in electrocatalytic nitrogen reduction reaction from various Mo-TM@GDY configurations; S104. Based on the formation energy, dissolution potential, and binding energy of the highly catalytically active Mo-TM@GDY configuration, structurally stable Mo-TM@GDY configurations were screened. S105. Among the structurally stable Mo-TM@GDY configurations, a configuration with high catalytic selectivity in the electrocatalytic nitrogen reduction reaction is selected to obtain the graphdiyne-supported bimetallic nitrogen fixation catalyst.

[0006] Preferably, in step S101, the configuration of the monolayer graphdiyne supercell is (2×2×1), and the supercell contains 72 carbon atoms; In step S102, a bimetallic atom system is constructed at the triangular pores of the monolayer graphdiyne supercell; the transition metal atom is one of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Tc, Ru, Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, and Hg.

[0007] Preferably, in step S103, the screening criteria for high catalytic activity include: firstly, in the electrocatalytic nitrogen reduction reaction, screening for Mo-TM@GDY configurations where the Gibbs free energy changes of both the first hydrogenation step and the last NH3 generation step are less than 0.5 eV; wherein the first hydrogenation step is: *N2 + H+ + e - → *N2H, the final step to produce NH3 is: *NH2 + H + +e - →*NH3; Then, construct end-adsorption and side-adsorption models for N2, calculate the Gibbs free energy changes of the N2 adsorption, activation, and stepwise hydrogenation processes of the obtained configurations, and determine the confinement potential U for each configuration. L (NH3); and using the reference limit potential of Ru(0001) as a threshold of -0.98V, the limit potential U was screened. L The configuration of (NH3) > -0.98V.

[0008] Preferably, the confinement potential U of the Mo-TM@GDY configuration L The smaller the absolute value of (NH3), the better the catalytic activity.

[0009] Preferably, in step S104, the forming energy E f and solubility potential U diss Calculated by the following formula: E f =E tot [GDY*+Mo-Tm]-E tot [GDY]–E[Mo-bulk]–E[TM-bulk] U diss =U 0 -E f / ne Among them, E tot[GDY*+Mo-Tm] represents the total energy of the Mo-TM@GDY configuration, E tot [GDY] represents the total energy of a monolayer graphdiyne supercell without bimetallic atoms, E[Mo-bulk] and E[TM-bulk] represent the energies of molybdenum atoms and transition metal atoms TM in the bulk phase, respectively, and U 0 The average standard solution potential of molybdenum atoms and transition metal atoms TM is represented, where ne is the number of electrons involved in the dissolution reaction; The binding energy E of the Mo-TM@GDY configuration b Calculated by the following formula: E b =E[total] E tot [GDY] E[Mo-atom]–E[TM-atom] Among them, E[total] and E tot [GDY] represents the total energy of a monolayer graphdiyne supercell with and without loaded bimetallic atoms, respectively; E[Mo-atom] and E[TM-atom] represent the energies of molybdenum atoms and transition metal atoms TM in vacuum, respectively. Filter out E f <6.96 eV, U diss >-1.68V and E b The Mo-TM@GDY configuration with <0 yields a structurally stable Mo-TM@GDY configuration.

[0010] Preferably, in step S104, in the structurally stable Mo-TM@GDY configuration, the bimetallic atoms are anchored to the corner positions of the ring structure composed of alkyne bonds within the monolayer graphdiyne supercell, coordinated with sp hybrid carbon atoms, and loaded into the triangular pores of the monolayer graphdiyne supercell.

[0011] Preferably, in step S105, the screening criteria for high catalytic selectivity include: evaluating the catalytic selectivity of the structurally stable Mo-TM@GDY configuration by comparing the adsorption free energy of nitrogen and hydrogen atoms and the difference in the limiting potentials of nitrogen reduction reaction and hydrogen evolution reaction in the Mo-TM@GDY configuration, wherein the Mo-TM@GDY configuration with high catalytic selectivity has a weaker adsorption capacity for hydrogen intermediates than for nitrogen molecules, and the difference between the limiting potential of nitrogen reduction reaction and the limiting potential of hydrogen evolution reaction is positive.

[0012] In a second aspect, the present invention provides a nitrogen fixation catalyst, which is a graphdiyne-supported bimetallic electrocatalytic nitrogen fixation catalyst obtained by the design method described in the first aspect. The graphdiyne-supported bimetallic electrocatalytic nitrogen fixation catalyst includes a graphdiyne support and a molybdenum and transition metal bimetallic active component supported on the graphdiyne support; wherein the transition metal is Cr, Mn, Fe or Co.

[0013] Preferably, molybdenum atoms and transition metal atoms are distributed on the graphdiyne support in a manner that is adjacent to or coordinated with each other, forming bimetallic active sites.

[0014] Preferably, the catalyst is applied to the electrochemical nitrogen reduction to ammonia synthesis reaction at room temperature and pressure.

[0015] Beneficial effects: This invention presents a design method for a graphdiyne-supported molybdenum-transition metal bimetallic electrocatalytic nitrogen fixation catalyst. By selecting a graphdiyne monolayer supercell to construct a bimetallic atom-supported configuration, and screening for structurally stable configurations with high NRR catalytic activity and selectivity, a high-performance Mo-TM@GDY bimetallic atom catalyst was obtained. This catalyst effectively activates nitrogen molecules and inhibits the hydrogen evolution reaction, providing important support for the development of electrochemical ammonia synthesis technology. The catalyst designed in this invention can be applied to the electrochemical nitrogen reduction to ammonia synthesis reaction at ambient temperature and pressure, and is particularly suitable for sustainable ammonia production processes driven by renewable electricity. This catalyst improves the ammonia synthesis activity and selectivity while reducing reaction energy consumption and environmental impact, demonstrating significant industrial application value. Attached Figure Description

[0016] To more clearly illustrate and understand the technical solutions in the embodiments of the present invention, the accompanying drawings used in the background technology and embodiment descriptions of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a single-layer graphitic diyne supercell; Figure 2 This is a schematic diagram of the structure of Mo-TM@GDY; Figure 3 This is the band structure diagram of a monolayer graphene diyne supercell; Figure 4 The confinement potential U for 10 Mo-TM@GDY configurations L ; Figure 5 The formation energies (E) of 10 different Mo-TM@GDY configurations f); Figure 6 The solubility potential (U) of 10 different Mo-TM@GDY configurations diss ); Figure 7 Binding energies (E) of 10 different Mo-TM@GDY configurations b ); Figure 8 A schematic diagram of a possible NRR reaction mechanism; Figure 9 The N2 adsorption free energy, H adsorption free energy, and the difference between them are given on Mo-TM@GDY. Figure 10 NRR Gibbs free energy change diagram and reaction intermediates on Mo-Cr@GDY; Figure 11 The diagram shows the NRR Gibbs free energy change and reaction intermediates on Mo-Mn@GDY. Detailed Implementation

[0018] The term "embodiment" used herein, as an "exemplary" description, is not necessarily superior to other embodiments. Unless otherwise specified, performance index tests in the embodiments of this application employ conventional calculation methods in the art. It should be understood that the terminology used in this application is merely for describing particular implementation methods and is not intended to limit the content disclosed in this application. Unless otherwise specified, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; other experimental methods and techniques not specifically mentioned in this application refer to experimental methods and techniques commonly used by one of ordinary skill in the art. In this document, including in the claims, conjunctions such as "comprising," "including," "having," "containing," "involving," and "accommodating" are understood to be open-ended, meaning "including but not limited to." Only the conjunctions "composed of" and "consisting of" are closing conjunctions. To better illustrate the content of this application, numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In the embodiments, some methods, means, instruments, and devices well known to those skilled in the art are not described in detail in order to highlight the main points of this application.

[0019] Without conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solution belongs to the content disclosed in the embodiments of this application.

[0020] Unless otherwise specified, all calculations in this invention employ conventional first-principles methods (such as VASP software) and the pseudopotentials and exchange-correlation functionals used in the calculations are conventional choices in the field of electrocatalysis. Unless otherwise specified, all test conditions are at room temperature and pressure (298.15 K, 1 atm).

[0021] In some embodiments, a method for designing a graphdiyne-supported molybdenum-transition metal bimetallic electrocatalytic nitrogen fixation catalyst includes the following steps: S101. A (2×2×1) monolayer graphdiyne (GDY) supercell containing 72 carbon atoms was selected as the support model, with the structure as follows: Figure 1 As shown, calculate its electronic configuration and geometry. Figure 3 The band structure diagram is for a single layer of GDY. S102. A bimetallic atomic system consisting of molybdenum (Mo) and 3d / 4d / 5d transition metals (TM) was constructed at the triangular pores of a monolayer graphdiyne supercell, forming a Mo-TM@GDY configuration, as shown in the figure. Figure 2 As shown, the transition metal is one of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Tc, Ru, Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, and Hg, covering a total of 30 bimetallic atom pair combinations; S103. Among the various Mo-TM@GDY configurations mentioned above, the Mo-TM@GDY configuration with high catalytic activity in the electrocatalytic nitrogen reduction reaction was selected; Nitrogen gas is adsorbed onto the catalyst. Through a charge transfer mechanism, the N-N bonds are opened, gradually combining hydrogen and nitrogen. During this gradual hydrogenation process, to achieve optimal NRR performance, the Gibbs free energy ΔG... H The value will approach an ideal value ΔG=0 to harmonize the reaction barrier. The Gibbs free energy ΔG is defined as: ΔG = G(sub+X) – G(sub) – G(X) Where G(sub+X) and G(sub) represent the system's free energy in the presence and absence of the adsorbate, respectively, and G(X) is the free energy of molecule X in a vacuum.

[0022] As an optional embodiment, the confinement potential (U) is determined by calculating the Gibbs free energy change of each elementary step of the NRR. L (NH3)) to evaluate catalytic activity. This example initially screens the scheme for the first hydrogenation step (*N2+H) in the nitrogen reduction reaction. + +e - →*N2H) and the final step of producing NH3 (*NH2+H) + +e -The Gibbs free energy change of (→*NH3) is less than 0.5 eV. Ten potential high-quality catalyst combinations were initially screened: Mo-V@GDY, Mo-Cr@GDY, Mo-Mn@GDY, Mo-Fe@GDY, Mo-Co@GDY, Mo-Ni@GDY, Mo-Cu@GDY, Mo-Y@GDY, Mo-Rh@GDY, and Mo-Ir@GDY.

[0023] For the 10 potential high-quality catalysts mentioned above, end-adsorption and side-adsorption models of N2 were constructed, and the Gibbs free energy changes of the N2 adsorption, activation, and stepwise hydrogenation whole reaction process were calculated. A schematic diagram of the NRR mechanism of the whole hydrogenation reaction is shown below. Figure 8 Calculate and determine the limiting potential (U) for each configuration. L (NH3)), such as Figure 4 Shown: Mo-V@GDY(-0.48V), Mo-Cr@GDY(-0.34V), Mo-Mn@GDY(-0.32V), Mo-Fe@GDY(-0.44V), Mo-Co@GDY(-0.43V) , Mo-Ni@GDY(-0.40V), Mo-Cu@GDY(-0.49V), Mo-Y@GDY(-0.49V), Mo-Rh@GDY(-0.47V) and Mo-Ir@GDY(-0.49V). U of the above ten solutions L (NH3) is higher than that of Ru(0001) (-0.98V). Among them, Mo-Cr@GDY (limiting potential of -0.34V) and Mo-Mn@GDY (limiting potential of -0.32V) are the configurations with the best catalytic activity.

[0024] S104. Employing formation energy (E) f ), binding energy (E) b ), solubility potential (U) diss The structural stability of the above 10 highly catalytically active Mo-TM@GDY configurations was evaluated, among which the formation energy E f The dissolution potential Udiss is calculated by the following formula: E f =E tot [GDY*+Mo-Tm]-E tot [GDY]–E[Mo-bulk]–E[TM-bulk] U diss =U 0 -E f / ne Among them, E tot [GDY*+Mo-Tm] represents the total energy after loading bimetallic atoms, E tot[GDY] represents the total energy of graphdiyne without bimetallic atoms, and E[Mo-bulk] and E[TM-bulk] represent the energies of molybdenum atoms and 3d / 4d / 5d transition metal atoms in the bulk phase, respectively. 0 The average standard solution potential of molybdenum atoms and transition metal atoms TM is represented by ne, where ne is the number of electrons involved in the dissolution reaction.

[0025] The formation energy and dissolution potential of the bimetallic atom catalyst can be calculated from this formula. A smaller formation energy and a larger dissolution potential indicate a more stable bond between the bimetallic atoms and the graphdiyne substrate. Zhang et al. successfully synthesized CuEr@GDY with a formation energy of 6.96 eV using a thermally assisted in-situ reduction anchoring method; Wu et al. recently successfully prepared Mg-C3N4 with a dissolution potential of -1.68 V, and this material exhibits sufficient stability for the carbon dioxide reduction reaction under electrochemical conditions. Therefore, E is used in the examples. f <6.96 eV as the screening criterion for formation energy, U diss >-1.68V is used as the screening criterion for solution potential.

[0026] The binding energy of Mo-TM@GDY (E b ) Calculated by the following formula: E b =E[total] E tot [GDY] E[Mo-atom]–E[TM-atom] E[total] and E tot [GDY] represents the total energy of the GDY monolayer with and without loaded atoms, respectively. E[Mo-atom] and E[TM-atom] represent the energies of Mo atoms and TM atoms in vacuum, respectively. In this embodiment, E... b <0 is used as a preliminary screening criterion for whether the structure is stable, E b The more negative the value, the stronger the bonding force; Filter out E f <6.96 eV, U diss >-1.68V and E b The Mo-TM@GDY configuration with <0 yields a structurally stable Mo-TM@GDY configuration. In the structurally stable Mo-TM@GDY configuration, the bimetallic atoms are anchored to the corner positions of the ring structure composed of alkyne bonds within the monolayer graphdiyne supercell, coordinated with sp-hybridized carbon atoms, and loaded within the triangular pores of the monolayer graphdiyne supercell.

[0027] For the above 10 potential high-quality catalysts, their formation energy E f The voltage range is 2.86 eV to 5.38 eV, such as... Figure 5 All 10 configurations met the screening criterion of less than 6.96 eV, indicating that they have the potential for experimentally stable synthesis. Among them, the optimal formation energy of Mo-Cr@GDY is 4.23 eV, and the formation energy of Mo-Mn@GDY is 4.32 eV.

[0028] Of the 10 potential high-quality catalysts mentioned above, besides Mo-Y@GDY(U diss Besides (-1.76V), the other nine potentially high-quality catalysts have solubility potentials U0. diss The range is -0.42V to -1.56V, such as... Figure 6 All nine configurations met the screening criterion of a solubility potential greater than -1.68V, indicating that they possess sufficient stability under electrochemical conditions. Among them, the optimal solubility potential for Mo-Cr@GDY is -1.40V, and for Mo-Mn@GDY it is -1.56V.

[0029] For the above 10 potential high-quality catalysts, their binding energy E b The range is -6.08 eV to -10.08 eV, such as... Figure 7 All of them met the screening criterion of less than 0, indicating that there is a strong interaction between Mo-TM and GDY in these 10 configurations, and the structure is very stable. Among them, the optimal binding energy of Mo-Cr@GDY is -8.59 eV, and the binding energy of Mo-Mn@GDY is -6.60 eV.

[0030] S105. In the structurally stable Mo-TM@GDY configuration, a configuration with high catalytic selectivity in electrocatalytic nitrogen reduction reaction was screened to obtain a graphdiyne-supported bimetallic nitrogen fixation catalyst.

[0031] The selectivity of the catalyst was evaluated by comparing the adsorption free energies of nitrogen molecules and hydrogen atoms on the catalyst surface, as well as the limiting potentials of the nitrogen reduction reaction and the hydrogen evolution reaction. The highly selective Mo-TM@GDY catalyst showed weaker adsorption capacity for hydrogen intermediates than for nitrogen molecules, and the difference between the limiting potentials of the nitrogen reduction reaction and the hydrogen evolution reaction was positive, effectively suppressing the hydrogen evolution side reaction and ensuring high selectivity for ammonia synthesis. The adsorption free energies of N2 and H2 on Mo-TM@GDY, and their difference, are shown below. Figure 9 As shown.

[0032] The NRR selectivity of the catalysts was evaluated by comparing the adsorption free energies of N2 and H. The results showed that N2 adsorption on Mo-Cr@GDY, Mo-Mn@GDY, Mo-Fe@GDY, and Mo-Co@GDY exhibited a greater energy advantage than H adsorption, and U... L (NH3)-U LThe (H2) differences were positive, at 0.23V, 0.04V, 0.17V, and 0.14V respectively, which effectively suppressed HER.

[0033] Therefore, considering all the above screening criteria and calculation results, this embodiment shows that four configurations—Mo-Cr@GDY, Mo-Mn@GDY, Mo-Fe@GDY, and Mo-Co@GDY—can simultaneously satisfy the requirements for activity, stability, and selectivity. Among them, Mo-Cr@GDY and Mo-Mn@GDY are the optimal configurations. The NRR Gibbs free energy change diagram and reaction intermediates of Mo-Cr@GDY are shown below. Figure 10 As shown, the NRR Gibbs free energy change diagram and reaction intermediates on Mo-Mn@GDY are as follows. Figure 11 As shown.

[0034] Four configurations—Mo-Cr@GDY, Mo-Mn@GDY, Mo-Fe@GDY, and Mo-Co@GDY—can serve as bimetallic electrocatalytic nitrogen fixation catalysts supported on graphdiyne. The catalysts specifically consist of a graphdiyne support and a bimetallic active component consisting of molybdenum and a transition metal supported on the support; the transition metal is Cr, Mn, Fe, or Co. Molybdenum atoms and transition metal atoms are distributed on the graphdiyne support in a near-proximity or coordinated manner, forming bimetallic active sites. In practice, these catalysts are applied to the electrochemical nitrogen reduction to ammonia synthesis reaction at ambient temperature and pressure.

[0035] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for designing a graphitic diyne-supported bimetallic nitrogen-fixing catalyst, characterized in that, Includes the following steps: S101. A single-layer graphitic diyne supercell was selected as the carrier model; S102. Construct a bimetallic atom system on the monolayer graphdiyne supercell to form a Mo-TM@GDY configuration; wherein the bimetallic atom system contains one molybdenum atom and one transition metal atom TM; S103. Screening out Mo-TM@GDY configurations with high catalytic activity in electrocatalytic nitrogen reduction reaction from various Mo-TM@GDY configurations; S104. Based on the formation energy, dissolution potential, and binding energy of the highly catalytically active Mo-TM@GDY configuration, structurally stable Mo-TM@GDY configurations were screened. S105. Among the structurally stable Mo-TM@GDY configurations, a configuration with high catalytic selectivity in the electrocatalytic nitrogen reduction reaction is selected to obtain the graphdiyne-supported bimetallic nitrogen fixation catalyst.

2. The design method of the graphitic diyne-supported bimetallic nitrogen-fixing catalyst according to claim 1, characterized in that, In step S101, the configuration of the monolayer graphdiyne supercell is (2×2×1), and the supercell contains 72 carbon atoms. In step S102, a bimetallic atom system is constructed at the triangular pores of the monolayer graphdiyne supercell; the transition metal atom is one of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Tc, Ru, Rh, Pd, Ag, Cd, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, and Hg.

3. The design method of the graphitic diyne-supported bimetallic nitrogen-fixing catalyst according to claim 1, characterized in that, In step S103, the screening criteria of the high catalytic activity include: firstly, in the electrocatalytic nitrogen reduction reaction, screening the Mo-TM@GDY configuration with the Gibbs free energy change of the first hydrogenation step and the last NH3 generation step both less than 0.5 eV; wherein the first hydrogenation step is: *N2+H++e - →*N2H, and the last NH3 generation step is: *NH2+H + +e - →*NH3. The end-adsorption and side-adsorption models of N2 were reconstructed, and the Gibbs free energy changes of N2 adsorption, activation and the whole reaction process of stepwise hydrogenation of the above obtained configurations were calculated to determine the limiting potential U of each configuration L (NH3) and the threshold value was the limiting potential-0.98V of Ru(0001) as a reference L (NH3) of-0.98V.

4. The design method of the graphitic diyne-supported bimetallic nitrogen-fixing catalyst according to claim 3, characterized in that, The limiting potential U of the Mo-TM@GDY configuration L The smaller the absolute value of (NH3), the better the catalytic activity.

5. The design method of the graphitic diyne-supported bimetallic nitrogen-fixing catalyst according to claim 1, characterized in that, In step S104, the forming energy E f and solubility potential U diss Calculated by the following formula: E f =E tot [WHEN*+Mo-Tm]-E tot [WHEN]–E[Mo-bulk]–E[TM-bulk] IN diss =U 0 -E f / not Among them, E tot [GDY*+Mo-Tm] represents the total energy of the Mo-TM@GDY configuration, E tot [GDY] represents the total energy of a monolayer graphdiyne supercell without bimetallic atoms, E[Mo-bulk] and E[TM-bulk] represent the energies of molybdenum atoms and transition metal atoms TM in the bulk phase, respectively, and U 0 The average standard solution potential of molybdenum atoms and transition metal atoms TM is represented, where ne is the number of electrons involved in the dissolution reaction; The binding energy E of the Mo-TM@GDY configuration b Calculated by the following formula: E b =E[total] E tot [WHEN] E[Mo-atom]–E[TM-atom] Among them, E[total] and E tot [GDY] represents the total energy of a monolayer graphdiyne supercell with and without loaded bimetallic atoms, respectively; E[Mo-atom] and E[TM-atom] represent the energies of molybdenum atoms and transition metal atoms TM in vacuum, respectively. Filter out E f <6.96 eV, U diss >-1.68V and E b The Mo-TM@GDY configuration with <0 yields a structurally stable Mo-TM@GDY configuration.

6. The design method of the graphitic diyne-supported bimetallic nitrogen-fixing catalyst according to claim 1, characterized in that, In step S104, in the structurally stable Mo-TM@GDY configuration, the bimetallic atoms are anchored to the corner positions of the ring structure composed of alkyne bonds within the monolayer graphdiyne supercell, coordinated with sp hybrid carbon atoms, and loaded into the triangular pores of the monolayer graphdiyne supercell.

7. The design method of the graphitic diyne-supported bimetallic nitrogen-fixing catalyst according to claim 1, characterized in that, In step S105, the screening criteria for high catalytic selectivity include: evaluating the catalytic selectivity of the structurally stable Mo-TM@GDY configuration by comparing the adsorption free energy of nitrogen and hydrogen atoms and the difference in the limiting potentials of nitrogen reduction reaction and hydrogen evolution reaction in the Mo-TM@GDY configuration. The Mo-TM@GDY configuration with high catalytic selectivity has a weaker adsorption capacity for hydrogen intermediates than for nitrogen molecules, and the difference between the limiting potential of nitrogen reduction reaction and the limiting potential of hydrogen evolution reaction is positive.

8. A nitrogen-fixing catalyst, characterized in that, The graphdiyne-supported bimetallic nitrogen fixation catalyst obtained by the design method according to any one of claims 1 to 7 comprises a graphdiyne support and a molybdenum and transition metal bimetallic active component supported on the graphdiyne support; wherein the transition metal is Cr, Mn, Fe or Co.

9. The nitrogen-fixing catalyst according to claim 8, characterized in that, Molybdenum atoms and transition metal atoms are distributed on the graphdiyne support in a manner that is adjacent to or coordinated with each other, forming bimetallic active sites.

10. The nitrogen-fixing catalyst according to claim 8 or 9, characterized in that, The catalyst was applied to the electrochemical nitrogen reduction to ammonia synthesis reaction at room temperature and pressure.

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