Design method of application of C4N3 anchored transition metal catalyst in preparation of ammonia from nitric oxide

Abstract

The invention provides a design method of application of a C4N3 anchored transition metal catalyst in preparation of ammonia from nitric oxide, which comprises the following steps: constructing a C4N3 structure anchored transition metal atom model, optimizing and acquiring energy information, the energy information comprising formation energy E and dissolution potential Udiss; when E is less than 0 and Udiss is greater than 0, calculating Gibbs free energy of nitric oxide, hydrogen protons and water adsorbed on transition metal atoms; when GNOlt; gH and GNOlt; the method comprises the following steps of: constructing a nitric oxide triple adsorption model and a coupling model and acquiring energy E1 and E2 when the Gibbs free energy is larger than GH2O, and calculating a Gibbs free energy change value G of each step according to the element reaction of the nitric oxide when the absolute value of the difference between the E1 and the E2 is smaller than 0.05; and when G is less than 0, if the same nitric oxide is preferentially reduced to prepare ammonia gas, the catalyst is good in performance.

Description

Technical Field

[0001] This invention belongs to the fields of chemistry and materials, and specifically relates to a design method for the application of a C4N3-anchored transition metal catalyst in the production of ammonia from nitric oxide. Background Technology

[0002] Ammonia (NH3), as an important raw material, plays an indispensable role in agricultural production, defense industry, chemical industry, refrigeration, and other fields, and is crucial to national economic development. However, to date, industrial ammonia synthesis still uses the traditional Haber-Bosch method. This method can synthesize ammonia on a large scale to meet the needs of agriculture and industry, but the reaction conditions are extremely harsh (300-500℃; 200-300 atm), resulting in large energy consumption and the emission of greenhouse gases, causing damage to the environment and climate. Therefore, developing a green and sustainable electrochemical ammonia synthesis method is one of the important issues in the field of electrocatalysis. In the field of electrochemistry, the most widely used electrochemical ammonia synthesis method currently uses nitrogen (N2) as the nitrogen source and water as the proton source. However, due to the high bond energy of the nitrogen-nitrogen triple bond, nitrogen is difficult to activate, which severely limits the nitrogen reduction efficiency and makes it difficult to scale up to an industrial scale. Therefore, it is necessary to find a suitable substance as a nitrogen source to replace nitrogen.

[0003] Nitric oxide (NO), an air pollutant, primarily originates from vehicle emissions, industrial emissions, and agricultural activities. Secondary sources include natural sources such as microbial activity, volcanic eruptions, lightning (during lightning discharge, nitrogen and oxygen in the air react to form nitric oxide), and biological degradation. Compared to nitrogen, nitric oxide has a lower bond energy (204 kJ / mol at room temperature, compared to 941 kJ / mol for nitrogen) and higher solubility in water. Therefore, the electrochemical and thermodynamic advantages of using nitric oxide to produce ammonia are greater than those of using nitrogen. Thus, the production of ammonia from nitric oxide shows promise.

[0004] Even though research on the production of ammonia by the reduction of nitric oxide is very advanced, the reduction of nitric oxide involves five electronic steps, numerous intermediates, and different reaction pathways. Currently, the specific pathways of nitric oxide reduction and the search for intermediates have not been thoroughly studied. Moreover, the Pt-based catalysts currently used have high costs and high limiting potentials (-0.5V), and the preferential adsorption of hydrogen protons and water also affects the reduction of nitric oxide. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to improve the selectivity and reaction efficiency in the production of ammonia from nitric oxide.

[0006] The present invention solves the above-mentioned technical problems through the following technical means: This invention provides a design method for the application of C4N3-anchored transition metal catalysts in the production of ammonia from nitric oxide. The method involves constructing a C4N3 structure anchored to transition metal atoms, optimizing the model, and obtaining energy information, including the formation energy E and the dissolution potential U. diss ; When E < 0 and U diss When the value is greater than 0, calculate the Gibbs free energy ΔG of nitric oxide, hydrogen protons, and water adsorbed on transition metal atoms. NO , △G H and △G H2O ; When △G NO <△G H And △G NO <△G H2O At that time, a triple adsorption model of nitric oxide was constructed and the energy E1 was obtained. Then, the triple adsorption model of nitric oxide was converted into a coupling model and the energy E2 was obtained. When the absolute value of the difference between E1 and E2 is less than 0.05, based on the elementary reaction of nitric oxide, an intermediate is constructed and energy information is obtained to calculate the Gibbs free energy change value ΔG for each step. When ΔG < 0, if the same nitric oxide is preferentially reduced to produce ammonia, it is a good catalyst.

[0007] Beneficial effects: This invention uses the C4N3 structure as a base to anchor transition metal atoms. The thermodynamics and electrochemical stability of the structure are systematically studied through first-principles calculations. After ensuring stability, competitive adsorption, side reaction screening, and preferential oxidation of the same nitric oxide to ammonia are conducted to finally obtain the target catalyst.

[0008] Preferably, the lattice constant of the C4N3 structure is a=b=14.50Å.

[0009] Preferably, the forming energy E=E b +E c , of which E b For binding energy, E c It is the cohesive energy. E b =E TM@C4N3 -E C4N3 -E TM E c =E TM -E TM-bulk / N bulk E TM@C4N3 The energy E that anchors the transition metal atoms in the C4N3 structure C4N3 For the energy of the C4N3 structure, E TM E represents the energy of a transition metal atom.TM-bulk N is the energy of the bulk phase in the unit cell of a transition metal atom. bulk This represents the number of transition metal atoms in bulk, and all energy units are eV.

[0010] Preferably, the solution potential U diss =Uθdiss-E b / (eNe); where Uθdiss is the standard solution potential, e is a single electron, and Ne is the number of atoms in the bulk phase unit cell of the transition metal atom.

[0011] Preferably, the transition metal is selected from 3d transition metals, 4d transition metals and 5d transition metals.

[0012] Preferably, △G NO =G NO / TM@C4N3 -G NO -G TM@C4N3 Among them, G NO / TM@C4N3 G represents the Gibbs free energy of nitric oxide adsorbed on a C4N3 structure and anchored to a transition metal atom. NO G represents the Gibbs free energy of nitric oxide. TM@C4N3 This represents the Gibbs free energy of the C4N3 structure anchored to transition metal atoms.

[0013] Preferably, △G H =G H / TM@C4N3 -G H -G TM@C4N3 Among them, G H / TM@C4N3 G represents the Gibbs free energy of hydrogen protons adsorbed in a C4N3 structure and anchored to transition metal atoms. H G represents the Gibbs free energy of the hydrogen proton. TM@C4N3 This represents the Gibbs free energy of the C4N3 structure anchored to transition metal atoms.

[0014] Preferably, △G H2O =G H2O / TM@C4N3 -G H2O -G TM@C4N3 Among them, G H2O / TM@C4N3 G represents the Gibbs free energy, which represents the energy of water adsorbed in a C4N3 structure anchoring transition metal atoms. H2O G represents the Gibbs free energy of water. TM@C4N3 This represents the Gibbs free energy of the C4N3 structure anchored to transition metal atoms.

[0015] Preferably, the nitric oxide adsorbed at any two N-termini in the nitric oxide triple adsorption model is brought closer to form a coupling configuration, and the energy information E2 is optimized and obtained.

[0016] Preferably, the ammonia gas is produced by preferentially reducing the same nitric oxide. Specifically, the energy of hydrogen protons added to the same nitric oxide is E3, and the energy of hydrogen protons added to different nitric oxides is E4. If the difference between E3 and E4 is less than 0, then the ammonia gas is produced by preferentially reducing the same nitric oxide.

[0017] Preferably, a catalyst is considered to meet the requirements if the difference between E3 and E4 in each step of the elementary reaction is less than 0.

[0018] Beneficial effects: This invention successfully screened Rh@C4N3 as the best performing catalyst. It not only has stability under thermodynamic and electrochemical conditions, but also has a significantly stronger adsorption capacity for nitric oxide than for hydrogen protons and water to avoid the influence of competitive adsorption. No side reactions are generated during the catalytic process, and the same nitric oxide is preferentially reduced to produce hydrogen, thereby improving selectivity and reaction efficiency. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the screening process for the design method of applying C4N3 anchored transition metal catalysts in the production of ammonia from nitric oxide in this invention. Figure 2 This is a schematic diagram of the C4N3 structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of the C4N3 structure anchoring transition metal atoms in an embodiment of the present invention; Figure 4 This is a diagram showing the formation energy and dissolution potential of the C4N3 structure anchoring transition metal atoms in an embodiment of the present invention. Figure 5 In the embodiments of the present invention, △G NO , △G H and △G H2O Line chart; Figure 6 This is a diagram of the triple adsorption configuration of nitric oxide in an embodiment of the present invention; Figure 7 This is a complete pathway diagram of the Rh@C4N3 catalyst used for nitric oxide reduction in embodiments of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0021] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0022] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0023] according to Figure 1-6 As shown, this embodiment provides a design method for the application of a transition metal@C4N3 catalyst in the production of ammonia from nitric oxide, specifically including the following steps: 1. Construct and optimize the C4N3 structure anchored transition metal atom model. (1) Import the C4N3 structure CIF file into Materials Studio software, and then convert it into an input file that the VASP calculation software can recognize. The input file includes POSCAR, INCAR, KPOINTS, POTCAR and submission script.

[0024] (2) POTCAR was generated using the vaspkit-103 plate; KPOINTS used the Gamma grid method to select K-space grid points to calculate the integral in the Brillouin zone, with K points set to 3×3×1. INCAR used the PBE functional under the generalized gradient approximation to describe the inter-electron interaction, with the energy convergence criterion set to 1×10. -5 eV, the force convergence criterion is 0.02eV / Å, the cutoff energy is 450eV, and ISPIN=2 is set to enable spin polarization.

[0025] Because the C4N3 structure is a two-dimensional material, a fixed basis vector optimization method was used, with other parameters set to default values. After the structure optimization is complete, CONTCAR and OUTCAR files will be generated in the calculation folder. Drag the CONTCAR file into the VESTA software to view the optimized C4N3 structure. Figure 2 As shown, the final energy information is extracted directly from the OUTCAR file.

[0026] Frequency calculations are performed by setting IBRION=5, POTIM=0.015, NFREE=2, and NSW=1 in INCAR, with all other settings using default values. Then, all substrate atoms except intermediate atoms are fixed in POSCAR. Atoms are then fixed by atomic ordinates using the VASPKET-402-1 command, and the calculation task is submitted.

[0027] (3) The calculation results show that the lattice constant of the C4N3 structure in the intrinsic state is consistent with the experiment, and the lattice constant is a=b=14.50Å.

[0028] (4) Convert the CONTCAR file to a CIF file and import it into Materials Studio. In the C4N3 structure, the transition metal atom is anchored by three adjacent nitrogen atoms. Then, the new CIF structure file is obtained and converted into a VASP-recognizable POSCAR format file by VESTA. Continue to optimize the structure and regenerate the POTCAR using the VASPkit-103 function. In the INCAR, the initial magnetic moment of the transition metal atom is given to 0-5 μB by the MAGMOM parameter. The DFT+U method is used to correct the Coulomb interaction between local electrons. The range of U values ​​used is 0-6 eV depending on the different metal atoms. The transition metal is selected from 3d transition metal, 4d transition metal and 5d transition metal. Hg and Tc are removed because Hg is toxic and Tc is radioactive.

[0029] (5) Subsequently, the structure file of the C4N3 structure anchored transition metal atom model obtained through VASP structure optimization is saved, i.e., CONTCAR. The C4N3 structure anchored transition metal atom structure model is as follows: Figure 3 As shown.

[0030] 2. Calculate the formation energy E and dissolution potential U of the C4N3 structure anchored transition metal atom model. diss (1) After obtaining the C4N3 structure anchored transition metal atom model, the formation energy E=E is determined according to the formula. b +E c , of which E b For binding energy, E c This is the cohesive energy. Where E is... b =E TM@C4N3 -E C4N3 -E TM E c =E TM -E TM-bulk / N bulk .

[0031] E TM@C4N3 The energy E that anchors the transition metal atoms in the C4N3 structure C4N3 For the energy of the C4N3 structure, E TM E represents the energy of a transition metal atom. TM-bulk N is the energy of the bulk phase in the unit cell of a transition metal atom. bulk This represents the number of transition metal atoms in bulk, and all energy units are eV.

[0032] According to the formula, the dissolution potential U diss =Uθdiss-E b / (eNe); where Uθdiss is the standard dissolution potential, e is a single electron, and Ne is the number of atoms in the bulk phase unit cell of the transition metal. Formation energy E and dissolution potential U diss Specifically, such as Figure 4 As shown.

[0033] (2) Calculate the formation energy E and the dissolution potential U diss Structures with a formation energy E greater than 0 are excluded due to their thermodynamic difficulty in synthesis and their solution potential U. diss Structures with values ​​less than 0 are unstable under electrochemical conditions.

[0034] (3) The final stable transition metal atoms are calculated to be Sc, Ti, Mn, Y, Zr, Nb, Rh, Hf, and Ta.

[0035] 3. Calculate the Gibbs free energy of the adsorbate. (1) After determining the stable transition metal atom model, an adsorption model of the transition metal atom with nitric oxide, hydrogen protons and water is established, the structure is optimized and energy information is obtained, and the formula ΔG is used. ads =G 吸附物 / TM@C4N3 -G 吸附物 -G TM@C4N3 Calculate the adsorption energy ΔG of nitric oxide. NO Hydrogen proton adsorption energy ΔG H Adsorption energy of water ΔG H2O .

[0036] △G NO =G NO / TM@C4N3 -G NO -G TM@C4N3 Among them, G NO / TM@C4N3 G represents the Gibbs free energy of nitric oxide adsorbed on a C4N3 structure and anchored to a transition metal atom. NO G represents the Gibbs free energy of nitric oxide. TM@C4N3 This represents the Gibbs free energy of the C4N3 structure anchored to transition metal atoms.

[0037] △G H =G H / TM@C4N3 -G H -G TM@C4N3 Among them, G H / TM@C4N3 G represents the Gibbs free energy of hydrogen protons adsorbed in a C4N3 structure and anchored to transition metal atoms. H G represents the Gibbs free energy of the hydrogen proton. TM@C4N3 This represents the Gibbs free energy of the C4N3 structure anchored to transition metal atoms.

[0038] △G H2O =G H2O / TM@C4N3 -G H2O-G TM@C4N3 Among them, G H2O / TM@C4N3 G represents the Gibbs free energy, which represents the energy of water adsorbed in a C4N3 structure anchoring transition metal atoms. H2O G represents the Gibbs free energy of water. TM@C4N3 This represents the Gibbs free energy of the C4N3 structure anchored to transition metal atoms.

[0039] (2) Only when △G NO <△G H And △G NO <△G H2O The result indicates that the adsorption strength of nitric oxide is higher than that of water and hydrogen protons, thus eliminating the interference of water and hydrogen protons competing for adsorption at the active sites. Figure 5 As shown.

[0040] 4. Construct a triple adsorption model and a coupling model for nitric oxide. (1) Consider the order and configuration of nitric oxide adsorption. The first nitric oxide adsorption configuration has N-terminal mode, O-terminal mode and side-on mode. After determining the first nitric oxide adsorption mode, the second and third are considered in the same way, and the adsorption configuration is finally determined. (2) The results showed that the first nitric oxide adsorbed on Sc, Ti, Y, Zr, and Rh transition metal atoms was N-terminal, while the remaining four transition metal atoms were all in side-on mode. The second nitric oxide adsorbed on these atoms was also in N-terminal mode, and the third nitric oxide adsorbed on all atoms except Mn was also in N-terminal mode. After the third nitric oxide adsorbed on Mn, the first nitric oxide adsorbed on it would become N-terminal. Schematic diagrams of different adsorption configurations are shown below. Figure 6 As shown.

[0041] (3) The triple adsorption model was finally determined to be three N-terminal adsorption modes for Sc, Ti, Mn, Y, Zr and Rh, and two N-terminal adsorption modes plus one side-on adsorption mode for the remaining three transition metal atoms. The structure was optimized and the model energy E1 was obtained.

[0042] (4) In order to eliminate the possibility of side reactions caused by nitric oxide coupling, we continued to construct a triple adsorption model of nitric oxide, bringing any two N-terminal adsorbed nitric oxides closer together to form a coupling model, optimizing the structure and extracting energy E2.

[0043] The specific energies of E1 and E2 are shown in Table 1, and the unit of energy is eV.

[0044]

[0045] Table 1 As shown in Table 1, the absolute values ​​of the differences between E1 and E2 for the above nine transition metal atoms are all less than 0.05, therefore all nine transition metal atoms meet the requirements.

[0046] 5. Investigation of the reduction reaction of nitric oxide Based on the elementary reactions of nitric oxide, intermediates were constructed, their structures optimized, and energy information obtained. The elementary reactions during the reduction of nitric oxide are as follows: (1) NO + H + +e - →NHO / NOH (2) NHO+H + +e - →NHOH / NH2O (3) NHOH + H + +e - →NH2OH (4) NH2O + H + +e - →NH2OH / NH+H2O (5) NH2OH + H + +e - →NH2+H2O (6) NH + H + +e - →NH2 (7) NH2 + H + +e - →NH3 First, the intermediate adsorption structure is constructed, optimized, and energy is calculated using Materials Studio, VESTA, and VASP. The Gibbs free energy change ΔG from step (1) to step (7) is calculated, where ΔG is obtained through G 基元步骤产物 -G 基元步骤反应物 -G H calculate.

[0047] The calculation requires ΔG < 0. It was found that the ΔG values ​​of transition metals Sc, Ti, Mn, Y, and Zr in step (1) are all greater than 0, which does not meet the requirements and is therefore excluded.

[0048] It was also found that the transition metal Nb had a ΔG greater than 0 in step (5), which did not meet the requirements and was therefore excluded.

[0049] 6. Prioritize the reduction of the same nitric oxide Based on the above elementary reactions, the intermediate adsorption structure was constructed, the structure was optimized and the energy was calculated by Materials Studio, VESTA and VASP. The configuration energy of hydrogen protons added to the same nitric oxide in steps (1) to (7) is E3, and the configuration energy of hydrogen protons added to different nitric oxides is E4. The value of E3-E4 was calculated.

[0050] Only when the value of E3-E4 is less than 0 does it indicate that hydrogen protons are more stable when added to the same nitric oxide and can react to produce ammonia; if the value of E3-E4 is greater than 0, it indicates that hydrogen protons do not preferentially reduce the same nitric oxide, which reduces the reaction efficiency and is therefore excluded.

[0051] The transition metal Hf was found to have a configuration energy of -599.28 eV when the third hydrogen proton is added to the same nitric oxide, and a configuration energy of -600.57 eV when the hydrogen proton is added to different nitric oxides. Therefore, E3-E4>0 is excluded.

[0052] The transition metal Ta was found to have a configuration energy of -600.57 eV when the third hydrogen proton is added to the same nitric oxide, and a configuration energy of -600.66 eV when the hydrogen proton is added to different nitric oxides. Therefore, E3-E4>0 is excluded.

[0053] Finally, only the transition metal Rh remained. It was found that the E3-E4 values ​​of each step were less than 0, which is the target catalyst, denoted as Rh@C4N3 catalyst.

[0054] 7. Investigation of the complete thermodynamic potential surface of nitric oxide reduction (1) After determining the Rh@C4N3 catalyst, its complete potential energy surface is plotted as follows: Figure 7 As shown; (2) The overall potential energy surface of this reaction is a process of decreasing energy, in which the NHO intermediate is protonated to NH2O instead of NHOH in the next step; (3) The NH2O intermediate is protonated to NH2OH in the next step; (4) The target catalyst identified above has the advantages of being stable under thermodynamic and electrochemical conditions. Moreover, hydrogen protons and water will not compete for the adsorption of nitric oxide, and there will be no side reactions and the same nitric oxide can be preferentially reduced, thereby improving the selectivity and reaction efficiency of the catalyst. Furthermore, the catalyst has a clear reaction intermediate and reaction pathway. Finally, the Rh@C4N3 catalyst has a limiting potential of -0.2.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A design method for the application of a C4N3-anchored transition metal catalyst in the production of ammonia from nitric oxide, characterized in that, Includes the following steps: A C4N3 structure anchored transition metal atom model was constructed, optimized, and its energy information, including formation energy E and dissolution potential U, was obtained. diss ; When E < 0 and U diss When the value is greater than 0, calculate the Gibbs adsorption energy ΔG of nitric oxide, hydrogen protons, and water adsorbed on transition metal atoms. NO , △G H and △G H2O ; When △G NO <△G H And △G NO <△G H2O At that time, a triple adsorption model of nitric oxide was constructed and energy E1 was obtained. Then, a coupling model was formed through the triple adsorption model of nitric oxide and energy E2 was obtained. When the absolute value of the difference between E1 and E2 is less than 0.05, based on the elementary reaction of nitric oxide, an intermediate is constructed and energy information is obtained to calculate the Gibbs free energy change value ΔG for each step. When ΔG < 0, if the same nitric oxide is preferentially reduced to produce ammonia, it is a high-performance catalyst.

2. The design method for the application of the C4N3 anchored transition metal catalyst in the production of ammonia from nitric oxide according to claim 1, characterized in that, The lattice constant of the C4N3 structure is a=b=14.50Å.

3. The design method for the application of the C4N3 anchored transition metal catalyst in the production of ammonia from nitric oxide according to claim 1, characterized in that, The formation energy E=E b +E c E b For binding energy, E c For cohesive energy; E b =E TM@C4N3 -E C4N3 -E TM E c =E TM -E TM-bulk / N bulk ; where E TM@C4N3 The energy E that anchors the transition metal atoms in the C4N3 structure C4N3 For the energy of the C4N3 structure, E TM E represents the energy of a transition metal atom. TM-bulk N is the energy of the bulk phase in the unit cell of a transition metal atom. bulk This represents the number of transition metal atoms in bulk, and all energy units are eV.

4. The design method for the application of the C4N3 anchored transition metal catalyst in the production of ammonia from nitric oxide according to claim 1, characterized in that, Dissolution potential U diss =Uθdiss-E b / (eNe); where Uθdiss is its standard dissolution potential, e is a single electron, and Ne is the number of atoms in the bulk phase unit cell of the transition metal atom.

5. The design method for the application of the C4N3 anchored transition metal catalyst in the production of ammonia from nitric oxide according to claim 1, characterized in that, The transition metal is selected from 3d transition metals, 4d transition metals and 5d transition metals.

6. The design method for the application of the C4N3 anchored transition metal catalyst in the production of ammonia from nitric oxide according to claim 1, characterized in that, △G NO =G NO / TM@C4N3 -G NO -G TM@C4N3 Among them, G NO / TM@C4N3 G represents the Gibbs free energy of nitric oxide adsorbed on a C4N3 structure and anchored to a transition metal atom. NO G represents the Gibbs free energy of nitric oxide. TM@C4N3 This represents the Gibbs free energy of the C4N3 structure anchored to transition metal atoms.

7. The design method for the application of the C4N3 anchored transition metal catalyst in the production of ammonia from nitric oxide according to claim 1, characterized in that, △G H =G H / TM@C4N3 -G H -G TM@C4N3 Among them, G H / TM@C4N3 G represents the Gibbs free energy of hydrogen protons adsorbed in a C4N3 structure and anchored to transition metal atoms. H G represents the Gibbs free energy of the hydrogen proton. TM@C4N3 This represents the Gibbs free energy of the C4N3 structure anchored to transition metal atoms.

8. The design method for the application of the C4N3 anchored transition metal catalyst in the production of ammonia from nitric oxide according to claim 1, characterized in that, △G H2O =G H2O / TM@C4N3 -G H2O -G TM@C4N3 Among them, G H2O / TM@C4N3 G represents the Gibbs free energy, which represents the energy of water adsorbed in a C4N3 structure anchoring transition metal atoms. H2O G represents the Gibbs free energy of water. TM@C4N3 This represents the Gibbs free energy of the C4N3 structure anchored to transition metal atoms.

9. The design method for the application of the C4N3 anchored transition metal catalyst in the production of ammonia from nitric oxide according to claim 1, characterized in that, In the triple adsorption model of nitric oxide, any two N-terminal adsorbed nitric oxide molecules are brought closer together to form a coupling configuration, and the energy information E2 is optimized and obtained.

10. The design method for the application of the C4N3 anchored transition metal catalyst in the production of ammonia from nitric oxide according to claim 1, characterized in that, The process of preferentially reducing the same nitric oxide to produce ammonia involves the following steps: the energy of a hydrogen proton added to the same nitric oxide is E3, and the energy of a hydrogen proton added to different nitric oxides is E4. If the difference between E3 and E4 is less than 0, then the process of preferentially reducing the same nitric oxide to produce ammonia is considered.

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