Method for calculating NO2 adsorbed by graphite diyne loaded transition metal based on first principle

Abstract

The invention designs a method for calculating NO2 adsorption of graphite diyne-loaded transition metals based on a first principle, geometric configurations of four graphite diyne-loaded transition metals (Ni, Mo) are calculated based on the first principle, and the strength of chemical bonds formed by the four graphite diyne-loaded transition metals and carbon atoms close to the four graphite diyne-loaded transition metals is calculated to test the structural stability of the catalyst. The method comprises the following steps: constructing a model for adsorbing NO2, geometrically optimizing the model, determining a stable structure for adsorbing NO2, generating a wave function file during NO2 adsorption, analyzing the wave function by using Multiwfn software, calculating the strength of a chemical bond formed by combination of metal elements and NO2, evaluating the combination mode of NO2 and a catalyst, and finally calculating the adsorption energy for adsorbing NO2. The chemical bond strength is combined to evaluate the NO2 adsorption condition, and the method is suitable for the design of an adsorption and catalysis NO2 material, activation of NO2 and reduction of energy required by adsorption and catalysis of NO2, so that the cost is saved, and meanwhile, the experiment direction can be guided.

Description

Technical Field

[0001] The invention relates to the technical field of electrical digital data processing, and in particular to a method for calculating NO2 adsorption by graphdiyne loaded with transition metals based on first principles. Background Art

[0002] Single-atom catalysts are heterogeneous catalysts in which metal atoms are highly dispersed on a carrier. This material has attracted increasing attention due to its uniform catalytic active sites and maximum atomic utilization. In addition, its uniform catalytic activity makes it easier to study its properties and mechanisms.

[0003] Graphdiyne is a two-dimensional layered material composed of sp hybridized and sp 2 The crystal composed of hybridized carbon atoms has a highly conjugated porous structure, good conductivity and controllable electronic structure. Due to its uniform porous structure, it becomes one of the best carriers of single-atom catalysts. The single-atom catalysts composed of it are involved in various fields, such as CO oxidation, NO2 reduction, hydrogenation, nitrogen reduction reaction, oxygen reduction reaction, etc. In recent years, significant progress has been made in NO2 reduction by graphene-supported single metal atom catalysts. Summary of the invention

[0004] The purpose of the present invention is to provide a method for calculating the adsorption of NO2 by transition metals loaded on graphdiyne based on first principles, to optimize the structure of the catalyst, to test its stability, to analyze its electronic structure and to evaluate its performance in adsorbing NO2, so as to provide a theoretical basis for the design of NO2 conversion catalysts.

[0005] The present invention designs a method for calculating NO2 adsorbed by transition metals loaded on graphene based on first principles, obtains the geometric configuration of four transition metals (Ni, Mo) loaded on graphene based on first principles calculation, calculates the chemical bond strength formed by four metals loaded on graphene and carbon atoms close to them to test the stability of the catalyst structure, constructs a model for adsorbing NO2, performs geometric optimization on the model, and determines the stable structure of adsorbed NO2. At the same time, a wave function file is generated when NO2 is adsorbed, and the wave function is analyzed using Multiwfn software to calculate the strength of the chemical bond formed by the metal element and NO2, which is used to evaluate the combination mode of NO2 and the catalyst, and finally calculates the adsorption energy of NO2 adsorption, and evaluates the adsorption of NO2 in combination with the chemical bond strength. The present invention is suitable for designing materials for adsorbing and catalyzing NO2, activating NO2, and reducing the energy required for adsorbing and catalyzing NO2, so as to save costs and guide the direction of experiments.

[0006] The method comprises the following steps: (1) Obtain the .cif file of the graphdiyne unit cell structure. The unit cell file is obtained from the MaterialsProject crystal database. Convert the .cif file into a .gjf file, expand the graphdiyne cell into a 2*2*1 supercell, and name it supercell.gjf; (2) Use supercell.gjf to generate the test.inp file and perform the cutoff energy and K-point convergence test on graphdiyne; (3) Generate opt.inp file using supercell.gjf, use CP2K software to optimize the structure of 2*2*1 supercell of graphdiyne, and generate optimized .gjf file through the obtained .restart file, which is the optimized stable structure configuration; (4) Construct structural models of Ni, Fe, Mo, and Ru loaded onto a 2*2*1 supercell of graphdiyne, generate .inp files, optimize the two structures, and calculate the energy of the optimized structures. In the output file, the energy of the 2*2*1 supercell of graphdiyne loaded with two different metals is obtained, and the wave function .molden file is obtained; (5) Analyze the wave function .molden file obtained in step 4, calculate the Mayer bond order, and display it using drawing software; (6) Construct a structural model of NO2 adsorbed on graphdiyne loaded with two different metals, generate a .inp file, optimize the structure, obtain the stable configuration of NO2 adsorbed on graphdiyne loaded with two different metals through the output file, and perform energy calculation on the optimized structure, obtain the final energy of the two structures in the output file and obtain a wave function .molden file; calculate the energy of a NO2 molecule, and then calculate the adsorption energy of NO2; analyze the wave function .molden file obtained in step 5, calculate the Mayer bond order, and express it using drawing software; (7) In step 2, the cutoff energy test result is 400Ry, and the k point of 221 is selected after the K point test; (8) In step 4, a 15 angstrom vacuum region is left above the model when constructing the model, and the loaded metal is a single atom, constituting a single atom catalyst; (9) In step 5, the wave function was analyzed using Multiwfn software and plotted using Origin; (10) In step 6, a 15 angstrom vacuum region was left above the model when constructing the model; (11) In step 7, the adsorption energy is calculated as E ads =E tot -E adsorbate -E catalysts， Where E adsis the adsorption energy, E tot is the total energy after adsorption of NO2, E adsorbate is the energy of NO2, E catalysts Loading single metal atom energy for graphdiyne; (12) In step 8, the wave function was analyzed using Multiwfn software and plotted using VMD.

[0007] The beneficial effect of the present invention is that based on the first principles calculation method of graphdiyne loaded transition metal adsorption of NO2, a single atom catalyst is designed from the perspective of theoretical calculation to activate NO2 and reduce the energy required for converting NO2 into usable energy products, thus providing a theoretical basis for the experiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a flow chart of the method of the present invention; Figure 2 This is a structural diagram of graphdiyne loaded with two metals in the present invention; Figure 3 This is a bond order analysis diagram of graphdiyne loaded with two metals in the present invention; Figure 4 The structural diagram of NO2 adsorption by two structures in the present invention; Figure 5 is a histogram of adsorption energy in the present invention; Figure 6 This is a bond order analysis diagram of the two structures adsorbing NO2 in the present invention. DETAILED DESCRIPTION

[0009] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments: (1) Obtain the .cif file of the graphene primitive cell structure, convert the .cif file into a .gjf file, and expand the graphene primitive cell into a 2*2*1 supercell named supercell.gjf; (2) Use supercell.gjf to generate the test.inp file and perform the cutoff energy and K-point convergence test on graphdiyne. The cutoff energy test result is 55Ry, and the K-point of 221 is selected after the K-point test; (3) Use supercell.gjf to generate opt.inp file, optimize the structure of the 2*2*1 supercell of graphene diyne, and obtain the stable configuration of the 2*2*1 supercell of graphene diyne through the information in the output file; (4) Construct structural models in which Ni, Fe, Mo, and Ru are loaded onto a 2*2*1 supercell of graphdiyne, respectively, leaving a 15 angstrom vacuum region on top. The loaded metal is a single atom, forming a single atom catalyst, and generate a .inp file. Optimize the two structures and perform energy calculation on the optimized structures. The energy of the 2*2*1 supercell of graphdiyne loaded with two different metals is obtained in the output file, and the wave function .molden file is obtained; (5) Analyze the wave function .molden file obtained in step 4, calculate the Mayer bond order and PDOS, and display them using drawing software; (6) Constructing a structural model of graphdiyne loaded with two different metals and adsorbing NO2, leaving a 15 angstrom vacuum area above the model when constructing the model, generating a .inp file, optimizing the structure, and obtaining the stable configuration of graphdiyne loaded with two different metals and adsorbing NO2 through the output file, and performing energy calculation on the optimized structure, obtaining the final energy of the two structures in the output file and obtaining the wave function .molden file; (7) Calculate the energy of a NO2 molecule, and then calculate the adsorption energy of NO2. The formula for calculating the adsorption energy is E ads =E tot -E adsorbate -E catalysts， Where E ads is the adsorption energy, E tot is the total energy after adsorption of NO2, E adsorbate is the energy of NO2, E catalysts Loading single metal atom energy for graphdiyne; (8) Analyze the wave function .molden file obtained in step 6, calculate the Mayer bond order, and display it using VMD software; (9) In step 4, the optimized stable configuration is as follows Figure 2 , the two different metals both stay at one corner of graphdiyne. By comparing graphdiyne monomer and graphdiyne loaded with a single metal atom, it can be observed that Mo causes obvious deformation of graphdiyne. (10) In step 5, a bond order diagram is drawn based on the calculated data, such as Figure 3 . Figure 3 The direct bonding relationship between the original graphene and the single metal atom after loading a single metal element is demonstrated, reflecting the adsorption strength and structural stability between the metal atom and graphene. Among them, the graphene loaded with Mo atoms is relatively stable. (11) In step 6, the specific configuration of NO2 adsorption is calculated as follows Figure 4 As shown; (12) In step 7, the adsorption energy of NO2 is calculated as Figure 5As shown, both configurations are negative, indicating that the adsorption of NO2 is chemical adsorption, which activates NO2; (13) In step 8, the bond order analysis is as follows Figure 6 As shown in the figure, through the analysis of bond order, it is inferred that the adsorption of NO2 in the two configurations is chemical adsorption, which is consistent with the results of adsorption energy analysis.

Claims

1. A method for calculating NO2 adsorption by transition metals loaded on graphdiyne based on first principles, characterized in that: Follow the steps below to implement it: (1) Obtain the .cif file of the graphene primitive cell structure, convert the .cif file into a .gjf file, and expand the graphene primitive cell into a 2*2*1 supercell named supercell.gjf; (2) Use supercell.gjf to generate the test.inp file and perform the cutoff energy and K-point convergence test on graphdiyne; (3) Use supercell.gjf to generate opt.inp file, optimize the structure of the 2*2*1 supercell of graphene diyne, and obtain the stable configuration of the 2*2*1 supercell of graphene diyne through the information in the output file; (4) Construct structural models of Ni and Mo loaded on a 2*2*1 supercell of graphdiyne respectively, generate .inp files, optimize the two structures, and calculate the energy of the optimized structures. In the output file, the energy of the 2*2*1 supercell of graphdiyne loaded with two different metals is obtained, and the wave function .molden file is obtained; (5) Analyze the wave function .molden file obtained in step (4), calculate the Mayer bond order, and display it using drawing software; (6) Construct a structural model of graphdiyne loaded with two different metals and adsorbing NO2, generate a .inp file, optimize the structure, obtain the stable configuration of graphdiyne loaded with two different metals and adsorbing NO2 through the output file, and perform energy calculation on the optimized structure, obtain the final energy of the two structures in the output file and obtain the wave function .molden file; (7) Calculate the energy of a NO2 molecule and then calculate the adsorption energy of NO2; (8) Analyze the wave function .molden file obtained in step (6), calculate the Mayer bond order, and display it using drawing software.

2. The method for calculating NO2 adsorption by transition metal loaded on graphdiyne based on first principles according to claim 2, characterized in that: In step (2), the cutoff energy test result is 400Ry, and after the K point test, a k point of 221 is selected.

3. The method for calculating NO2 adsorption by transition metal loaded on graphdiyne based on first principles according to claim 2, characterized in that: In step (4), a vacuum region of 15 angstroms is left above the model when the model is constructed, and the loaded metal is a single atom, constituting a single atom catalyst.

4. The method for calculating NO2 adsorption by transition metal loaded on graphdiyne based on first principles according to claim 2, characterized in that: In step (5), the wave function is analyzed using Multiwfn software and plotted using Origin.

5. The method for calculating NO2 adsorption by transition metal loaded on graphdiyne based on first principles according to claim 2, characterized in that: In step (6), a 15 angstrom vacuum region is left above the model when the model is constructed.

6. The method for calculating NO2 adsorption by transition metal loaded on graphdiyne based on first principles according to claim 2, characterized in that: In step (7), the adsorption energy is calculated as E ads =E tot -E adsorbate -E catalysts， Where E ads is the adsorption energy, E tot is the total energy after adsorption of NO2, E adsorbate is the energy of NO2, E catalysts Loading single metal atom energy for graphdiyne.

7. The method for calculating NO2 adsorption by transition metal loaded on graphdiyne based on first principles according to claim 2, characterized in that: In step (8), the wave function is analyzed using Multiwfn software.

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