Oxygen reduction reaction theory simulation calculation method based on first principle, medium and program product

Abstract

The invention relates to an oxygen reduction reaction theory simulation calculation method based on a first principle, a medium and a program product. According to the simulation calculation method, the whole process of disordered structure preprocessing, slab model construction, VASP input file generation, oxygen reduction reaction energy barrier and overpotential calculation and differential charge density analysis is achieved through an automatic process. According to the method, a hydrogen electrode (CHE) calculation technology is adopted, and various reaction mechanisms such as a four-electron process AEM mechanism, an OPM mechanism and a two-electron process are comprehensively considered, so that the free energy change of each reaction step is accurately calculated. Compared with the prior art, the method has the advantages that the calculation efficiency is improved, the operation threshold is reduced, a powerful tool is provided for deeply understanding an oxygen reduction reaction mechanism, and the method is of great significance to research in the fields of fuel cells, metal-air cells and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of oxygen reduction reaction theoretical simulation, and in particular to a first-principles-based oxygen reduction reaction theoretical simulation calculation method, medium, and program product. Background Art

[0002] In the field of materials science and chemistry, oxygen reduction reaction (ORR) is a key reaction in fuel cells and metal-air batteries, and its efficiency directly affects the performance of energy conversion devices. Traditional experimental methods are often time-consuming and costly. With the development of computational chemistry, first-principles calculations provide a new way to understand and predict ORR. However, existing computational methods have problems of complex operation and low efficiency, especially when dealing with disordered structures and large-scale calculations.

[0003] Although first-principles calculations can theoretically provide accurate analysis of the ORR reaction mechanism, they face several major challenges in practical applications. First, traditional calculation methods are difficult to handle for disordered structures containing fractional occupancy, and they need to be converted into ordered structures, which is a cumbersome process and prone to errors. Second, the existing calculation process lacks automation, making high-throughput calculations difficult to achieve. In addition, for novice researchers, the complex operation process and high threshold calculation requirements limit the application of this technology. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a theoretical simulation calculation method, medium, and program product for oxygen reduction reaction based on first principles, which significantly improves the calculation efficiency and operability by automatically processing disordered structures, generating VASP input files, calculating ORR energy barriers and overpotentials, and differential charge density.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] The first aspect of the present invention provides a first-principle-based theoretical simulation method for oxygen reduction reaction, comprising the following steps:

[0007] S1. Preprocessing of disordered structures:

[0008] a. Receive a cif file with an unordered structure with score placeholders;

[0009] b. Expand the received cif file to generate an expanded cell structure;

[0010] c. Randomly generate n ordered structures based on the expanded cell structure;

[0011] d. Calculate the electrostatic energy of the system for each ordered structure;

[0012] e. Screening to obtain several ordered structures with the lowest electrostatic energy;

[0013] f. Perform DFT calculation and structural relaxation on the ordered structures obtained by screening to obtain the ordered structure with the lowest total energy;

[0014] S2. Construction of slab model and generation of VASP input file:

[0015] g. Based on the obtained ordered structure with the lowest total energy, a slab model of the material surface for simulating the oxygen reduction reaction is constructed;

[0016] h. Using the slab model, use the Pymatgen library to generate the input file required for VASP calculation, and the input file can be used for first principle calculation;

[0017] S3: Calculation of energy barriers and overpotentials for oxygen reduction reactions:

[0018] i. Using the generated VASP input file, calculate the energy barrier and overpotential of the oxygen reduction reaction using the computational hydrogen electrode (CHE) method;

[0019] j. calculating the free energy change for each reaction step of the oxygen reduction reaction to determine the overpotential;

[0020] S4: Calculation of differential charge density:

[0021] k. Based on the calculated structural information of the oxygen reduction reaction intermediates, electronic self-consistent calculations are performed on each intermediate, slab model part, and adsorbate part to obtain a charge density file;

[0022] 1. Using the charge density file, call vaspkit software to calculate the differential charge density and describe the change in charge distribution in the system to intuitively show the redistribution of charge during the oxygen reduction reaction.

[0023] Furthermore, in S1, the conditions for performing the cell expansion process on the received cif file include:

[0024] Make sure that the total number of each type of atom in the expanded unit cell is an integer.

[0025] Furthermore, in S2, the required input files include POSCAR, INCAR, KPOINTS, and POTCAR files.

[0026] Furthermore, in S3, the free energy-related parameters include: zero-point energy, change in total ground state energy, temperature, change in entropy, and electrode potential.

[0027] Furthermore, in step g to step l, the three reaction mechanisms of four-electron process AEM mechanism, four-electron process OPM mechanism and two-electron process are respectively carried out.

[0028] Further, the electron transfer process of the AEM mechanism is:

[0029] *+O2+H + +e - →*OOH

[0030] *OOH+H + +e - →*O+H2O

[0031] *O+H + +e - →*OH

[0032] *OH+H + +e - →*+H2O

[0033] The electron transfer process of the OPM mechanism is:

[0034] **+O2→*OO*

[0035] *OO*+H + +e - →*OH*O

[0036] *OH*O+H + +e - →*O*+H2O

[0037] *O*+H + +e - →*OH

[0038] *OH+H + +e - →**+H2O

[0039] The electron transfer of the two-electron process is:

[0040] *+O2+H + +e - →*OOH

[0041] *OOH+H + +e - →*O+H2O2

[0042] *O, *OH, and *OOH are reaction intermediates adsorbed on the catalyst surface in the slab model.

[0043] Furthermore, in S3, the formula used to calculate the free energy change of each reaction step is as follows:

[0044] ΔG=ΔZPE+ΔE-T×ΔS+ΔGU

[0045] Where ΔZPE is the zero-point energy, ΔE is the change in total ground-state energy, T is the temperature (298K), ΔS is the change in entropy, ΔGU=eU, where U is the electrode potential. The zero-point energy and entropy of the intermediate are obtained by calculating the vibration frequency. Therefore, the total energy and zero-point energy of each intermediate need to be calculated. The overpotential is the largest of all reaction energy barriers.

[0046] Further, in S4, the differential charge density is calculated based on the obtained charge density file, wherein the differential charge density Δρ is calculated by subtracting the charge density ρslab of the slab part and the charge density ρabsorbate of the adsorbate part from the charge density ρ of the system, that is, Δρ=ρ-ρslab-ρabsorbate.

[0047] In a second aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned theoretical simulation calculation method for oxygen reduction reaction based on first principles.

[0048] In a second aspect, the present invention provides a computer program product, comprising a computer program, which, when executed by a processor, implements the steps of the above-mentioned theoretical simulation calculation method of oxygen reduction reaction based on first principles.

[0049] Compared with the prior art, the present invention has the following technical advantages:

[0050] 1) The first-principles-based theoretical calculation method for oxygen reduction reaction provided by the present invention significantly improves the accuracy and efficiency of theoretical calculation through automated preprocessing steps, accurate slab model construction, and efficient differential charge density calculation. This method not only lowers the operating threshold and makes high-throughput calculation possible, but also provides important theoretical support for experimental design and material selection by providing an in-depth understanding of the microscopic mechanism of oxygen reduction reaction.

[0051] 2) In addition, the present invention can accurately predict the energy barrier and overpotential of the oxygen reduction reaction by integrating advanced computational hydrogen electrode (CHE) methods and differential charge density analysis, thus providing key guidance for the performance optimization of fuel cells and metal-air batteries. The implementation of this method will help accelerate the discovery and development of new energy materials, thereby promoting the innovation and development of energy conversion technology.

[0052] 3) Finally, the method of the present invention greatly reduces tedious manual operations and saves precious time of scientific researchers by providing a complete set of calculation processes and automated scripts. This simplified operation process not only improves the reproducibility and reliability of calculations, but also promotes the sharing of knowledge and the dissemination of technology within the scientific research community by lowering the threshold for novices, thus accelerating the speed of scientific discovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the flow chart of the theoretical simulation calculation method of oxygen reduction reaction based on first principles in the present invention. DETAILED DESCRIPTION

[0054] The present invention significantly improves the computational efficiency and operability by automatically processing disordered structures, generating VASP input files, calculating ORR energy barriers and overpotentials, and differential charge density. This method not only simplifies the operation process and reduces the requirements for user experience, but also makes high-throughput calculations possible by providing Python scripts and automated processes, thus providing a powerful theoretical tool for material design and battery performance optimization.

[0055] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0056] Example 1

[0057] The first aspect of the present invention provides a theoretical simulation calculation method for oxygen reduction reaction based on first principles, see Figure 1 , including the following steps:

[0058] S1. Preprocessing of disordered structures:

[0059] a. Receive a cif file with an unordered structure with score placeholders;

[0060] b. Expand the received cif file to generate an expanded cell structure;

[0061] c. Randomly generate n ordered structures based on the expanded cell structure;

[0062] d. Calculate the electrostatic energy of the system for each ordered structure;

[0063] e. Screening to obtain several ordered structures with the lowest electrostatic energy;

[0064] f. Perform DFT calculation and structural relaxation on the ordered structures obtained by screening to obtain the ordered structure with the lowest total energy;

[0065] In S1, the conditions for expanding the cell of the received cif file include:

[0066] Make sure that the total number of each type of atom in the expanded unit cell is an integer.

[0067] The detailed principle analysis of this step is as follows:

[0068] a. Receive a cif file with a disordered structure with fractional position occupancy: In materials science, crystal structures are often represented by cif (Crystallographic Information File) files. Cif files are text files containing crystal structure data and follow the standards of the International Union of Crystallography (IUCr). Disordered structures refer to the fact that the positions of some atoms in the crystal structure are uncertain or there are multiple possible arrangements, which are represented by fractional position occupancy in the cif file.

[0069] b. Expand the received cif file to generate an expanded cell structure: Unit cell expansion refers to duplicating the unit cell of the crystal multiple times in three-dimensional space to ensure that the positions of all atoms in the unit cell are integer coordinates. This is done to convert the disordered structure into an ordered structure so that it can be processed by the computing software.

[0070] c. Randomly generate n ordered structures based on the expanded cell structure: Since the atomic positions in the disordered structure are fractionally occupied, multiple possible ordered structures can be randomly generated after the cell is expanded. This step is to create multiple possible crystal structure models for further calculation and analysis.

[0071] d. Calculate the electrostatic energy of the system for each ordered structure: Electrostatic energy refers to the energy generated by the electrostatic force between atoms in the crystal structure. The electrostatic energy of each ordered structure is calculated to evaluate the stability of these structures.

[0072] e. Screening several ordered structures with the lowest electrostatic energy: The structure with the lowest electrostatic energy usually corresponds to the most stable crystal structure. These structures are screened to find the crystal structure that is most likely to be observed in the experiment.

[0073] f. Perform DFT calculation and structural relaxation on the screened ordered structures to obtain the ordered structure with the lowest total energy: DFT (Density Functional Theory) is a method for calculating electronic structure in quantum mechanics and is used to predict the physical and chemical properties of materials. Structure relaxation refers to the process of adjusting the atomic positions until the system energy reaches the lowest point in the DFT calculation. This step is to find the most energetically stable crystal structure.

[0074] S2. Construction of slab model and generation of VASP input file:

[0075] g. Based on the obtained ordered structure with the lowest total energy, a slab model of the material surface for simulating the oxygen reduction reaction is constructed;

[0076] h. Using the slab model, use the Pymatgen library to generate the input file required for VASP calculation, and the input file can be used for first principle calculation;

[0077] In S2, the required input files include POSCAR, INCAR, KPOINTS, and POTCAR files.

[0078] The detailed principle analysis of this step is as follows:

[0079] g. Based on the obtained ordered structure with the lowest total energy, a slab model is constructed to simulate the material surface where the oxygen reduction reaction occurs: In materials science, the slab model is a computational model used to simulate solid surfaces and interfaces. This model usually cuts the solid surface into thin slices (slabs) along a certain direction, and leaves enough vacuum area on one or both sides of the slice to reduce the artificial interaction caused by periodic boundary conditions.

[0080] h. Using the slab model, use the Pymatgen library to generate the input files required for VASP calculations: Pymatgen (Python Materials Genomics) is a powerful open source Python library for materials analysis. It provides extensive input / output support, including support for file formats required for VASP calculations. Through the Pymatgen library, the input files required for VASP calculations, such as POSCAR, INCAR, KPOINTS, and POTCAR, can be automatically generated.

[0081] Slab model: A computational model used to simulate material surfaces, often used in computational catalysis and surface science.

[0082] VASP: Vienna Ab-initio Simulation Package, Vienna Ab-initio Simulation Package, is a widely used first-principles calculation software for simulating electronic structure properties and molecular dynamics.

[0083] Pymatgen: Python Materials Genomics, Python Materials Genomics, an open source Python library for materials analysis. In S2, the required input files include:

[0084] POSCAR: A file used to describe the crystal structure in VASP calculations, containing information such as unit cell parameters, atomic types and coordinates.

[0085] INCAR: A file used to specify calculation parameters in VASP calculations, such as exchange-correlation functionals, electronic convergence criteria, etc.

[0086] KPOINTS: A file used to specify k-point sampling in VASP calculations, which affects the calculation of properties such as band structure and state density.

[0087] POTCAR: A file used to describe the pseudopotential information of atoms in VASP calculations, including the electronic structure of atoms and the treatment of core electrons.

[0088] S3: Calculation of energy barriers and overpotentials for oxygen reduction reactions:

[0089] i. Using the generated VASP input file, the computational hydrogen electrode (CHE) method is used to calculate the energy barrier and overpotential of the oxygen reduction reaction. Computational Hydrogen Electrode (CHE) is a theoretical method used to simulate electrochemical interfaces and calculate thermodynamic parameters of electrochemical reactions. By simulating the adsorption and desorption of hydrogen atoms on the electrode surface, the CHE method can provide a reference system for other electrochemical reactions, thereby calculating the relative potentials of other reactions;

[0090] j. calculating the free energy change for each reaction step of the oxygen reduction reaction to determine the overpotential;

[0091] In S3, the free energy-related parameters include: zero-point energy, change in total ground state energy, temperature, change in entropy, and electrode potential.

[0092] In step g to step l, the three reaction mechanisms of four-electron process AEM mechanism, four-electron process OPM mechanism and two-electron process are respectively carried out.

[0093] In S3, the formula used to calculate the free energy change of each reaction step is as follows:

[0094] ΔG=ΔZPE+ΔE-T×ΔS+ΔGU

[0095] Where ΔZPE is the zero-point energy, ΔE is the change in total ground-state energy, T is the temperature (298K), ΔS is the change in entropy, ΔGU=eU, where U is the electrode potential. The zero-point energy and entropy of the intermediate are obtained by calculating the vibration frequency. Therefore, the total energy and zero-point energy of each intermediate need to be calculated. The overpotential is the largest of all reaction energy barriers.

[0096] S4: Calculation of differential charge density:

[0097] k. Based on the calculated structural information of the oxygen reduction reaction intermediates, electronic self-consistent calculations are performed on each intermediate, slab model part, and adsorbate part to obtain a charge density file;

[0098] 1. Using the charge density file, call vaspkit software to calculate the differential charge density and describe the change in charge distribution in the system to intuitively show the redistribution of charge during the oxygen reduction reaction.

[0099] Among them: The electron transfer process of the AEM mechanism is:

[0100] *+O2+H + +e - →*OOH

[0101] *OOH+H + +e - →*O+H2O

[0102] *O+H + +e - →*OH

[0103] *OH+H + +e - →*+H2O

[0104] The electron transfer process of the OPM mechanism is:

[0105] **+O2→*OO*

[0106] *OO*+H + +e - →*OH*O

[0107] *OH*O+H + +e - →*O*+H2O

[0108] *O*+H + +e - →*OH

[0109] *OH+H + +e - →**+H2O

[0110] The electron transfer of the two-electron process is:

[0111] *+O2+H + +e - →*OOH

[0112] *OOH+H + +e - →*O+H2O2

[0113] *O, *OH, and *OOH are reaction intermediates adsorbed on the catalyst surface in the slab model.

[0114] In S4, the differential charge density is calculated based on the obtained charge density file, wherein the differential charge density Δρ is calculated by subtracting the charge density ρslab of the slab part and the charge density ρabsorbate of the adsorbate part from the charge density ρ of the system, that is, Δρ=ρ-ρslab-ρabsorbate.

[0115] Example 2

[0116] The present embodiment provides a computer-readable storage medium, on which a special computer program is stored, which is intended to be executed by a processor to implement a theoretical simulation calculation method for oxygen reduction reaction (ORR) based on first principles. The oxygen reduction reaction is efficiently and accurately simulated theoretically, thereby providing a powerful tool for the research of materials science and energy conversion technology. The computer program includes all the instruction sets required to implement the above method, including the pretreatment of disordered structures, the construction of slab models, the generation of VASP input files, the calculation of energy barriers and overpotentials of oxygen reduction reactions, and the calculation of differential charge density and other key steps. When the processor executes these instructions, it can automatically complete the entire process from receiving disordered structure cif files with fractional occupancy, to generating cell expansion structures, calculating electrostatic energy, screening ordered structures, building slab models, generating VASP input files, until calculating reaction energy barriers and overpotentials. In addition, the program can also be calculated and analyzed according to the mechanism of oxygen reduction reaction, such as four-electron process AEM mechanism, four-electron process OPM mechanism and two-electron process. By calling VASPKit software, the program can also calculate the differential charge density, providing an intuitive charge distribution image for understanding the reaction mechanism and the interaction between the catalyst and the reactants. The design of this computer-readable storage medium not only improves the efficiency and accuracy of theoretical calculations of oxygen reduction reactions, but also simplifies operations through automated processes and reduces the requirements for user experience. This enables more researchers to use this tool to promote scientific discoveries and technological innovations in related fields.

[0117] Example 3

[0118] The present embodiment provides an advanced computer program product, which includes a specially designed computer program, which is intended to complete the various steps of the theoretical simulation calculation method of oxygen reduction reaction (ORR) based on first principles through processor execution. This innovative program product greatly improves the efficiency and accuracy of theoretical calculations in an automated manner, and is of great significance to the research and development of materials science, energy conversion technology and electrochemical catalysts. The computer program integrates multiple key links such as disordered structure pretreatment, slab model construction, VASP input file generation, oxygen reduction reaction energy barrier and overpotential calculation, and differential charge density calculation. When the processor runs this program, it can automatically execute the complete process of receiving the cif file of the disordered structure until all necessary calculation steps are completed and the theoretical simulation results of the oxygen reduction reaction are output. The design of the program takes into account a variety of oxygen reduction reaction mechanisms, including the AEM mechanism of the four-electron process, the OPM mechanism, and the two-electron process, to ensure the comprehensiveness and applicability of the calculation results. In addition, the program can also call vaspkit software to calculate the differential charge density, providing detailed information required for a deep understanding of the reaction mechanism. The development of this computer program product makes complex first-principles calculations easier to manage and operate, reduces the requirements for users' professional background, and enables more researchers to conveniently conduct theoretical simulation studies of oxygen reduction reactions. At the same time, the efficiency of the program also makes high-throughput calculations possible, which helps accelerate the discovery of new materials and the advancement of energy conversion technologies.

[0119] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A theoretical simulation calculation method for oxygen reduction reaction based on first principles, characterized in that: The following steps are involved: S1. Preprocessing of disordered structures: a. Receive a cif file with an unordered structure with score placeholders; b. Expand the received cif file to generate an expanded cell structure; c. Randomly generate n ordered structures based on the expanded cell structure; d. Calculate the electrostatic energy of the system for each ordered structure; e. Screening to obtain several ordered structures with the lowest electrostatic energy; f. Perform DFT calculation and structural relaxation on the ordered structures obtained by screening to obtain the ordered structure with the lowest total energy; S2. Construction of slab model and generation of VASP input file: g. Based on the obtained ordered structure with the lowest total energy, a slab model of the material surface for simulating the oxygen reduction reaction is constructed; h. Using the slab model, use the Pymatgen library to generate the input file required for VASP calculation, and the input file can be used for first principle calculation; S3: Calculation of energy barriers and overpotentials for oxygen reduction reactions: i. Using the generated VASP input file, calculate the energy barrier and overpotential of the oxygen reduction reaction using the computational hydrogen electrode method; j. calculating the free energy change for each reaction step of the oxygen reduction reaction to determine the overpotential; S4: Calculation of differential charge density: k. Based on the calculated structural information of the oxygen reduction reaction intermediates, electronic self-consistent calculations are performed on each intermediate, slab model part, and adsorbate part to obtain a charge density file; 1. Using the charge density file, call vaspkit software to calculate the differential charge density and describe the change in charge distribution in the system to intuitively show the redistribution of charge during the oxygen reduction reaction.

2. The method for theoretical simulation of oxygen reduction reaction based on first principles according to claim 1, characterized in that: In S1, the conditions for expanding the cell of the received cif file include: Make sure that the total number of each type of atom in the expanded unit cell is an integer.

3. The method for theoretical simulation of oxygen reduction reaction based on first principles according to claim 1, characterized in that: In S2, the required input files include POSCAR, INCAR, KPOINTS, and POTCAR files.

4. The method for theoretical simulation of oxygen reduction reaction based on first principles according to claim 1, characterized in that: In S3, the free energy-related parameters include: zero-point energy, change in total ground state energy, temperature, change in entropy, and electrode potential.

5. The method for theoretical simulation of oxygen reduction reaction based on first principles according to claim 1, characterized in that: In step g to step l, the three reaction mechanisms of four-electron process AEM mechanism, four-electron process OPM mechanism and two-electron process are respectively carried out.

6. The method for theoretical simulation of oxygen reduction reaction based on first principles according to claim 5, characterized in that: in: The electron transfer process of the AEM mechanism is: *+O2+H + +e - →*OOH *OOH+H + +e - →*O+H2O *O+H + +e - →*OH *OH+H + +e - →*+H2O The electron transfer process of the OPM mechanism is: **+O2→*OO* *OO*+H + +e - →*OH*O *OH*O+H + +and - →*O*+H2O *O*+H + +e - →*OH *OH+H + +e - →**+H2O The electron transfer of the two-electron process is: *+O2+H + +e - →*OOH *OOH+H + +e - →*O+H2O2 *O, *OH, and *OOH are reaction intermediates adsorbed on the catalyst surface in the slab model.

7. The method for theoretical simulation of oxygen reduction reaction based on first principles according to claim 5, characterized in that: In S3, the formula used to calculate the free energy change of each reaction step is as follows: ΔG=ΔZPE+ΔE-T×ΔS+ΔGU Where ΔZPE is the zero-point energy, ΔE is the change in total ground-state energy, T is the temperature, ΔS is the change in entropy, ΔGU=eU, where U is the electrode potential, the zero-point energy and entropy of the intermediates are obtained by calculating the vibrational frequencies, the total energy and zero-point energy of each intermediate are calculated, and the overpotential is the largest of all reaction energy barriers.

8. The method for theoretical simulation of oxygen reduction reaction based on first principles according to claim 1, characterized in that: In S4, the differential charge density is calculated based on the obtained charge density file, wherein the differential charge density Δρ is calculated by subtracting the charge density ρslab of the slab part and the charge density ρabsorbate of the adsorbate part from the charge density ρ of the system, that is, Δρ=ρ-ρslab-ρabsorbate.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the theoretical simulation calculation method of oxygen reduction reaction based on first principles described in any one of claims 1 to 8 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the theoretical simulation calculation method of oxygen reduction reaction based on first principles described in any one of claims 1 to 8 are implemented.

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