Structural Screening Method and System for Defective Metal-Organic Framework Materials

Abstract

An embodiment of the present invention discloses a method and system for screening the structure of defective metal-organic framework materials. The method includes: obtaining the structure information of a large number of metal-organic framework materials to be screened, splitting the metal centers of the metal-organic framework materials to be screened according to the structure information, performing geometric structure optimization on the metal centers of the metal-organic framework materials to be screened, and retaining the stable structures in the metal-organic framework materials to be screened; respectively counting the maximum number of ligands n connected to each metal center, removing the groups connected to the ligands in the metal centers according to a preset processing principle, and performing geometric structure optimization on the metal centers of each defective structure; adding H2 molecules near the defective positions in the metal centers to construct a corresponding H2 adsorption and cracking model; using the metal-organic framework materials to be screened with the activation energy barrier reaching a preset value as the target defective structure. The technical problem of difficult structure screening of metal-organic framework materials in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical fields of computational chemistry and nano-composite catalytic materials, and particularly relates to a method and a system for screening the structure of defective metal-organic framework materials. Background Art

[0002] Among numerous green energy sources, hydrogen energy has received extensive attention due to its high calorific value, strong reducibility, wide raw materials, and less combustion pollution. In addition to being used for power generation, it can also play an important role in industrial sectors such as steelmaking, chemical industry, and cement. Hydrogen has been widely used as an important industrial raw material. Dicyclopentadiene (DCPD) is a by-product of ethylene cracking and is mainly used to develop DCPD petroleum resins, new polymer materials, and fine chemical products, etc. In the actual production process, it is necessary to hydrogenate DCPD to improve the material properties. Currently, the DCPD hydrogenation process mainly has the disadvantages of long hydrogenation time, the need for filtration and recovery of the catalyst, and low production efficiency. In the future, it is still necessary to improve the process and select more suitable hydrogen cracking catalytic materials.

[0003] Meanwhile, metal-organic framework materials (MOFs) have received extensive attention due to their diverse chemical structures and highly adjustable physical and chemical properties. MOFs materials can be synthesized using various metal elements in the periodic table, including transition elements such as iron, cobalt, nickel, tungsten, molybdenum, and rare earth elements such as scandium, yttrium, and lanthanides. Among them, rare earth elements can show some strange structural and reaction characteristics due to their high coordination numbers and unique electronic structures. Therefore, in theory, it is possible to rely on the highly designable nature of MOFs materials to develop catalytic MOFs materials that can effectively crack hydrogen. However, it is precisely due to its highly designable nature that the number of experiments required to find the target MOFs is extremely large, and the traditional design idea of obtaining results through continuous experiments almost fails. Summary of the Invention

[0004] For this reason, embodiments of the present invention provide a method and a system for screening the structure of defective metal-organic framework materials to at least partially solve the technical problem of difficult structure screening of metal-organic framework materials in the prior art.

[0005] To achieve the above object, embodiments of the present invention provide the following technical solutions:

[0006] The present invention provides a method for screening the structure of defective metal-organic framework materials, the method comprising:

[0007] Obtain the structural information of a large number of metal-organic framework materials to be screened, split the metal centers of the metal-organic framework materials to be screened according to the structural information, optimize the geometric structures of the metal centers of the metal-organic framework materials to be screened, and retain the stable structures in the metal-organic framework materials to be screened, so as to screen out the metal-organic framework materials to be screened with stable structures from a large number of metal-organic framework materials to be screened, and use the calculated stable structures of the metal-organic framework materials to be screened as the to-be-screened structure dataset;

[0008] Respectively count the maximum number of ligands n connected to each metal center, remove the groups connected to the ligands in the metal center according to the preset processing principle, and respectively construct defective structures with 1, 2, 3,... up to n / 2 ligands removed, and optimize the geometric structures of the metal centers of each defective structure;

[0009] Add H 2 molecules near the defect positions in the metal centers after constructing the defective structures to construct H 2 adsorption cracking models corresponding to various defective metal centers;

[0010] In the constructed H 2 adsorption cracking model, traverse the defective structures with the catalytic cracking performance reaching the preset threshold and the transition states existing in the catalytic H 2 adsorption cracking process, and calculate the Gibbs free energies of different steps in the defect structure adsorption H 2 cracking process, and compare the activation energy barriers of the metal-organic framework materials to be screened with different defect distributions and structures in the catalytic H 2 adsorption cracking process, and use the metal-organic framework materials to be screened with the activation energy barrier reaching the preset value as the target defective structure. 2

[0011] In some embodiments, when optimizing the geometric structures of the metal centers of the metal-organic framework materials to be screened and the geometric structures of the metal centers of each defective structure, the optimization conditions specifically include:

[0012] Use the DFT method and the B3LYP hybrid functional to perform structural optimization calculations, and all calculations in the structural optimization process are carried out at the same precision;

[0013] Select the default value of the valence electron selection functional, select 300 - 600 times for the maximum number of iterations, and select the maximum step size according to the different structures and metal elements of the metal-organic framework materials to be screened between and ;

[0014] ​For the inner electrons, adopt the DFT semi-core hypothesis points, calculate with the self-consistent convergence threshold in the range of 1.0e-7 / atom to 1.0e-5 / atom, set the maximum number of cycles to 2000 to 2500 times, and set the global domain orbital cut-off value to

[0015] In the structural optimization, the convergence threshold of energy is 5.0e-6 Ha to 1.0e-5 Ha, and the convergence threshold of force is 0.001 The convergence threshold of the maximum displacement is

[0016] In some embodiments, construct H corresponding to multiple defective metal centers 2 When constructing the adsorption and cracking model, select the metal atom with the most defective positions and the adjacent non-metal elements such as O, N, P, S, etc. as the adsorption activation sites, and preset the distance between the metal element M and the H atom to be The direction of the H-H bond should be selected as the direction most favorable for the hydrogen cracking reaction, and the H-H bond length is

[0017] In some embodiments, catalyze H 2 The reaction path of the adsorption and cracking process and H 2 The conditions for analyzing the activation energy barrier of the adsorption and cracking specifically include:

[0018] Select the default value of the functional for the valence electrons, select the maximum number of iterations to be 400 to 500 times, and select the maximum step size according to the structure of the metal-organic framework material to be screened and the different metal elements between to ;

[0019] For the inner electrons, adopt the DFT semi-core hypothesis point method to process, calculate with the self-consistent convergence threshold in the range of 1.0e-7 / atom to 1.0e-6 / atom, set the maximum number of cycles to 2000 to 2500 times, and set the global domain orbital cut-off value to to

[0020] In the structural optimization, the convergence threshold of energy is 5.0e-6 Ha to 5.0e-5 Ha, and the convergence threshold of force is 0.001 The convergence threshold of the maximum displacement is

[0021] In some embodiments, the metal-organic framework materials to be screened specifically include:

[0022] Metal-organic framework materials synthesized from several soluble metal salts and organic ligands.

[0023] In some embodiments, the soluble metal salts specifically include transition elements such as niobium, nickel, iron, tin, titanium, vanadium, silver, manganese, cobalt, tungsten, copper, zinc, molybdenum, palladium, chromium, zirconium, aluminum, etc., and nitrates, chlorides, phosphates, sulfates, acetates, etc. of rare earth elements yttrium, scandium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, being one or several of them.

[0024] In some embodiments, the organic ligands specifically include one or several of organic molecules such as 1,4-benzenedicarboxylic acid, 1,2-benzenedicarboxylic acid, 1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, benzenehexacarboxylic acid, 2-hydroxyterephthalic acid, 2-sulfoterephthalic acid, 2-nitroterephthalic acid, 2-aminoterephthalic acid, 1,1':4',1”-terphenyl-4,4”-dicarboxylic acid, 1,1'-biphenyl-4,4'-dicarboxylic acid, piperazine, pyrazine, dimethylimidazole, triethylenediamine, 4,4'-bipyridine, 1,3-bis(4-pyridyl)propane.

[0025] The present invention also provides a structure screening system for defective metal-organic framework materials, and the system includes:

[0026] A structure generation unit to be screened, configured to obtain structure information of a large number of metal-organic framework materials to be screened, split out metal centers of the metal-organic framework materials to be screened according to the structure information, perform geometric structure optimization on the metal centers of the metal-organic framework materials to be screened, retain stable structures in the metal-organic framework materials to be screened, so as to screen out metal-organic framework materials to be screened with stable structures from a large number of metal-organic framework materials to be screened, and use the calculated stable structures of the metal-organic framework materials to be screened as a dataset of structures to be screened;

[0027] A structure optimization unit, configured to respectively count the maximum number of ligands n connected to each metal center, remove groups of the parts connected to the ligands in the metal centers according to a preset processing principle, and respectively construct defective structures with 1, 2, 3... up to n / 2 ligands removed, and perform geometric structure optimization on the metal centers of each defective structure;

[0028] A cracking model generation unit, configured to add H 2 molecules near the defect positions in the metal centers after constructing the defective structures, so as to construct H 2 adsorption cracking models corresponding to various defective metal centers;

[0029] A result output unit, configured to traverse defective structures with catalytic cracking performance reaching a preset threshold in the constructed H 2 adsorption cracking models and in the catalytic H 2 cracking 2The transition states existing in the adsorption cracking process, and calculate the adsorption of H by the defect structure 2 The Gibbs free energy of different steps in the cracking process, and compare the catalytic H of the metal-organic framework materials to be screened with different defect distributions and structures 2 The activation energy barrier in the adsorption cracking process, and use the metal-organic framework material to be screened with the activation energy barrier reaching a preset value as the target defect structure.

[0030] The present invention also provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, the steps of the above method are implemented.

[0031] The present invention also provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above method are implemented.

[0032] The structure screening method for defect-type metal-organic framework materials provided by the present invention includes obtaining the structure information of a large number of metal-organic framework materials to be screened, splitting the metal centers of the metal-organic framework materials to be screened according to the structure information, optimizing the geometric structures of the metal centers of the metal-organic framework materials to be screened, and retaining the stable structures in the metal-organic framework materials to be screened, so as to screen out the metal-organic framework materials to be screened with stable structures from a large number of metal-organic framework materials to be screened, and using the calculated stable structures of the metal-organic framework materials to be screened as the data set of structures to be screened; then respectively counting the maximum number of ligands n connected to each metal center, removing the groups connected to the ligands in the metal centers according to the preset processing principle, and respectively constructing defect structures with 1, 2, 3,... up to n / 2 ligands removed, and optimizing the geometric structures of the metal centers of each defect structure; adding H 2 molecules near the defect positions in the metal centers after constructing the defect structures to construct H 2 adsorption cracking models corresponding to various defect metal centers; in the constructed H 2 adsorption cracking models, traverse the defect structures with the catalytic cracking performance reaching the preset threshold and the transition states existing in the catalytic H 2 adsorption cracking process, and calculate the adsorption of H by the defect structures 2 The Gibbs free energy of different steps in the cracking process, and compare the catalytic H of the metal-organic framework materials to be screened with different defect distributions and structures 2 adsorption cracking process, and use the metal-organic framework material to be screened with the activation energy barrier reaching a preset value as the target defect structure. 2 The activation energy barrier in the adsorption cracking process, and use the metal-organic framework material to be screened with the activation energy barrier reaching a preset value as the target defect structure.

[0033] In this way, the structure screening method for defective metal-organic framework materials provided by the present invention adopts a high-throughput calculation method, which improves the efficiency of screening the structures of target materials; combining the modeling method of defect construction with high-throughput calculation can solve the problem that it is difficult to deeply analyze the reaction mechanism of microscopic structures with the traditional research idea of experiment + analysis, avoiding the blindness of experiments. This method also has certain reference value for other research aspects; the research on the influence of defects on the performance of MOFs is also of great significance for promoting the practical application of MOFs materials and has good practical value for promoting the actual production and application of MOFs materials. Thus, the technical problem of difficult structure screening of metal-organic framework materials in the prior art is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained according to the provided drawings.

[0035] The structures, ratios, sizes, etc. shown in this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limited conditions under which the present invention can be implemented. Therefore, they do not have technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed by the present invention.

[0036] Figure 1 is a flowchart of the structure screening method for defective metal-organic framework materials provided by the present invention;

[0037] Figure 2 and Figure 3 is a structural model diagram of Embodiment 1 of the present invention;

[0038] Figure 4 and Figure 5 is a structural model diagram of Embodiment 2 of the present invention;

[0039] Figure 6 is a structural block diagram of the structure screening system for defective metal-organic framework materials provided by the present invention;

[0040] Figure 7 is a structural block diagram of a computer device provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0042] To solve the problem that traditional experimental verification methods cannot meet the screening of metal-organic framework materials, a method of using theoretical calculations instead of traditional experiments can be adopted to accelerate the R & D process of new materials. Computational chemistry theories mainly include molecular dynamics (MD), Monte Carlo method (MC), ab initio theory based on Hartree-Fock self-consistent field calculations, and density functional theory (DFT). Previously, limited by the backwardness of computer levels and the incompatibility with computational theories, large-scale calculations at high-precision levels could not be completed. Currently, the combination of these improved theories and modern computer science enables the simulation of material properties at a quite high precision. With the continuous improvement of computer computing power, theoretical simulation and calculation of materials have become increasingly common, especially in the fields of adsorption and catalysis, playing an irreplaceable role in analyzing adsorption catalysis mechanisms, atomic migration, electron transition, energy changes, etc.

[0043] Ideal MOFs materials have almost perfect structural symmetry and space translation symmetry. However, in actual experimental processes, due to the influence of various experimental factors, there are always many defects in MOFs materials. Just as the existence of defects in metal materials has an important impact on various properties of metals, the existence of these defects also has an important impact on the structural stability, small molecule or atomic conductivity, adsorption and catalysis, etc. of MOFs materials. Then it can be envisioned that by adjusting the geometric structure and spatial distribution of defects, the adverse effects of defects can be controlled and the promoting effect of defects on catalytic reactions can be maximized, thereby enhancing the catalytic performance of the original MOFs materials, and even enabling materials that originally had almost no catalytic activity to obtain catalytic ability. Although it is difficult to directly study the effects caused by defects through traditional experimental analysis processes, theoretical calculations have been able to deeply analyze the catalytic reaction process on the defect structure and screen for possible microstructures that are beneficial to improving the catalytic ability of MOFs materials.

[0044] Accordingly, the present invention provides a method for screening the structure of defective metal-organic framework materials based on high-throughput calculation, which can obtain MOF structures from the publicly available MOFs material structure database, perform structure splitting and defect construction, and accurately screen out possible MOF defect structures with functions such as adsorption and catalysis among the MOF candidate structures through high-throughput calculations such as the HF method (Hartree-Fock method) and density functional theory (DFT). This method can study the reaction mechanism of MOF materials in the defect region, guide the change of the experimental synthesis steps of MOF materials to artificially create defects, and finally obtain defective MOF materials with better catalytic performance.

[0045] Please refer to Figure 1 , Figure 1 which is a schematic flowchart of the structure screening method for defective metal-organic framework materials provided by the present invention.

[0046] In a specific embodiment, the structure screening method for defective metal-organic framework materials provided by the present invention includes the following steps:

[0047] S110: Obtain the structure information of a large number of metal-organic framework materials to be screened, split out the metal centers of the metal-organic framework materials to be screened according to the structure information, perform geometric structure optimization on the metal centers of the metal-organic framework materials to be screened, and retain the stable structures in the metal-organic framework materials to be screened, so as to screen out the metal-organic framework materials to be screened with stable structures in a large number of metal-organic framework materials to be screened, and use the calculated stable structures of the metal-organic framework materials to be screened as the to-be-screened structure dataset;

[0048] In a specific usage scenario, the spatial structure, secondary structure units (SBUs), and organic ligands of MOFs in databases such as the Cambridge Structural Database System (CSDS) and the Crystallography Open Database (COD) can be extracted, the core - metal center in the MOF structure can be split out, the geometric structure can be optimized using the Density Functional Theory (DFT) method, the stable structures can be screened out, and the calculated stable structures can be used as the to-be-screened structure dataset.

[0049] Specifically, the metal-organic framework materials to be screened may include metal-organic framework materials synthesized from several soluble metal salts and organic ligands.

[0050] Among them, the soluble metal salts specifically include nitrates, chlorides, phosphates, sulfates, acetates, etc. of transition elements such as niobium, nickel, iron, tin, titanium, vanadium, silver, manganese, cobalt, tungsten, copper, zinc, molybdenum, palladium, chromium, zirconium, aluminum, and rare earth elements such as yttrium, scandium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

[0051] The organic ligands specifically include one or more of 1,4-benzenedicarboxylic acid, 1,2-benzenedicarboxylic acid, 1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, mellitic acid, 2-hydroxyterephthalic acid, 2-sulfonateterephthalic acid, 2-nitroterephthalic acid, 2-aminoterephthalic acid, 1,1':4',1"-phenyl-4,4"-dicarboxylic acid, 1,1'-diphenyl-4,4'-dicarboxylic acid, piperazine, pyrazine, dimethylimidazole, triethylenediamine, 4,4'-bipyridine, 1,3-di(4-pyridine)propane and other organic molecules.

[0052] S120: Counting the maximum number n of ligands connected to each of the metal centers, removing the groups of the metal centers connected to the ligands according to a preset processing principle, and constructing defect structures with 1, 2, 3, ..., up to n / 2 ligands removed, and optimizing the geometric structure of the metal center of each defect structure.

[0053] That is to say, for a single metal center structure, the maximum number of ligands n connected to it is counted, and based on two opposite principles, namely the principle of concentration as much as possible and the principle of dispersion as much as possible, the groups in the metal center that are connected to the ligands (such as carboxyl COO-) are removed, and defect structures with 1, 2, 3, and so on, removed are constructed (rounded up when n / 2 is not an integer), and the DFT method is used to optimize the geometric structure of the defect structure, retaining the stable structure for subsequent screening.

[0054] S130: Add H near the defect position in the metal center after the defect structure is constructed 2 molecules to construct H corresponding to various defective metal centers 2 Adsorption-decomposition model.

[0055] S140: In the construction of H 2 In the adsorption cracking model, traversing H 2 The defect structure with catalytic cracking performance reaching a preset threshold and the 2 The transition state in the adsorption cracking process is calculated, and the adsorption of H 2 The Gibbs free energy of different steps in the cracking process is compared with the metal organic framework materials with different defect distribution and structure in catalyzing H 2The activation energy barrier during the adsorption cracking process, and the metal-organic framework material to be screened with the activation energy barrier reaching a preset value is used as the target defect structure.

[0056] Specifically, using the DFT method, combined with the Complete linear synchronous transit (LST) and quadratic synchronous transit (QST) methods, in the multiple defect metal center H 2 adsorption cracking models constructed in step S130, search for the defect MOFs structures with good catalytic cracking performance and the possible transition states during the catalytic H 2 adsorption cracking process. Then use the finite displacement method to calculate the Gibbs free energy (G) of different steps during the adsorption cracking process of the defect MOFs structure, and compare the energy barriers of MOFs materials with different defect distributions and structures during the catalytic H 2 adsorption cracking process, and finally obtain the defect MOFs structures with good catalytic 2 performance. 2 In steps S110 and S120, when optimizing the geometric structures of the metal centers of the metal-organic framework materials to be screened and the metal centers of each defect structure, the optimization conditions specifically include: 2 Perform structural optimization calculations using the DFT method and the B3LYP hybrid functional, and all calculations during the structural optimization process are carried out at the same precision;

[0057] Select the default value of the valence electron selection functional, select the maximum number of iterations from 300 to 600 times, and select the maximum step size according to the structures of the metal-organic framework materials to be screened and different metal elements within the range from

[0058] to

[0059] to ; Select the DFT semi-core hypothesis point for the core electrons, calculate that the self-consistent convergence threshold is in the range of 1.0e-7 / atom to 1.0e-5 / atom, set the maximum number of cycles to 2000 to 2500 times, and set the global domain orbital cut-off value to

[0060] to to

[0061] The convergence threshold of energy in the structural optimization is 5.0e-6 Ha to 1.0e-5 Ha, and the convergence threshold of force is 0.001 The convergence threshold of the maximum displacement is

[0062] That is to say, in steps S110 and S120, the conditions for the geometric structure optimization calculation of the metal center and the defective metal center structure in the MOFs material are as follows: the DFT method is adopted, the B3LYP hybrid functional is used, and all calculations are carried out at the same precision; the valence electrons are selected as the default values set by the functional, the maximum number of iterations is selected from 300 to 600 times, and the maximum step size is selected between and according to the different MOFs structures and metal elements. The DFTSemi-core Pseudo pots (DSPP) is adopted for the inner electrons to reduce the calculation cost. The self-consistent convergence threshold of the calculation is in the range of 1.0e-7 / atom to 1.0e-5 / atom, the maximum number of cycles is set to 2000 to 2500 times, and the global domain orbital cut-off value is set to and The convergence thresholds of energy, force, and maximum displacement in the structure optimization are 5.0e-6 Ha to 1.0e-5 Ha,

[0063] Among them, the content analyzed by the DFT method also includes density of states analysis, electron density analysis, molecular orbitals analysis, etc.

[0064] In step S130, when constructing the H 2 adsorption cracking models corresponding to various defective metal centers, the metal atoms with the most defective positions and the adjacent non-metal elements such as O, N, P, and S are selected as the adsorption activation sites, and the distance between the metal element M and the H atom is preset as The direction of the H-H bond should be selected as the direction most favorable for the hydrogen cracking reaction, and the H-H bond length is

[0065] Among them, the conditions for analyzing the reaction path of the catalytic H 2 adsorption cracking process and the activation energy barrier of the H 2 adsorption cracking specifically include:

[0066] The valence electrons are selected as the default values set by the functional, the maximum number of iterations is selected from 400 to 500 times, and the maximum step size is selected between and according to the different structures and metal elements of the metal-organic framework materials to be screened;

[0067] The DFT semi-core hypothesis point method is adopted to process the electrons in the nucleus. The self-consistent convergence threshold is calculated within the range of 1.0e-7 / atom to 1.0e-6 / atom, and the maximum number of cycles is set to 2000 to 2500 times. The global domain orbital cut-off value is set to to

[0068] In the structural optimization, the energy convergence threshold is 5.0e-6 Ha to 5.0e-5 Ha, and the force convergence threshold is 0.001 The convergence threshold for the maximum displacement is

[0069] To facilitate the understanding of the technical effects achieved by the present invention, the following takes two specific usage scenarios as examples to briefly describe the specific process of the method provided by the present invention in the structural screening.

[0070] Example 1

[0071] High-throughput calculations are performed on the MOF structure Y-UiO66-DOBDC formed by the rare earth metal element yttrium (Y) and the 2,5-dihydroxy-1,4-benzenedicarboxylic acid (DOBDC) ligand. The initial lattice structure is improved from the crystal structure in the Cambridge Structural Database (CSDS) of the University of Cambridge. By constructing metal center models with different defects as the input files for high-throughput calculations, some of the constructed models are shown in Figure 2 、 Figure 3 All calculations are completed with the same calculation accuracy. All calculations use the default valence shell electron arrangement structure. The B3LYP hybrid functional is used in the structural optimization, the maximum number of iterations is 500 times, and the maximum step size is selected The DFT semi-core hypothesis point (DSPP) method is adopted to process the electrons in the nucleus. The self-consistent convergence value of the SCF calculation should be within the range less than 1.0e-6 / atom, and the maximum number of cycles is set to 2000 times. The global domain orbital cut-off value is set to In the structural optimization, the energy convergence threshold, the force convergence threshold, and the maximum displacement convergence threshold are 1.0e-5 Ha, Afterwards, the Complete LST / QST method is used to search for the transition state in the H2 adsorption and cleavage process, and the finite displacement method is used to calculate the Gibbs free energy of the relevant configurations. After the calculation results are obtained, experimental synthesis is carried out, and the test results show that the materials obtained by this method are in good agreement with the experimentally synthesized materials.

[0072] Example 2

[0073] The MOF structure Ce-MOF-808 formed by the rare earth metal element cerium (Ce) and the 1,3,5-benzenetricarboxylate (BTC) ligand was calculated and defect-engineered. The crystal structure was from the Cambridge Structural Database (CSDS) (No. 1509776). By constructing metal center models with different defects as input files for high-throughput calculations, some of the constructed models are shown in Figure 3 , Figure 4 . All calculations were completed with the same calculation precision. All calculations used the default valence electron arrangement structure. The B3LYP hybrid functional was used for structure optimization, with a maximum number of iterations of 500 times, and the maximum step size was selected as . The DFT semi-core hypothesis point (DSPP) method was used to handle the electrons in the nucleus. The self-consistent convergence value of the SCF calculation should be within the range of less than 1.0e-6 / atom, and the maximum number of cycles was set to 2400 times. The global domain orbital cut-off value was set to . The convergence thresholds for energy, force, and maximum displacement in the structure optimization were 1.0e-5 Ha, . Then, the Complete LST / QST method was used to search for the transition state in the H2 adsorption and cleavage process, and the finite displacement method was used to calculate the Gibbs free energy of the relevant configurations. After obtaining the calculation results, experimental synthesis was carried out, and the test results showed that the materials obtained by this method were in good agreement with the experimentally synthesized materials.

[0074] In the above specific embodiments, the structure screening method for defective metal-organic framework materials provided by the present invention obtains the structural information of a large number of metal-organic framework materials to be screened, and splits the metal centers of the metal-organic framework materials to be screened according to the structural information. The geometric structures of the metal centers of the metal-organic framework materials to be screened are optimized, and the stable structures in the metal-organic framework materials to be screened are retained, so as to screen out the metal-organic framework materials to be screened with stable structures from a large number of metal-organic framework materials to be screened, and use the calculated stable structures of the metal-organic framework materials to be screened as the dataset of structures to be screened; then, the maximum number of ligands n connected to each metal center is statistically analyzed, and the groups connected to the ligands in the metal center are removed according to the preset processing principle, and defective structures with 1, 2, 3,..., up to n / 2 ligands removed are respectively constructed, and the geometric structures of the metal centers of each defective structure are optimized; H 2 molecules are added near the defect positions in the metal centers after constructing the defective structures to construct H 2 adsorption and cleavage models corresponding to various defective metal centers; in the constructed H 2 adsorption and cleavage models, H 2A defective structure with catalytic cracking performance reaching a preset threshold and in the catalytic H 2 The transition state existing in the adsorption cracking process, and calculate the adsorption of H by the defective structure 2 The Gibbs free energy of different steps in the cracking process, and compare the activation energy barriers of the metal-organic framework materials to be screened with different defect distributions and structures in the catalytic H 2 Adsorption cracking process, and use the metal-organic framework material to be screened with the activation energy barrier reaching the preset value as the target defective structure.

[0075] In this way, the structure screening method for defective metal-organic framework materials provided by the present invention adopts a high-throughput calculation method, which improves the efficiency of screening the structure of target materials; combining the defect construction modeling method with high-throughput calculation can solve the problem that the traditional experimental + analysis research idea is difficult to deeply analyze the reaction mechanism of microscopic structures, avoiding the blindness of experiments. This method also has certain reference value for other aspects of research; the research on the influence of defects on the performance of MOFs is also of great significance for promoting the practical application of MOFs materials, and has good practical value for promoting the actual production and application of MOFs materials. Thus, the technical problem of difficult structure screening of metal-organic framework materials in the prior art is solved.

[0076] In addition to the above method, the present invention also provides a structure screening system for defective metal-organic framework materials, as Figure 6 shown, the system includes:

[0077] A structure generation unit 601 to be screened, which is used to obtain the structure information of a large number of metal-organic framework materials to be screened, split the metal centers of the metal-organic framework materials to be screened according to the structure information, optimize the geometric structures of the metal centers of the metal-organic framework materials to be screened, and retain the stable structures in the metal-organic framework materials to be screened, so as to screen out the metal-organic framework materials to be screened with stable structures from a large number of metal-organic framework materials to be screened, and use the calculated stable structures of the metal-organic framework materials to be screened as the data set of structures to be screened;

[0078] A structure optimization unit 602, which is used to respectively count the maximum number of ligands n connected to each metal center, remove the groups connected to the ligands in the metal centers according to the preset processing principle, and respectively construct defective structures with 1, 2, 3,..., up to n / 2 ligands removed, and optimize the geometric structures of the metal centers of each defective structure;

[0079] A cracking model generation unit 603, which is used to add H 2 molecules near the defect positions in the metal centers after constructing the defective structures, so as to construct H corresponding to various defective metal centers 2Adsorption-decomposition model;

[0080] The result output unit 604 is used to construct the H 2 In the adsorption cracking model, traversing H 2 The defect structure with catalytic cracking performance reaching a preset threshold and the 2 The transition state in the adsorption cracking process is calculated, and the adsorption of H 2 The Gibbs free energy of different steps in the cracking process is compared with the metal organic framework materials with different defect distribution and structure in catalyzing H 2 The activation energy barrier in the cracking process is adsorbed, and the metal organic framework material to be screened whose activation energy barrier reaches a preset value is used as the target defect structure.

[0081] In some embodiments, when the geometric structure of the metal center of the metal organic framework material to be screened is optimized, and the geometric structure of the metal center of each defect structure is optimized, the optimization conditions specifically include:

[0082] The DFT method and B3LYP hybrid functional were used for structural optimization calculations, and all calculations in the structural optimization process were performed at the same accuracy;

[0083] The default value of the valence electron selection functional setting is selected, the maximum number of iterations is selected from 300 to 600 times, and the maximum step length is selected according to the structure of the metal organic framework material to be screened and the difference between the metal elements. arrive Choose between;

[0084] The DFT semi-nuclear assumption point is adopted for the electrons in the nucleus, and the self-consistent convergence threshold is calculated in the range of 1.0e-7 / atom to 1.0e-5 / atom. The maximum number of cycles is set to 2000 to 2500 times, and the global domain orbital cutoff value is set to arrive

[0085] The convergence threshold of energy in structural optimization is 5.0e-6Ha~1.0e-5Ha, and the convergence threshold of force is 0.001 The convergence threshold of the maximum displacement is

[0086] In some embodiments, H corresponding to various defective metal centers are constructed. 2 In the adsorption cracking model, the metal atom with the most defect positions and the adjacent non-metallic elements such as O, N, P, S are selected as the adsorption activation sites, and the distance between the metal element M and the H atom is preset to The direction of the HH bond should be the most favorable for the hydrogen splitting reaction, and the HH bond length is

[0087] In some embodiments, the reaction path of the catalytic H 2 adsorption cracking process and the conditions for the analysis of the activation energy barrier of H 2 adsorption cracking specifically include:

[0088] The default value of the valence electron selection functional is set, the maximum number of iterations is selected from 400 to 500 times, and the maximum step size is selected between and depending on the structure of the metal-organic framework material to be screened and the different metal elements;

[0089] The core electrons are treated by the DFT semi-core hypothesis point method, the self-consistent convergence threshold is calculated in the range of 1.0e-7 / atom to 1.0e-6 / atom, the maximum number of cycles is set to 2000 to 2500 times, and the global domain orbital cut-off value is set to and

[0090] The energy convergence threshold in the structure optimization is 5.0e-6 Ha to 5.0e-5 Ha, and the force convergence threshold is 0.001 The convergence threshold of the maximum displacement is

[0091] In some embodiments, the metal-organic framework materials to be screened specifically include:

[0092] Metal-organic framework materials synthesized from several soluble metal salts and organic ligands.

[0093] In some embodiments, the soluble metal salts specifically include transition elements such as niobium, nickel, iron, tin, titanium, vanadium, silver, manganese, cobalt, tungsten, copper, zinc, molybdenum, palladium, chromium, zirconium, aluminum, etc., and nitrates, chlorides, phosphates, sulfates, acetates, etc. of rare earth elements yttrium, scandium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, etc. one or more of them.

[0094] In some embodiments, the organic ligands specifically include one or more of organic molecules such as 1,4-benzenedicarboxylic acid, 1,2-benzenedicarboxylic acid, 1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, benzenehexacarboxylic acid, 2-hydroxyterephthalic acid, 2-sulfonatoterephthalic acid, 2-nitroterephthalic acid, 2-aminoterephthalic acid, 1,1':4',1”-terphenyl-4,4”-dicarboxylic acid, 1,1'-biphenyl-4,4'-dicarboxylic acid, piperazine, pyrazine, dimethylimidazole, triethylenediamine, 4,4'-bipyridine, 1,3-bis(4-pyridyl)propane, etc.

[0095] In the above specific embodiments, the structure screening system for defective metal-organic framework materials provided by the present invention obtains the structural information of a large number of metal-organic framework materials to be screened, splits out the metal centers of the metal-organic framework materials to be screened according to the structural information, optimizes the geometric structures of the metal centers of the metal-organic framework materials to be screened, and retains the stable structures in the metal-organic framework materials to be screened, so as to screen out the metal-organic framework materials to be screened with stable structures from a large number of metal-organic framework materials to be screened, and uses the calculated stable structures of the metal-organic framework materials to be screened as the to-be-screened structure data set; then, the maximum number of ligands n connected to each metal center is statistically counted respectively, the groups connected to the ligands in the metal centers are removed according to the preset processing principle, and defective structures with 1, 2, 3,..., up to n / 2 ligands removed are respectively constructed, and the geometric structures of the metal centers of each defective structure are optimized; H 2 molecules are added near the defective positions in the metal centers after constructing the defective structures to construct H 2 adsorption cracking models corresponding to various defective metal centers; in the constructed H 2 adsorption cracking models, traverse the defective structures with the catalytic cracking performance reaching the preset threshold and the transition states existing in the catalytic H 2 adsorption cracking process, calculate the Gibbs free energies of different steps in the process of defective structure adsorption of H 2 cracking, and compare the activation energy barriers of the metal-organic framework materials to be screened with different defective distributions and structures in the catalytic H 2 adsorption cracking process, and use the metal-organic framework materials to be screened with the activation energy barrier reaching the preset value as the target defective structures. 2

[0096] In this way, the structure screening system for defective metal-organic framework materials provided by the present invention adopts a high-throughput calculation method, which improves the efficiency of screening the structures of target materials; combining the modeling method of defect construction with high-throughput calculation can solve the problem that it is difficult to deeply analyze the reaction mechanism of microscopic structures by the traditional research idea of experiment + analysis, and avoid the blindness of experiments. This method also has certain reference value for other aspects of research; the research on the influence of defects on the performance of MOFs is also of great significance for promoting the practical application of MOFs materials and has good practical value for promoting the actual production and application of MOFs materials. Thus, the technical problem of difficult structure screening of metal-organic framework materials in the prior art is solved.

[0097] In one embodiment, a computer device is provided. The computer device can be a server, and its internal structure diagram can be as Figure 7 ​As shown in the figure. The computer device includes a processor, a memory, and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a model prediction. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The model prediction of the computer device is used to store static information and dynamic information data. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it realizes the steps in the above method embodiments.

[0098] Those skilled in the art can understand that Figure 7 the structure shown in the figure is only a block diagram of some structures related to the solution of the present invention, and does not constitute a limitation on the computer device to which the solution of the present invention is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements.

[0099] Corresponding to the above embodiments, the embodiment of the present invention further provides a computer storage medium, which contains one or more program instructions. Among them, the one or more program instructions are used to be executed by a weight verification system to perform the method as described above.

[0100] The present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the above method.

[0101] In the embodiment of the present invention, the processor may be an integrated circuit chip with signal processing capabilities. The processor may be a general-purpose processor, a digital signal processor (DSP for short), an application-specific integrated circuit (ASIC for short), a field-programmable gate array (FPGA for short), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0102] The various methods, steps, and logic block diagrams disclosed in the embodiments of the present invention can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of the present invention can be directly embodied as being executed and completed by a hardware decoding processor, or can be executed and completed by a combination of hardware and software modules in the decoding processor. The software module can be located in a mature storage medium in the art such as a random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, register, etc. The processor reads the information in the storage medium and combines its hardware to complete the steps of the above method.

[0103] The storage medium can be a memory, for example, it can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories.

[0104] Among them, the non-volatile memory can be a read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory.

[0105] The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct rambus random access memory (DRRAM).

[0106] The storage media described in the embodiments of the present invention are intended to include, but not be limited to, these and any other suitable types of memories.

[0107] Those skilled in the art should be able to realize that in one or more of the above examples, the functions described in the present invention can be implemented by a combination of hardware and software. When applying software, the corresponding functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. The computer-readable medium includes computer storage media and communication media, where the communication media includes any medium that facilitates the transmission of a computer program from one place to another. The storage media can be any available medium accessible by a general-purpose or special-purpose computer.

[0108] The above specific implementation manners further elaborate on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only the specific implementation manners of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for screening the structures of defective metal-organic framework materials, characterized in that, the method includes: Obtaining the structural information of a large number of metal-organic framework materials to be screened, splitting out the metal centers of the metal-organic framework materials to be screened according to the structural information, optimizing the geometric structures of the metal centers of the metal-organic framework materials to be screened, and retaining the stable structures in the metal-organic framework materials to be screened, so as to screen out the metal-organic framework materials to be screened with stable structures from the large number of metal-organic framework materials to be screened, and taking the calculated stable structures of the metal-organic framework materials to be screened as the data set of structures to be screened; Respectively counting the maximum number of ligands n connected to each metal center, removing the groups of the metal centers connected to the ligands according to the preset processing principle, and respectively constructing defective structures with 1, 2, 3... up to n / 2 ligands removed, and optimizing the geometric structures of the metal centers of each defective structure; Add H near the defect position in the metal center after constructing the defective structure 2 molecules to construct the H 2 adsorption and cracking model corresponding to various defective metal centers; In the constructed H 2 adsorption cracking model, traverse the H 2 defect structures with catalytic cracking performance reaching the preset threshold and the transition states existing in the catalytic H 2 adsorption cracking process, and calculate the Gibbs free energy of different steps in the defect structure adsorption H 2 cracking process. Compare the activation energy barriers of the metal-organic framework materials to be screened with different defect distributions and structures in the catalytic H 2 adsorption cracking process, and use the metal-organic framework materials to be screened with the activation energy barrier reaching the preset value as the target defect structure.

2. The method for screening the structures of defective metal-organic framework materials according to claim 1, characterized in that, When optimizing the geometric structures of the metal centers of the metal-organic framework materials to be screened and the metal centers of each defective structure, the optimization conditions specifically include: Using the DFT method and the B3LYP hybrid functional to perform structural optimization calculations, and all calculations in the structural optimization process are carried out at the same precision; Selecting the default value of the valence electron selection functional, selecting the maximum number of iterations as 300 - 600 times, and selecting the maximum step size between 0.15 Å and 0.3 Å according to the structures of the metal-organic framework materials to be screened and different metal elements; Adopting the DFT semi-core hypothesis point for the core electrons, calculating the self-consistent convergence threshold in the range of 1.0e-7 / atom to 1.0e-5 / atom, setting the maximum number of cycles as 2000 times to 2500 times, and setting the global domain orbital cut-off value as 5.8 Å to 6.0 Å; The convergence threshold of energy in the structural optimization is 5.0e-6 Ha - 1.0e-5 Ha, the convergence threshold of force is 0.001 Ha / Å - 0.002 Ha / Å, and the convergence threshold of the maximum displacement is 1.0e-3 - 1.0e-2 Å.

3. The method for screening the structures of defective metal-organic framework materials according to claim 1, characterized in that, Construct H corresponding to various defective metal centers 2 When constructing the adsorption and cracking model, select the metal atom with the most defective positions and the adjacent non-metal elements O, N, P, and S as the adsorption activation sites. Preset the distance between the metal element M and the H atom to be 2 - 2.5 Å. The direction of the H-H bond should be selected as the direction most favorable for the hydrogen cracking reaction, and the H-H bond length is 0.741 Å.

4. The method for screening the structures of defective metal-organic framework materials according to claim 1, characterized in that, Catalytic H 2 The reaction pathway of the adsorption cracking process and H 2 The conditions for the analysis of the activation energy barrier of adsorption cracking specifically include: Selecting the default value of the valence electron selection functional, selecting the maximum number of iterations as 400 - 500 times, and selecting the maximum step size between 0.15 Å and 0.3 Å according to the structures of the metal-organic framework materials to be screened and different metal elements; Processing the core electrons in the way of the DFT semi-core hypothesis point, calculating the self-consistent convergence threshold in the range of 1.0e-7 / atom to 1.0e-6 / atom, setting the maximum number of cycles as 2000 times to 2500 times, and setting the global domain orbital cut-off value as 5.8 Å to 6.2 Å; The convergence threshold of energy during structural optimization is 5.0e-6 Ha to 5.0e-5 Ha, the convergence threshold of force is 0.001 Ha / Å to 0.002 Ha / Å, and the convergence threshold of the maximum displacement is 1.0e-3 to 5.0e-2 Å.

5. The method for screening the structure of defective metal-organic framework materials according to any one of claims 1-4, characterized in that, the metal-organic framework materials to be screened specifically include: metal-organic framework materials synthesized from several soluble metal salts and organic ligands.

6. The method for screening the structure of defective metal-organic framework materials according to claim 5, characterized in that, the soluble metal salts specifically include one or several of nitrates, chlorides, phosphates, sulfates, and acetates of transition elements such as niobium, nickel, iron, tin, titanium, vanadium, silver, manganese, cobalt, tungsten, copper, zinc, molybdenum, palladium, chromium, zirconium, aluminum, and rare earth elements such as yttrium, scandium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

7. The method for screening the structure of defective metal-organic framework materials according to claim 5, characterized in that, the organic ligands specifically include one or several of organic molecules such as 1,4-benzenedicarboxylic acid, 1,2-benzenedicarboxylic acid, 1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, benzenehexacarboxylic acid, 2-hydroxyterephthalic acid, 2-sulfoterephthalic acid, 2-nitroterephthalic acid, 2-aminoterephthalic acid, 1,1':4',1''-terphenyl-4,4''-dicarboxylic acid, 1,1'-biphenyl-4,4'-dicarboxylic acid, piperazine, pyrazine, dimethylimidazole, triethylenediamine, 4,4'-bipyridine, and 1,3-bis(4-pyridyl)propane.

8. A structure screening system for defective metal-organic framework materials, characterized in that, the system includes: a structure generation unit to be screened, which is used to obtain the structure information of a large number of metal-organic framework materials to be screened, split the metal centers of the metal-organic framework materials to be screened according to the structure information, perform geometric structure optimization on the metal centers of the metal-organic framework materials to be screened, retain the stable structures in the metal-organic framework materials to be screened, so as to screen out the metal-organic framework materials to be screened with stable structures from a large number of metal-organic framework materials to be screened, and use the calculated stable structures of the metal-organic framework materials to be screened as the data set of structures to be screened; a structure optimization unit, which is used to respectively count the maximum number of ligands n connected to each metal center, remove the groups connected to the ligands in the metal centers according to the preset processing principle, and respectively construct defective structures with 1, 2, 3... up to n / 2 ligands removed, and perform geometric structure optimization on the metal centers of each defective structure; A cracking model generation unit is used to add H near the defect position in the metal center after constructing the defective structure 2 molecules to construct H corresponding to various defective metal centers 2 adsorption cracking models; A result output unit, used for traversing H in the constructed H 2 adsorption cracking model, and traversing H 2 defect structures with catalytic cracking performance reaching a preset threshold and transition states existing in the catalytic H 2 adsorption cracking process, and calculating the Gibbs free energy of different steps in the defect structure adsorption H 2 cracking process, comparing the activation energy barriers of the metal-organic framework materials to be screened with different defect distributions and structures in the catalytic H 2 adsorption cracking process, and using the metal-organic framework materials to be screened with the activation energy barrier reaching a preset value as the target defect structure.

9. A computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, when the processor executes the program, it implements the steps of the method according to any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium storing a computer program thereon, characterized in that, when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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