Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
  • C01C1/00—Ammonia; Compounds thereof
  • C01C1/02—Preparation, purification or separation of ammonia
  • C01C1/04—Preparation of ammonia by synthesis
  • C01C1/0405—Preparation of ammonia by synthesis from N2 and H2 in presence of a catalyst
  • C01C1/0411—Preparation of ammonia by synthesis from N2 and H2 in presence of a catalyst characterised by the catalyst
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/002—Mixed oxides other than spinels, e.g. perovskite
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/56—Platinum group metals
  • B01J23/63—Platinum group metals with rare earths or actinides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/56—Platinum group metals
  • B01J23/64—Platinum group metals with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/648—Vanadium, niobium or tantalum or polonium
  • B01J23/6482—Vanadium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/56—Platinum group metals
  • B01J23/64—Platinum group metals with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/652—Chromium, molybdenum or tungsten
  • B01J23/6522—Chromium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/56—Platinum group metals
  • B01J23/64—Platinum group metals with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • B01J23/656—Manganese, technetium or rhenium
  • B01J23/6562—Manganese
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

• the present invention relates to an ammonia synthesis catalyst and an ammonia synthesis method.
• ammonia (NH 3 ) has attracted attention as a component that can be used as an energy carrier for hydrogen energy.
• the Haber-Bosch (HB) method using an iron-based catalyst as a catalyst is used industrially.
• research has been progressing on various types of ammonia synthesis catalysts with the aim of synthesizing ammonia under conditions milder than the HB method.
• One aspect of the present invention aims to provide an ammonia synthesis catalyst that enables more efficient synthesis of NH3 .
• One aspect of the present invention is IrSc, FePd3 , MnTc3 , IrY, CrPd3 , MnPd3 , RhY, Co3Pt , CrPt3 , FeRh3, CrRh3 , Ni3Ti , Ir3V , Pt3Ti , Co3Rh , Pd3Ti , Ni 3 Zr, Co 3 W, NiPd 3 , FeNi 3 , Ir 3 Mn, IrMn, MnPt, MnNi 3 , Ir 3 Re, MnRh, Pd 3 V, MnPt 3 , Rh 3 V and Rh 3 Ti An ammonia synthesis catalyst containing one or more selected components.
• One aspect of the present invention enables more efficient synthesis of NH3 .
• FIG. 1 is a diagram showing the configuration of a catalyst selection system to which a catalyst selection method is applied; FIG. It is a figure showing an example of a data table.
• FIG. 3 is a diagram showing an example of the relationship between the energy levels in each elementary reaction of NH 3 synthesis using a catalyst.
• FIG. 2 is a functional block diagram showing the configuration of a catalyst selection device. It is a figure showing an example of an activity map.
• FIG. 3 is a diagram showing an example of the relationship between the interface and the NH 3 synthesis rate when the catalyst is iron.
• FIG. 2 is a functional block diagram showing an example of the configuration of a first calculation unit. It is an explanatory diagram when rearranging candidate substances in a data table.
• FIG. 2 is a functional block diagram showing an example of the configuration of a second calculation unit.
• FIG. 2 is a block diagram showing the hardware configuration of a catalyst selection device.
• 3 is a flowchart showing a catalyst selection method.
• FIG. 3 is a diagram showing an example of an activity map showing the relationship between the adsorption energy between a nitrogen intermediate and a catalyst and the dissociation activation energy of the transition state of the nitrogen intermediate on the catalyst. It is a flowchart which shows an example of a 1st energy calculation process. It is a figure which shows an example of the result of plotting the descriptor of a candidate substance. It is a flowchart which shows an example of a 2nd energy calculation process.
• FIG. 3 is a diagram showing an example of an activity map in which 30 types of secondary screening candidate substances are plotted. The correlation between the energy of the intermediate or transition state on the standard catalyst calculated by DFT calculation and the energy of the intermediate or transition state on the same standard catalyst as the horizontal axis calculated by the catalyst selection method.
• FIG. FIG. 3 is a diagram comparing activity maps of a catalyst selected by a catalyst selection method and a catalyst created using DFT calculation.
• FIG. 3 is a diagram showing an example of a state in which 30 types of alloys selected by the catalyst selection method are plotted on an activity map created using the catalyst selection method.
• 1 is a flowchart showing an example of a method for manufacturing a catalyst.
• FIG. 2 is a diagram plotting the relationship between Rh ratio and energy for 2310 types of structures of CrRh alloys. It is a diagram plotting the relationship between the Mn ratio and energy for 2310 types of structures of IrMn alloys.
• This is a diagram showing the relationship between the adsorption energy ( EN ) between the catalyst and the nitrogen intermediate (N * ) of the candidate catalyst and the reference catalyst, and the calculation result of the NH3 synthesis rate synthesized by the candidate catalyst and the reference catalyst.
• FIG. 3 is a diagram showing the experimental results of the adsorption energy (E N ) between the catalyst and the nitrogen intermediate (N * ) and the synthesis rate of NH 3 for a reference catalyst.
• the NH3 synthesis catalyst according to this embodiment includes IrSc, FePd3 , MnTc3 , IrY, CrPd3 , MnPd3 , RhY, Co3Pt , CrPt3 , FeRh3 , CrRh3 , Ni3Ti , Ir3V , Pt 3 Ti, Co 3 Rh, Pd 3 Ti, Ni 3 Zr, Co 3 W, NiPd 3 , FeNi 3 , Ir 3 Mn, IrMn, MnPt, MnNi 3 , Ir 3 Re, MnRh, Pd 3 V, MnPt 3 , Contains at least one component of Rh 3 V and Rh 3 Ti. These components may be contained alone or in combination of two or more.
• the NH3 synthesis catalyst according to this embodiment includes IrSc, FePd3 , MnTc3 , IrY, CrPd3 , MnPd3 , RhY, Co3Pt , CrPt3 , FeRh3 , CrRh3 , Ni3Ti , Ir3V , Pt 3 Ti, Co 3 Rh, Pd 3 Ti, Ni 3 Zr, Co 3 W, NiPd 3 , FeNi 3 , Ir 3 Mn, IrMn, MnPt, MnNi 3 , Ir 3 Re, MnRh, Pd 3 V, MnPt 3 , It is preferable to consist of any one of Rh 3 V and Rh 3 Ti.
• the NH 3 synthesis catalyst according to the present embodiment was selected using a catalyst selection system and a catalyst selection method, which will be described later.
• the catalyst selection system and the like described above descriptors selected by analyzing the elementary reactions of NH 3 synthesis are used, so it is possible to efficiently and accurately select a catalyst that lowers the activation energy. Therefore, by using a catalyst selected by the catalyst selection system or the like for NH 3 synthesis, the energy required for NH 3 synthesis can be lowered, so that NH 3 can be synthesized efficiently.
• NH 3 is attracting attention as one of the promising candidates for hydrogen carrier.
• NH 3 is generally synthesized using the HB method, but since it is performed at high temperature and high pressure, from the viewpoint of reducing CO 2 emissions and energy efficiency, it is important to efficiently synthesize NH 3 in order to produce NH 3 with high efficiency. It is important to use a NH3 synthesis catalyst that can synthesize NH3. Since the NH 3 synthesis catalyst according to the present embodiment can efficiently synthesize NH 3 , it is possible to improve the production of NH 3 .
• FIG. 1 is a diagram showing the configuration of a catalyst selection system to which a catalyst selection method is applied.
• the catalyst selection system 1 includes a catalyst selection device 10, a storage section 20, and a machine learning potential 30.
• the catalyst selection device 10, the storage unit 20, and the machine learning potential 30 are connected via the communication network 40, and the input values to the catalyst selection device 10, the storage unit 20, and the machine learning potential 30 are The output values of the catalyst selection device 10, the storage unit 20, and the machine learning potential 30 may be transmitted via the communication network 40. At least one of the storage unit 20 and the machine learning potential 30 may be stored on the cloud.
• the catalyst selection device 10, the storage unit 20, and the machine learning potential 30 are connected via the communication network 40, but they may also be connected by wire. Further, the catalyst selection system 1 may be a single device such as a PC (Personal Computer) that includes each component within the device.
• PC Personal Computer
• the catalyst selection device 10 uses the machine learning potential 30 to select NH 3 synthesis catalyst candidates for a catalytic reaction that synthesizes NH 3 as a target product from H 2 and N 2 as raw materials. Note that details of the catalyst selection device 10 will be described later.
• the storage unit 20 stores a data table including information on the catalyst and adsorbent, the structure and energy of the catalyst and adsorbent optimized using the machine learning potential 30, and deviations from scaling lines.
• the data table records information on the catalyst and adsorbent, the structure and energy of the catalyst and adsorbent optimized using the machine learning potential 30, and information on deviation from the scaling line, etc. be done.
• the deviation from the scaling line is determined by the energy coordinates (the coordinates between the adsorption energy of N * and the dissociation activation energy of NN * ) optimized using machine learning potential 30 for the same catalyst composition and the same crystal plane. , is the difference in the dissociation activation energy of N ⁇ N * between the coordinates on the scaling line in the adsorption energy of N * . Therefore, the deviation from the scaling line is calculated only for the dissociative activation energy of NN * .
• the catalyst may be a single metal, an alloy containing multiple metals, or a compound containing metals.
• the catalyst information includes the catalyst name (catalyst composition), information on the crystal plane of the catalyst, etc.
• catalyst names examples include CoRh and the like.
• crystal plane of the catalyst examples include [001], [111], and [211].
• the adsorbent is a component used to produce a target product, and is nitrogen (N 2 ) or hydrogen (H 2 ).
• Information on the adsorbent includes the name of the adsorbent, etc.
• adsorbent substance names include no adsorbent, N * , NN * , and the like.
• Examples of the optimized structure of the catalyst and adsorbent include the intermediate structure and transition state structure of the substance.
• the energy of the optimized catalyst and adsorbent includes the energy of catalytic reaction.
• the energy of the catalytic reaction include the energy of reaction components that appear in a plurality of elementary reactions in the process of synthesizing the target product NH 3 from the raw materials H 2 and N 2 in the catalytic reaction.
• Reaction components include raw materials, intermediates of raw materials, transition states of intermediates, and the like. These include the dissociation activation energy between the transition state of the intermediate of the raw material and the catalyst that occurs in the elementary reaction in the process of synthesizing the target product from the raw material in the catalyst, and the adsorption energy between the intermediate and the catalyst.
• the elementary reactions for NH 3 synthesis include, for example, the following formulas (I) to (VII).
• * means an empty adsorption site on the surface of the catalyst to which reaction components such as elements and molecules contained in the raw materials are adsorbed.
• the raw materials are N 2 and H 2
• the intermediates of the raw materials are N 2 *, H * , NH *, NH 2 *, and NH 3 *
• the intermediates of the raw materials are N 2 * , H * , NH *, NH 2 * , and NH 3 *
• the transition states are NN * , NH * , NH-H * , NH2- H * .
• FIG. 3 shows an example of the relationship between the energy levels in each elementary reaction of NH 3 synthesis using a catalyst in these formulas.
• the catalyst in formula (III) among the above formulas (I) to (VII)
• the dissociation activation energy (E N- N ) of N-N * which is the transition state of the nitrogen intermediate, is the largest, and the adsorption energy (E N ) between the nitrogen intermediate N * and the catalyst is approximately constant. It is the most stable.
• the dissociation activation energy of N-N * on the catalyst (E N-N ) and the adsorption energy of N * and the catalyst (E N ) greatly influence the synthesis of NH3 .
• the machine learning potential 30 is an interatomic potential using a machine learning method that outputs energy from information regarding the structure of atoms.
• machine learning potentials include Neural Network Potential (NNP), Gaussian Approximation Potential (GAP), Spectral Neighbor Analysis Potential (SNAP), and Moment Tensor Potential (MTP). Examples include Tensor Potential).
• NNP Neural Network Potential
• GAP Gaussian Approximation Potential
• SNAP Spectral Neighbor Analysis Potential
• MTP Moment Tensor Potential
• Examples include Tensor Potential).
• NNP Neural Network Potential
• GAP Gaussian Approximation Potential
• SNAP Spectral Neighbor Analysis Potential
• MTP Moment Tensor Potential
• Tensor Potential Tensor Potential
• FIG. 4 is a functional block diagram showing the configuration of the catalyst selection device 10.
• the catalyst selection device 10 includes a descriptor selection unit 11, a map creation unit 12, a preparation unit 13, a first calculation unit 14, a first plot unit 15, a first screening unit 16, a second calculation unit It has a section 17, a second plot section 18, a second screening section 19, a narrowing section 21, and an output section 22.
• the descriptor selection unit 11 selects, as a descriptor, the energy of an intermediate structure or transition state structure included in an elementary reaction of a catalytic reaction such as the above formulas (I) to (VII).
• the map creation unit 12 creates a map (activity map) representing the reactivity of the descriptor and the catalytic reaction. Note that instead of the activity map, a map representing descriptors and selectivity of the catalytic reaction may be created.
• the activity map clarifies the relationship between the descriptor and the reactivity (selectivity) of the catalyst
• inputting the descriptor is regarded as a model that predicts the reactivity (selectivity) of the catalyst, and it can be used to directly describe the reactivity (selectivity) of the catalyst.
• the reactivity of the catalyst may be predicted from the child.
• the activity map as a model, the reactivity of the catalyst can be directly predicted from the descriptors obtained by the first calculation unit 14 and the second calculation unit 17, and the reactivity of the catalyst can be predicted using the data table (see FIG. 8).
• Candidate substances may be screened. In this case, the catalyst selection device 10 does not need to include the first plot section 15 and the second plot section 18.
• FIG. Figure 5 shows the relationship between two descriptors of the elementary reactions of reaction components in NH 3 synthesis (see equations (I) to (VII) above) and the NH 3 synthesis rate (NH 3 synthesis rate). represent. Note that the NH 3 synthesis rate in FIG. 5 represents the yield of synthesized NH 3 .
• the two descriptors used in the activation map shown in FIG. 5 are referred to as descriptors 1 and 2.
• the dissociation activation energy (E N-N ) of the transition state (N-N * ) of the nitrogen intermediate in the catalyst and the nitrogen intermediate (N * ) and the adsorption energy (E N ) of the catalyst greatly affect the synthesis of NH 3 .
• descriptors 1 and 2 preferably use the adsorption energy (E N ) between N * and the catalyst and the dissociation activation energy (E NN ) of NN * on the catalyst.
• the activity map can be created, for example, by Microkinetics using descriptors.
• the catalyst is an NH 3 synthesis catalyst and the NH 3 synthesis reaction is caused. Therefore, as described above, the descriptor is the elementary reaction of the reaction components in the above NH 3 synthesis (the above formula It is preferable to use the energies of N * and N ⁇ N * in the formulas (I) to (VII)). If the energy of N * and N-N * is used as a descriptor, it can be expressed that there is a linear relationship between multiple catalysts based on the magnitude of the reaction rate of the catalyst. A map that allows you to visually and easily understand areas with high activity can be obtained. As will be described later, the straight line appearing on the activity map can be used as a scaling line (see FIG. 5) serving as a threshold for the reaction rate of the catalyst.
• General Microkinetics consists of elementary reaction enumeration, energy calculation, and reaction rate calculation as follows.
• Microkinetics using descriptors will be explained.
• the execution procedure of Microkinetics using a descriptor is as follows. 1. Preparation: 1-1. Describe all elementary reactions related to NH3 synthesis. 1-2. Calculate all intermediates and transition states that occur in elementary reactions related to NH 3 synthesis. For example, calculate all intermediates and transition states for some reference catalyst. That is, all intermediates and transition states that occur when using these reference catalysts are calculated. Then, from among all intermediates and transition states, only two reaction components (e.g., intermediates or transition states) to be used as descriptors are selected and two descriptors (e.g., adsorption energy of N * , N- Calculate the dissociative activation energy of N * .
• two reaction components e.g., intermediates or transition states
• the number of descriptors is not limited to two, and may be one or three or more, and it is preferable to use a descriptor that has an effect on the reaction rate of the catalyst.
• linear regression not only linear regression but also non-linear regression techniques may be used to calculate the other parameters mentioned above.
• the preparation unit 13 prepares multiple types of catalyst candidate substances.
• the candidate substance for the catalyst may be a material that has been used for the synthesis of NH 3 , a material that is being considered for use in the synthesis of NH 3 , a material that has never been used for the synthesis of NH 3 , or the like.
• the material may be a single metal, an alloy containing multiple metals, or a metal compound such as a metal oxide, nitride, or carbide.
• the candidate substance may include a substance in which one type of element on the surface of one candidate substance is replaced with another different element, as another candidate substance different from the one candidate substance.
• the number of candidate substances for the catalyst is not particularly limited and can be selected as appropriate, and may be, for example, tens, hundreds, thousands, etc.
• a plurality of candidate substances may be prepared for each surface with different crystal planes.
• the rate of reaction between a candidate substance and an element tends to vary depending on the crystal plane of the candidate substance that appears on the surface of the candidate substance.
• FIG. 6 shows an example of the relationship between the crystal plane of the iron surface and the NH 3 synthesis rate when the catalyst is iron (Fe).
• the catalyst when the catalyst is iron, the NH3 synthesis rate differs depending on the crystal plane on the surface of the catalyst, and when the crystal plane is the (111) or (211) plane, the The catalyst has a higher NH 3 synthesis rate than the case. Therefore, it is preferable to prepare a plurality of candidate substance surfaces for each crystal plane.
• the first calculation unit 14 calculates a descriptor regarding the catalytic reaction using the candidate substances, with all the candidate substances prepared by the preparation unit 13 fixed.
• the descriptors include the first intermediate energy at which an intermediate of a reaction component containing a substance derived from raw materials (N 2 , H 2 ) is adsorbed on the surface of a candidate substance, and the energy of a reaction component adsorbed on the surface of a candidate substance. After the transition state of an intermediate is adsorbed, a first energy including a first transition state energy in a separation elementary reaction in which a reaction component is separated into two or more substances is calculated.
• the first calculation unit 14 may calculate only the first intermediate energy or the first transition state energy as the first energy.
• the first calculation unit 14 calculates the descriptor using the machine learning potential 30.
• the first calculation unit 14 can shorten the descriptor calculation time compared to the case where first-principles calculation (DFT calculation) based on density functional theory (DFT) is used. .
• the first calculation unit 14 may determine the descriptor calculation by one calculation, or may determine the descriptor calculation by multiple calculations (for example, 10 times). When calculating multiple times, the average value of multiple calculated values may be used, or the maximum value or minimum value of multiple calculated values may be used.
• the first calculation unit 14 calculates the adsorption position of the reaction component including the material derived from the raw material on the surface of the candidate substance included in the elementary reaction, with all the candidate substances fixed. It is preferable to optimize the structure of an intermediate structure containing the candidate substance and the reaction component. Thereby, the first calculation unit 14 can select an intermediate structure having a stable structure.
• optimization refers to finding an optimal value that minimizes the energy for a given structure. Note that the following optimization also has the same meaning.
• the first calculation unit 14 extracts a structure in which the adsorption position of the reaction component to the candidate substance is optimal and the first intermediate energy between the candidate substance and the intermediate of the reaction component is the most stable. Thereby, the first calculation unit 14 can obtain the first intermediate energy of the intermediate of the reaction component in a short time, although with low accuracy.
• the first calculation unit 14 preferably includes a first structure optimization unit 141, a second structure optimization unit 142, and a first transition state energy acquisition unit 143.
• the first calculation unit 14 can obtain the first transition state energy in a short time, although with low accuracy.
• the first structure optimization unit 141 optimizes the structure of an intermediate structure containing a candidate substance of a reaction component and a reaction component on the surface of a candidate substance included in a separated elementary reaction from one molecule to two molecules, and 1. Calculate the optimized structure. That is, the first structure optimization unit 141 optimizes the structure of an intermediate structure containing a candidate substance and a reaction component in a separated elementary reaction in which one molecule becomes two molecules, with all the structures of the candidate substance fixed. is performed to calculate the first optimized structure.
• the second structure optimization unit 142 calculates a second optimized structure by optimizing the structure when separated into two or more substances including a candidate substance for a reaction component and a reaction component.
• the first transition state energy acquisition unit 143 obtains transition state energy from the first optimized structure obtained by the first structure optimization unit 141 and the second optimized structure obtained by the second structure optimization unit 142. A certain first transition state energy is calculated.
• AB * is a molecule in a state adsorbed to a candidate substance
• AB * is a molecule in a transition state of AB * in the process of separating AB * into A * and B *
• the first structure optimization unit 141 fixes the entire structure of the candidate substance and converts AB * into two molecules. is placed on the surface of the candidate substance, and the structure of an intermediate structure containing the candidate substance and AB * is optimized.
• the second structure optimization unit 142 optimizes the structure so that there are two molecules consisting of A * and B * .
• the first transition state energy acquisition unit 143 uses the NEB (Nudged Elastic Band) method to obtain one molecule of AB * and two molecules of A * and B * , so that one molecule of AB * is A *.
• NEB Noise Elastic Band
• the transition state energy required to form two molecules consisting of and B * is calculated as the first transition state energy.
• the first plotting unit 15 plots the candidate substance based on the first energy (the energy including the first intermediate energy and the first transition state energy), which is the descriptor calculated by the first calculating unit 14. is plotted on the activity map (see FIG. 5) displayed by the map creation section 12 to create a first map with plots.
• the first energy the energy including the first intermediate energy and the first transition state energy
• the first screening unit 16 screens candidate substances based on the first plotted map created by the first plotting unit 15, and selects primary screening candidate substances. That is, as a screening method, the first screening unit 16 narrows down candidate substances plotted in a high activity region containing a catalyst with high activity (high NH 3 synthesis rate) as primary screening candidate substances.
• a scaling line (see FIG. 5) may be provided on an activity map in which candidate substances are plotted, and the highly active region may be a range smaller than a predetermined value with respect to the scaling line. Further, candidate substances may be narrowed down based on a range that is less than a predetermined value than the energy of NH 3 production by the catalyst. The range may be such that the NH 3 synthesis rate is equal to or higher than a predetermined value.
• the predetermined value of the NH 3 synthesis rate is preferably 10 ⁇ 4 [1/s] or more.
• the number of candidate substances to be further narrowed down can be selected as appropriate depending on the range of the high activity region to be set, etc., and is preferably 5 to 30, more preferably 8 to 55, and 10 to 20. More preferably.
• the activity map can be created by Microkinetics using descriptors, as described above.
• descriptors the energies of N * and NN * in the elementary reactions of the reaction components in the above NH3 synthesis (see equations (I) to (VII) above) can be used to create an activity map.
• generation energy E Alloy - N A ⁇ E A (bulk) - N B ⁇ E B (bulk) ... (i) (In the formula, E Alloy is the bulk energy of alloy AB, E A (bulk) is the bulk energy of metal A, E B (bulk) is the bulk energy of metal B, and N A is is the number of atoms of metal A in the alloy, and NB is the number of atoms of metal B in the alloy.)
• the range smaller than a predetermined value with respect to the scaling line is selected appropriately depending on the target product to be synthesized, the type of substance used, etc., but in the case of an NH3 synthesis catalyst, for example, the range is 0.25 eV or more with respect to the scaling line. A small range is preferable.
• the range of less than a predetermined value than the production energy is appropriately selected depending on the target product to be synthesized, the type of substance used, etc., but in the case of an NH3 synthesis catalyst, for example, the range is less than 0.05 eV/atom than the production energy. It is preferable to set it as the range of.
• the number of primary screening candidate substances to be narrowed down can be selected as appropriate depending on the number of candidate substances and the number of secondary screening candidate substances described below, and may be, for example, several dozen types or several hundred types. .
• the first screening unit 16 when the first screening unit 16 plots the candidate substances on the activity map and narrows down the primary screening candidate substances, the first screening unit 16 plots the candidate substances on the activity map to narrow down the first screening candidate substances, as shown in FIG.
• a data table may be used that lists only information related to the above integers).
• the candidate substances in the data table listing only candidate substances may be sorted in the order of their inclusion in the high activity region, and candidate substances that are included in the high activity area and have a threshold value or higher may be narrowed down as primary screening candidate substances.
• the first screening unit 16 may use the rearranged data table to plot the candidate substances on the activity map using the first plotting unit 15 to narrow down the primary screening candidate substances.
• the second calculation unit 17 calculates a descriptor regarding the catalytic reaction using the primary screening candidate substance with the surface of the primary screening candidate substance being relaxed. calculate.
• a second intermediate energy at which an intermediate of a reaction component (N 2 , H 2 ) used as a descriptor is adsorbed on the surface of a primary screening candidate substance After a reactive component is adsorbed on the surface of the primary screening candidate substance, a second energy including a second transition state energy in a separation elementary reaction in which the reactive component is separated into two or more substances is calculated.
• the state in which the surface of the catalyst is relaxed is the state in which the catalyst is allowed to move, and the state in which the structure can be changed by moving several layers (for example, about two layers) from the surface of the catalyst, and the state in which the catalyst surface is relaxed is the state in which the catalyst can move several layers (for example, about 2 layers) from the surface of the catalyst and change its structure. It means to be in a similar state.
• the second calculation unit 17 may calculate only the second intermediate energy or the second transition state energy as the second energy.
• the second calculation unit 17 calculates the descriptor using the machine learning potential 30, similar to the first calculation unit 14. By using the machine learning potential 30, the second calculation unit 17 can shorten the descriptor calculation time compared to the case where DFT calculation or the like is used.
• the second calculation unit 17 calculates the primary screening candidate substance included in the elementary reaction, similar to the first calculation unit 14, with the surface of the primary screening candidate substance relaxed. It is preferable to optimize the structure of the intermediate structure containing the primary screening candidate substance and the reaction component by changing the adsorption position of the reaction component containing the substance derived from the raw material on the surface of the intermediate structure. Thereby, the second calculation unit 17 can select an intermediate structure having a stable structure.
• the second calculation unit 17 determines that the adsorption structure of the reaction component to the primary screening candidate substance is correct, and that the second intermediate energy between the primary screening candidate substance and the intermediate of the reaction component is the highest. Preferably, stable structures are extracted. By optimizing the structure, the structure of the molecule in the state adsorbed to the candidate substance (for example, AB * structure) changes, as in the case of optimizing the structure in the first structure optimization unit 141. There are cases. Since the second calculation unit 17 can exclude such a structure, it can obtain the second intermediate energy of the reaction component with high accuracy.
• the second calculation unit 17 preferably includes a first structure optimization unit 171, a second structure optimization unit 172, and a second transition state energy acquisition unit 173. Thereby, the second calculation unit 17 can obtain the second transition state energy with high accuracy when the descriptor is the transition state energy of the transition state of the intermediate.
• the first structure optimization unit 171 optimizes the structure of an intermediate structure containing the primary screening candidate substance and the reaction component on the surface of the primary screening candidate substance included in the separation elementary reaction from one molecule to two molecules. is performed to calculate the first optimized structure. That is, the first structure optimization unit 171 generates an intermediate structure containing a primary screening candidate substance and a reaction component in a state where the surface of the primary screening candidate substance is relaxed in a separation elementary reaction in which one molecule becomes two molecules. A first optimized structure is calculated by optimizing the structure.
• the second structure optimization unit 172 optimizes the separated structure of the reaction component when it is separated into two or more substances, and calculates a second optimized structure.
• the second transition state energy acquisition unit 173 like the first transition state energy acquisition unit 143, combines the first optimized structure obtained by the first structure optimization unit 171 and the second structure optimization unit 172.
• a second transition state energy which is a transition state energy, is calculated from the second optimized structure.
• AB * is a molecule in a state adsorbed to a candidate substance
• AB * is a molecule in a transition state of AB * in the process of separating AB * into A * and B * .
• a * is an intermediate of the A molecule
• B * is an intermediate of the B molecule
• the reaction in which one molecule of AB * becomes two molecules of A * and B * is the above reaction.
• the first structure optimization unit 171 performs the first structure optimization process while the surface of the primary screening candidate substance is relaxed. Similar to the conversion section 141, AB * is placed on the surface of the primary screening candidate substance, and the structure of the intermediate structure containing the primary screening candidate substance and AB * is optimized.
• the second structure optimization unit 172 optimizes the separated structure so that it becomes two molecules consisting of A * and B * .
• the second transition state energy acquisition unit 173 performs the same process as the first transition state energy acquisition unit 143, and calculates the transition state energy required when one molecule of AB * becomes two molecules of A * and B * . Calculated as 2 transition state energy.
• the second plotting section 18 plots the primary screening candidate substances on the activity map (see FIG. 5) based on the second energy, which is the descriptor calculated by the second calculating section 17. Create a map with a second plot.
• the second screening unit 19 screens the primary screening candidate substances based on the second plotted map created by the second plotting unit 18, and selects the secondary screening candidate substances. That is, the second screening unit 19 can select the primary screening candidate substance plotted in the high activity region of the second plotted map as the secondary screening candidate substance by the screening method.
• the method for screening candidate substances for the primary screening is the same as the method for narrowing down the candidate substances to the primary screening candidate substances in the first screening section 16 described above, so the details will be omitted.
• the number of secondary screening candidate substances to be selected can be selected as appropriate depending on the number of primary screening candidate substances, and may be, for example, several dozen types or several hundred types.
• the narrowing down unit 21 narrows down the secondary screening candidate substances selected by the second screening unit 19 based on catalyst stability, catalyst cost, etc.
• the number of secondary screening candidate substances to be narrowed down can be selected as appropriate depending on the number of selected secondary screening candidate substances, and may be, for example, several types or dozens of types.
• the output unit 22 outputs the secondary screening candidate substances selected by the second screening unit 19 or the secondary screening candidate substances narrowed down by the narrowing unit 21 by display or the like.
• the catalyst selection device 10 uses the first calculation section 14, the first plotting section 15, the first screening section 16, or the second calculation section 14, depending on the number of candidate substances in the preparation section 13.
• the section 17, the second plot section 18, and the second screening section 19 may not be provided. That is, the catalyst selection device 10 may narrow down the candidate substances by omitting calculations with all candidate substances fixed or calculations with the surface of the candidate substances relaxed.
• FIG. 10 is a block diagram showing the hardware configuration of the catalyst selection device 10.
• the catalyst selection device 10 is composed of an information processing device (computer), and physically includes a CPU (Central Processing Unit: processor) 101 which is an arithmetic processing unit, and a RAM which is a main storage device. It can be configured as a computer system including a random access memory (Random Access Memory) 102, a ROM (Read Only Memory) 103, an input device 104 as an input device, an output device 105, a communication module 106, an auxiliary storage device 107 such as a hard disk, and the like. These are interconnected by a bus 108. Note that the output device 105 and the auxiliary storage device 107 may be provided externally.
• a bus 108 the output device 105 and the auxiliary storage device 107 may be provided externally.
• the CPU 101 controls the overall operation of the catalyst selection device 10 and performs various information processing.
• the CPU 101 can select a catalyst by executing, for example, a catalyst selection method or a catalyst selection program, which will be described later, which are stored in the ROM 103 or the auxiliary storage device 107.
• the RAM 102 is used as a work area for the CPU 101 and may include a nonvolatile RAM that stores main control parameters and information.
• the ROM 103 stores basic input/output programs and the like.
• the catalyst selection program may be stored in ROM 103.
• the input device 104 is an input device such as a keyboard, a mouse, an operation button, a touch panel, a display screen, etc., and receives information input by a user as an instruction signal, and outputs the instruction signal to the CPU 101.
• the output device 105 is a display device such as a monitor display, a speaker, a printing device such as a printer, or the like.
• information such as catalyst selection results is displayed on a display device such as a monitor display, and the displayed screen is updated in response to an input operation via the input device 104 or the communication module 106.
• the communication module 106 is a data transmitting/receiving device such as a network card, and functions as a communication interface that takes in information from an external data recording server, etc., and outputs analysis information to other electronic devices.
• the auxiliary storage device 107 is a storage device such as an SSD (Solid State Drive) and an HDD (Hard Disk Drive), and stores, for example, various data, files, etc. necessary for the operation of the catalyst selection device 10.
• SSD Solid State Drive
• HDD Hard Disk Drive
• Each function of the catalyst selection device 10 is performed by loading predetermined computer software (including a catalyst selection program) from the main storage device such as the RAM 102 or the auxiliary storage device 107 and executing it by the CPU 101. This is realized by reading and writing data in the device or the auxiliary storage device 107, etc., and operating the input device 104, output device 105, and communication module 106.
• predetermined computer software including a catalyst selection program
• each part of the catalyst selection device 10 shown in FIG. 4 is configured such that a processor executes pre-stored predetermined computer software (including a catalyst selection program) in a computer equipped with the catalyst selection device 10. This is realized through the cooperation of software and hardware.
• the catalyst selection program can be stored, for example, in the main memory device or auxiliary memory device 107 included in the computer. Further, the catalyst selection program may be stored on a computer connected to a communication line such as the Internet, and provided by downloading part or all of the catalyst selection program via the communication line. Further, the catalyst selection program may be configured to be provided or distributed via a communication line.
• the catalyst selection program can be recorded (installed) in a computer from a state where part or all of it is stored in a portable storage medium such as an optical disk such as a CD-ROM or DVD-ROM, or a semiconductor memory such as a flash memory. ).
• a portable storage medium such as an optical disk such as a CD-ROM or DVD-ROM, or a semiconductor memory such as a flash memory.
• Catalyst selection method The method for selecting a catalyst will be explained.
• the catalyst selection method can be performed using the catalyst selection system 1 described above. Therefore, some explanations of the matters already explained will be omitted.
• FIG. 11 is a flowchart showing a catalyst selection method. As shown in FIG. 11, the method for selecting a catalyst is a method for selecting an NH 3 synthesis catalyst used in a catalytic reaction to produce NH 3 as a target product from H 2 and N 2 as raw materials.
• the descriptor selection unit 11 selects as a descriptor the energy of the intermediate structure or transition state structure included in the elementary reactions of the catalytic reactions such as the above formulas (I) to (VII). Child selection step: Step S11).
• Descriptors for catalytic reactions include the adsorption energy when a reactive component is adsorbed onto the surface of a candidate substance, and the adsorption energy in a separation elementary reaction in which a reactive component is separated into two or more substances after it is adsorbed on the surface of a candidate substance. It is preferable to use transition state energy.
• the adsorption energy when the reaction component is adsorbed onto the surface of the candidate substance for example, the adsorption energy (E N ) between the catalyst and the nitrogen intermediate (N * ) is used.
• the transition state energy in a separation elementary reaction in which a reaction component is adsorbed onto the surface of a candidate substance and then separated into two or more substances is the dissociation activation energy of the nitrogen transition state (N-N * ) in the catalyst. (E N-N ) is used.
• the catalyst selection method analyzes the elementary reactions included in the NH3 synthesis reaction and selects and uses the energy related to the elementary reaction that has the greatest impact on NH3 synthesis as a descriptor. It is possible to accurately select a catalyst that can efficiently synthesize 3 .
• the map creation unit 12 creates an activity map representing the reactivity of the descriptor and the catalytic reaction (activity map creation step: step S12).
• the descriptors of the catalytic reaction are the adsorption energy (E N ) between the catalyst and the nitrogen intermediate (N * ), and the dissociation activation energy (E N - N ) of the nitrogen transition state (N-N * ) on the catalyst. ) is shown in FIG. 12.
• the preparation unit 13 prepares several thousand types (for example, 2000 types) of candidate substances for the catalyst (preparation step: step S13).
• the first calculation unit 14 calculates a descriptor regarding the catalytic reaction using the candidate substances, with all the candidate substances prepared in the preparation unit 13 fixed (first calculation step: step S14).
• the first intermediate energy at which an intermediate of a reaction component containing a substance derived from the raw materials (N 2 , H 2 ) used for the descriptor is adsorbed on the surface of the candidate substance and calculating the first energy including the first transition state energy in a separation elementary reaction in which the transition state of the intermediate of the reaction component is separated into two or more substances after the transition state of the intermediate of the reaction component is adsorbed on the surface of the candidate substance.
• the first calculation unit 14 calculates a descriptor of the candidate substance using the machine learning potential 30.
• the calculation of the first energy may be determined by one calculation, or may be determined by multiple calculations (for example, 10 times). When calculating multiple times, the average value of multiple calculated values may be used, or the maximum value or minimum value of multiple calculated values may be used.
• the first calculation unit 14 calculates the It is preferable to optimize the structure of the intermediate structure containing the candidate substance and the reaction component by changing the adsorption position of the reaction component containing the substance derived from the raw material. Thereby, an intermediate structure having a stable structure can be selected.
• the first calculation unit 14 determines that the adsorption structure of the reaction component to the candidate substance is correct and that the first intermediate energy between the candidate substance and the intermediate of the reaction component is the most stable. Preferably, the structure is extracted. As a result, the first intermediate energy between the candidate substance and the intermediate of the reaction component is calculated with low accuracy but in a short time.
• the first calculation step (step S14) includes a first structure optimization step (step S141), a second structure optimization step (step S142), and a first transition state energy acquisition step ( It is preferable to include step S143).
• step S141 the first structure optimization step
• step S142 the second structure optimization step
• step S143 the first transition state energy acquisition step
• the first structure optimization step (step S141) includes the candidate substance and the reaction component of the reaction component on the surface of the candidate substance included in the separation elementary reaction from one molecule to two molecules by the first structure optimization unit 141. Structural optimization is performed on the intermediate structure, and a first optimized structure is calculated. That is, in the first structure optimization step (step S141), the first structure optimization unit 141 performs a reaction with a candidate substance in a separation elementary reaction from one molecule to two molecules, with all the structures of the candidate substance fixed. A first optimized structure is calculated by performing structural optimization on an intermediate structure including the components.
• a second optimized structure is calculated by optimizing the structure when separated into two or more substances including a candidate substance for a reaction component and a reaction component.
• the step of acquiring the first transition state energy includes the first optimized structure obtained in the first structure optimization step (step S141) and the second structure obtained in the second structure optimization step (step S142).
• a first transition state energy which is a transition state energy, is calculated from the optimized structure.
• AB * is a molecule in a state adsorbed to a candidate substance
• AB * is a molecule in a transition state of AB * in the process of separating AB * into A * and B * .
• a * is an intermediate of the A molecule
• B * is an intermediate of the B molecule
• the reaction in which one molecule of AB * becomes two molecules of A * and B * is the above reaction.
• the first structure optimization step (step S141) is performed by the first structure optimization unit 141 to With the entire structure of the substance fixed, AB * is placed on the surface of the candidate substance, and the structure of an intermediate structure containing the candidate substance and AB * is optimized.
• step S142 the structure is optimized so that there are two molecules consisting of A * and B * .
• the first transition state energy acquisition unit 143 collects one molecule of AB * and two molecules of A * and B * using a NEB (Nudged Elastic Band). Using the method, the transition state energy required when one molecule of AB * becomes two molecules of A * and B * is calculated as the first transition state energy.
• NEB Noise Elastic Band
• the first plotting unit 15 calculates the first energy (the energy including the first intermediate energy and the first transition state energy), which is the descriptor calculated in the first calculation step (step S14). ) on the activity map (see FIG. 12) created in the map creation step (step S12) to create a first map with plots (first plot step: step S15).
• the first screening unit 16 screens candidate substances based on the first plotted map created in the first plotting step (step S15) to select primary screening candidate substances (first screening step: Step S16).
• the first screening unit 16 narrows down candidate substances plotted in a high activity region containing a catalyst with high activity (high NH 3 synthesis rate) as primary screening candidate substances.
• the primary screening candidate substances are narrowed down to, for example, 100 to 500 types.
• the number of primary screening candidate substances to be narrowed down can be selected as appropriate depending on the number of candidate substances and the number of secondary screening candidate substances. A hundred types is enough.
• FIG. 14 shows an example of the results of plotting descriptors of candidate substances.
• FIG. 14 shows, as descriptors, the adsorption energy (E N ) between the catalyst and the nitrogen intermediate (N * ), and the dissociation of the nitrogen transition state (N-N * ) in the catalyst.
• An activity map showing the relationship with activation energy (E N ⁇ N ) is shown. Further, in order to clearly show the plotted points, the display of the value obtained by converting the NH 3 synthesis rate (NH 3 yield) into a common logarithm (log 10 ) is omitted.
• the first screening unit 16 when the first screening unit 16 plots candidate substances on the activity map to narrow down the first screening candidate substances, the first screening unit 16 plots the candidate substances on the activity map to narrow down the first screening candidate substances.
• a data table listing only information regarding N may be used (see FIG. 8).
• the candidate substances in the data table listing only the candidate substances may be rearranged in the order of their inclusion in the high activity region, and the candidate substances included in the high activity area and having a threshold value or higher may be narrowed down as primary screening candidate substances.
• the first screening unit 16 may use the rearranged data table to plot candidate substances on the activity map by the first plotting unit 15 to narrow down the candidate substances for the first screening.
• the second calculation unit 17 calculates a catalytic reaction using the first screening candidate substance while the surface of the first screening candidate substance is relaxed.
• a descriptor is calculated (second calculation step: step S17).
• the second calculation unit 17 calculates the second energy of the primary screening candidate substance using the machine learning potential 30. preferable.
• the second calculation unit 17 performs the first calculation step (step S14) while the surface of the primary screening candidate substance is relaxed.
• the second calculation unit 17 determines that the adsorption position of the reaction component with respect to the first screening candidate substance is correct and that the first screening candidate substance It is preferable to extract the structure in which the second intermediate energy between the reaction component and the intermediate of the reaction component is the most stable. Thereby, the second intermediate energy of the reaction component is calculated with high accuracy.
• the second calculation unit 17 calculates the first structure optimization process (step S171), the second structure optimization process (step S172), and the second structure optimization process (step S172), as shown in FIG. It is preferable to include a step of obtaining two transition state energies (step S173). Thereby, the transition state energy of the transition state of the intermediate is calculated with high accuracy.
• the first structure optimization unit 171 performs a reaction with the primary screening candidate substance on the surface of the primary screening candidate substance included in the separation elementary reaction from one molecule to two molecules.
• a first optimized structure is calculated by performing structural optimization on an intermediate structure including the components. That is, in the first structure optimization step (step S171), the first structure optimization unit 171 performs the primary screening in a state where the surface of the primary screening candidate substance is relaxed in a separated elementary reaction in which one molecule becomes two molecules. The structure of an intermediate structure containing a screening candidate substance and a reaction component is optimized, and a first optimized structure is calculated.
• the second structure optimization unit 172 similarly to the second structure optimization unit 142, optimizes the separated structure when the reaction component is separated into two or more substances. is performed to calculate the second optimized structure.
• the second transition state energy acquisition section 173 like the first transition state energy acquisition section 143, performs the second transition state energy acquisition step (step S173).
• the second transition state energy which is the transition state energy, is calculated from the first optimized structure and the second optimized structure obtained in the second structure optimization step (step S172).
• AB * is a molecule in a state adsorbed to a candidate substance
• AB * is a molecule in a transition state of AB * in the process of separating AB * into A * and B * .
• a * is an intermediate of the A molecule
• B * is an intermediate of the B molecule
• the reaction in which one molecule of AB * becomes two molecules of A * and B * is the above reaction.
• the first structure optimization step (step S171) is performed by the first structure optimization unit 171.
• AB * is placed on the surface of the first screening candidate substance, similar to the first structure optimization step (step S141), and the first screening candidate substance and AB * are separated. Optimize the structure of the included intermediate structure.
• step S172 the separated structure is optimized so that there are two molecules consisting of A * and B * .
• the transition state energy acquisition step (step S173) is performed by the second transition state energy acquisition unit 173 in the same manner as the transition state energy acquisition step (step S143), and one molecule of AB * is A * and B * .
• the transition state energy required to form two molecules consisting of is calculated as the second transition state energy.
• the second plotting unit 18 plots the plot based on the second energy (the energy including the second intermediate energy and the second transition state energy), which is the descriptor calculated by the second calculation unit 17.
• the primary screening candidate substance is plotted on the activity map (see FIG. 12) created in the map creation step (step S12) to create a second plotted map (second plotting step: step S18).
• the second screening unit 19 screens the primary screening candidate substances based on the map with the second plot created in the second plotting step (step S18), and selects the secondary screening candidate substances (second Screening process: Step S19).
• the second screening unit 19 can select the primary screening candidate substance plotted in the high activity region containing the highly active catalyst in the second plotting step (step S18) as the secondary screening candidate substance.
• 30 to 100 secondary screening candidate substances are selected.
• Secondary screening candidate substances include, for example, IrSc, FePd 3 , MnTc 3 , IrY, CrPd 3 , MnPd 3 , RhY, Co 3 Pt, CrPt 3 , FeRh 3 , CrRh 3 , Ni 3 Ti, Ir 3 V, Pt. 3 Ti, Co 3 Rh, Pd 3 Ti, Ni 3 Zr, Co 3 W, NiPd 3 , FeNi 3 , Ir 3 Mn, IrMn, MnPt, MnNi 3 , Ir 3 Re, MnRh, Pd 3 V, MnPt 3 , Rh Examples include alloys such as 3 V and Rh 3 Ti.
• the 30 types of secondary screening candidate substances include IrSc, FePd 3 , MnTc 3 , IrY, CrPd 3 , MnPd 3 , RhY, Co 3 Pt, CrPt 3 , and FeRh. 3 , CrRh3 , Ni3Ti , Ir3V, Pt3Ti , Co3Rh , Pd3Ti , Ni3Zr, Co3W, NiPd3, FeNi3 , Ir3Mn, IrMn , MnPt, MnNi3 , An alloy of Ir 3 Re, MnRh, Pd 3 V, MnPt 3 , Rh 3 V and Rh 3 Ti is selected.
• Table 1 shows an example of a table displaying catalysts selected as 30 types of secondary screening candidate substances.
• 30 secondary screening candidate substances include IrSc, FePd 3 , MnTc 3 , IrY, CrPd 3 , MnPd 3 , RhY, Co 3 Pt, CrPt 3 , FeRh 3 , CrRh 3 , Ni 3 Ti, Ir3V , Pt3Ti , Co3Rh, Pd3Ti, Ni3Zr , Co3W , NiPd3 , FeNi3 , Ir3Mn , IrMn , MnPt, MnNi3 , Ir3Re , MnRh, Pd 3 V, MnPt 3 , Rh 3 V and Rh 3 Ti alloys are plotted.
• the number of secondary screening candidate substances to be selected can be appropriately selected depending on the number of primary screening candidate substances, etc., and may be, for example, several types or several tens of types.
• the narrowing down section 21 may narrow down the secondary screening candidate substances obtained in the second screening step (step S19) based on catalyst stability or catalyst cost (narrowing down step: step S20).
• the secondary screening candidate substances are narrowed down to, for example, 30 to 50 types.
• the number of secondary screening candidate substances to be narrowed down can be appropriately selected depending on the number of selected secondary screening candidate substances, and may be, for example, several types to several dozen types.
• the output section 22 outputs the secondary screening candidate substances selected by the second screening section 19 or the secondary screening candidate substances narrowed down by the narrowing down section 21 by display or the like (output step: step S21).
• an NH 3 synthesis catalyst with good NH 3 production efficiency can be selected.
• NH 3 synthesis catalysts with good NH 3 production efficiency selected by the catalyst selection method include IrSc, FePd 3 , MnTc 3 , IrY, CrPd 3 , MnPd 3 , RhY, Co 3 Pt, CrPt 3 , FeRh 3 , CrRh 3 , Ni 3 Ti, Ir 3 V, Pt 3 Ti, Co 3 Rh, Pd 3 Ti, Ni 3 Zr, Co 3 W, NiPd 3 , FeNi 3 , Ir 3 Mn, IrMn, MnPt, MnNi 3 , Ir Examples include alloys such as 3Re , MnRh, Pd3V , MnPt3 , Rh3V and Rh3Ti .
• the 30 types of NH 3 synthesis catalysts include IrSc, FePd 3 , MnTc 3 , IrY, CrPd 3 , MnPd.
• RhY , Co3Pt , CrPt3, FeRh3 , CrRh3 , Ni3Ti, Ir3V, Pt3Ti , Co3Rh , Pd3Ti , Ni3Zr , Co3W , NiPd3 , FeNi3 , Ir 3 Mn, IrMn, MnPt, MnNi 3 , Ir 3 Re, MnRh, Pd 3 V, MnPt 3 , Rh 3 V and Rh 3 Ti are selected.
• the catalyst selected by the catalyst selection method is an NH 3 synthesis catalyst with a high NH 3 synthesis rate and excellent NH 3 production efficiency is determined by, for example, the energy of the catalyst selected by the catalyst selection method. This can be determined by comparing the energy of the catalyst and the energy of the catalyst selected by quantum chemical calculations commonly used in the past, and verifying the discrepancy.
• FIG. 17 shows the correlation between the energy of the intermediate or transition state described above and the energy calculated by the catalyst selection method according to the present embodiment.
• DFT calculation is a conventional quantum chemical calculation method commonly used.
• the reference catalyst required when creating an activity map is, for example, an elemental metal such as Co, Rh, Ru, Cu, Fe, Re, or Pt.
• the machine learning potential 30 can reproduce substantially the same calculation results as those obtained by DFT calculation. Therefore, it can be said that by using the catalyst selection method, the energies of intermediates and transition states on various catalysts can be predicted with high accuracy.
• FIG. 18 also shows a catalyst activity map created using the catalyst selection method.
• the catalyst activity maps shown in FIGS. 18(a) and 18(b) were created using a calculation temperature of 400° C. and a pressure of 100 bar.
• the activity map of the catalyst selected using the catalyst selection method (see Figure 18(b)) is different from the activity map of the catalyst created using DFT calculation (see Figure 18(a)). They show almost the same tendency. Therefore, an activation map created using the energy calculated by the machine learning potential 30 can reproduce an activation map that is substantially the same as an activation map created using the energy calculated by DFT calculation.
• the above 30 types of alloys were selected as NH 3 synthesis catalysts with high NH 3 production efficiency using the catalyst selection method, as shown in the catalyst activity map created using the catalyst selection method, as shown in Figure 19. It can be determined that the NH 3 synthesis catalyst has a high NH 3 synthesis rate and is excellent in NH 3 production efficiency.
• the pure metals plotted in the activity map of FIG. 19 are commonly used catalysts, and the 30 types of alloys mentioned above have a higher NH 3 synthesis rate than the pure metals that are generally used as catalysts. It can be judged that high NH 3 production efficiency is exhibited. Note that the activity map in FIG. 19 was created with the temperature at the time of calculation being 400° C. and the pressure being 100 bar, similarly to FIG. 18.
• the catalyst selected by the catalyst selection method is an NH 3 synthesis catalyst with good NH 3 production efficiency.
• the catalyst selection method includes a first calculation step (step S14), a first plotting step (step S15), and a first plotting step (step S15) depending on the number of candidate substances prepared in the preparation step (step S13).
• the first screening step (step S16), the second calculation step (step S17), the second plotting step (step S18), and the second screening step (step S19) may be omitted. That is, in the catalyst selection method, the candidate substances may be narrowed down by omitting calculations with all candidate substances fixed or calculations with the surface of the candidate substances relaxed.
• the catalyst selection method calculates the first energies of the plurality of candidate substances prepared in the preparation step (step S13) in the first calculation step (step S14), and in the first screening step (step S16), Primary screening candidate substances are narrowed down from the candidate substances plotted on the first plotted map created in the first plotting step (step S15). Then, the catalyst selection method is to calculate the second energy of the primary screening candidate substance selected in the second calculation step (step S17), and then perform the secondary plotting step (step S18) in the second screening step (step S16). A secondary screening candidate substance is selected from among the primary screening candidate substances plotted on the second plotted map created in .
• the catalyst selection method in the first step, in the catalyst selection method, with all candidate substances fixed, descriptors regarding catalytic reactions using candidate substances are calculated in a short time with low accuracy, and an activity map is created.
• the primary screening candidate substances are narrowed down from the plotted candidate substances.
• descriptors regarding the catalytic reaction using the narrowed down primary screening candidate substances are recalculated with high accuracy while the surface of the primary screening candidate substances is relaxed.
• the primary screening candidate substances are further narrowed down based on the calculated more accurate descriptor of the primary screening candidate substance, and the secondary screening candidate substances are selected.
• the catalyst selection method can quickly and accurately select an effective catalyst from candidate substances, so it is suitable for the catalytic reaction that synthesizes the target product (NH 3 ) from the raw materials (H 2 and N 2 ).
• NH 3 synthesis catalyst can be efficiently selected.
• the method for producing the NH 3 synthesis catalyst according to the present embodiment is not particularly limited, and can be appropriately selected depending on the types of components contained in the NH 3 synthesis catalyst.
• An example of a method for producing an NH 3 synthesis catalyst is shown in FIG. 20.
• the method for producing an NH 3 synthesis catalyst may include a selection step of selecting a catalyst (step S31) and a preparation step of preparing the catalyst (step S32).
• step S31 a catalyst is selected using the catalyst selection method described above.
• the preparation step (step S32) prepares the catalyst selected in the selection step (step S31).
• the method for preparing the catalyst is not particularly limited, and a general method for preparing the catalyst may be used depending on the type of catalyst selected.
• the selected catalysts are based on, for example, the inorganic materials database "AtomWork” and the substances/materials database “AtomWork-Adv” provided by the National Institute for Materials Science (NIMS). You can make adjustments by searching and referring to documents disclosed in publicly available databases such as ⁇ .
• the method for producing an NH 3 synthesis catalyst allows the catalyst selected by the above catalyst selection method to be adjusted, it is possible to appropriately produce an NH 3 synthesis catalyst that can efficiently synthesize NH 3 .
• NH 3 is synthesized by bringing a gas containing hydrogen and nitrogen into contact with the NH 3 synthesis catalyst according to the present embodiment described above.
• the method for synthesizing NH 3 according to this embodiment is not particularly limited except that the NH 3 synthesis catalyst according to this embodiment described above is used as a catalyst, and for example, a general method for synthesizing NH 3 using a catalyst. may be used.
• the reaction of synthesizing ammonia from hydrogen and nitrogen theoretically, 2 mol of ammonia can be obtained by reacting 1 mol of nitrogen with 3 mol of hydrogen (N 2 +3H 2 ⁇ 2NH 3 ). Therefore, it is preferable to use a gas containing hydrogen and nitrogen in which the molar ratio of hydrogen to nitrogen (H 2 /N 2 ) is 0.5/1 to 3/1.
• the gas containing hydrogen and nitrogen may further contain an inert gas such as argon as a carrier gas in addition to hydrogen gas and nitrogen gas, but from the viewpoint of increasing the amount of NH 3 produced, Preferably, it consists of only hydrogen gas and nitrogen gas.
• the method of bringing a gas containing hydrogen and nitrogen into contact with the NH 3 synthesis catalyst according to the present embodiment is not particularly limited, and any general method capable of bringing a gas into contact with the catalyst can be adopted as appropriate.
• a method of bringing such a NH 3 synthesis catalyst into contact with a gas containing hydrogen and nitrogen for example, after filling a sealable reaction vessel with an NH 3 synthesis catalyst, the atmospheric gas in the reaction vessel is brought into contact with hydrogen.
• a method in which a gas containing hydrogen and nitrogen is brought into contact with the NH 3 synthesis catalyst by circulating a gas containing hydrogen can be used as appropriate.
• the reaction temperature should be 300°C to 500°C because the higher the temperature, the lower the equilibrium concentration. It can be set to °C.
• the pressure conditions for carrying out such a reaction are not particularly limited, and may be set to 0.1 MPa to 10 MPa in order to further reduce the energy required for the synthesis of NH 3 .
• NH 3 can be synthesized more efficiently.
• the NH 3 synthesis rate was determined by preparing a catalyst and performing calculations corresponding to the catalytic reaction when NH 3 was synthesized from nitrogen and hydrogen by the reaction of the catalyst.
• the NH 3 synthesis rate is actually calculated by preparing a catalyst and measuring the amount of NH 3 synthesized from nitrogen and hydrogen through the catalytic reaction of the adjusted catalyst. be done.
• MATLANTIS registered trademark
• NNP neural network potential
• the candidate catalyst and reference catalyst used as catalysts, and the temperature and pressure at the time of calculation are as follows.
• Reference catalyst Ru, Re, Pt ⁇ Temperature: 523K ⁇ Pressure: 0.8 bar
• the catalyst is an alloy composed of a plurality of elements
• the catalyst must be alloyed with each metal without agglomeration and separation at a desired composition. Whether or not alloying occurs when a plurality of elements are mixed can be evaluated based on the stability of the catalyst structure. Therefore, it can be said that the preparation of the catalyst in the experiment roughly corresponds to the structural stability of the catalyst (alloy). Therefore, the structural stability of the catalyst was calculated using a cluster model, which corresponds to the preparation of the catalyst.
• a cluster structure consisting of two types of elements (elements 1 and 2) and 55 atoms was prepared, and a genetic algorithm was used to search for the position of the most stable element in each alloy composition.
• Each cluster structure underwent structural optimization every time a new structure was generated.
• the stability of the cluster structure consisting of elements 1 and 2 was evaluated using excess energy E exc .
• Excess energy E exc was determined from the following formula (11). The excess energy E exc indicates how stable the alloy cluster structure is compared to when elements 1 and 2 are not mixed.
• E exc (E cluster -n Metal1 ⁇ E Metal1 -n Metal2 ⁇ E Metal2 )/55 (11)
• E cluster is the energy of the alloy cluster
• n Metal1 is the number of atoms of element 1 in the cluster
• E Metal1 is the energy of the cluster structure when composed of 1 single atom
• n Metal2 is the energy of element 2 in the cluster.
• the number of atoms, E Metal2 represents the energy of the cluster structure when it is composed of 2 single atoms.
• the catalyst is a CrRh alloy, as shown in FIG. 21, when the composition ratio of Cr and Rh is 1:3, that is, the number of Cr elements is 13 and the number of Rh elements is 42, The excess energy E exc of the stable structure was a negative value, confirming that the CrRh alloy was stabilized (alloyed). At this time, the diameter of the CrRh alloy was about 1.09 nm.
• the catalyst is an IrMn alloy, as shown in FIG. 22, when the composition ratio of Ir and Mn is 1:1, that is, the number of Ir elements is 27 and the number of Mn elements is 28, the maximum The excess energy E exc of the stable structure was a negative value, and it was confirmed that the IrMn alloy was stabilized (alloyed). At this time, the diameter of the IrMn alloy was about 1.03 nm.
• the catalytic reactions approximately correspond to the results of reaction rate simulations (Microkinetics) obtained from all elementary reactions for the catalytic NH 3 synthesis. Therefore, in order to obtain results corresponding to the catalytic reaction, Microkinetics was performed and the NH 3 synthesis rate of the catalyst was calculated. Microkinetics consists of enumerating elementary reactions, calculating the energy of elementary reactions, and calculating reaction rates.
• E reference E slab+ads -E slab -(xE N +yE H )...(12)
• E slab + ads is the energy of the structure where molecules are adsorbed on the surface
• E slab is the energy of the slab structure
• E N is the energy of the element based on gaseous N 2
• E H is the energy of the element based on gaseous H 2 .
• energy of the element x is the number of N in the adsorbed molecule
• y is the number of H in the adsorbed molecule.
• Table 2 shows the calculation results of the NH3 synthesis rate synthesized by the candidate catalyst and the reference catalyst.
• the relationship between the adsorption energy ( EN ) between the catalyst and the nitrogen intermediate (N * ) of the candidate catalyst and the reference catalyst and the calculation results of the NH3 synthesis rate synthesized by the candidate catalyst and the reference catalyst is shown in the figure. 23.
• FIG. 24 shows experimental results of the adsorption energy (E N ) between the catalyst and the nitrogen intermediate (N * ) and the synthesis rate of NH 3 for the reference catalyst. Note that Figure 24 is based on Andrew J. Medford et al.
• the NH 3 synthesis rate was higher in the order of Ru, Re, and Pt, and the NH 3 synthesis rate when using the reference catalyst was calculated based on the experimental results. The results showed an equivalent relationship.
• the NH 3 synthesis rate is highest for Pd 3 V among Pd 3 V, CrRh 3 , Co 3 Rh, IrMn, and IrSc ; , Co 3 Rh, IrMn, and IrSc. Therefore , when candidate catalysts are actually used, the NH 3 synthesis rate is the highest for Pd 3 V , CrRh 3 , Co 3 Rh, IrMn, and IrSc ; , IrMn, and IrSc.
• Catalyst FePd 3 , MnTc 3 , IrY, CrPd 3 , MnPd 3 , RhY, Co 3 Pt, CrPt 3 , FeRh 3 , Ni 3 Ti, Ir 3 V, Pt 3 Ti, Pd 3 Ti, Ni 3 Zr, Co 3 W, NiPd 3 , FeNi 3 , Ir 3 Mn, MnPt, MnNi 3 , Ir 3 Re, MnRh, MnPt 3 , Rh 3 V and Rh 3 Ti).
• the above 25 types of catalysts are compared to the above 5 types of catalysts (Pd 3 V, CrRh 3 , Co 3 ) calculated as candidate catalysts. Rh, IrMn, IrSc), this catalyst is selected by the catalyst selection method described above. Therefore, it can be said that the above 25 types of catalysts also increase the NH 3 synthesis rate similarly to the above 5 types of catalysts.
• Catalyst Selection System 10 Catalyst Selection Device 11 Descriptor Selection Unit 12 Map Creation Unit 13 Preparation Unit 14 First Calculation Unit 15 First Plot Unit 16 First Screening Unit 17 Second Calculation Unit 18 Second Plot Unit 19 Second Screening unit 21 Narrowing unit 22 Output unit 20 Storage unit 30 Machine learning potential 141, 171 First structure optimization unit 142, 172 Second structure optimization unit 143 First transition state energy acquisition unit 173 Second transition state energy acquisition Department

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