A design method of a chromium-doped ruthenium dioxide catalyst and a ruthenium dioxide catalyst

Abstract

The present application belongs to the technical field of electrolytic water electrocatalysis, and relates to a design method of a chromium-doped ruthenium dioxide catalyst and a ruthenium dioxide catalyst. Chromium is used as a doping element to dope a seven-layer RuO2 supercell to obtain surface chromium doping configurations with different spatial arrangement forms under each doping concentration. The ground state surface chromium doping configuration under each doping concentration is selected, the OER free energy path of the seven-layer RuO2 supercell and the ground state surface chromium doping configuration is calculated, and the activity improvement difference of the ground state surface chromium doping configuration is obtained. The spin density distribution of the OER reaction intermediate adsorption structure of the seven-layer RuO2 supercell and the ground state surface chromium doping configuration is obtained, and the site magnetic moment increment and the intermediate magnetic moment increment of the ground state surface chromium doping configuration are obtained. Based on the activity improvement difference, the site magnetic moment increment and the intermediate magnetic moment increment, the doping concentration value range and the spatial arrangement form when the oxygen evolution reaction activity of the ruthenium dioxide is increased are obtained, so as to design the chromium-doped ruthenium dioxide catalyst.

Description

Technical Field

[0001] This invention relates to the field of electrocatalysis technology for water electrolysis, and in particular to a design method for a chromium-doped ruthenium dioxide catalyst and the ruthenium dioxide catalyst itself. Background Technology

[0002] Hydrogen production via water electrolysis is a crucial technological route for achieving renewable energy conversion and green hydrogen energy identification. However, the oxygen evolution reaction (OER) at the anolyte involves multiple proton-electron transfer and O-O bond formation processes, exhibiting slow kinetics and being a key step limiting the overall efficiency of water electrolysis. Therefore, developing highly active and stable OER electrocatalysts suitable for acidic media is a significant research direction in the field of energy catalysis.

[0003] Ruthenium dioxide (RuO2) is considered one of the most representative noble metal oxide catalysts under acidic OER conditions due to its high intrinsic OER activity. However, RuO2-based catalysts still face challenges such as the difficulty in precisely controlling the adsorption intensity of key oxygen-containing intermediates and insufficient structural stability under high potentials. Existing research has primarily focused on adjusting the coordination environment, electronic structure, and interfacial charge distribution of RuO2 through heteroatom doping, defect engineering, and heterointerface engineering, thereby optimizing the adsorption free energy of oxygen-containing intermediates and the OER reaction pathway. However, the mechanistic explanations of these strategies concentrate on traditional charge and orbital manipulation, neglecting the crucial role of spin degree-of-freedom manipulation as a potential regulatory dimension in constructing high-performance OER electrocatalysts. By rationally controlling the spin arrangement and spin coupling of the active metal centers, it is possible to optimize the adsorption energy of reaction intermediates, lower the rate-determining barrier of the oxygen evolution reaction to enhance catalytic activity, and simultaneously adjust the redox properties of metal sites, strengthen metal-oxygen lattice bonding, inhibit excessive dissolution of active metals under acidic conditions, and improve the long-term operational stability of the catalyst.

[0004] Since the final product of OER, O2, is a triplet molecule, while the reactant OH... -The / H2O state is singlet. This change in spin multiplicity implies that spin coupling between the catalyst and the oxygen-containing intermediate may play a crucial role in electron transfer and O2 / O2 bond formation. This understanding has driven the gradual inclusion of spin factors in RuO2-based OER catalysis research. Existing theories have revealed that the surface magnetism of RuO2 affects the generation of ground-state O2. Therefore, some schemes induce Mn-Ru ferromagnetic coupling through Mn doping and further enhance the acidic OER activity with the aid of an external magnetic field. However, the separation of spin contribution and electronic effect is not clear. In addition, some schemes utilize ferromagnetic interactions to break the spin symmetry of Ru sites to improve the acidic water oxidation performance; however, the activity enhancement also depends on changes in the overall magnetic order. In summary, existing spin modulation strategies mainly involve two methods: inducing ferromagnetic coupling to reconstruct the overall magnetic order or applying an external magnetic field. The former makes it difficult to separate the contribution of charge rearrangement from the activity enhancement, while the latter introduces an external field dependence not inherent in the catalyst itself. Neither method can rely solely on the intrinsic spin modulation of the catalyst's own magnetic structure.

[0005] In summary, existing methods for improving the oxygen evolution reaction activity of RuO2 through spin modulation suffer from mixed modulation mechanisms, making it difficult to achieve high catalytic activity and long-term structural stability of RuO2 catalysts by utilizing local spin degree of freedom modulation without relying on external magnetic fields or reconstructing the overall magnetic order. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the existing catalyst design methods for improving the reactivity of RuO2 through spin regulation have mixed regulation mechanisms, making it difficult to achieve both high catalytic activity and long-term structural stability of RuO2 catalysts without relying on external magnetic fields or interfering with electron charge effects.

[0007] To address the aforementioned technical problems, this invention provides a method for designing a chromium-doped ruthenium dioxide catalyst, comprising: A seven-layer RuO2 supercell was obtained. Chromium was used as the doping element to dop the seven-layer RuO2 supercell with different doping concentrations and different doping sites to obtain surface chromium doping configurations with different spatial arrangements under each doping concentration. Calculate the total energy of the ferromagnetic and antiferromagnetic states of the surface chromium doped configuration with different spatial arrangements for each doping concentration, and take the surface chromium doped configuration with the lowest total energy of the ferromagnetic and antiferromagnetic states as the ground state surface chromium doped configuration at that doping concentration. The OER free energy paths of the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration were calculated using a computational hydrogen electrode model, thereby obtaining the activity improvement difference of the ground-state surface chromium-doped configuration at different doping concentrations. The spin density distribution of the adsorption structure of OER reaction intermediates in the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration was obtained, thereby obtaining the site magnetic moment increment and intermediate magnetic moment increment of the ground-state surface chromium-doped configuration at different doping concentrations. Based on the activity improvement difference, site magnetic moment increment, and intermediate magnetic moment increment of the ground-state surface chromium doping configuration under different doping concentrations, the range of doping concentration values ​​and spatial arrangement of ruthenium dioxide oxygen evolution reaction activity are obtained, thereby designing chromium-doped ruthenium dioxide catalysts.

[0008] Preferably, a seven-layer RuO2 supercell is obtained, and the RuO2 supercell is doped with chromium as the doping element based on different doping concentrations and different doping sites to obtain surface chromium-doped configurations with different spatial arrangements for each doping concentration, including: Multiple first doping concentrations were obtained by replacing only one surface Ru atom site of a seven-layer RuO2 supercell with chromium atoms, and multiple second doping concentrations were obtained by replacing two surface Ru atom sites of a seven-layer RuO2 supercell with chromium atoms. Based on each first doping concentration, chromium atoms are replaced and doped at one surface Ru atom site of the seven-layer RuO2 supercell. By traversing the dopable Ru atom sites on the surface, surface chromium doping configurations with different spatial arrangements under each first doping concentration are obtained. Based on various second doping concentrations, chromium atoms were replaced and doped at two surface Ru atom sites in a seven-layer RuO2 supercell. The relative spatial positions of the two surface chromium atom sites were adjusted after the replacement doping to obtain surface chromium doping configurations with different spatial arrangements under each second doping concentration.

[0009] Preferably, the total energy of the ferromagnetic and antiferromagnetic states of the surface chromium doped configuration with different spatial arrangements at each doping concentration is calculated, and the surface chromium doped configuration with the lowest total energy of the ferromagnetic and antiferromagnetic states is taken as the ground state surface chromium doped configuration at that doping concentration, including: Structural relaxation was performed on each surface chromium-doped configuration at each doping concentration to obtain the initial configuration of the surface chromium-doped configuration; Static self-consistent calculations were performed on the initial configuration of the chromium-doped surface to obtain the total energy of the ferromagnetic and antiferromagnetic states of the chromium-doped surface.

[0010] Preferably, the OER free energy paths of the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration are calculated using a computational hydrogen electrode model, thereby obtaining the activity enhancement difference of the ground-state surface chromium-doped configuration at different doping concentrations, including: Four surface adsorption configurations were constructed for each of the seven-layer RuO2 supercells and ground-state chromium-doped configurations at each doping concentration. DFT calculations were performed on each surface adsorption configuration to obtain the total ground-state electron energy for each surface adsorption configuration. Using a computational hydrogen electrode model based on the total ground-state electron energy for each surface adsorption configuration, the four-step reaction Gibbs free energy change of the seven-layer RuO2 supercell and the ground-state chromium-doped surface configuration at each doping concentration was calculated. For a seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration, the theoretical overpotential is calculated based on the maximum value in the Gibbs free energy change of the four-step reaction. Based on the difference between the theoretical overpotential of the ground-state surface chromium-doped configuration at each doping concentration and the theoretical overpotential of the seven-layer RuO2 supercell, the activity enhancement difference of the ground-state surface chromium-doped configuration at each doping concentration is obtained.

[0011] Preferably, the spin density distribution of the OER reaction intermediate adsorption structure of the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration is obtained, thereby obtaining the site magnetic moment increment and intermediate magnetic moment increment of the ground-state surface chromium-doped configuration at different doping concentrations, including: Four surface adsorption configurations were constructed for each of the seven-layer RuO2 supercells and the ground-state surface chromium-doped configurations at each doping concentration. Self-consistent DFT calculations were performed on each surface adsorption configuration after enabling spin polarization to obtain the electronic structure output file for each surface adsorption configuration. Based on the electronic structure output file of each surface adsorption configuration, the three-dimensional spin density distribution of each surface adsorption configuration is extracted, thereby obtaining the spin density spatial distribution of the seven-layer RuO2 supercell and the ground state surface chromium doped configuration under different OER intermediates for each doping concentration. For each surface adsorption configuration, atomic projection magnetic moment decomposition is performed to extract the local magnetic moments of the atoms at the key active sites on the catalytic surface and the total magnetic moment of the adsorption intermediates for each surface adsorption configuration. For each doping concentration, the local magnetic moment increment of the site magnetic moment of the ground-state chromium-doped surface configuration and the same surface adsorption configuration of the seven-layer RuO2 supercell is obtained based on the difference between the atomic local magnetic moment of the key active site of the catalytic surface of the surface adsorption configuration of the ground-state chromium-doped surface configuration and the atomic local magnetic moment of the key active site of the catalytic surface of the surface adsorption configuration of the seven-layer RuO2 supercell. For the ground-state surface chromium-doped configuration and the same surface adsorption configuration of the seven-layer RuO2 supercell at each doping concentration, the difference between the total magnetic moment of the adsorption intermediate of the surface adsorption configuration of the ground-state surface chromium-doped configuration and the total magnetic moment of the adsorption intermediate of the surface adsorption configuration of the seven-layer RuO2 supercell is used to obtain the increment of the intermediate magnetic moment of the ground-state surface chromium-doped configuration at that doping concentration.

[0012] Preferably, it further includes: The spin orientation of chromium atom sites in the ground-state surface chromium doping configuration at each doping concentration is flipped to obtain the spin-flipped configuration of the ground-state surface chromium doping configuration at each doping concentration. By comparing the total energy, theoretical overpotential, four-step reaction Gibbs free energy change, site magnetic moment increment, and intermediate magnetic moment increment of the ground-state surface chromium doping configuration and its spin-flip configuration at each doping concentration, the activity contribution of the ground-state surface chromium doping configuration to the OER reaction at each doping concentration can be obtained.

[0013] Preferably, it further includes: For each ground-state chromium-doped configuration of the surface at each doping concentration, multiple surface model terminal structures with different O / OH coverage were constructed, and the relative free energy of each surface model terminal structure at different potentials was calculated using a potential-dependent free energy calculation method. Based on the working potential range of acidic OER, the surface model terminal structure with the lowest relative free energy at each working potential is obtained, and used as the target surface model terminal structure at each working potential. Using the target surface model terminal structure at various working potentials as the reaction substrate, the OER four-step proton-electron transfer reaction model is validated.

[0014] Preferably, the doping concentrations corresponding to the increased oxygen evolution reaction activity of ruthenium dioxide are 8.33% and 16.67%.

[0015] Preferably, the range of doping concentrations and spatial arrangement corresponding to the increase in the oxygen evolution reaction activity of ruthenium dioxide are obtained, thereby designing a chromium-doped ruthenium dioxide catalyst, including: Select a target doping concentration from the range of doping concentration values, and use chromium atoms to dope one or two surface Ru atom sites of the seven-layer RuO2 supercell based on the spatial arrangement of the target doping concentration, thereby preparing a chromium-doped ruthenium dioxide catalyst.

[0016] The present invention also provides a ruthenium dioxide catalyst, which is designed by the above-described design method for chromium-doped ruthenium dioxide catalysts.

[0017] The design method for chromium-doped ruthenium dioxide catalysts provided in this application has the following advantages: 1. By doping a seven-layer RuO2 supercell with chromium as the doping element at different doping concentrations and doping sites, surface chromium-doped configurations with different spatial arrangements at each doping concentration were obtained. The surface chromium-doped configuration with the lowest total energy of the ferromagnetic and antiferromagnetic states at each doping concentration was selected as the ground-state surface chromium-doped configuration for that doping concentration. Then, by comparing the OER free energy path and the spin density distribution of the adsorption structure of the OER reaction intermediates of the seven-layer RuO2 supercell and the ground-state surface chromium-doped configurations at each doping concentration, the activity enhancement difference of the ground-state surface chromium-doped configurations at different doping concentrations was obtained. By analyzing the values ​​of magnetic moment increments at sites and intermediates, the range of doping concentrations and spatial arrangement corresponding to increased ruthenium dioxide oxygen evolution reaction activity can be determined. Based on this range of doping concentrations, a seven-layer RuO2 supercell is doped to obtain a chromium-doped ruthenium dioxide catalyst. This application proposes and verifies a novel regulatory pathway based on a chromium-doped seven-layer RuO2 supercell (with chromium atoms replacing ruthenium atoms). By controlling the adsorption free energy of oxygen-containing intermediates through chromium doping, high catalytic activity and long-term structural stability of the RuO2 catalyst are achieved without relying on an external magnetic field or interfering with electron charge effects. 2. This application also combines activity screening with working potential surface stability by flipping the spin of Cr in the ground-state chromium-doped configuration, thereby determining the true active center, the role of spin configuration in key OER reaction steps, and the stable surface state at the working potential. Attached Figure Description

[0018] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein: Figure 1 A flowchart illustrating the design method for the chromium-doped ruthenium dioxide catalyst provided in this application; Figure 2 This application provides a schematic diagram of a seven-layer RuO2 supercell and its surface chromium-doped configuration; wherein, Figure 2 (a) in the diagram is a schematic diagram of a seven-layer RuO2 supercell. Figure 2 (b) in the diagram is a schematic diagram of the surface chromium doping configuration with a doping concentration of 8.33%. Figure 2 (c) in the diagram is a schematic diagram of the surface chromium doping configuration with a doping concentration of 16.67%; Figure 3 The distorted octahedral coordination environment of the chromium atom sites provided in this application 2g A schematic diagram of the partial wave density of states for orbital occupancy and the 3d suborbitals of chromium atom sites; where, Figure 3 (a) represents the t under the distorted octahedral coordination environment of the chromium atom sites. 2g Track occupancy diagram, Figure 3(b) in the diagram is a schematic diagram of the partial wave density of states of the 3d suborbital of the chromium atom site; Figure 4 The diagram shows the OER free energy steps of the seven-layer RuO2 supercell and surface chromium-doped configuration provided in this application, as well as the adsorption configuration of key OER reaction intermediates; wherein... Figure 4 (a) shows schematic diagrams of the OER free energy steps at different active sites in seven-layer RuO2 supercells with surface chromium doping concentrations of 8.33% and 16.67%. Figure 4 (b) is a schematic diagram of the adsorption configuration of the OER key reaction intermediate when the chromium atom sites in the surface chromium doping configuration with a doping concentration of 16.67% serve as active centers. Figure 5 This application provides a schematic diagram of the spin density distribution and partial wave density of states; wherein, Figure 5 (a) in the diagram is a schematic diagram of the spin density distribution of a seven-layer RuO2 supercell on a clean surface. Figure 5 (b) represents the seven-layer RuO2 supercell in Schematic diagram of spin density distribution in the O adsorption state. Figure 5 (c) represents the seven-layer RuO2 supercell in Schematic diagram of spin density distribution in the OOH adsorbed state. Figure 5 (d) in the diagram represents the partial density of states of the d orbitals of active Ru and the Op orbitals of adsorbed oxygen at the Ru sites in the seven-layer RuO2 supercell. Figure 5 (e) in the diagram is a schematic diagram of the spin density distribution of a surface chromium-doped configuration with a doping concentration of 16.67% on a clean surface. Figure 5 In the diagram, (f) represents the surface chromium doping configuration with a doping concentration of 16.67%. Schematic diagram of spin density distribution in the O adsorption state. Figure 5 In the diagram, (g) represents a surface chromium doping configuration with a doping concentration of 16.67%. Schematic diagram of spin density distribution in the OOH adsorbed state. Figure 5 (h) is a schematic diagram of the partial density of states of d orbitals and adsorbed oxygen Op orbitals of chromium atom sites in a surface chromium doping configuration with a doping concentration of 16.67%. Figure 6 The adsorption free energies of OH, O and OOH at Ru sites and chromium atom sites in the seven-layer RuO2 supercell, the surface chromium doped configuration with a doping concentration of 8.33%, and the surface chromium doped configuration with a doping concentration of 16.67% are provided in this application. Figure 7 A schematic diagram showing the relationship between the free energy of the surface coverage of the 16.67% chromium-doped surface configuration provided in this application and the electric potential. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0020] It should be noted that the first-principles calculations in this application are based on density functional theory (DFT) and performed using the Vienna Ab initio Simulation software package (VASP). The ion potential is processed using the projected fused wave (PAW) method and the generalized gradient approximation (GGA) in the form of the exchange-correlation functional Perdew-Burke-Ernzerhof (PBE). It should be noted that the GGA+U calculation parameters are used in all subsequent first-principles calculation steps involving electronic structure solving, specifically including: the calculation of the structural relaxation, ferromagnetic state, and total energy of the antiferromagnetic state in S20 with different Cr doping configurations; and the calculation of the pure ion potential in S30. The calculations include: surface and adsorption configuration structure optimization, ground-state electron total energy and OER free energy calculation; spin density, atomic projected local magnetic moment and partial wave density of states calculation in S40; structure optimization, total energy and adsorption free energy calculation for Cr site spin-flip configuration in S60; and structure optimization and potential-dependent surface free energy calculation for different O / OH covered terminals in S70. Among these, S10 is the structure model construction step, and S50 is the calculation result screening step, without performing a separate new DFT calculation; the surface wave cutoff energy is set to 450 eV, the Brillouin zone integration adopts the Monkhorst-Pack method, and the k-point grid is set to 3 × 2 × 1. Meanwhile, in order to more reasonably describe the local electronic correlation effect of Ru 4d and chromium (Cr) 3d orbitals, this application adopts the GGA+U method to introduce coulomb mutual correction for first-principles calculations. Referring to the existing DFT+U studies of RuO2 and Cr containing transition metal oxide systems, the effective coulomb parameters of Ru and Cr atoms are set to 2.0 eV and 2.1 eV, respectively. All subsequent structural optimizations, adsorption free energies and electronic structure analyses use the same effective coulomb parameters to ensure the consistency of relative comparisons between different systems.

[0021] Please see Figure 1 , Figure 1 The diagram shows a flowchart of the design method for chromium-doped ruthenium dioxide catalyst provided in this application, which includes steps S10 to S50.

[0022] S10: Obtain a seven-layer RuO2 supercell. Using chromium as the doping element, the seven-layer RuO2 supercell is doped with different doping concentrations and different doping sites to obtain surface chromium doped configurations with different spatial arrangements under each doping concentration.

[0023] Furthermore, in some embodiments of this application, S10 includes: S100~S102.

[0024] S100: Obtain multiple first doping concentrations by replacing only one surface Ru atom site of a seven-layer RuO2 supercell with chromium atoms, and multiple second doping concentrations by replacing two surface Ru atom sites of a seven-layer RuO2 supercell with Cr atoms.

[0025] S101: Based on each first doping concentration, chromium atoms are replaced and doped at one surface Ru atom site of the seven-layer RuO2 supercell. The dopable Ru atom sites on the surface are traversed to obtain surface chromium doped configurations with different spatial arrangements for each first doping concentration.

[0026] S102: Based on various second doping concentrations, chromium atoms are replaced and doped at two surface Ru atom sites in a seven-layer RuO2 supercell. The relative spatial positions of the two surface chromium atom sites are adjusted after the replacement doping to obtain surface chromium doping configurations with different spatial arrangements under each second doping concentration.

[0027] like Figure 2 As shown in (a) of this application, in one example, the seven-layer RuO2 supercell (110) is constructed using a 3 × 2 seven-layer surface model. The vacuum layer thickness is set to 15 Å to avoid correlation between periods. In addition, to simulate bulk constraint, the bottom four layers of atoms are fixed during the calculation, allowing only the top three layers of atoms and surface adsorbates to fully relax. Here, RuO2 indicates that the material used in the model is ruthenium dioxide; "(110)" is the Miller index of the crystal plane, indicating that the crystal plane with the Miller index (110) in the rutile structure RuO2 is selected as the exposed surface of the model. Therefore, RuO2(110) indicates that the (110) crystal plane of RuO2 is used as the catalytic reaction surface.

[0028] When Cr is used as a dopant element to dope a seven-layer RuO2 supercell, Cr atoms replace the Ru sites on the surface of the seven-layer RuO2 supercell. In the example of this application, doping concentrations of 8.33% and 16.67% are selected. At a doping concentration of 8.33%, one surface Ru atom in the seven-layer RuO2 supercell is replaced by one Cr atom; at a doping concentration of 16.67%, two surface Ru atoms on the same surface in the seven-layer RuO2 supercell are replaced by two Cr atoms. These two Cr atoms can have different relative spatial positions and magnetic moment arrangements. Specifically, Ru atoms can be systematically replaced with Cr atoms in the corresponding POSCAR file to generate doped configurations with different spatial arrangements at different doping concentrations, such as... Figure 2 (b) in the diagram is a schematic diagram of the surface chromium doping configuration with a doping concentration of 8.33%. Figure 2(c) is a schematic diagram of the surface chromium doping configuration with a doping concentration of 16.67%.

[0029] Specifically, this application considers different doping concentrations and doping sites, systematically examines the stability differences of Cr atoms under different local environments, and eliminates modeling randomness by comparing the lowest energy configurations of different doping sites, thereby more reliably determining the ground state electrode structure of the system.

[0030] S20: Calculate the total energy of the ferromagnetic and antiferromagnetic states of the surface chromium doped configuration with different spatial arrangements for each doping concentration, and take the surface chromium doped configuration with the lowest total energy of the ferromagnetic and antiferromagnetic states as the ground state surface chromium doped configuration at that doping concentration.

[0031] Furthermore, in some embodiments of this application, S20 includes: S200~S201.

[0032] S200: Structural relaxation is performed on each surface chromium-doped configuration at each doping concentration to obtain the initial configuration of the surface chromium-doped configuration, specifically including: S200-1 to S200-3.

[0033] S200-1: Input the crystal structure file, parameter control file, k-point mesh file, pseudopotential file, and runtime control file for each surface chromium doping configuration at each doping concentration into the magnetic state calculation directory.

[0034] S200-2: Set the maximum number of ion step iterations in the parameter control file to 30 and then start the VASP relaxation calculation.

[0035] S200-3: Relaxation ends when the ion step iteration reaches the point where the maximum atomic force is <0.02eV / Å, generating the initial configuration file for the chromium-doped surface.

[0036] S201: Perform static self-consistent calculations on the initial configuration of the chromium-doped surface to obtain the total energy of the ferromagnetic and antiferromagnetic states of the chromium-doped surface, specifically including: S201-1~S201-2.

[0037] S201-1: Use the initial configuration file of the surface chromium-doped configuration as the crystal structure file of the surface chromium-doped configuration, set the maximum number of ion steps in the parameter control file to 0, and then start the self-consistent calculation.

[0038] S201-2: Based on the 1F energy value in the output file after the self-consistent calculation, the total energy of the ferromagnetic and antiferromagnetic states of the chromium-doped surface configuration is obtained.

[0039] S30: Using a computational hydrogen electrode model, calculate the OER free energy path of the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration, thereby obtaining the activity improvement difference of the ground-state surface chromium-doped configuration at different doping concentrations.

[0040] Furthermore, in some embodiments of this application, S30 includes: S300~S303.

[0041] S300: Construct four surface adsorption configurations for each of the seven-layer RuO2 supercells and the ground-state chromium-doped surface configurations at each doping concentration, and perform DFT calculations on each surface adsorption configuration to obtain the total ground-state electron energy of each surface adsorption configuration.

[0042] S301: Using the calculated hydrogen electrode model based on the total ground-state electron energy of each surface adsorption configuration, calculate the four-step reaction Gibbs free energy change of the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration.

[0043] S302: For a seven-layer RuO2 supercell and a ground-state surface chromium-doped configuration at each doping concentration, calculate the theoretical overpotential based on the maximum value of the Gibbs free energy change in the four-step reaction.

[0044] S303: Based on the difference between the theoretical overpotential of the ground-state surface chromium-doped configuration at each doping concentration and the theoretical overpotential of the seven-layer RuO2 supercell, the activity enhancement difference of the ground-state surface chromium-doped configuration at each doping concentration is obtained.

[0045] Specifically, the OER process of the seven-layer RuO2 supercell and the ground-state chromium-doped configuration is described based on the traditional adsorbate evolution mechanism. The free energy of each proton-electron transfer step is calculated using a computational hydrogen electrode model. Under the reversible hydrogen electrode scale, the OER thermodynamic free energy expressions under acidic and basic conditions can be equivalently transformed. The OER process is decomposed into four consecutive proton-electron transfer steps: , , , , in, Indicates surface active sites. O、 OH, and OOH represent the key adsorption intermediates in the OER process.

[0046] For the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration, optimize their pure surface, OH、 O and The OOH adsorbed state structure was analyzed, and the thermodynamic activity of OER at different active sites was evaluated based on its free energy change. The free energy of the adsorbed species was calculated by combining the total DFT energy, zero-point vibrational energy (ZPE), and entropy correction. The zero-point vibrational energy data of each adsorbed species are shown in Table 1. Table 1

[0047] Specifically, the free energy of adsorbed species The calculation formula is: , in, This represents the total energy of the DFT; This indicates the zero-point vibration energy correction term; This represents the entropy correction term.

[0048] Since DFT has errors in describing the binding energy of gas-phase O2, this application embodiment uses the standard water oxidation reaction free energy of 4.92 eV to indirectly determine the free energy of the fourth step.

[0049] Furthermore, the OER theory overpotential Determined by the maximum free energy step in the four steps: , , , , , S40: Obtain the spin density distribution of the OER reaction intermediate adsorption structure of the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration, thereby obtaining the site magnetic moment increment and intermediate magnetic moment increment of the ground-state surface chromium-doped configuration at different doping concentrations.

[0050] Furthermore, in some embodiments of this application, S40 includes: S400~S404.

[0051] S400: Construct four surface adsorption configurations for a seven-layer RuO2 supercell and a ground-state chromium-doped surface configuration for each doping concentration. After enabling spin polarization for each surface adsorption configuration, perform self-consistent DFT calculations to obtain the electronic structure output file for each surface adsorption configuration.

[0052] S401: Based on the electronic structure output file of each surface adsorption configuration, extract the three-dimensional spin density distribution of each surface adsorption configuration, thereby obtaining the spin density spatial distribution of the seven-layer RuO2 supercell and the ground state surface chromium doped configuration at each doping concentration under different OER intermediates.

[0053] S402: Perform atomic projection magnetic moment decomposition for each surface adsorption configuration to extract the localized atomic magnetic moments of the key active sites on the catalytic surface and the total magnetic moment of the adsorption intermediates for each surface adsorption configuration.

[0054] S403: For the ground-state chromium-doped surface configuration and the same surface adsorption configuration of the seven-layer RuO2 supercell at each doping concentration, the site magnetic moment increment of the ground-state chromium-doped surface configuration is obtained based on the difference between the atomic local magnetic moment of the key active site of the catalytic surface of the surface adsorption configuration of the ground-state chromium-doped surface configuration and the atomic local magnetic moment of the key active site of the catalytic surface of the surface adsorption configuration of the seven-layer RuO2 supercell.

[0055] S404: For the ground-state surface chromium-doped configuration and the same surface adsorption configuration of the seven-layer RuO2 supercell at each doping concentration, the difference between the total magnetic moment of the adsorption intermediate of the surface adsorption configuration of the ground-state surface chromium-doped configuration and the total magnetic moment of the adsorption intermediate of the surface adsorption configuration of the seven-layer RuO2 supercell is used to obtain the increment of the magnetic moment of the intermediate of the ground-state surface chromium-doped configuration at that doping concentration.

[0056] Specifically, this application further performed spin-polarization static self-consistent calculations on the OER intermediate adsorption structure based on the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration, and plotted the spin density distribution map of the OER intermediate adsorption structure using the calculated charge density file. The results were compared between the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration. O、 OH、 The spin density distribution after OOH adsorption can be obtained, thus revealing the effect of Cr doping at different concentrations on the local magnetic configuration of the seven-layer RuO2 supercell surface and the spin polarization of adsorbed oxygen species.

[0057] Optionally, in some embodiments, the grid in the k-point grid file can be multiplied to encrypt the k-point sampling grid by setting the charge readout control parameter ICHARG=11, static density of states calculation can be performed, and then the orbital resolved projection density of states data can be extracted and plotted for analysis.

[0058] S50: Based on the activity improvement difference, site magnetic moment increment, and intermediate magnetic moment increment of the ground state surface chromium doping configuration under different doping concentrations, the range of doping concentration values ​​and spatial arrangement of chromium doped chromium dioxide reaction activity are obtained, thereby designing a chromium doped chromium dioxide catalyst.

[0059] For example, for multiple doped configurations with different Cr substitution sites and magnetic moment arrangements at the same Cr doping concentration, the total energy of each configuration under different magnetic moment arrangements is calculated, and the configuration with the lowest total energy is determined as the ground-state surface chromium-doped configuration at that doping concentration, thereby excluding spatial arrangements with relatively low stability. Using the theoretical overpotential of the undoped RuO2(110) surface as a benchmark, the activity enhancement difference of each ground-state surface chromium-doped configuration is calculated. ,in, This represents the theoretical overpotential of the undoped RuO2(110) surface. This represents the theoretical overpotential of the target active site in the Cr-doped configuration. When This indicates that the theoretical overpotential decreases after Cr doping, and the thermodynamic activity of OER is improved; The larger the value, the more significant the increase in activity.

[0060] Furthermore, the changes in magnetic moments at active sites before and after Cr doping were calculated. Since the sign of the local magnetic moment primarily indicates the spin direction, the absolute value of the magnetic moment was used to evaluate the local spin polarization intensity. The increment of the site magnetic moment is expressed as... ,in, This represents the absolute value of the local magnetic moment of the target active site in the Cr-doped configuration. This represents the absolute value of the local magnetic moment at the corresponding Ru active site in undoped RuO2(110). This indicates that Cr substitution enhances the local spin polarization of the active center.

[0061] for OH、 O and For adsorption intermediates such as OOH, the sum of the absolute values ​​of the local magnetic moments of each atom constituting the intermediate is defined as the total magnetic moment of the intermediate, and the increment of the intermediate magnetic moment is expressed as... ,in, This represents the total magnetic moment of the corresponding adsorption intermediate in the Cr-doped configuration. This represents the total magnetic moment of the homoadsorbed intermediate in undoped RuO2(110). When The result indicates that Cr doping enhances the local spin polarization of the adsorption intermediate.

[0062] Based on the above parameters, the doping configuration that simultaneously satisfies the following conditions is identified as a candidate configuration with good doping effect: (1) This configuration is the ground state configuration with the lowest total energy at the corresponding doping concentration; (2) Difference in activity enhancement That is, the theoretical overpotential after Cr doping is lower than that of undoped RuO2(110); (3) Increment of magnetic moment at the site That is, the local spin polarization of the Cr active site is enhanced; (4) Magnetic moment increment of key adsorption intermediates related to the potential-determining step That is, the enhanced local spin polarization can be transferred from the Cr active site to the oxygen-containing intermediate.

[0063] In this application, the potential determination step of OER is as follows: O→ Therefore, the focus is on comparing the magnetic moment increments of O and OOH intermediates. When the magnetic moment increments of both O and OOH are greater than 0, it indicates that Cr doping can enhance the spin polarization of oxygen-containing intermediates involved in the O-O bond formation process.

[0064] When multiple candidate configurations satisfy the above conditions exist, the configuration with the largest activity enhancement difference is preferred. The highest doping concentration and spatial arrangement were used to screen out Cr-doped configurations that have both low theoretical overpotential and strong local spin polarization. The doping concentration, Cr substitution sites and magnetic moment arrangement were then used as target design parameters for ruthenium dioxide catalysts.

[0065] Furthermore, the doping concentrations corresponding to the increased oxygen evolution reaction activity of ruthenium dioxide are 8.33% and 16.67%. Specifically, the theoretical overpotential of the Cr site is lower than that of undoped RuO2 (110) at both doping concentrations, indicating that both have an activity-enhancing effect; the 16.67% Cr doping configuration has a greater activity enhancement, so 16.67% is preferred.

[0066] Specifically, the range of doping concentrations and spatial arrangement corresponding to the increase in the oxygen evolution reaction activity of ruthenium dioxide are obtained, thereby designing chromium-doped ruthenium dioxide catalysts, including: Select a target doping concentration from the range of doping concentration values, and use chromium atoms to dope one or two surface Ru atom sites of the seven-layer RuO2 supercell based on the spatial arrangement of the target doping concentration, thereby preparing a chromium-doped ruthenium dioxide catalyst.

[0067] In some embodiments of this application, the effect of magnetic configuration on reaction free energy can also be directly verified by spin reversal comparison. That is, under the condition of consistent atomic composition and basic structural model, the spin direction of Cr site is reversed, and the magnetic moment of adsorbed O before and after reversal is compared. O- The change in OOH free energy is used to determine the contribution of the ground-state surface chromium doping configuration to the key steps of OER. Specifically, it also includes S60~S61.

[0068] S60: The spin direction of chromium atom sites in the ground-state surface chromium doping configuration at each doping concentration is flipped to obtain the spin-flipped configuration of the ground-state surface chromium doping configuration at each doping concentration.

[0069] S61: Compare the total energy, theoretical overpotential, four-step reaction Gibbs free energy change, site magnetic moment increment, and intermediate magnetic moment increment of the ground-state surface chromium doping configuration and its spin-flip configuration at each doping concentration to obtain the contribution of the ground-state surface chromium doping configuration to the activity of the OER reaction at each doping concentration.

[0070] In some embodiments of this application, a surface O / OH coverage stability model can also be constructed to determine stable surface terminals under acidic OER operating potential, thereby verifying the OER reaction model. Specifically, it also includes: S70~S72.

[0071] S70: For each ground-state chromium-doped configuration, construct multiple surface model terminal structures with different O / OH coverage, and calculate the relative free energy of each surface model terminal structure at different potentials using a potential-dependent free energy calculation method.

[0072] Specifically, the formation process of a mixed-cover surface containing m OH groups and nm O groups can be represented as follows: , in, This indicates a reference surface that is not covered by O or OH. This represents a mixed-coverage surface containing m OH species and nm O species in n adsorbable surface sites.

[0073] S71: Based on the working potential range of acidic OER, obtain the surface model terminal structure with the lowest relative free energy at each working potential, and use it as the target surface model terminal structure at each working potential.

[0074] S72: Based on the target surface model terminal structure at various working potentials as the reaction substrate, verify the OER four-step proton-electron transfer reaction model.

[0075] For example, the energies of different magnetic configurations of bulk RuO2 are first calculated to determine the ground state of the system. Specifically, in the embodiments of this application, the energy of the antiferromagnetic state is calculated to be 87.28 meV lower than that of the nonmagnetic state, and the magnetic moment of the Ru atom is ±1.19 μm. BThis is consistent with existing literature reports. Based on this, a seven-layer RuO2 supercell maintaining antiferromagnetic alignment characteristics was constructed to simulate OER catalytic processes, such as... Figure 2 As shown in (a), the seven-layer RuO2 supercell adopts a 3 × 2 seven-layer RuO2(110) slab structure with one side being a fully oxygen-sealed end surface. Existing calculation studies have found that this structure has high thermodynamic stability under high potential OER conditions. Therefore, this application uses it as the basis surface for subsequent research on Cr doping effect and OER activity.

[0076] The surface chromium-doped configuration is constructed by replacing Ru sites on the surface of a seven-layer RuO2 supercell with Cr atoms. For a doping concentration of 8.33%, comparing the energies of two non-equivalent surface Ru sites replaced by Cr atoms in the surface chromium-doped configurations, the energy difference between the two configurations is approximately 554 meV. The lower-energy configuration is shown below. Figure 2 As shown in (b), for a doping concentration of 16.67%, further investigation was conducted on the different relative positions and magnetic coupling modes of the two Cr atoms, including alternating parallel, adjacent parallel, and antiparallel arrangements. Calculation results show that the system has the lowest energy when the Cr atoms are distributed alternately and maintain parallel magnetic moments. This configuration is as follows: Figure 2 As shown in (c) of the diagram. From Figure 2 As can be seen from (a) to (c), the spin direction of the Cr atom sites is consistent with the original spin direction of the Ru sites they replace in the seven-layer RuO2 supercell. The Cr atom substitution doping did not destroy the original antiferromagnetic network of the seven-layer RuO2 supercell, but preserved the interleaved spin arrangement mode of the substrate.

[0077] Table 2 shows a comparison of the local magnetic moments of key metal sites on the surface of the seven-layer RuO2 supercell and the ground-state chromium-doped configuration provided in this example. Here, M (active site) represents the local magnetic moment of the metal site corresponding to the OER active center; M (adjacent Ru) represents the local magnetic moment of the Ru atom adjacent to the active site. The unit of magnetic moment is μ. B .

[0078] Table 2

[0079] As shown in Table 2, after Cr doping, the local magnetic moment of the Cr atom sites is significantly greater than that of the Ru sites in the seven-layer RuO2 supercell, with an increase of more than double. To explain the orbital origin of this enhanced magnetic moment, this example further analyzes the local coordination environment and 3d orbital occupancy characteristics of the Cr atom sites, such as... Figure 3 The figure shows the t under the distorted octahedral coordination environment of the chromium atom sites provided in this application. 2g A schematic diagram of the partial wave density of states for orbital occupancy and the 3d suborbitals of chromium atom sites; where, Figure 3(a) represents the t under the distorted octahedral coordination environment of the chromium atom sites. 2g Track occupancy diagram, Figure 3 (b) in the diagram is a schematic diagram of the partial wave density of states of the 3d suborbitals of the chromium atom sites. Figure 3 As can be seen in (a), the Cr atom sites are in a distorted octahedral coordination environment similar to rutile RuO2. According to the definition of local orbitals in rutile RuO2, d x2-y2 d yz d zx Belonging to t 2g The Cr 3d orbitals exhibit spin-parallel occupancy at Cr atomic sites. Meanwhile, the magnetic moment change of Ru atoms connected to bridge oxygen sites is relatively small, indicating that the magnetic perturbation introduced by Cr doping is mainly concentrated at Cr atomic sites and in their nearest Cr–O–Ru coordination environments, and does not show long-range propagation to the entire surface. Compared to the Ru 4d orbitals, the Cr 3d orbitals exhibit a narrower and sharper density of states peak near the Fermi level, which is direct evidence of enhanced 3d electron localization. Figure 3 As can be seen in (b), the orbital-resolved PDOS display shows that Cr 3d t 2g The state forms a narrow and strong occupied peak below the Fermi level, with the spin-down channel almost completely filled and the spin-up channel empty, directly contributing to... 2.72 μ B The local magnetic moment. Meanwhile, Crt 2g The strong hybridization with the adjacent O 2p band indicates that there is significant covalent mixing between the two in the valence band region, which is the fundamental reason why spin polarization in the Cr–O–Ru unit can be effectively transferred to the oxygen atom.

[0080] After obtaining the ground-state surface chromium-doped configurations at different doping concentrations, this example first calculates the OER free energy path of the seven-layer RuO2 supercell as a benchmark for activity evaluation, such as... Figure 4 As shown in (a), the theoretical overpotential of the seven-layer RuO2 supercell is 0.46 V, and the four proton-electron transfer steps... → OH、 OH → O、 O → OOH and The free energy changes for OOH → O2 are 0.73 eV, 1.27 eV, 1.69 eV, and 1.23 eV, respectively. O → The OOH step has the largest free energy step (1.69 eV) and is the potential-determining step for the seven-layer RuO2 supercell. It should be noted that the overpotential calculated in this example is close to the reported result of 0.49 eV in existing DFT literature, indicating that the seven-layer RuO2 supercell has high intrinsic OER activity. However, the overpotential of 0.46 V is still higher than the thermodynamic limit of an ideal catalyst, suggesting further optimization is possible.

[0081] For a ground-state chromium-doped configuration with a doping concentration of 8.33%, this example investigates the OER free energy paths of Cr atomic sites and their adjacent Ru sites as active centers. The theoretical overpotentials for Cr atomic sites and adjacent Ru sites are 0.38 V and 0.48 V, respectively. The overpotentials for Cr atomic sites are 0.080 V lower than the 0.46 V for the seven-layer RuO2 supercell, while those for Ru sites are slightly higher. The potential-determining step for both types of sites is... O → The presence of OOH indicates that the improvement in OER activity due to low-concentration Cr doping is mainly concentrated at the Cr atom sites themselves. The formation of OOH remains a key step limiting OER activity. The activity difference of approximately 0.10 V between Cr and Ru sites indicates that the catalytic enhancement introduced by Cr doping is site-selective, localized at Cr sites rather than uniformly enhancing the entire surface through long-range electronic effects.

[0082] When the Cr doping concentration increased to 16.67%, the activity advantage of Cr sites further expanded, such as... Figure 4 As shown in (a), its theoretical overpotential is reduced to 0.30 V, which is significantly better than 0.46 V for the seven-layer RuO2 supercell and 0.38 V for the Cr atom sites in the 8.33% Cr doped system. The overpotential of the Ru site is 0.47 V, which is still close to that of the seven-layer RuO2 supercell. The potential-determining steps of the two sites are also the same. O → OOH further confirms that the increased activity mainly comes from the Cr site itself.

[0083] Figure 4 (b) shows the key reaction intermediate configuration when the Cr atom sites in the ground-state chromium-doped configuration with a doping concentration of 16.67% act as active centers. Both OH and O are stably adsorbed at the Cr top sites, while the H atom on the distal O of the OOH intermediate remains connected to the adjacent bridging oxygen (O). br The formation of O···H interactions indicates that Cr doping preserves the typical two-site reaction characteristics of the seven-layer RuO2 supercell. Simultaneously, quantitative comparison of bond lengths reveals that the seven-layer RuO2 supercell... The OOH bond length and O brThe H-distances are 1.303 Å and 1.610 Å, respectively. In the 16.67% Cr-doped system, the corresponding values ​​become 1.273 Å and 1.770 Å. This change indicates that although Cr doping did not alter the two-site configuration of OOH itself, it effectively modulated the... The local geometry and hydrogen bond interaction strength of OOH affect the stability of key intermediates in OER.

[0084] Furthermore, to explain the electronic structure mechanism by which Cr doping modulates OER activity, this example compares the spin density distribution of a seven-layer RuO2 supercell and a ground-state surface chromium-doped configuration with a doping concentration of 16.67% after adsorption of O and OOH, as shown below. Figure 5 As shown in (a), (b), and (c), in the seven-layer RuO2 supercell, Ru (Ru) connected to the apical oxygen is cus ) and Ru connected to the adjacent bridging site oxygen (Ru br They are arranged in opposite magnetic moments, with magnetic moments respectively. 1.21 μ B and 1.63 μ B This reflects the antiferromagnetic coupling characteristics of the seven-layer RuO2 supercell. However, the adsorbed oxygen species around the active sites showed almost no significant spin density. The magnetic moments of the two oxygen atoms within the OO structure in OOH are only 0.27 μm. B and 0.41 μ B This indicates that the spin coupling between the oxygen-containing intermediate and the surface magnetic center is relatively limited.

[0085] like Figure 5 As shown in (e), (f), and (g), the local magnetic moment of the Cr atom sites in the ground-state surface chromium-doped configuration with a doping concentration of 16.67% increases to -2.72 μm. B The magnetic moment of the adjacent Ru site is 1.67 μ. B The two remain in opposite order, Cr 3+ t 2g 3 The half-filled configuration not only endows Cr atomic sites with high local magnetic moments, but also, through its connection with bridging O atoms, contributes to the high local magnetic moments of Cr atoms. 2- The optimized antiferromagnetic superexchange pathway, conforming to the Goodenough-Kanamori rule, further leads to strong spin polarization coupling along the Cr–O–Ru pathway. Quantitatively, the seven-layer RuO2 supercell… The magnetic moment of O atoms adsorbed in O is 0.11 μ B The concentration increased to 0.26 μ after doping with 16.67% Cr. B This indicates that Cr is doped in The O precursor stage can already significantly modulate the local spin state of adsorbed oxygen. For The corresponding magnetic moments in the seven RuO2 supercells of OOH are 0.27 μ. B and 0.41 μ B After doping with 16.67% Cr, the concentration increased to 0.57 μ. B and 0.64 μ B These results quantitatively demonstrate that the enhanced local spin polarization centers formed by Cr doping can be transmitted through Cr t 2g –O 2p–Ru t 2g The exchange coupling channel effectively injects spin polarization characteristics into the adsorbed oxygen-containing intermediate.

[0086] like Figure 5 As shown in (d) and (h), compared with the Ru sites in the seven-layer RuO2 supercell, the Cr 3d state in the Cr-doped system exhibits more significant spin splitting, with greater separation between the density of states energy positions of the spin-up and spin-down channels. Orbit-resolved analysis confirms that this enhanced spin splitting mainly originates from Cr t 2g The contribution of the state, its half-filled electron configuration, is conducive to the formation of strong exchange splitting and obvious asymmetric distribution of spin channels. More importantly, Cr t 2g The enhanced spin splitting, induced by Cr–O hybridization, also leads to significant spin polarization in the O 2p state of adsorbed oxygen. Spin density and PDOS analysis together reveal the electronic origin of the enhanced OER activity of Cr doping. 2g 3 The half-full configuration brings enhanced t 2g 3 Spin splitting, via Cr t 2g –O2p hybridization induces O2p spin polarization, giving adsorbed oxygen-containing intermediates enhanced spin characteristics. Since O and OOH are key intermediates closely related to the formation of O–O bonds in the OER process, their enhanced spin polarization means that the electronic structure of these intermediates achieves better spin matching with the active center of the catalyst, which may reduce the free energy cost of related reaction steps.

[0087] To further verify the direct correlation between the Cr–O–Ru local spin configuration and the free energy of the key OER steps, this example constructs a Cr spin-flip configuration using the ground-state surface chromium-doped configuration at 8.33% doping concentration as a control system, and compares its... O→ Free energy change of the OOH step: While maintaining structural model consistency, the spin orientation of Cr atomic sites was artificially flipped by adjusting the initial magnetic moment setting, changing it from the antiferromagnetic arrangement of Cr–O–Ru in the ground state to a spin arrangement approximately parallel to the neighboring Ru sites. After structural optimization, the total energy difference between this spin-flipped configuration and the ground-state chromium-doped configuration is approximately 23 meV, indicating that the two local spin arrangements are relatively close in energy, making them suitable for comparing the effects of spin orientation changes on the adsorbed oxygen electronic structure and reaction free energy. Furthermore, in the stable Cr–O–Ru ground-state chromium-doped configuration... The magnetic moment of adsorbed O atoms in O is 0.26 μ. B After the Cr spin flips, the magnetic moment of the adsorbed O atom becomes 0.11 μ B This indicates that both the spin polarization direction and intensity of adsorbed oxygen have changed significantly; at the same time, O→ The OOH step increases the free energy by 0.10 eV, a result that clearly demonstrates that the chromium-doped configuration of the Cr–O–Ru ground-state surface itself can reduce... O → The free energy step of the key step OOH, and the strength of this coupling originates from Cr t 2g 3 The superexchange interaction tends to be half-filled configuration; in addition, in the 16.67% Cr system, the overpotential of Cr atomic sites decreased from 0.46 V in the pure system to 0.30 V, a decrease of 0.16 V, of which the spin configuration contributed 62%, which also shows that the spin effect is the dominant factor in the enhanced activity.

[0088] Based on the above spin density and electronic state analysis, Figure 6 The adsorption free energies of key OER intermediates in different ground-state chromium-doped configurations were further compared to establish a quantitative correlation between enhanced spin polarization and thermodynamic optimization. Compared to the seven-layer RuO2 supercell, the adsorption free energies of Cr atoms in the 16.67% Cr-doped system were significantly higher. OH、 O and The adsorption free energy of OOH shifts upwards in all seven RuO2 supercells. OH、 O and The adsorption free energies of OOH were 0.73 eV, 2.00 eV, and 3.69 eV, respectively, while after 16.67% Cr doping, the corresponding values ​​increased to 1.52 eV, 2.65 eV, and 4.18 eV, respectively, with upward shifts of 0.79 eV, 0.65 eV, and 0.49 eV, respectively. This indicates that the regulatory effect of Cr doping on different oxygen-containing intermediates is not entirely consistent. The change in OH was the most significant, followed by O and OOH exhibits certain differentiated regulatory characteristics. For the seven-layer RuO2 supercell, oxygen-containing intermediates (especially O) are usually over-adsorbed, causing subsequent O → OOH or OOH → O2 steps to become thermodynamic bottlenecks. The moderate adsorption weakening caused by Cr doping precisely alleviates this contradiction, helps to balance the free energy distribution of different OER elementary steps, and reduces the maximum free energy step. Combined with previous spin density and PDOS analysis, the physical root of this adsorption weakening effect lies in the fact that the enhanced local spin polarization of Cr sites changes the electronic structure matching mode between oxygen-containing intermediates and the surface through Cr 3d–O 2p exchange coupling, causing the adsorption intensity to shift in a direction more favorable to catalytic cycling.

[0089] Under actual electrochemical OER conditions, the catalyst surface does not always remain in an ideal bare state. Instead, as the electrode potential increases and the reaction environment changes, an O / OH capping layer gradually forms on the surface. The actual catalytic cycle takes place on these capping layers. Therefore, analyzing OER activity solely based on a fixed surface structure is insufficient. It is also necessary to identify the most likely stable terminals under the reaction conditions to verify the rationality of the above activity analysis model and confirm whether the enhanced local spin polarization characteristics of Cr atom sites are still maintained under high potential conditions. Therefore, this example also uses the ground-state chromium-doped surface configuration with a doping concentration of 16.67% as the object, constructing various surface model terminal structures with different O / OH capping degrees, and calculating the surface free energy (URHE) of different terminal structures with varying electrode potentials. The results are as follows: Figure 7 As shown.

[0090] from Figure 7 It can be seen that the surface free energy of all O / OH terminal structures decreases linearly with increasing potential, but the rate of decrease differs significantly: the slope of the O-saturated 11-O terminal is -22e, showing the fastest decrease; the slope of the OH-saturated 11-OH terminal is -11e, showing the slowest decrease; the slopes of the remaining mixed O / OH terminals are located at... 13e to Between 19e, this difference stems from the fundamentally different responses of the two terminals to electrode potentials, with each surface O adsorption site involving the transfer of two proton-electron pairs (O). ad + 2H + +2e - + H2O), while the OH terminal only involves one (OH) ad + H + + e - (+ H2O), so the O terminal is more sensitive to the location.

[0091] In the low potential region of URHE < 1.098 V, OH-saturated 11-OH terminals have the lowest surface free energy, indicating that below the OER initiation potential, the surface tends to exist in the form of OH-saturated coverage. As the potential increases, the free energy of the O-covered structure decreases rapidly due to a larger decreasing slope. The two types of terminals cross at URHE = 1.098 V. When the potential is higher than this value, O-saturated 11-O terminals become the structure with the lowest free energy, indicating that under high-potential OER operating conditions (URHE > 1.23 V), the surface thermodynamics is most favorable for the formation of O-enriched terminals. This O-enriched terminal is consistent with the OER activity analysis mentioned above. The adsorption of the O intermediate at the metal site is consistent with the basic reaction model, and the computational surface used closely approximates the actual reaction conditions.

[0092] In summary, this example, by comparing 8.33% and 16.67% Cr doping concentrations, non-equivalent substitution sites, and different Cr-Cr magnetic arrangements, determined the surface structure with the lowest energy at each doping concentration, avoiding accidental conclusions based solely on a single doping model. Simultaneously, by obtaining a theoretical overpotential of 0.30 V for Cr atom sites in the 16.67% Cr doped system, which is approximately 0.16 V lower than the 0.46 V of the seven-layer RuO2 supercell, and with the overpotential of adjacent Ru sites still close to that of the seven-layer RuO2 supercell, it is demonstrated that the activity enhancement is concentrated at the Cr active centers. Furthermore, this example also verifies that Cr substitution did not disrupt the antiferromagnetic arrangement of the seven-layer RuO2 supercell, and the magnetic moment of the Cr atom sites increased to -2.72 μm. B And enhances the spin polarization of adsorbed oxygen species through Cr 3d-O 2p hybridization, and The magnetic moments of the two O atoms in OOH are 0.27 μm from the seven-layer RuO2 supercell. B and 0.41 μ B Increased to 0.57 μ B and 0.64 μ B In addition, this example directly verifies the effect of magnetic configuration on reaction free energy through spin flipping comparison: after flipping the Cr spin from the ground-state antiferromagnetic alignment to approximately parallel with the neighboring Ru, The magnetic moment of O adsorbed in O is 0.26 μ B It becomes -0.11 μ B ,and O→ The OOH step increases the free energy by approximately 0.10 eV, indicating that a stable Cr-O-Ru spin arrangement can lower the critical free energy step. Finally, this example combines activity screening with surface stability at the working potential. The surface phase diagram shows that the 100%-O terminal is most stable above 1.098 V, forming an O-rich surface at the acidic OER working potential, which is consistent with... This study aligns with the reaction model where O is the key intermediate, improving the correspondence between the calculated design and actual reaction conditions. First-principles calculations were used to investigate the OER activity on the surface of a Cr-doped seven-layer RuO2 supercell. The effects of Cr doping concentration and active sites on the OER free energy pathway were examined. Combined with magnetic moment, spin density, partial wave density of states, and surface thermodynamic analysis, the microscopic mechanism by which Cr doping regulates the adsorption free energy of oxygen-containing intermediates was revealed, providing a theoretical reference for the spin engineering design of RuO2-based acidic OER catalysts.

[0093] This application also provides a ruthenium dioxide catalyst, which is designed using the above-described design method for chromium-doped ruthenium dioxide catalysts.

[0094] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0095] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0096] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0097] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0098] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for designing a chromium-doped ruthenium dioxide catalyst, characterized in that, include: A seven-layer RuO2 supercell was obtained. Chromium was used as the doping element to dop the seven-layer RuO2 supercell with different doping concentrations and different doping sites to obtain surface chromium doping configurations with different spatial arrangements under each doping concentration. Calculate the total energy of the ferromagnetic and antiferromagnetic states of the surface chromium doped configuration with different spatial arrangements for each doping concentration, and take the surface chromium doped configuration with the lowest total energy of the ferromagnetic and antiferromagnetic states as the ground state surface chromium doped configuration at that doping concentration. The OER free energy paths of the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration were calculated using a computational hydrogen electrode model, thereby obtaining the activity improvement difference of the ground-state surface chromium-doped configuration at different doping concentrations. The spin density distribution of the adsorption structure of OER reaction intermediates in the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration was obtained, thereby obtaining the site magnetic moment increment and intermediate magnetic moment increment of the ground-state surface chromium-doped configuration at different doping concentrations. Based on the activity improvement difference, site magnetic moment increment, and intermediate magnetic moment increment of the ground-state surface chromium doping configuration under different doping concentrations, the range of doping concentration values ​​and spatial arrangement of ruthenium dioxide oxygen evolution reaction activity are obtained, thereby designing chromium-doped ruthenium dioxide catalysts.

2. The design method for a chromium-doped ruthenium dioxide catalyst according to claim 1, characterized in that, A seven-layer RuO2 supercell was obtained. Chromium was used as the dopant element to dope the RuO2 supercell at different doping concentrations and doping sites, resulting in surface chromium-doped configurations with different spatial arrangements for each doping concentration, including: Multiple first doping concentrations were obtained by replacing only one surface Ru atom site of a seven-layer RuO2 supercell with chromium atoms, and multiple second doping concentrations were obtained by replacing two surface Ru atom sites of a seven-layer RuO2 supercell with chromium atoms. Based on each first doping concentration, chromium atoms are replaced and doped at one surface Ru atom site of the seven-layer RuO2 supercell. By traversing the dopable Ru atom sites on the surface, surface chromium doping configurations with different spatial arrangements under each first doping concentration are obtained. Based on various second doping concentrations, chromium atoms were replaced and doped at two surface Ru atom sites in a seven-layer RuO2 supercell. The relative spatial positions of the two surface chromium atom sites were adjusted after the replacement doping to obtain surface chromium doping configurations with different spatial arrangements under each second doping concentration.

3. The design method for a chromium-doped ruthenium dioxide catalyst according to claim 1, characterized in that, Calculate the total energy of the ferromagnetic and antiferromagnetic states for different spatial arrangements of surface chromium doped configurations at each doping concentration. The surface chromium doped configuration with the lowest total energy of the ferromagnetic and antiferromagnetic states is taken as the ground-state surface chromium doped configuration at that doping concentration, including: Structural relaxation was performed on each surface chromium-doped configuration at each doping concentration to obtain the initial configuration of the surface chromium-doped configuration; Static self-consistent calculations were performed on the initial configuration of the chromium-doped surface to obtain the total energy of the ferromagnetic and antiferromagnetic states of the chromium-doped surface.

4. The design method for a chromium-doped ruthenium dioxide catalyst according to claim 1, characterized in that, The OER free energy paths of the seven-layer RuO2 supercell and the ground-state chromium-doped configuration at each doping concentration were calculated using a computational hydrogen electrode model. This allowed for the acquisition of the activity enhancement differences of the ground-state chromium-doped configuration at different doping concentrations, including: Four surface adsorption configurations were constructed for each of the seven-layer RuO2 supercells and ground-state chromium-doped configurations at each doping concentration. DFT calculations were performed on each surface adsorption configuration to obtain the total ground-state electron energy for each surface adsorption configuration. Using a computational hydrogen electrode model based on the total ground-state electron energy for each surface adsorption configuration, the four-step reaction Gibbs free energy change of the seven-layer RuO2 supercell and the ground-state chromium-doped surface configuration at each doping concentration was calculated. For a seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration, the theoretical overpotential is calculated based on the maximum value in the Gibbs free energy change of the four-step reaction. Based on the difference between the theoretical overpotential of the ground-state surface chromium-doped configuration at each doping concentration and the theoretical overpotential of the seven-layer RuO2 supercell, the activity enhancement difference of the ground-state surface chromium-doped configuration at each doping concentration is obtained.

5. The design method for a chromium-doped ruthenium dioxide catalyst according to claim 1, characterized in that, The spin density distribution of the OER reaction intermediate adsorption structure of the seven-layer RuO2 supercell and the ground-state surface chromium-doped configuration at each doping concentration was obtained, thereby obtaining the site magnetic moment increment and intermediate magnetic moment increment of the ground-state surface chromium-doped configuration at different doping concentrations, including: Four surface adsorption configurations were constructed for each of the seven-layer RuO2 supercells and the ground-state surface chromium-doped configurations at each doping concentration. Self-consistent DFT calculations were performed on each surface adsorption configuration after enabling spin polarization to obtain the electronic structure output file for each surface adsorption configuration. Based on the electronic structure output file of each surface adsorption configuration, the three-dimensional spin density distribution of each surface adsorption configuration is extracted, thereby obtaining the spin density spatial distribution of the seven-layer RuO2 supercell and the ground state surface chromium doped configuration under different OER intermediates for each doping concentration. For each surface adsorption configuration, atomic projection magnetic moment decomposition is performed to extract the local magnetic moments of the atoms at the key active sites on the catalytic surface and the total magnetic moment of the adsorption intermediates for each surface adsorption configuration. For each doping concentration, the local magnetic moment increment of the site magnetic moment of the ground-state chromium-doped surface configuration and the same surface adsorption configuration of the seven-layer RuO2 supercell is obtained based on the difference between the atomic local magnetic moment of the key active site of the catalytic surface of the surface adsorption configuration of the ground-state chromium-doped surface configuration and the atomic local magnetic moment of the key active site of the catalytic surface of the surface adsorption configuration of the seven-layer RuO2 supercell. For the ground-state surface chromium-doped configuration and the same surface adsorption configuration of the seven-layer RuO2 supercell at each doping concentration, the difference between the total magnetic moment of the adsorption intermediate of the surface adsorption configuration of the ground-state surface chromium-doped configuration and the total magnetic moment of the adsorption intermediate of the surface adsorption configuration of the seven-layer RuO2 supercell is used to obtain the increment of the intermediate magnetic moment of the ground-state surface chromium-doped configuration at that doping concentration.

6. The design method for a chromium-doped ruthenium dioxide catalyst according to claim 1, characterized in that, Also includes: The spin orientation of chromium atom sites in the ground-state surface chromium doping configuration at each doping concentration is flipped to obtain the spin-flipped configuration of the ground-state surface chromium doping configuration at each doping concentration. By comparing the total energy, theoretical overpotential, four-step reaction Gibbs free energy change, site magnetic moment increment, and intermediate magnetic moment increment of the ground-state surface chromium doping configuration and its spin-flip configuration at each doping concentration, the activity contribution of the ground-state surface chromium doping configuration to the OER reaction at each doping concentration can be obtained.

7. The design method for a chromium-doped ruthenium dioxide catalyst according to claim 1, characterized in that, Also includes: For each ground-state chromium-doped configuration of the surface at each doping concentration, multiple surface model terminal structures with different O / OH coverage were constructed, and the relative free energy of each surface model terminal structure at different potentials was calculated using a potential-dependent free energy calculation method. Based on the working potential range of acidic OER, the surface model terminal structure with the lowest relative free energy at each working potential is obtained, and used as the target surface model terminal structure at each working potential. Using the target surface model terminal structure at various working potentials as the reaction substrate, the OER four-step proton-electron transfer reaction model is validated.

8. The design method for a chromium-doped ruthenium dioxide catalyst according to claim 1, characterized in that, The doping concentrations corresponding to the increased oxygen evolution reaction activity of ruthenium dioxide are 8.33% and 16.67%.

9. The design method for a chromium-doped ruthenium dioxide catalyst according to claim 1, characterized in that, By obtaining the range of doping concentrations and spatial arrangement corresponding to the increased activity of ruthenium dioxide in the oxygen evolution reaction, a chromium-doped ruthenium dioxide catalyst was designed, including: Select a target doping concentration from the range of doping concentration values, and use chromium atoms to dope one or two surface Ru atom sites of the seven-layer RuO2 supercell based on the spatial arrangement of the target doping concentration, thereby preparing a chromium-doped ruthenium dioxide catalyst.

10. A ruthenium dioxide catalyst, characterized in that, The ruthenium dioxide catalyst is designed using the design method for chromium-doped ruthenium dioxide catalysts according to any one of claims 1 to 9.

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