A method for predicting the energy barrier of hydrogen evolution reaction by hydrogen atom adsorption energy on high entropy alloy surface

Abstract

The present invention provides a method for predicting the energy barrier of hydrogen evolution reaction by hydrogen atom adsorption energy on the surface of high entropy alloy, comprising: generating a PdPtRhIrRu high entropy alloy with randomly distributed elements, and optimizing the structure by density functional theory calculation method. Hydrogen atoms are placed at different adsorption sites, and the stable adsorption positions of hydrogen atoms are determined by analysis. Then, the high entropy alloy surface fully covered with hydrogen atoms is used as the initial state, and the model after hydrogen precipitation is used as the final state, and the reaction energy barrier is obtained by using the Climbing Image Nudged Elastic Band (CI‑NEB) method. Finally, the relationship between the hydrogen atom adsorption energy and the reaction energy barrier is analyzed, and a relationship formula is obtained to realize the prediction of the reaction energy barrier by adsorption energy. Compared with the energy barrier prediction method commonly used in pure metals - #imgabs0# relationship, the prediction accuracy of this method in high entropy alloys is 0.79, which is significantly better than BEP's 0.29. The present invention realizes the prediction of the reaction energy barrier with high computational cost by adsorption energy with low computational cost through DFT calculation, thereby reducing the design and simulation cost of high entropy alloy hydrogen evolution reaction catalyst.

Description

Technical Field

[0001] The present invention relates to the field of catalysis, and in particular to a method for predicting the energy barrier of a hydrogen evolution reaction by means of hydrogen atom adsorption energy on a high entropy alloy surface. Background Art

[0002] Electrocatalytic water splitting, with its CO₂-free production process, has become a promising technology for hydrogen production. However, currently, only 4–5% of hydrogen is produced from water electrolysis. This is primarily due to the low activity, poor stability, and high cost of commercially available Pt / C and Rh / C electrocatalysts. Therefore, the search for hydrogen evolution catalysts with superior catalytic performance is a current research frontier and hot topic in this field.

[0003] High-entropy alloys (HEAs) are alloys composed of five or more metals in equal or approximately equal amounts. They possess high catalytic activity, excellent stability, and long lifespan, and show great promise in electrocatalytic hydrogen production. However, HEAs have complex surface structures and random element distribution, leading to significant variations in the electronic properties of alloying elements. This results in multiple active sites, making the d-band model, linear relationships, and BEP relationships common in traditional pure metal catalyst systems difficult to apply to HEAs. Consequently, HEA catalyst design remains at a trial-and-error stage.

[0004] On the surface of pure metals, the reaction energy barrier of chemical reactions is predicted by the BEP relationship. The reaction energy barrier can be predicted through an equation based on the BEP relationship using the system energy difference before and after the reaction. However, due to the random distribution of adjacent metal elements on the surface of high-entropy alloys, the BEP relationship on their surface becomes invalid. The accuracy of predicting the energy barrier using reaction energy is 0.29. Therefore, there is an urgent need to develop a simple and accurate energy barrier prediction method. Summary of the Invention

[0005] In view of the low accuracy of the existing BEP method in predicting the energy barrier of hydrogen evolution reaction on the surface of high-entropy alloys, the present invention conducts high-throughput calculation research on the surface adsorption energy of high-entropy alloys. Taking the typical catalyst system IrPtPdRhRu metal as the research object, the first-principles method is used to explore the distribution law of hydrogen atom adsorption energy on the surface of high-entropy alloys, clarify the influence mechanism of hydrogen atom adsorption energy on the reaction barrier, study the prediction of hydrogen atom adsorption energy on the energy barrier of hydrogen evolution reaction, realize the process of predicting complex reaction energy barriers using simple adsorption energy parameters, establish the structure-activity relationship between high-entropy alloy surface structure and catalytic activity, realize the reverse design of high-performance high-entropy alloy hydrogen evolution catalysts, and lay a theoretical foundation for the industrial application of high-entropy alloy hydrogen evolution catalysts.

[0006] In order to solve the above technical problems, a technical solution adopted by the present invention is:

[0007] The present invention predicts the energy barrier of hydrogen evolution reaction by hydrogen atom adsorption energy on the surface of high entropy alloy, generates PdPtRhIrRu high entropy alloy with random element distribution, and optimizes its structure by density functional theory calculation method. Hydrogen atoms are placed at different adsorption sites on the surface of the optimized high entropy alloy to form an atomic adsorption structure under 1 / 9ML coverage, and the structure is optimized to obtain the adsorption energy of hydrogen atoms corresponding to different adsorption sites, and judge the stable adsorption position of hydrogen atoms. Hydrogen atoms are fully covered in stable positions on the surface of high entropy alloy, and a stable adsorption structure is obtained after structural optimization as the initial structure of hydrogen evolution reaction. A model after hydrogen precipitation on the surface of high entropy alloy is built, and a stable structure is obtained after structural optimization as the final structure of hydrogen evolution reaction. The transition state of hydrogen evolution reaction on the surface of high entropy alloy is searched by CI-NEB method to obtain the energy barrier of hydrogen evolution reaction. The relationship between the adsorption energy and reaction energy barrier corresponding to the two hydrogen atoms participating in the reaction is analyzed to realize the prediction of adsorption energy on reaction energy barrier.

[0008] A method for predicting the energy barrier of hydrogen evolution reaction based on the adsorption energy of hydrogen atoms on the surface of a high entropy alloy comprises at least the following steps:

[0009] (1) Using Python scripts, 200 3×3×4 layer high entropy alloy models were randomly generated with the elemental composition of IrPdPtRhRu and the element content ratio of 7:7:7:7:8, and their structures were optimized.

[0010] (2) Hydrogen atoms were adsorbed on the surface of IrPdPtRhRu high entropy alloy at the FCC, HCP and TOP positions with a coverage of 1 / 9 ML, the adsorption structure was optimized, the adsorption energy of hydrogen atoms at different adsorption positions was calculated, and its stable adsorption position was obtained;

[0011] (3) On the surface of a 3×3×4 layer high entropy alloy model of IrPdPtRhRu, a hydrogen atom is adsorbed at different FCC adsorption positions, and the energy of the adsorption system is calculated. Combining the energy of the high entropy alloy substrate and the energy of the hydrogen atom, the hydrogen atom adsorption energy of the hydrogen atom at different FCC positions on the high entropy alloy surface is obtained;

[0012] (4) Constructing the initial adsorption configuration of hydrogen atoms at 1ML coverage on the surface of a high-entropy alloy, and performing structural optimization to obtain a stable adsorption structure, and obtaining the system energy of the initial structure. By changing the positions of two hydrogen atoms on the surface of a high-entropy alloy at 1ML coverage, causing them to precipitate to form hydrogen, as the final adsorption model, and performing structural optimization, the system energy of the final structure is obtained;

[0013] (5) Using the CI-NEB method, points are uniformly inserted between the initial structure and the final structure, and the structure of different insertion points is optimized to obtain the system energy, the energy change in the process of diffusion from the initial structure to the final structure, and the energy barrier that needs to be crossed.

[0014] (6) The adsorption energy of hydrogen atoms at the two FCC positions involved in the hydrogen evolution reaction is combined with the energy barrier that needs to be crossed during the hydrogen evolution reaction to obtain a linear relationship between the hydrogen atom adsorption energy and the energy barrier, and thus a prediction formula for the hydrogen evolution reaction energy barrier is obtained.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. There is no need to search for reaction transition states on the surface of high-entropy alloys, thereby reducing the time required for a large number of simulation steps. The CI-NEB method of searching for transition states yields accurate results, but consumes a lot of time and manpower. The method of predicting reaction energy barriers using the BEP relationship consumes less time but has low accuracy. The linear relationship between adsorption energy and energy barrier obtained through the CI-NEB search of some systems can realize the process of predicting complex reaction energy barriers using simple hydrogen atom adsorption energy. The calculation of hydrogen atom adsorption energy is very simple; 2. The prediction of reaction energy barriers is more accurate. In pure metals, due to the existence of the BEP relationship, the reaction energy barrier can be predicted by reaction energy. However, due to the complex surface elemental composition of high-entropy alloys, the BEP relationship is not clear enough. After calculation, the accuracy of predicting the energy barrier using reaction energy is: 0.29, while the prediction method using adsorption energy can increase the accuracy to: 0.79, realizing an efficient and accurate prediction method for high-entropy alloy hydrogen evolution reaction catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a diagram of four adsorption positions of hydrogen atoms on the surface of the IrPdPtRhRu high entropy alloy of the present invention.

[0018] Figure 2 This is the adsorption energy distribution diagram of the hydrogen atoms at four adsorption positions on the surface of the IrPdPtRhRu high entropy alloy of the present invention.

[0019] Figure 3 This is a structural diagram of hydrogen atoms adsorbed on the surface of the IrPdPtRhRu high entropy alloy at FCC positions of 1 / 9ML and 1ML.

[0020] Figure 4 These are six possible pathways for hydrogen evolution reaction on the surface of the IrPdPtRhRu high entropy alloy of the present invention.

[0021] Figure 5 It is a structural diagram of the initial state and final state of the hydrogen evolution reaction on the surface of the IrPdPtRhRu high entropy alloy of the present invention.

[0022] Figure 6 This is the CI-NEB search energy barrier result of the hydrogen evolution reaction on the surface of the IrPdPtRhRu high entropy alloy of the present invention.

[0023] Figure 7 This is the BEP relationship formula and accuracy of the hydrogen evolution reaction on the surface of the IrPdPtRhRu high entropy alloy of the present invention.

[0024] Figure 8 The invention discloses a formula and an accuracy rate for the relationship between hydrogen atom adsorption energy and reaction energy barrier in a hydrogen evolution reaction on the surface of an IrPdPtRhRu high entropy alloy. DETAILED DESCRIPTION

[0025] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0026] Example 1

[0027] A Python script was used to randomly generate an IrPdPtRhRu high-entropy alloy model, maximizing its elemental distribution. The structure was optimized using VASP software, and the RPBE DFT method was used based on first-principles calculations to determine the stable adsorption sites of hydrogen atoms.

[0028] Using a Python script, we randomly generated 200 3×3×4 IrPdPtRhRu high-entropy alloy models with fixed element types and element ratios. The lattice constant was 3.856 Å and the element content ratio was 7:7:7:7:8. The element coordinates were output to fix the 3rd and 4th layers of the high-entropy alloy substrate, and the 1st and 2nd layers of atoms were fully relaxed. This was used as the input file for structural optimization. The RPBE DFT method was used to optimize the structure of the high-entropy alloy. The first-principles theory was used and the RPBE DFT method was used for calculation. The energy convergence accuracy was 1×10 -4 eV, the convergence accuracy of the force is A 3 × 3 × 1 k-point grid is used.

[0029] Hydrogen atoms are adsorbed on the surface of the high entropy alloy substrate after structural optimization, with an adsorption height of 1 angstrom. The positions of hydrogen atoms are adjusted to be located at FCC, HCP, and TOP positions, respectively. The adsorption positions are as follows: Figure 1 As shown. The structure was optimized again and the adsorption energy at different adsorption sites was calculated. The adsorption energy corresponding to the four different adsorption positions on the surface of 200 IrPdPtRhRu high entropy alloys is shown as follows: Figure 2 As shown, the adsorption energies are compared and the distribution is analyzed. The largest number of hydrogen atoms can be stably adsorbed at the FCC position, and a stable adsorption site on the surface of the high entropy alloy, the FCC site, can be obtained.

[0030] The FCC adsorption position 1ML on the high entropy alloy surface is fully covered with 9 hydrogen atoms, and the adsorption height is 1 angstrom, which is used as the initial structure for structural optimization; there are 6 nearest neighbor hydrogen atoms near the central hydrogen atom on each substrate surface, which are combined with one of the hydrogen atoms at the nearest neighbor position to form hydrogen gas. The two hydrogen atoms are 0.7 angstroms apart and are precipitated above the central atom at 2.0 angstroms from the high entropy alloy surface. The remaining hydrogen atoms that do not participate in the reaction are adsorbed at a height of 1.0 angstrom as the final structure and are structurally optimized. The initial structure and final structure of the hydrogen evolution reaction on the surface of the IrPdPtRhRu high entropy alloy are shown in Figure 2. Figure 5 As shown. CI-NEB calculations were performed using the optimized initial and final structures. Three points were evenly inserted between the hydrogen atom transformation paths in the initial and final states. After structural optimization, the energy of each structure was obtained, and then the activation energy barrier that the hydrogen evolution reaction needed to cross was obtained. The energy trend obtained after CI-NEB calculations is shown in the figure below. Figure 6 , where the highest energy point is the activation energy barrier that needs to be overcome in the reaction process.

[0031] On each high entropy alloy surface, the central FCC position atom is used as the precipitation point, and the CI-NEB calculation of the hydrogen evolution reaction is performed on its six nearest hydrogen atoms. The reaction energy barriers of six paths can be obtained on each high entropy alloy surface, such as Figure 4 As shown, the path with the lowest hydrogen evolution reaction energy barrier is selected, and the adsorption energies of the two hydrogen atoms participating in the reaction on the high entropy alloy surface and the hydrogen evolution reaction energy barrier are used as a set of data. Six CI-NEB calculations are performed on 60 high entropy alloy surfaces, and finally 60 sets of lowest reaction energy barriers and adsorption energy data of hydrogen atoms participating in the reaction are obtained. The relationship between the adsorption energies of the two hydrogen atoms participating in the reaction and the hydrogen evolution reaction energy barrier in these 60 sets of data is analyzed, and the prediction equation for the hydrogen evolution reaction energy barrier can be obtained.

[0032] E a =-(E FCC1 +E FCC2 )-0.08

[0033] Using the energy barrier predicted by adsorption energy as the horizontal axis and the energy barrier calculated by actual CI-NEB as the vertical axis, we can obtain Figure 8 The closer the predicted energy barrier is to the actual energy barrier, the better the prediction effect is. That is, the smaller the deviation of the numerical point from the diagonal position is, the better the prediction effect is.

[0034] Based on the BEP relationship, there is a linear relationship between reaction energy and energy barrier. The difference between the system energy at the end of hydrogen evolution reaction and the system energy at the initial state is the reaction energy of the hydrogen evolution reaction process. Figure 7The results of hydrogen evolution reaction on the surface of IrPdPtRhRu high entropy alloy show that the accuracy of predicting the reaction energy barrier on the surface of high entropy alloy using reaction energy is as low as 0.29, while the new hydrogen atom adsorption energy prediction method can improve the accuracy to 0.79.

[0035] The present invention is not limited to this. The above description is only an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for predicting the energy barrier of hydrogen evolution reaction by hydrogen atom adsorption energy on the surface of high entropy alloy, characterized in that: The method comprises at least the following steps: (1) Use Python script to randomly generate a 3 ´ 3 4-layer high entropy alloy model to make its element distribution as dispersed as possible; optimize the high entropy alloy model to obtain a stable high entropy alloy model; (2) Construct the adsorption configuration of hydrogen atoms at different adsorption positions on the surface of high-entropy alloys, optimize the structure, obtain a stable adsorption structure model, calculate the adsorption energy of hydrogen atoms at different adsorption positions, statistically analyze the distribution of hydrogen atom adsorption energy, and determine the stable adsorption site of hydrogen atoms on the surface of high-entropy alloys; (3) Build a model of the stable adsorption sites of hydrogen atoms under 1 ML coverage, and optimize the structure to obtain a stable structural model as the initial structure of the hydrogen evolution reaction; build a model of adjacent hydrogen atoms combining to form hydrogen after precipitation from the high entropy alloy surface, and optimize the structure to obtain a stable structural model as the final structure of the hydrogen evolution reaction; (4) The CI-NEB method is used to search for the transition state structures of different hydrogen evolution reaction paths on the surfaces of different high entropy alloys to obtain the energy barrier of the hydrogen evolution reaction; by analyzing the relationship between the reaction energy barrier and the adsorption energy of hydrogen atoms participating in the reaction, a prediction formula for the reaction energy barrier is obtained, and the effect of hydrogen atom adsorption energy on the hydrogen evolution reaction energy barrier is predicted.

2. The method according to claim 1, wherein The method for constructing a high entropy alloy surface is as follows: A Python script was used to randomly generate a 3 ´ 3 high entropy alloy model with 4 layers and 36 atoms. Its lattice constant was 3.856 Å, and the element composition was IrPdPtRhRu with an element content ratio of 7:7:7:7:

8.

3. The method according to claim 1, wherein The method for constructing the adsorption configuration of hydrogen atoms on the IrPdPtRhRu high entropy alloy surface at 1 / 9 ML and 1 ML coverage is as follows: Using Materials studio software, hydrogen atoms were placed at three initial adsorption positions: FCC, HCP, and TOP. The initial distance between the hydrogen atoms and the surface was set to 1 angstrom, and the adsorption model of hydrogen atoms at a coverage of 0.1 ML was obtained. The number of adsorbed hydrogen atoms was increased to reach a coverage of 1 ML, and the adsorption models of the FCC, HCP, and TOP positions were constructed respectively.

4. The method according to claim 1, wherein The method for calculating the adsorption energy of hydrogen atoms on the surface of high entropy alloys is as follows: The adsorption model built in Materials studio software was converted into POSCAR format using VESTA software and finally imported into VASP. The RPBE DFT method was used to optimize it to obtain a stable adsorption configuration. The adsorption system model, high entropy alloy substrate model, and hydrogen molecule model were structurally optimized respectively. During the optimization process, the lowest two layers of atomic coordinates of the high entropy alloy substrate were fixed, and only the two layers of atomic coordinates close to the adsorption surface were relaxed. The hydrogen atoms were fully relaxed, and finally the adsorption energy of hydrogen atoms at different adsorption positions on the surface of the IrPdPtRhRu high entropy alloy was obtained.

5. The method according to claim 1, wherein The method for determining the stable adsorption position of hydrogen atoms on the surface of high entropy alloys is as follows: Using the stable adsorption structure obtained by structural optimization, the corresponding hydrogen atom adsorption energy is calculated, the adsorption energy distribution range of hydrogen atoms at the FCC, HCP, and TOP adsorption positions is counted, and the corresponding adsorption numbers under different adsorption energies are counted to determine the stable adsorption position of hydrogen atoms.

6. The method according to claim 1, wherein The method for calculating the energy barrier of hydrogen evolution reaction on the surface of high entropy alloy is as follows: Based on the optimized high-entropy alloy model at 1 ML coverage, the hydrogen atoms adsorbed at the two nearest FCC positions were combined into hydrogen gas, with the two hydrogen atoms 0.7 Å apart. The hydrogen gas coordinates were raised in the z-axis direction so that it was not bonded to the high-entropy alloy surface and was 2.0 Å away. The constructed model was optimized using the RPBE DFT method. The optimized structure was used as the final state of the hydrogen evolution reaction, and the high-entropy alloy adsorption model at 1 ML coverage of optimized hydrogen atoms was used as the initial state of the hydrogen evolution reaction. The CI-NEB method was used to calculate the energy barrier of the hydrogen evolution reaction on the surface of IrPdPtRhRu high-entropy alloy.

7. The method according to claim 1, wherein The method for calculating the reaction energy of hydrogen evolution reaction on the surface of high entropy alloy is as follows: The structures of the initial state and the final state obtained after structural optimization are subjected to energy processing to obtain the total energy of the adsorption system in the initial state and the final state respectively, and the reaction energy of the hydrogen evolution reaction on the surface of the high entropy alloy is obtained by taking the difference.

8. The method according to claim 1, wherein The method for predicting the energy barrier of hydrogen evolution reaction using adsorption energy is as follows: On each high entropy alloy surface, the path for hydrogen evolution reaction is the hydrogen atoms at the two nearest FCC positions. On the 3´3 high entropy alloy surface, there are 6 paths, that is, each hydrogen atom combines with the 6 adjacent hydrogen atoms to form hydrogen. The path with the lowest reaction energy barrier is taken, and the adsorption energies of the two hydrogen atoms participating in the reaction are defined as E FCC1 and E FCC2 , the energy barrier of hydrogen evolution reaction is defined as E a ;analyze E FCC1 and E FCC2 and E a The numerical relationship of the high entropy alloy is fitted to obtain E a prediction formula; on the surface of any IrPdPtRhRu high-entropy alloy, the energy barrier of the hydrogen evolution reaction on the surface can be obtained by a simple hydrogen adsorption energy calculation using this energy barrier prediction formula, realizing the process of predicting the energy barrier of the hydrogen evolution reaction using the hydrogen atom adsorption energy on the surface of the high-entropy alloy.

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