High-entropy intermetallic compound, preparation method and application thereof

Abstract

This invention provides a high-entropy intermetallic compound, its preparation method, and its applications, belonging to the field of catalysts. The preparation method of this invention includes the following steps: mixing zinc salt, erbium salt, nickel salt, platinum salt, iron salt, cobalt salt, organic ligand, and water for a hydrothermal reaction to obtain a precursor; annealing the precursor in a reducing gas to undergo a reduction reaction, thereby obtaining the high-entropy intermetallic compound. A significant characteristic of the high-entropy intermetallic compound prepared by this invention is that Pt atoms at atomic steps and interfaces can undergo dynamic migration and self-repair reconstruction, which accelerates proton transfer and improves catalyst activity. Furthermore, due to the migration of Pt atoms, the amorphous Brønsted acid layer can be reconstructed in situ at the interface during the reaction. Frank incomplete dislocations and defects appearing during the reaction promote the formation of Brønsted acid active sites, improving the intrinsic activity of the catalyst.

Description

Technical Field

[0001] This invention relates to the field of catalysts, specifically to a high-entropy intermetallic compound, its preparation method, and its applications. Background Technology

[0002] Earth possesses extremely abundant seawater resources, which, as a raw material for hydrogen electrolysis, greatly reduce dependence on traditional fossil fuels. However, impurities in seawater can cause metals to dissolve from the catalyst surface, significantly affecting the catalyst's activity and stability.

[0003] Researchers have developed various strategies, such as functional modification of nanomaterial structures and selection of corrosion-resistant alloy electrode materials, to delay chloride ion corrosion of the anode. However, the catalytic activity and stability of materials used in seawater electrolysis remain low. Summary of the Invention

[0004] This invention provides a high-entropy intermetallic compound, its preparation method, and its application. The high-entropy intermetallic compound prepared by this invention exhibits good catalytic activity and stability when used for hydrogen production via water electrolysis.

[0005] This invention provides a method for preparing high-entropy intermetallic compounds, comprising the following steps: A precursor is obtained by hydrothermal reaction of zinc salt, erbium salt, nickel salt, platinum salt, iron salt, cobalt salt, organic ligand and water. The precursor is annealed in a reducing gas to undergo a reduction reaction, yielding the high-entropy intermetallic compound.

[0006] Preferably, the zinc salt includes one or more of zinc chloride, zinc nitrate, and zinc acetate; the erbium salt includes one or more of erbium chloride, erbium nitrate, and erbium acetate; the nickel salt includes one or more of nickel chloride, nickel nitrate, and nickel acetate; the platinum salt includes one or more of platinum chloride, platinum nitrate, and platinum acetate; the iron salt includes one or more of ferric chloride, ferric nitrate, and ferric acetate; and the cobalt salt includes one or more of cobalt chloride, cobalt nitrate, and cobalt acetate.

[0007] Preferably, the molar ratio of the zinc salt to the erbium salt is 4~6:1; The molar ratio of the erbium salt to the nickel salt is 4~6:1; The molar ratio of the erbium salt to the platinum salt is 4~6:1; The molar ratio of the erbium salt to the iron salt is 4~6:1; The molar ratio of erbium salt to cobalt salt is 4~6:1.

[0008] Preferably, the molar ratio of the zinc salt to the organic ligand is 2~3:4; The organic ligand includes glycine.

[0009] Preferably, the hydrothermal reaction is carried out at a temperature of 200°C for 720 minutes.

[0010] Preferably, the reducing gas includes hydrogen; The annealing temperature is 600~800℃, and the time is 3~5h.

[0011] Preferably, after annealing, the process further includes: activating the obtained product by mixing it with a perchloric acid solution.

[0012] This invention also provides high-entropy intermetallic compounds prepared by the preparation method described in the above technical solution.

[0013] This invention also provides the application of the high-entropy intermetallic compounds described in the above technical solution in hydrogen production by water electrolysis.

[0014] Preferably, the water is seawater.

[0015] This invention synthesizes a novel high-entropy intermetallic compound (ZnErNiPtFeCo-HEI) with an innovative structure using hydrothermal and reduction methods. Its significant feature is the dynamic migration and self-repairing reconstruction of Pt atoms at the atomic steps and interfaces in the ZnErNiPtFeCo-HEI prepared by the hydrothermal and reduction methods. This accelerates proton transfer and enhances catalyst activity. Furthermore, due to the migration of Pt atoms, the amorphous Brønsted acid layer can be reconstructed in situ at the interface during the reaction. Frankl incomplete dislocations and defects appearing during the reaction promote the formation of Brønsted acid active sites, enhancing the supply and transfer of H-reaction intermediates, and successfully controlling the reaction process. The reaction energy barrier of the H reaction intermediate enhances the intrinsic activity of the catalyst. The results of the examples show that the ZnErNiPtFeCo-HEI catalyst prepared in this invention is highly effective in the hydrogen evolution reaction in seawater: the high-entropy intermetallic compound (ZnErNiPtFeCo-HEI) catalyst, consisting of zinc, erbium, nickel, platinum, iron, and cobalt, is highly effective in the electrolysis of seawater at a current density of 10 mA cm⁻¹. -2 It exhibits an overpotential as low as 49 mV and maintains good stability over 1000 hours, demonstrating excellent performance in hydrogen production from seawater electrolysis.

[0016] Furthermore, the high-entropy intermetallic compounds prepared in this invention are applied to solar-powered seawater electrolysis systems, representing a significant advancement in sustainable energy conversion. Attached Figure Description

[0017] Figure 1 The diagram shows the process flow, core effect diagram, HAADF-STEM image, strain analysis results, three-dimensional atomic resolution image, and EDS image for the preparation of high-entropy intermetallic compounds in Example 1. Figure 2 High-resolution XPS Fe 2p and Ni 2p spectra of the intermetallic compounds PtErCoNiFeZn, ErCoNiFeZn, CoNiFeZn and NiFeZn prepared in Example 1; Figure 3 High-resolution XPS Er 2p and Co 2p spectra of the PtErCoNiFeZn and ErCoNiFeZn intermetallic compounds prepared in Example 1; Figure 4 The in-situ X-ray image, in-situ Raman image, and in-situ infrared spectrum of PtErCoNiFeZn prepared in Example 1 are shown below. Figure 5 Density functional theory calculation results for PtErCoNiFeZn and ErCoNiFeZn prepared in Example 1; Figure 6 The overpotentials of the hydrogen evolution reaction of PtErCoNiFeZn prepared in Example 1 in different electrolytes. Detailed Implementation

[0018] This invention provides a method for preparing high-entropy intermetallic compounds, comprising the following steps: A precursor is obtained by hydrothermal reaction of zinc salt, erbium salt, nickel salt, platinum salt, iron salt, cobalt salt, organic ligand and water. The precursor is annealed in a reducing gas to undergo a reduction reaction, yielding the high-entropy intermetallic compound.

[0019] This invention involves mixing zinc salt, erbium salt, nickel salt, platinum salt, iron salt, cobalt salt, organic ligand, and water to carry out a hydrothermal reaction to obtain a precursor.

[0020] In this invention, the molar ratio of zinc salt to erbium salt is preferably 4 to 6:1, and in a specific embodiment of this invention it can be 5:1; the zinc salt preferably includes one or more of zinc chloride, zinc nitrate and zinc acetate, and the erbium salt preferably includes one or more of erbium chloride, erbium nitrate and erbium acetate.

[0021] In this invention, the molar ratio of erbium salt to nickel salt is preferably 4 to 6:1, and in a specific embodiment of this invention it can be 5:1; the nickel salt preferably includes one or more of nickel chloride, nickel nitrate and nickel acetate.

[0022] In this invention, the molar ratio of erbium salt to platinum salt is preferably 4 to 6:1, and in a specific embodiment of this invention it can be 5:1; the platinum salt preferably includes one or more of platinum chloride, platinum nitrate and platinum acetate.

[0023] In this invention, the molar ratio of erbium salt to iron salt is preferably 4 to 6:1, and in a specific embodiment of this invention it can be 5:1; the iron salt preferably includes one or more of ferric chloride, ferric nitrate and ferric acetate.

[0024] In this invention, the molar ratio of erbium salt to cobalt salt is preferably 4 to 6:1, and in a specific embodiment of this invention it can be 5:1; the cobalt salt preferably includes one or more of cobalt chloride, cobalt nitrate and cobalt acetate.

[0025] In this invention, the molar ratio of the zinc salt to the organic ligand is preferably 2-3:4, and in a specific embodiment of this invention, it can be 2.5:4; the organic ligand preferably includes glycine. The organic ligand provides a substrate and, by forming chelate / coordination complexes with different metal ions, homogenizes the reaction kinetics of the precursor, promoting the simultaneous decomposition or co-reduction of multiple metals.

[0026] In this invention, the preferred ratio of zinc salt to water is 0.4~0.6 mmol:1L.

[0027] In this invention, the preferred temperature for the hydrothermal reaction is 200°C, and the preferred time is 720 min.

[0028] After the hydrothermal reaction, the present invention preferably further includes drying the resulting reaction system.

[0029] After obtaining the precursor, the present invention anneales the precursor in a reducing gas to induce a reduction reaction, thereby obtaining the high-entropy intermetallic compound. Annealing induces a reduction reaction and simultaneously removes the organic ligands.

[0030] In this invention, the reducing gas is preferably in a flowing state, and the reducing gas preferably includes hydrogen.

[0031] In this invention, the annealing temperature is preferably 600~800℃ and the annealing time is preferably 3~5h. In specific embodiments of this invention, the annealing temperature can be 650℃, 700℃ or 750℃ and the annealing time can be 3.5h, 4h or 4.5h.

[0032] After annealing, the present invention preferably further includes: activating the obtained product by mixing it with a perchloric acid solution.

[0033] In this invention, the concentration of the perchloric acid solution is preferably 0.2~0.4 mol / L; the activation time is preferably 0.5 h. Activation can remove free metals, residual impurities, and disordered thin layers on the surface, and can also perform light etching to expose highly active surface sites.

[0034] After activation, the present invention preferably further includes: separating and drying the obtained product.

[0035] This invention also provides high-entropy intermetallic compounds prepared by the preparation method described in the above technical solution.

[0036] In this invention, the high-entropy intermetallic compound is preferably a particle with a particle size of 100-300 nm. In specific embodiments of this invention, the particle size can be 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, or 190 nm.

[0037] This invention also provides the application of the high-entropy intermetallic compounds described in the above technical solution in hydrogen production by water electrolysis.

[0038] In this invention, the electricity used for hydrogen production by water electrolysis is preferably from solar energy, and the water is preferably seawater.

[0039] The following detailed description, in conjunction with embodiments, illustrates the high-entropy intermetallic compounds, their preparation methods, and applications provided by this invention. However, these descriptions should not be construed as limiting the scope of protection of this invention.

[0040] Example 1 (1) Dissolve 0.4 mmol of zinc chloride, 0.1 mmol of erbium chloride, 0.1 mmol of nickel chloride, 0.1 mmol of chloroplatinic acid, 0.1 mmol of ferric chloride, 0.1 mmol of cobalt chloride and 0.8 mmol of glycine in 1 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 200 °C for 720 min. After hydrothermal reaction, place the resulting system in an oven to dry. (2) Grind the dried salt powder thoroughly for 10 min and anneal it at 600℃ for 3 h under a H2 / Ar mixed gas flow with a hydrogen gas integral of 10%.

[0041] (3) The material obtained in step (2) is placed in 0.2 M HClO4 solution for 0.5 h, centrifuged and dried overnight to obtain the finished product.

[0042] Example 2 (1) Dissolve 0.5 mmol of zinc chloride, 0.1 mmol of erbium chloride, 0.1 mmol of nickel chloride, 0.1 mmol of chloroplatinic acid, 0.1 mmol of ferric chloride, 0.1 mmol of cobalt chloride and 0.8 mmol of glycine in 1 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 200 °C for 720 min. After hydrothermal reaction, place the resulting system in an oven to dry. (2) Grind the dried salt powder thoroughly for 10 min and anneal it at 700 °C for 4 h under a 10% H2 / Ar mixed gas flow with a hydrogen gas integral of 10%.

[0043] (3) The material obtained in step (2) is placed in 0.3 M HClO4 solution for 0.5 h, centrifuged and dried overnight to obtain the finished product.

[0044] Example 3 (1) Dissolve 0.6 mmol of zinc chloride, 0.1 mmol of erbium chloride, 0.1 mmol of nickel chloride, 0.1 mmol of chloroplatinic acid, 0.1 mmol of ferric chloride, 0.1 mmol of cobalt chloride and 0.8 mmol of glycine in 1 mL of deionized water. After complete dissolution, perform hydrothermal reaction at 200 °C for 720 min. After hydrothermal reaction, place the resulting system in an oven to dry. (2) Grind the dried salt powder thoroughly for 10 min and anneal it at 800℃ for 5 h under a 10% H2 / Ar mixed gas flow with a hydrogen gas integral of 10%.

[0045] (3) The material obtained in step (2) is placed in 0.4 M HClO4 solution for 0.5 h, centrifuged and dried overnight to obtain the finished product.

[0046] Comparative Example 1 The only difference from Example 1 is that platinum chloride was not added, resulting in ErCoNiFeZn.

[0047] Comparative Example 2 The only difference from Example 1 is that platinum chloride and erbium chloride were not added, resulting in CoNiFeZn.

[0048] Comparative Example 3 The only difference from Example 1 is that platinum chloride, erbium chloride, and cobalt chloride were not added, resulting in NiFeZn.

[0049] Figure 1 The diagram shows the process flow, core effect diagram, HAADF-STEM image, strain analysis results, three-dimensional atomic resolution image, and EDS image for the preparation of high-entropy intermetallic compounds in Example 1.

[0050] Figure 1 In Figure 'a', the process diagram for preparing high-entropy intermetallic compounds is shown. Figure 1 Schematic diagram of b and c as the core effects; Figure 1 In the image, d~k represents the HAADF-STEM image of PtErCoNiFeZn prepared in Example 1; Figure 1 The strain analysis results of PtErCoNiFeZn prepared in Example 1 were performed using GPA. Figure 1In the image, j is a three-dimensional atomic resolution image of PtErCoNiFeZn prepared in Example 1, showing the intensity distribution. Figure 1 The values ​​l to q are EDS diagrams of PtErCoNiFeZn prepared in Example 1.

[0051] Depend on Figure 1 It can be seen that the successful synthesis of the catalyst resulted in a uniform distribution of metal elements.

[0052] Figure 2 High-resolution XPS Fe 2p and Ni 2p spectra of the intermetallic compounds PtErCoNiFeZn, ErCoNiFeZn, CoNiFeZn and NiFeZn prepared in Example 1.

[0053] Depend on Figure 2 It can be seen that the strain effect causes the binding energy of surface metal elements (Fe / Ni) to shift.

[0054] Figure 3 High-resolution XPS Er 2p and Co 2p spectra of the PtErCoNiFeZn and ErCoNiFeZn intermetallic compounds prepared in Example 1.

[0055] Depend on Figure 3 It can be seen that the strain effect causes the binding energy of surface metal elements (Er / Co) to shift.

[0056] Figure 4 The in-situ X-ray image, in-situ Raman image, and in-situ infrared spectrum of PtErCoNiFeZn prepared in Example 1 are shown.

[0057] pass Figure 4 The adaptively constructed amorphous Brønsted acid layer was further validated.

[0058] Figure 5 Density functional theory calculation results for PtErCoNiFeZn and ErCoNiFeZn prepared in Example 1.

[0059] Depend on Figure 5 It can be seen that strain and reconstruction effects significantly modulate the Pt metal sites on the PECNFZ-HEI (PtErCoNiFeZn) surface. The adsorption energy of OH is reduced, thus effectively lowering the energy barrier of the catalytic reaction. Under tensile strain, the d-band center shifts towards the Fermi level, leading to a decrease in the filling degree of antibonding orbitals, thereby enhancing the stability of the adsorbed state. Compressive strain moves the d-band center away from the Fermi level, increasing the filling degree of antibonding states and lowering the desorption energy barrier of the adsorption intermediates.

[0060] Electrochemical measurements were performed on a CHI 760E electrochemical workstation using a standard three-electrode system in 1M KOH (1), 1M KOH + 0.5M NaCl (2), and 1M KOH + Seawater (3) (deionized water was used as the solvent in (1) and (2)). A high-entropy intermetallic compound served as the working electrode, a platinum sheet as the counter electrode, and an Hg / HgO electrode as the reference electrode. Before recording the polarization curves, cyclic voltammetry was used at 50 mV s⁻¹. -1 The electrode was activated 500 times at a scan rate until the voltammogram became stable and repeatable. The polarization curve was measured at 5 mV / s. -1 The scan rate was recorded. Electrochemical impedance spectroscopy (EIS) was performed at a given potential from 100 kHz to 0.1 Hz with an AC amplitude of 10 mV. Overall water splitting was conducted using the above solution in a two-electrode system, and polarization curves were obtained at 5 mV s⁻¹. -1 The scan rate was recorded. All polarization curves were compensated for with 90% iR.

[0061] Figure 6 The overpotentials of the hydrogen evolution reaction of PtErCoNiFeZn prepared in Example 1 in different electrolytes.

[0062] Table 1. Hydrogen evolution reaction overpotentials of the products obtained in Examples 1-3

[0063] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-entropy intermetallic compound, characterized in that, Includes the following steps: A precursor is obtained by hydrothermal reaction of zinc salt, erbium salt, nickel salt, platinum salt, iron salt, cobalt salt, organic ligand and water. The precursor is annealed in a reducing gas to undergo a reduction reaction, yielding the high-entropy intermetallic compound.

2. The preparation method according to claim 1, characterized in that, The zinc salt includes one or more of zinc chloride, zinc nitrate, and zinc acetate; the erbium salt includes one or more of erbium chloride, erbium nitrate, and erbium acetate; the nickel salt includes one or more of nickel chloride, nickel nitrate, and nickel acetate; the platinum salt includes one or more of platinum chloride, platinum nitrate, and platinum acetate; the iron salt includes one or more of ferric chloride, ferric nitrate, and ferric acetate; and the cobalt salt includes one or more of cobalt chloride, cobalt nitrate, and cobalt acetate.

3. The preparation method according to claim 1 or 2, characterized in that, The molar ratio of the zinc salt to the erbium salt is 4~6:1; The molar ratio of the erbium salt to the nickel salt is 4~6:1; The molar ratio of the erbium salt to the platinum salt is 4~6:1; The molar ratio of the erbium salt to the iron salt is 4~6:1; The molar ratio of erbium salt to cobalt salt is 4~6:

1.

4. The preparation method according to claim 1, characterized in that, The molar ratio of the zinc salt to the organic ligand is 2~3:4; The organic ligand includes glycine.

5. The preparation method according to claim 1, characterized in that, The hydrothermal reaction was carried out at a temperature of 200°C for 720 minutes.

6. The preparation method according to claim 1, characterized in that, The reducing gas includes hydrogen; The annealing temperature is 600~800℃, and the time is 3~5h.

7. The preparation method according to claim 1, characterized in that, After annealing, the process further includes: activating the obtained product by mixing it with a perchloric acid solution.

8. The high-entropy intermetallic compound prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the high-entropy intermetallic compound of claim 8 in hydrogen production by water electrolysis.

10. The application according to claim 9, characterized in that, The water in question is seawater.

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