High-entropy metal sulfide nano material and preparation method thereof

Abstract

The invention discloses a high-entropy metal sulfide nano material and a preparation method thereof, and relates to the field of high-entropy materials.Transition metal chlorate and sodium chloride are placed in a first reaction boat in the upstream area of a reaction container; placing the zinc sulfide nano-template in a second reaction boat in a downstream area of the reaction container; heating the reaction container to 500-525 DEG C at a first heating rate, keeping the temperature for 20-40 minutes, and transporting metal chloride gas volatilized by the eutectic effect of the precursor to a second reaction boat in a downstream area along with the dynamic airflow, so that the zinc sulfide nano-template reacts with the metal chloride gas; and cooling to room temperature at a second cooling rate, and collecting a solid product in the second reaction boat to obtain the high-entropy metal sulfide nano material. According to the method, the complex microstructure of the precursor template can be copied, and topological conversion is realized; and the chemical morphology, the components, the crystal structure and the like of the high-entropy nano material can be regulated and controlled.

Description

Technical Field

[0001] This invention relates to the field of high-entropy materials, specifically to a high-entropy metal sulfide nanomaterial and its preparation method. Background Technology

[0002] High-entropy materials, especially high-entropy sulfides, have shown great application potential in electrochemical energy storage, electrocatalysis, and photocatalysis. Compared with traditional binary or ternary sulfides, high-entropy sulfides, by introducing five or more metal elements to form a single-phase solid solution, can significantly modulate the electronic structure of the material, maximize the density of active sites, and improve structural stability. However, their synthesis is extremely challenging due to the large differences in atomic / ionic radii and the high requirements for mixing entropy increase in multi-component systems.

[0003] Existing methods for synthesizing high-entropy materials, such as Joule heating, arc discharge, and high-temperature solid-state sintering, typically rely on ultra-high temperatures (>1000℃) to melt or rapidly diffuse the raw materials, followed by rapid quenching to freeze the high-temperature disordered solid solution state to room temperature. While this synthesis route enables rapid mixing of multiple components, the ultra-high temperatures and rapid cooling place extremely high demands on equipment, making large-scale deployment difficult. Furthermore, high temperatures easily lead to severe agglomeration and grain coarsening of nanoparticles, resulting in a significant reduction in the material's specific surface area and making it difficult to retain the fine microstructure of precursors, such as porous or hollow structures, thus limiting its performance in applications requiring high specific surface area.

[0004] While solvothermal / hydrothermal methods can synthesize nanomaterials at relatively low temperatures, the reaction system suffers from liquid phase surface tension. During drying, capillary forces easily lead to the collapse and adhesion of porous or sheet-like structures. Furthermore, the hydrolysis rates and precipitation kinetics of different metal ions in the liquid phase vary greatly, making it difficult to achieve atomic-level homogeneous mixing of more than five metal elements. This often results in the formation of multiphase mixtures rather than a single high-entropy solid solution.

[0005] Chemical vapor deposition (CVD) is commonly used to prepare high-quality two-dimensional sulfide films or nanosheets, such as the growth of ZnS on a substrate using zinc powder and sulfur source gas. However, traditional CVD processes typically rely on toxic gases such as H2S and CS2 as sulfur sources and are mainly suitable for growing epitaxial films on specific substrates. They are difficult to mass-produce independent powder materials with complex three-dimensional morphologies, such as macroporous or hollow spheres. More importantly, when introducing multiple metal precursors, the significant differences in volatilization temperature and reactivity of each metal-organic source or halide make it extremely difficult to control the stoichiometry of the components, leading to uneven product composition.

[0006] Template methods have been extensively studied to control the microstructure of sulfides. Current ZnS template transformations are mostly carried out in the liquid phase, utilizing ion exchange between ZnS and a metal salt solution. However, this method is limited by the mass transfer resistance in the liquid phase, resulting in a slow reaction rate. Furthermore, as mentioned earlier, the liquid phase environment easily damages the fragile structure of the template.

[0007] Although gas-solid reactions can avoid disrupting the surface tension of the liquid phase, traditional gas-solid reactions between metal chlorides and ZnS typically require high temperatures (>700℃) to overcome the reaction energy barrier and allow the metal chlorides to fully volatilize and participate in the reaction. At high temperatures, the ZnS template is prone to sintering, phase transformation, or structural collapse, thus negating the benefits of the template method.

[0008] Therefore, how to simultaneously drive the reaction of multiple metal chlorides with vastly different volatility with ZnS at low temperatures and form a uniform high-entropy solid solution is an urgent problem that needs to be solved. Summary of the Invention

[0009] The purpose of this invention is to provide a high-entropy metal sulfide nanomaterial and its preparation method. Under low-temperature conditions, through a gas-solid reaction mechanism, it is possible to achieve atomic-level uniform mixing of multiple metal elements and to regulate their chemical morphology, composition, crystal structure and other microstructures.

[0010] The first objective of the invention is a method for preparing high-entropy metal sulfide nanomaterials, comprising the following steps:

[0011] Step 1: The precursor is placed in the first reaction boat in the upstream region of the reaction vessel, wherein the precursor includes sodium chloride and at least four transition metal chloride salts;

[0012] Step 2: Place the zinc sulfide nanotemplate in the second reaction boat in the downstream region of the reaction vessel;

[0013] Step 3: The reaction vessel is subjected to at least three cycles of inert gas purging and discharging to remove air;

[0014] Step 4: Inert gas is introduced upstream of the reaction vessel and the downstream of the reaction vessel is evacuated to form a dynamic airflow from upstream to downstream in the reaction vessel, so that the pressure inside the reaction vessel is 200~300Pa.

[0015] Step 5: Heat the reaction vessel to 500~525℃ at the first heating rate and hold for 20~40 min. The metal chloride gas volatilized by the eutectic effect of the precursor is transported to the second reaction boat in the downstream region by the dynamic gas flow, so that the zinc sulfide nanotemplate reacts with the metal chloride gas.

[0016] Step 6: Cool to room temperature at the second cooling rate, collect the solid product in the second reaction boat, and obtain high-entropy metal sulfide nanomaterials.

[0017] In this invention, sodium chloride is used as a flux. Transition metal chlorides typically have high melting points or high sublimation temperatures. When sodium chloride is added to transition metal chlorides, the two form a eutectic mixture, which lowers the evaporation temperature of the transition metal chlorides by approximately 200-300°C. Simultaneously, under a low pressure environment of 200-300 Pa, the evaporation temperature of the transition metal chlorides is further reduced by approximately 100-200°C, promoting the generation of metal chloride gas and its rapid downstream transport.

[0018] Finally, at a relatively low reaction temperature of 500~525℃, zinc sulfide undergoes a gas-solidification chemical reaction with metal chloride gas, namely:

[0019] ZnS + MCl2 = MS + ZnCl2; where M is Fe, Co, Ni, Cu, etc.

[0020] The product ZnCl2 has an extremely high saturated vapor pressure at the reaction temperature, while its partial pressure remains consistently low. According to Le Chatelier's principle, the equilibrium strongly shifts towards the forward reaction, thus thermodynamically driving the reaction to proceed completely at a lower temperature. In this reaction, because the ZnCl2 byproduct has a relatively high saturated vapor pressure, it can be rapidly discharged from the reaction vessel. Therefore, due to Le Chatelier's principle, the chemical reaction shifts to the forward direction, propelling the entire reaction to occur.

[0021] Furthermore, the precursors include sodium chloride and four transition metal chlorides: ferrous chloride, cobalt chloride, nickel chloride, and cuprous chloride. Ferrous chloride, cobalt chloride, nickel chloride, and cuprous chloride exhibit excellent miscibility with the flux sodium chloride and can form significant eutectic mixtures. In addition to the aforementioned four transition metal chlorides, other precursors may include cadmium chloride, manganese chloride, lead chloride, indium chloride, and silver chloride.

[0022] Many metals (Fe, Co, Ni, Cu) can undergo the above chemical reactions to obtain high-entropy nanomaterials, such as Fe. 0.21 Co 0.19 Ni 0.17 Cu 0.38 Zn 0.24 S, and thus the present invention can regulate the chemical composition of high-entropy nanomaterials.

[0023] This invention utilizes a topological chemical transformation mechanism and the Kirkendall effect. Under low-temperature conditions, gaseous transition metal chlorides diffuse to the surface and internal pores of zinc sulfide nanotemplates, undergoing a displacement reaction with zinc sulfide. Due to the difference between the outward diffusion rate of zinc ions and the inward diffusion rate of metal ions, as well as the rapid escape of the byproduct zinc chloride gas, the reaction proceeds layer by layer while maintaining the integrity of the original framework.

[0024] Crucially, the unique low-temperature reaction conditions of this invention effectively suppress grain coarsening and sintering at high temperatures. This allows the product to replicate the microstructure of the zinc sulfide precursor. Specifically, the zinc sulfide nanotemplate has various morphologies and crystal structures, including spherical, sheet-like, and three-dimensional macroporous structures. After the above reaction, the high-entropy nanomaterial can maintain the original template's morphology and crystal structure.

[0025] Therefore, this method can directionally control the microstructure of the final high-entropy metal sulfide nanomaterials by simply selecting zinc sulfide templates with different morphologies, and obtain functional materials with high specific surface area, abundant active sites and excellent mass transfer channels, which is difficult to achieve by traditional high-temperature solid-state methods or conventional hydrothermal methods.

[0026] Preferably, the zinc sulfide nanotemplate is zinc sulfide nanoparticle powder, zinc sulfide nanosheet powder, or zinc sulfide nano three-dimensional macroporous powder.

[0027] Preferably, in step 1, the transition metal chloride salt and sodium chloride are mixed and ground until a uniformly mixed powdered precursor is obtained, and the powdered precursor is placed in the first reaction boat in the upstream region of the reaction vessel.

[0028] The powdered precursor ensures sufficient contact area between the transition metal chloride and sodium chloride to rapidly form a eutectic mixture. Furthermore, within a particle size range of 60-80 μm, it effectively prevents the precursor powder from being accidentally blown away or carried away in a dynamic carrier gas flow field, ensuring the stable and continuous volatilization and transport of the reactants to the downstream reaction zone.

[0029] The inner diameter of the reaction vessel is 55-65 mm, and the distance between the first and second reaction boats is 10-20 mm. The downstream evacuation rate of the reaction vessel is 5-10 m / s. 3 / h. The first heating rate is 8~15℃ / min. The second cooling rate is 10~15℃ / min.

[0030] The reaction vessel has an inner diameter of 55~65mm and a diameter of 5~10m. 3 A pumping rate of / h creates an optimal flow field match. Under this geometric scale and velocity combination, a stable laminar flow field can be formed within the reaction chamber, effectively avoiding vortex mixing caused by turbulence. This stable plug flow ensures that the metal chloride vapor can be directionally and uniformly transported to the downstream growth zone. This prevents excessively high gas velocity due to excessively narrow pipe diameter, which would result in insufficient residence time for reactants and direct extraction. It also avoids dead zones caused by excessively large pipe diameter, which would lead to the accumulation of byproduct ZnCl2 and inhibit the forward reaction.

[0031] At the same time, the high-speed dynamic airflow can instantly carry the generated volatile ZnCl2 away from the reaction interface. According to Le Chatelier's principle, the extremely low partial pressure of by-products causes the displacement reaction equilibrium to shift strongly to the right, ensuring that the reaction can proceed completely even at a relatively low temperature of 500~525℃, and ensuring that the multi-component metal source is continuously supplied in a constant proportion, which is to achieve a uniform distribution of atomic-level components in high-entropy materials.

[0032] Secondly, the 10-20 mm distance between the first and second reaction boats prevents the template from sintering, agglomerating, or undergoing crystal transformation due to localized overheating, thus ensuring that the high-entropy product perfectly inherits the microstructure of the original template. Simultaneously, it drives the reactants to preferentially undergo heterogeneous nucleation and epitaxial growth on the zinc sulfide template surface, achieving a topological chemical transformation from template to product.

[0033] During the heating phase, the rapid rate of heating allows the system to quickly traverse the initial melting zone of the precursor, prompting the metal chlorides to concentrate and enter the gas phase upon reaching the target reaction temperature, thus improving the nucleation density and uniformity in the early stages of the reaction. In the cooling phase after the reaction, rapid cooling effectively suppresses long-range atomic diffusion and grain coarsening at high temperatures, freezing the size of high-entropy sulfide nanocrystals at the nanoscale. This effectively prevents grain growth, sintering agglomeration, or multiphase separation caused by slow cooling. This is crucial for maintaining fine nanostructures such as spherical, plate-like, or three-dimensional macroporous structures, ensuring that the final product has a high specific surface area and abundant active sites.

[0034] On the other hand, high-entropy metal sulfide nanomaterials were prepared according to the above preparation method.

[0035] The weight ratio of transition metal chloride to sodium chloride is 10~12:5~6. The weight ratio of zinc sulfide nanotemplate to transition metal chloride is 1~2:10~12.

[0036] Sodium chloride, as an inert flux, effectively encapsulates and disperses metal chloride microcrystals in the composition of this invention, preventing localized sintering or agglomeration at high temperatures and ensuring stable volatilization of the metal components in the form of monomolecules or small clusters. If the sodium chloride content is too high, it will excessively dilute the metal source concentration, reducing the reaction rate; if the sodium chloride content is too low, a continuous eutectic liquid phase network cannot be formed, leading to asynchronous volatilization and component segregation.

[0037] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0038] Traditional high-entropy material synthesis typically relies on ultra-high temperature environments exceeding 1000°C to overcome atomic diffusion barriers, resulting in extremely high energy consumption and stringent requirements for equipment heat resistance. This invention presents a high-entropy metal sulfide nanomaterial and its preparation method. Through a low-eutectic salt medium and dynamic gas-phase transport approach, the activation energy of the reaction is significantly reduced, successfully lowering the core reaction temperature to 500–525°C. This improvement lowers the reaction temperature by approximately 50%, substantially reducing heat energy consumption, while effectively avoiding the abnormal grain growth and agglomeration phenomena commonly seen at high temperatures.

[0039] Traditional ultra-high temperature quenching methods often require up to 10... 5 The extreme cooling rate of ℃ / s poses a significant challenge to the cooling system and operational control, and also presents considerable safety hazards. In contrast, this invention achieves the construction of high-quality crystal structures with a cooling rate of 10~15℃ / min. This invention reduces the difficulty of process operation and the technical threshold, making this scheme easy to scale up in conventional tube furnace systems, and has good prospects for industrial application.

[0040] This invention can replicate the complex microstructure of precursor templates to achieve topological transformation; it can also utilize a continuous gas phase supply and byproduct removal mechanism to ensure uniform doping of multiple metal elements at the atomic scale and eliminate local segregation; and it can control the chemical morphology, composition, crystal structure, etc. of high-entropy nanomaterials. Attached Figure Description

[0041] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0042] Figure 1 -A is a scanning electron microscope (SEM) image of the high-entropy sulfide nanomaterials prepared in Example 1;

[0043] Figure 1 -B is the X-ray diffraction (XRD) pattern of the high-entropy sulfide nanomaterials prepared in Example 1;

[0044] Figure 1 -C is the energy scattering spectrum (EDS) of the high-entropy sulfide nanomaterials prepared in Example 1;

[0045] Figure 2 -A is the thermogravimetric curve of the high-entropy sulfide nanomaterial prepared in Example 1;

[0046] Figure 2 -B is the anodic polarization curve of the high-entropy sulfide nanomaterial prepared in Example 1;

[0047] Figure 3-A is a scanning electron microscope (SEM) image of the high-entropy sulfide nanomaterials prepared in Example 2;

[0048] Figure 3 -B is the X-ray diffraction (XRD) pattern of the high-entropy sulfide nanomaterials prepared in Example 2;

[0049] Figure 3 -C is the energy scattering spectrum (EDS) of the high-entropy sulfide nanomaterials prepared in Example 2;

[0050] Figure 4 -A is a scanning electron microscope (SEM) image of the high-entropy sulfide nanomaterials prepared in Example 3;

[0051] Figure 4 -B is the X-ray diffraction (XRD) pattern of the high-entropy sulfide nanomaterial prepared in Example 3;

[0052] Figure 4 -C is the energy scattering spectrum (EDS) of the high-entropy sulfide nanomaterials prepared in Example 3;

[0053] Figure 5 -A is a scanning electron microscope (SEM) image of the high-entropy sulfide nanomaterials prepared in Example 4;

[0054] Figure 5 -B is the X-ray diffraction (XRD) pattern of the high-entropy sulfide nanomaterial prepared in Example 4;

[0055] Figure 6 -A is a scanning electron microscope (SEM) image of the high-entropy sulfide nanomaterials prepared in Example 5;

[0056] Figure 6 -B is the X-ray diffraction (XRD) pattern of the high-entropy sulfide nanomaterial prepared in Example 5;

[0057] Figure 7 -A is a scanning electron microscope (SEM) image of the high-entropy sulfide nanomaterials prepared in Example 6;

[0058] Figure 7 -B is the X-ray diffraction (XRD) pattern of the high-entropy sulfide nanomaterial prepared in Example 6. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. However, this does not limit the invention to the scope of the embodiments described. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0060] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0061] Example 1

[0062] A method for preparing high-entropy metal sulfide nanomaterials includes the following steps:

[0063] Step 1: Mix 11 parts of transition metal chloride and 5.5 parts of sodium chloride and grind them until a uniformly mixed powdered precursor is obtained. The particle size of the powdered precursor is 75 μm. Place the powdered precursor in the first reaction boat in the upstream region of the reaction vessel.

[0064] Step 2: Place 1.5 parts of zinc sulfide nanoparticle powder into the second reaction boat in the downstream region of the reaction vessel; wherein, the inner diameter of the reaction vessel is 60 mm, and the distance between the first reaction boat and the second reaction boat is 15 mm;

[0065] Step 3: Place the reaction vessel in a tube furnace and perform three cycles of inert gas purging and discharging to remove air.

[0066] Step 4: Inert gas is introduced upstream of the reaction vessel at 5 sccm. An oil pump is connected downstream of the reaction vessel to evacuate the gas at a rate of 8 m / s. 3 / h, forming a dynamic airflow from upstream to downstream in the reaction vessel, making the pressure in the reaction vessel 200Pa;

[0067] Step 5: The reaction vessel is heated to 525°C at a first heating rate of 10°C / min and held for 30 min. The metal chloride gas volatilized by the eutectic effect of the precursor is transported to the second reaction boat in the downstream region by the dynamic gas flow, so that the zinc sulfide nanoparticles react with the metal chloride gas.

[0068] Step 6: Cool to room temperature at a second cooling rate of 10℃ / min, collect the solid product in the second reaction boat, and obtain high-entropy metal sulfide nanomaterials.

[0069] The first and second reaction boats can be quartz boats, alumina boats, magnesium oxide boats, or boron nitride boats.

[0070] The reaction vessel is a tubular structure and can be made of quartz glass, high-purity alumina ceramic, or corundum-mullite multiphase ceramic.

[0071] In some embodiments, the inert gas is nitrogen or argon.

[0072] This embodiment includes four transition metal chlorides: ferrous chloride, cobalt chloride, nickel chloride, and cuprous chloride.

[0073] Scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy experiments were performed on the high-entropy metal sulfide nanomaterials obtained in this embodiment. The results are as follows: Figure 1 As shown.

[0074] Figure 1 -A shows a scanning electron microscope (SEM) image of the prepared high-entropy sulfide nanomaterials. As can be seen from the image, the product exhibits a uniform spherical particle morphology with a narrow particle size distribution, no obvious large particle agglomerations or irregular lumps, and a simple morphology. This indicates that the preparation method of this invention allows the precursor to diffuse and deposit uniformly on the zinc sulfide template surface, achieving a topological transformation from template to product. The nanoparticle size distribution is in the submicron to micron range, with clear inter-particle boundaries and good dispersion. This is due to the mild reaction temperature of 525℃, which avoids the abnormal grain growth phenomenon commonly seen under traditional ultra-high temperature conditions.

[0075] Figure 1 -B shows the X-ray diffraction (XRD) pattern of the prepared high-entropy sulfide nanomaterials. The high-entropy sulfide nanoparticles are a single phase, with no other impurity peaks appearing. The diffraction peaks are sharp and have high intensity, indicating that the product has good crystallinity. Even at a low temperature of 525℃, this invention can still drive the ordered arrangement of multi-component atoms, overcoming the problem of insufficient atomic diffusion kinetics at low temperatures, and demonstrating the synergistic promoting effect of the low-eutectic salt medium and dynamic gas pressure environment on reducing the reaction activation energy.

[0076] Figure 1 -C represents the energy scattering (EDS) spectrum of the prepared high-entropy sulfide nanomaterials. The characteristic peaks of S, Fe, Co, Ni, Cu, and Zn are clearly detected, confirming the introduction of all designed elements into the target high-entropy system. The coordinated intensity ratios of the characteristic peaks of each metal element, combined with the uniformity of the SEM morphology, indicate that the elements are uniformly distributed within the nanoparticles. This demonstrates that the dynamic airflow not only plays a transport role but also prevents local component segregation through continuous concentration gradient updates, ensuring the achievement of high entropy.

[0077] The thermal and electrochemical stability of the high-entropy metal sulfide nanomaterials obtained in this embodiment were tested.

[0078] Thermogravimetric curves are as follows Figure 2As shown in Figure A, the product's mass decreases by less than 1% when heated from room temperature to 600℃. The material maintains a constant mass at 600℃, demonstrating its excellent thermal stability. The anodic polarization curve is shown below. Figure 2 As shown in Figure B, the product is at 10mAcm -2 At a current density of [value missing], it remained stable for nearly 900 hours without significant degradation. For electrocatalytic or battery materials, a lifetime of 900 hours is a highly competitive indicator. This demonstrates that the material's structure did not collapse and active sites were not lost under strong electric fields and electrolyte corrosion.

[0079] Therefore, this invention not only solves the problem of the difficulty in synthesizing high-entropy materials, but also fundamentally improves the durability of the materials, enabling them to show good application potential in long-term industrial applications.

[0080] Example 2

[0081] Based on Example 1, 1.5 parts of zinc sulfide nanoparticle powder were replaced with 1.5 parts of zinc sulfide nanosheet powder.

[0082] In step 5, the reaction vessel is heated to 500°C at a first heating rate of 10°C / min and held at that temperature for 30 min. The metal chloride gas volatilized from the eutectic effect of the precursor is transported to the second reaction boat in the downstream region by a dynamic gas flow, allowing the zinc sulfide nanosheet powder to react with the metal chloride gas. Scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy experiments were performed on the high-entropy metal sulfide nanomaterials obtained in this embodiment. The results are as follows: Figure 3 As shown.

[0083] Depend on Figure 3 As can be seen from -A, the product prepared at 500℃ exhibits a two-dimensional sheet-like structure, consisting of a large number of ultrathin nanosheets stacked and interwoven to form a three-dimensional porous network.

[0084] In this embodiment, the zinc sulfide nanotemplate is zinc sulfide nanosheet powder, thus yielding high-entropy metal sulfide nanosheets. At high temperatures, the sheets tend to agglomerate and aggregate; moreover, compared to nanoparticles, nanosheets have smaller radial dimensions, allowing for easier ion diffusion and thus easier reaction. Therefore, the temperature in this embodiment is lower than the 525°C in Example 1. This demonstrates that the present invention can precisely control the product morphology by fine-tuning the temperature and the zinc sulfide nanotemplate, meeting the needs of different application scenarios.

[0085] Figure 3 -B and Figure 1 The XRD patterns of the -B phases showed no impurity peaks, indicating that temperature changes did not affect the phase purity. This method exhibits excellent phase stability in the 500–525 °C range. Furthermore, this invention can obtain high-purity, high-entropy phases even at lower temperatures, up to 500 °C.

[0086] Figure 3-C detected characteristic peaks of all target elements, including S, Fe, Co, Ni, Cu, and Zn, with the intensity ratios of each metal element peak being coordinated and showing no obvious segregation.

[0087] In summary, the results of Examples 1 and 2 together demonstrate that the present invention can not only efficiently synthesize high-purity, high-entropy metal sulfides at low temperatures, but also precisely control the key properties of the product, such as microstructure, grain size, and specific surface area, by finely adjusting the reaction temperature and changing the morphology of the zinc sulfide nanotemplate.

[0088] Example 3

[0089] Based on Example 1, 1.5 parts of zinc sulfide nanoparticle powder were replaced with 1.5 parts of zinc sulfide nanoparticle macroporous powder. Scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy experiments were performed on the high-entropy metal sulfide nanomaterials obtained in this example. The results are as follows: Figure 4 As shown.

[0090] like Figure 4 As shown in -A, the product inherits the three-dimensional ordered macroporous structure of the precursor template. The image reveals a regularly arranged array of pores, with pore walls composed of an interconnected nanoframework. This indicates that the metal chloride gas not only deposits on the template surface but also penetrates deep into the three-dimensional macropores, achieving cation exchange from the inside out while maintaining the integrity of the macroscopic framework without collapse.

[0091] Figure 4 The XRD pattern of -B shows that, despite the introduction of a complex three-dimensional macroporous structure, the high-entropy sulfide three-dimensional macroporous material is a single phase with no other impurity peaks.

[0092] Figure 4 The EDS spectrum of -C detected characteristic peaks of all target elements: S, Fe, Co, Ni, Cu, and Zn.

[0093] Therefore, by selecting precursor templates with different geometric configurations, this invention can accurately replicate and transform functional materials with specific macroscopic pore structures while maintaining the homogeneity of high-entropy components.

[0094] Example 4

[0095] Based on Example 1, in step 5, the reaction vessel is heated to 490°C at a first heating rate of 10°C / min and held at that temperature for 30min. The metal chloride gas volatilized from the eutectic effect of the precursor is transported to the second reaction boat in the downstream region by a dynamic gas flow, allowing the zinc sulfide nanoparticles to react with the metal chloride gas. Scanning electron microscopy and X-ray diffraction experiments were performed on the high-entropy metal sulfide nanomaterials obtained in this example, and the results are as follows: Figure 5 As shown.

[0096] Figure 5 The SEM image of the -A sample shows that the product particles have blurred outlines, rough and uneven surfaces, indicating an incompletely transformed state. Some areas still retain the aggregated morphology of the precursor and lack clear crystal boundaries.

[0097] Figure 5 The XRD pattern of -B showed obvious impurity peaks. In addition to the target high-entropy sulfide phase, significant ZnS diffraction peaks were also detected.

[0098] 490℃ is slightly lower than the temperature protected by this invention. At this temperature, although the eutectic salt may have melted, the thermal energy of the system is insufficient to completely overcome the activation energy barrier of multi-component atomic diffusion and displacement reactions. The reaction rate of the metal chloride gas with the ZnS template is too slow, resulting in incomplete cation exchange that cannot be completed within 30 minutes of holding at this temperature. Therefore, unreacted ZnS template remains in the product, forming a complex mixture of high-entropy sulfides and ZnS, rather than a single high-entropy phase. Therefore, a pure-phase high-entropy material cannot be obtained at 490℃.

[0099] Example 5

[0100] Based on Example 1, in step 5, the reaction vessel is heated to 540°C at a first heating rate of 10°C / min and held at that temperature for 30min. The metal chloride gas volatilized from the eutectic effect of the precursor is transported to the second reaction boat in the downstream region by a dynamic gas flow, allowing the zinc sulfide nanoparticles to react with the metal chloride gas. Scanning electron microscopy and X-ray diffraction experiments were performed on the high-entropy metal sulfide nanomaterials obtained in this example, and the results are as follows: Figure 6 As shown.

[0101] Figure 6 The SEM image of -A shows that the product has undergone severe grain coarsening. The originally nano-sized particles have fused into large micron-sized aggregates, the specific surface area has been significantly reduced, and the pore structure has collapsed.

[0102] Figure 6 The XRD pattern of -B shows a two-phase high-entropy sulfide with extremely sharp and high-intensity diffraction peaks.

[0103] The excessively high temperature of 540℃ accelerates surface diffusion and grain boundary migration of atoms. Small grains dissolve and merge into larger grains, leading to abnormal grain size growth and undermining the advantages of nanostructures. Furthermore, the high temperature causes the hexagonal high-entropy phase to transform into a trigonal high-entropy phase, resulting in a state of two-phase coexistence. Therefore, two-phase high-entropy nanomaterials can be obtained at 540℃, but this sacrifices the morphological advantages of nanomaterials.

[0104] Example 6

[0105] Based on Example 1, in step 1, 11 parts of transition metal chloride were ground to obtain a powdered precursor, which was then placed in the first reaction boat in the upstream region of the reaction vessel. Scanning electron microscopy and X-ray diffraction experiments were performed on the high-entropy metal sulfide nanomaterials obtained in this example, and the results are as follows: Figure 7 As shown.

[0106] Figure 7 The SEM image of -A shows that the product is an irregular mass of large particles with indistinct boundaries and extremely uneven distribution. The uniform spherical structure seen in Example 1 or the lamellar structure seen in Example 2 did not appear.

[0107] Figure 7 The XRD pattern of -B showed mixed peaks of ZnS and NiS again, with severe peak broadening and poor crystallinity.

[0108] After removing sodium chloride, the system lacks a eutectic salt medium. Transition metal chlorides exist primarily in solid or gaseous form at 525°C. Without molten salt as a carrier, the diffusion of metal ions relies mainly on the gas phase, resulting in extremely low efficiency and uneven distribution. This leads to the reaction occurring only locally, with most of the ZnS template remaining unconverted, and the resulting product exhibiting low crystallinity and severe agglomeration.

[0109] Therefore, sodium chloride is not only a reaction medium, but also a key component in reducing the activation energy of the reaction, promoting uniform atomic diffusion, and achieving low-temperature synthesis.

[0110] The above description is merely some specific embodiments of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing high-entropy metal sulfide nanomaterials, characterized in that, Includes the following steps: Step 1: The precursor is placed in the first reaction boat in the upstream region of the reaction vessel, wherein the precursor includes sodium chloride and at least four transition metal chloride salts; Step 2: Place the zinc sulfide nanotemplate in the second reaction boat in the downstream region of the reaction vessel; Step 3: The reaction vessel is subjected to at least three cycles of inert gas purging and discharging to remove air; Step 4: Inert gas is introduced upstream of the reaction vessel and the downstream of the reaction vessel is evacuated to form a dynamic airflow from upstream to downstream in the reaction vessel, so that the pressure inside the reaction vessel is 200~300Pa. Step 5: Heat the reaction vessel to 500~525℃ at the first heating rate and hold for 20~40 min. The metal chloride gas volatilized by the eutectic effect of the precursor is transported to the second reaction boat in the downstream region by the dynamic gas flow, so that the zinc sulfide nanotemplate reacts with the metal chloride gas. Step 6: Cool to room temperature at the second cooling rate, collect the solid product in the second reaction boat, and obtain high-entropy metal sulfide nanomaterials.

2. The method for preparing a high-entropy metal sulfide nanomaterial according to claim 1, characterized in that, The precursors include sodium chloride and four transition metal chlorides: ferrous chloride, cobalt chloride, nickel chloride, and cuprous chloride.

3. The method for preparing a high-entropy metal sulfide nanomaterial according to claim 1, characterized in that, In step 1, the transition metal chloride salt and sodium chloride are mixed and ground until a uniformly mixed powdered precursor is obtained. The particle size of the powdered precursor is 60-80 μm. The powdered precursor is placed in the first reaction boat in the upstream region of the reaction vessel.

4. The method for preparing a high-entropy metal sulfide nanomaterial according to claim 1, characterized in that, The inner diameter of the reaction vessel is 55~65mm, and the distance between the first reaction boat and the second reaction boat is 10~20mm.

5. The method for preparing a high-entropy metal sulfide nanomaterial according to claim 1, characterized in that, The weight ratio of transition metal chloride to sodium chloride is 10~12:5~6.

6. The method for preparing a high-entropy metal sulfide nanomaterial according to claim 1, characterized in that, The weight ratio of zinc sulfide nanotemplate to transition metal chloride is 1~2:10~12.

7. The method for preparing a high-entropy metal sulfide nanomaterial according to claim 1, characterized in that, The downstream pumping rate of the reaction vessel is 5~10m. 3 / h.

8. The method for preparing a high-entropy metal sulfide nanomaterial according to claim 1, characterized in that, The first heating rate is 8~15℃ / min, and the second cooling rate is 10~15℃ / min.

9. The method for preparing a high-entropy metal sulfide nanomaterial according to claim 1, characterized in that, The zinc sulfide nanotemplate is zinc sulfide nanoparticle powder, zinc sulfide nanosheet powder, or zinc sulfide nano three-dimensional macroporous powder.

10. High-entropy metal sulfide nanomaterials prepared by the preparation method according to any one of claims 1-9.

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