A high-entropy metal sulfide CdFeCoNiCuS x Its preparation methods and applications

Abstract

The application discloses a high-entropy metal sulfide CdFeCoNiCuS x and a preparation method and application thereof, ethanol is mixed with thiourea to form a eutectic solvent; then, Cd salt, Fe salt, Co salt, Ni salt and Cu salt are added into the eutectic solvent in equal molar amounts according to the molar number of the metal contained in each of the salts, and heating and stirring are performed until the salts are fully mixed to obtain a precursor; the precursor is placed in a joule heating instrument to perform a reaction under a protective atmosphere, and a high-entropy metal sulfide CdFeCoNiCuS x is obtained. The high-entropy metal sulfide is used for Fenton-like oxidation degradation of tetracycline. The high-entropy metal sulfide has good structural stability, ensures the stability of the high-entropy metal sulfide in a wide pH range, and improves the interaction between the catalyst and tetracycline through the synergistic effect of specific metal elements, so that the charge state in the metal sulfide is changed, the interface charge transfer is effectively accelerated, the diffusion process of tetracycline is improved, and efficient degradation of tetracycline is realized.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials and their organic pollutant degradation technology, specifically relating to a high-entropy metal sulfide CdFeCoNiCuS x Its preparation method and its application in the Fenton-like oxidative degradation of tetracycline. Background Technology

[0002] Advanced oxidation processes have proven to be highly efficient technologies for treating recalcitrant organic pollutants. Among them, Fenton-like oxidation, as an advanced oxidation technology, is widely used for the removal of organic pollutants due to its advantages such as high degradation efficiency, strong operability, and good environmental compatibility. The key factor in the efficiency of Fenton-like oxidation is the generation of active free radicals, which can convert organic pollutants into CO2 and H2O, or other biodegradable small molecules. However, in Fenton-like reactions, the catalyst is prone to aggregation and corrosion at acidic pH conditions, thereby reducing its catalytic activity and stability, limiting its application in wastewater treatment.

[0003] Transition metal sulfides, with their good electrical conductivity and potential for high activity, have attracted widespread attention in recent years. However, transition metal sulfides generally exhibit poor stability, and the catalyst is prone to detachment from the substrate under high oxidation chemistry conditions. Furthermore, mono-, binary, and ternary transition metal sulfides containing only small amounts of metal elements lack broad compositional tunability. In contrast, high-entropy metal sulfides (HEMS) containing multiple metal elements offer excellent compositional tunability. Their structures uniformly mix multiple metal elements (≥5), benefiting from high-entropy properties to stabilize their phases and exhibiting good structural stability. Therefore, developing efficient, durable, and low-cost high-entropy metal sulfides for the efficient catalytic oxidation and degradation of organic pollutants in wastewater is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a high-entropy metal sulfide CdFeCoNiCuS x Based on its good structural stability, it ensures its stability over a wide pH range. At the same time, through the synergistic effect of multiple elements, it improves the interaction between the catalyst and pollutants, thereby changing the charge state in metal sulfides, effectively accelerating interfacial charge transfer, and improving the diffusion process of pollutants. It has excellent Fenton-like oxidation degradation performance.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0006] A high-entropy metal sulfide CdFeCoNiCuS x The preparation method includes the following steps:

[0007] (1) Mix ethanol and thiourea to form a eutectic solvent;

[0008] (2) Based on the molar amount of each metal contained, add the same amount of Cd salt, Fe salt, Co salt, Ni salt and Cu salt to the eutectic solvent in step (1), heat and stir until fully mixed, separate the solid and liquid and dry to obtain the precursor;

[0009] (3) Under a protective atmosphere, the precursor is reacted in a Joule heater to obtain the high-entropy metal sulfide CdFeCoNiCuS. x .

[0010] Preferably, in step (1), the molar ratio of ethanol to thiourea is 1 to 3:1.

[0011] Preferably, in step (2), the Cd salt, Fe salt, Co salt, Ni salt and Cu salt are their respective chlorides, and the molar ratio of the total chloride to thiourea is 2 to 4:1.

[0012] Preferably, in step (2), the heating temperature is 50-60°C.

[0013] Preferably, in step (3), the protective atmosphere is an Ar atmosphere.

[0014] Preferably, in step (3), the parameters of the Joule heater are set as follows: voltage 30-40V, current 300-350A, reaction time 15-20s, and reaction temperature 1000-1500℃.

[0015] This invention also provides high-entropy metal sulfides CdFeCoNiCuS prepared by the above method. x .

[0016] The present invention also provides the above-mentioned high-entropy metal sulfide CdFeCoNiCuS x Its application is to use it for Fenton-like oxidation degradation of tetracycline.

[0017] This invention rapidly synthesizes high-entropy metal sulfides CdFeCoNiCuS with uniform mixing and entropy stability of specific metal element combinations using Joule heating technology. x The high entropy characteristics of CdFeCoNiCuS x It possesses good structural stability, ensuring its stability over a wide pH range. At the same time, the synergistic effect of specific metal elements enhances the interaction between the catalyst and tetracycline, thereby altering the charge state in the metal sulfide, effectively accelerating interfacial charge transfer, improving the diffusion process of tetracycline, and achieving efficient degradation of tetracycline.

[0018] The advantages of this invention are:

[0019] (1) The high-entropy metal sulfide CdFeCoNiCuS of the present invention x It uniformly mixes multiple metal elements, and through the synergistic effect of specific metal elements, it achieves efficient degradation of tetracycline.

[0020] (2) The high-entropy metal sulfide CdFeCoNiCuS of the present invention x It exhibits good structural and catalytic stability, and its catalytic degradation performance remains essentially unchanged after multiple cycles.

[0021] (3) The high-entropy metal sulfide CdFeCoNiCuS of the present invention x It employs Joule heating technology, which is simple, fast, and efficient. Attached Figure Description

[0022] Figure 1 The high-entropy metal sulfide CdFeCoNiCuS of Example 1 x XRD pattern.

[0023] Figure 2 The high-entropy metal sulfide CdFeCoNiCuS of Example 1 x The TEM spectrum (a) and the corresponding elemental mapping diagram (b).

[0024] Figure 3 The high-entropy metal sulfide CdFeCoNiCuS of Example 1 x Atom ratio diagram calculated using XPS.

[0025] Figure 4 The graphs show the Fenton-like degradation of tetracycline by different samples, where a represents the high-entropy metal sulfide CdZnAgPdPtS. x (Comparative Example 1), b is a high-entropy metal sulfide CdPdAgZnCuS x (Comparative Example 2) c is a high-entropy metal sulfide CdRuRhPdAgS x (Comparative Example 3) d is a high-entropy metal sulfide CdFeCoNiCuS x (Example 1)

[0026] Figure 5 The graphs show the Fenton-like degradation of tetracycline by different samples, where a represents the high-entropy metal sulfide CdFeCoNiCuS. x -80% (Comparative Example 4), b is a high-entropy metal sulfide CdFeCoNiCuS x -60% (Comparative Example 5), c is a high-entropy metal sulfide CdFeCoNiCuS x -40% (Comparative Example 6), d is a high-entropy metal sulfide CdFeCoNiCuS x(Example 1)

[0027] Figure 6 The high-entropy metal sulfide CdFeCoNiCuS of Example 1 x Stability assessment diagram. Detailed Implementation

[0028] The invention will be further explained below with reference to specific implementation examples.

[0029] Fenton-like degradation experiment:

[0030] First, 20 mL of 50 mg / L tetracycline solution was added to five beakers, and the initial absorbance was measured. Then, 10 mg of catalyst was added to each beaker, and the initial temperature was 25 °C. Next, a magnetic stirrer was turned on (600 rpm / min), and after the catalyst and pollutant reached adsorption equilibrium, 20 μL of 30% H₂O₂ was added to each beaker to initiate the reaction. For experimental accuracy, only one time point was sampled from each beaker (e.g., [missing information]). Figure 5 The sampling time points were 2 min, 10 min, 20 min, 40 min, and 60 min. Samples were taken at different time intervals, and their concentrations were measured using a UV-Vis spectrophotometer. The degradation rate Dr was calculated using the formula: Dr=(C0-C)×100 / C0, where C0 is the concentration of tetracycline when adsorption equilibrium is reached, C is the concentration of tetracycline solution measured at time t, and t is the reaction time.

[0031] Example 1

[0032] First, 0.01 mol of ethanol and 0.005 mol of thiourea were weighed and mixed to form a eutectic solvent. Second, 0.0025 mol of CdCl2, 0.0025 mol of FeCl3, 0.0025 mol of CoCl2, 0.0025 mol of NiCl2, and 0.0025 mol of CuCl2 were weighed and added to the eutectic solvent. The mixture was stirred continuously in a 60°C oil bath until dry at 500 rpm / min. The dried sample was collected. Then, the dried sample was placed in a graphite sheet and transferred to a Joule heater for reaction. The Joule heater was programmed with rapid heating mode, voltage 40V, current 350A, reaction time 20s, and reaction temperature range 1127°C. After the reaction, the collected product was washed three times with deionized water and ethanol to remove residual salts. Finally, the obtained sample was vacuum dried at 40°C for 12h and denoted as high-entropy metal sulfide CdFeCoNiCuS. x .

[0033] like Figure 1As shown, the diffraction peaks of the standard cards for the five single-metal sulfides (CdS, FeS, CoS, NiS, CuS) and the high-entropy metal sulfides CdFeCoNiCuS can be observed. x The diffraction peaks do not match, indicating that a new high-entropy metal sulfide phase was prepared by Joule heating technology.

[0034] like Figure 2 As shown, high-entropy metal sulfides CdFeCoNiCuS can be observed. x The morphological structure was observed, and high-entropy metal sulfides CdFeCoNiCuS were also observed through elemental mapping. x The uniform distribution of Cd, Fe, Co, Ni, Cu, and S elements in the sample proves its high-entropy metal sulfide CdFeCoNiCuS x Successful preparation.

[0035] like Figure 3 As shown, high-entropy metal sulfides CdFeCoNiCuS x The atomic ratio is Cd:Fe:Co:Ni:Cu:S = 0.41:6.8:2.32:3.94:12.18:7.76.

[0036] Comparative Example 1

[0037] First, 0.01 mol of ethanol and 0.005 mol of thiourea were weighed and mixed to form a eutectic solvent. Second, 0.0025 mol of CdCl₂, 0.0025 mol of ZnCl₂, 0.0025 mol of AgCl, 0.0025 mol of PdCl₂, and 0.0025 mol of PtCl₄ were weighed and added to the eutectic solvent. The mixture was stirred continuously in a 60°C oil bath until dry at a stirring speed of 500 rpm / min. The dried sample was collected; then, it was placed in a graphite sheet and transferred to a Joule heater for reaction. The Joule heater was programmed with rapid heating mode, voltage 40V, current 350A, reaction time 20s, and reaction temperature range 1127℃. After the reaction, the product was collected and washed three times with deionized water and ethanol to remove residual salts. Finally, the obtained sample was vacuum dried at 40℃ for 12h and denoted as high-entropy metal sulfide CdZnAgPdPtS. x .

[0038] Comparative Example 2

[0039] First, 0.01 mol of ethanol and 0.005 mol of thiourea were weighed and mixed to form a eutectic solvent. Second, 0.0025 mol of CdCl₂, 0.0025 mol of PdCl₂, 0.0025 mol of AgCl, 0.0025 mol of ZnCl₂, and 0.0025 mol of CuCl₂ were weighed and added to the eutectic solvent. The mixture was stirred continuously in a 60°C oil bath until dry at a stirring speed of 500 rpm / min. The dried sample was collected; then, it was placed in a graphite sheet and transferred to a Joule heater for reaction. The Joule heater was programmed with rapid heating mode, voltage 40V, current 350A, reaction time 20s, and reaction temperature range 1127℃. After the reaction, the product was collected and washed three times with deionized water and ethanol to remove residual salts. Finally, the obtained sample was vacuum dried at 40℃ for 12h and designated as high-entropy metal sulfide CdPdAgZnCuS. x .

[0040] Comparative Example 3

[0041] First, 0.01 mol of ethanol and 0.005 mol of thiourea were weighed and mixed to form a eutectic solvent. Second, 0.0025 mol of CdCl2, 0.0025 mol of RuCl2, 0.0025 mol of RhCl3·3H2O, 0.0025 mol of PdCl2, and 0.0025 mol of AgCl were weighed and added to the eutectic solvent. The mixture was continuously stirred in a 60°C oil bath until dry at a stirring speed of 500 rpm. The dried sample was collected; then, it was placed in a graphite sheet and transferred to a Joule heater for reaction. The Joule heater was programmed with rapid heating mode, voltage 40V, current 350A, reaction time 20s, and reaction temperature range 1127℃. After the reaction, the product was collected and washed three times with deionized water and ethanol to remove residual salts. Finally, the obtained sample was vacuum dried at 40℃ for 12h and denoted as high-entropy metal sulfide CdRuRhPdAgS. x .

[0042] Comparative Example 4

[0043] First, 0.01 mol of ethanol and 0.005 mol of thiourea were weighed and mixed to form a eutectic solvent. Next, 0.0025 mol of FeCl3, 0.0025 mol of CoCl2, 0.0025 mol of NiCl2, 0.0025 mol of CuCl2, and 0.04 mol of CdCl2 were weighed and added to the eutectic solvent. The mixture was stirred continuously in a 60°C oil bath until dry at 500 rpm / min. The dried sample was collected. Then, the dried sample was placed in a graphite sheet and transferred to a Joule heater for reaction. The Joule heater was set to rapid heating mode, voltage 40V, current 350A, reaction time 20s, and reaction temperature range 1127°C. After the reaction, the collected product was washed three times with deionized water and ethanol to remove residual salts. Finally, the obtained sample was vacuum dried at 40°C for 12h and denoted as high-entropy metal sulfide CdFeCoNiCuS. x -80%.

[0044] Comparative Example 5

[0045] First, 0.01 mol of ethanol and 0.005 mol of thiourea were weighed and mixed to form a eutectic solvent. Second, 0.0025 mol of FeCl3, 0.0025 mol of CoCl2, 0.0025 mol of NiCl2, 0.0025 mol of CuCl2, and 0.015 mol of CdCl2 were weighed and added to the eutectic solvent. The mixture was stirred continuously in a 60°C oil bath until dry at 500 rpm / min. The dried sample was collected. Then, the dried sample was placed in a graphite sheet and transferred to a Joule apparatus for reaction. The Joule apparatus was set to rapid heating mode, voltage 40V, current 350A, reaction time 20s, and reaction temperature range 1127°C. After the reaction, the collected product was washed three times with deionized water and ethanol to remove residual salts. Finally, the obtained sample was vacuum dried at 40°C for 12h and denoted as high-entropy metal sulfide CdFeCoNiCuS. x -60%.

[0046] Comparative Example 6

[0047] First, 0.01 mol of ethanol and 0.005 mol of thiourea were weighed and mixed to form a eutectic solvent. Second, 0.0025 mol of FeCl3, 0.0025 mol of CoCl2, 0.0025 mol of NiCl2, 0.0025 mol of CuCl2, and 0.0067 mol of CdCl2 were weighed and added to the eutectic solvent. The mixture was stirred continuously in a 60°C oil bath until dry at 500 rpm / min. The dried sample was collected. Then, the dried sample was placed in a graphite sheet and transferred to a Joule heater for reaction. The Joule heater was programmed with rapid heating mode, voltage 40V, current 350A, reaction time 20s, and reaction temperature range 1127°C. After the reaction, the collected product was washed three times with deionized water and ethanol to remove residual salts. Finally, the obtained sample was vacuum dried at 40°C for 12h and denoted as high-entropy metal sulfide CdFeCoNiCuS. x -40%.

[0048] Figure 4 The high-entropy metal sulfide CdFeCoNiCuS prepared in Example 1 of this invention x High-entropy metal sulfides Cd, Zn, Ag, Pd, and PtS of different metal types were prepared in Comparative Examples 1-3, respectively. x CdPdAgZnCuS x 、CdRuRhPdAgS x The Fenton-like degradation performance diagram shows that high-entropy metal sulfides CdFeCoNiCuS x The tetracycline degradation rate of 93.66% can be achieved within 60 minutes, which is far higher than the degradation performance of the other three high-entropy metal sulfides. This indicates that the synergistic effect of the combination of specific metal elements can produce excellent Fenton-like degradation performance, thus achieving efficient degradation of tetracycline.

[0049] Figure 5 The high-entropy metal sulfide CdFeCoNiCuS prepared in Example 1 of this invention x The high-entropy metal sulfides CdFeCoNiCuS prepared in Comparative Examples 4–6 respectively x -80%, high-entropy metal sulfides CdFeCoNiCuS x -60%, high-entropy metal sulfides CdFeCoNiCuS x The graph shows a -40% Fenton-like degradation performance, indicating that only when added in an equimolar ratio can the high-entropy metal sulfide CdFeCoNiCuS be obtained. x Only then can it possess excellent Fenton-like degradation performance, thereby achieving efficient degradation of tetracycline.

[0050] Figure 6The high-entropy metal sulfide CdFeCoNiCuS prepared in Example 1 of this invention x The stability study diagram shows that after each cycle of the stability experiment, the reacted catalyst was collected by centrifugation, washed repeatedly with deionized water several times, and then dried in a vacuum oven for use in the next cycle. The diagram shows that the high-entropy metal sulfide CdFeCoNiCuS... x Exhibiting excellent stability, the degradation performance difference was less than 1% after five cycles of the experiment, remaining essentially unchanged, indicating that the high-entropy metal sulfide CdFeCoNiCuS prepared by the Joule heating synthesis of this invention with a specific combination of metal elements x It has excellent stability and can be used multiple times.

Claims

1. A high-entropy metal sulfide CdFeCoNiCuS x The application, characterized in that, It can be used for Fenton-like oxidation degradation of tetracycline; The high-entropy metal sulfide CdFeCoNiCuS x The specific preparation process includes the following steps: (1) Mix ethanol with thiourea to form a eutectic solvent; (2) Based on the molar amount of each metal contained, add the same amount of Cd salt, Fe salt, Co salt, Ni salt and Cu salt to the eutectic solvent in step (1), heat and stir until fully mixed, separate the solid and liquid and dry to obtain the precursor; (3) Under a protective atmosphere, the precursor is placed in a Joule heater to react, thus obtaining the high-entropy metal sulfide CdFeCoNiCuS. x .

2. The application according to claim 1, characterized in that, In step (1), the molar ratio of ethanol to thiourea is 1 to 3:

1.

3. The application according to claim 1, characterized in that, In step (2), the Cd salt, Fe salt, Co salt, Ni salt and Cu salt are their respective chlorides, and the total molar ratio of chloride to thiourea is 2~4:

1.

4. The application according to claim 1, characterized in that, In step (2), the heating temperature is 50~60 ℃.

5. The application according to claim 1, characterized in that, In step (3), the protective atmosphere is an Ar atmosphere.

6. The application according to claim 1, characterized in that, In step (3), the parameters of the Joule heater are set as follows: voltage 30~40 V, current 300~350 A, reaction time 15~20 s, and reaction temperature 1000~1500 ℃.

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