阅读说明：本技术 二硫化钼纳米片及其制备方法、应用以及电化学还原降解卤代抗生素的方法 (Molybdenum disulfide nanosheet, preparation method and application thereof, and method for degrading halogenated antibiotics through electrochemical reduction ) 是由 江鸿 杨靖 于 2020-12-24 设计创作，主要内容包括：本发明提供了一种二硫化钼纳米片及其制备方法、应用以及电化学还原降解卤代抗生素的方法。本发明合成薄层二硫化钼纳米片作为电化学还原中的阴极催化剂,能够高效去除水环境中难降解的卤代抗生素,显著降解抗生素在水环境中的累积,为有效阻断耐药基因传递提供了经济高效的适用方法,具有广泛的应用前景。实验结果表明,以本发明合成的薄层二硫化钼纳米片作为电化学还原中的阴极材料,在4个小时内可有效降解污水中的卤代抗生素。(The invention provides a molybdenum disulfide nanosheet, a preparation method and application thereof, and a method for degrading halogenated antibiotics through electrochemical reduction. The synthesized thin-layer molybdenum disulfide nanosheet is used as a cathode catalyst in electrochemical reduction, so that the halogenated antibiotics which are difficult to degrade in the water environment can be efficiently removed, the accumulation of the antibiotics in the water environment is remarkably degraded, an economical and efficient application method is provided for effectively blocking the transfer of drug-resistant genes, and the application prospect is wide. Experimental results show that the thin-layer molybdenum disulfide nanosheet synthesized by the method can be used as a cathode material in electrochemical reduction, and halogenated antibiotics in sewage can be effectively degraded within 4 hours.)

1. A preparation method of molybdenum disulfide nanosheets is characterized by comprising the following steps:

a) mixing ammonium molybdate tetrahydrate, thiourea and water to obtain a mixed solution;

b) and heating the mixed solution for reaction to form the molybdenum disulfide nanosheet.

2. The method of claim 1, wherein the molar ratio of ammonium molybdate tetrahydrate to thiourea is 1: 14.

3. The preparation method according to claim 1, wherein the temperature of the temperature-raising reaction is 200 to 220 ℃ and the time is 18 to 24 hours.

4. Molybdenum disulfide nanosheet prepared by the preparation method of any one of claims 1 to 3.

5. Use of molybdenum disulphide nanosheets as defined in claim 4 as a cathode catalyst for the electrochemical reductive degradation of a halogenated antibiotic.

6. A method for electrochemically reducing and degrading a halogenated antibiotic, comprising:

taking an electrode containing a cathode catalyst as a working electrode, taking liquid containing halogenated antibiotics as electrolyte, and carrying out electrochemical reduction in a three-electrode system to degrade the halogenated antibiotics;

the cathode catalyst is the molybdenum disulfide nanoplates of claim 4.

7. The method of claim 6, wherein the electrochemical reduction is performed under potentiostatic conditions;

the potential of the electrochemical reduction is-0.8V to-1.4V.

8. The method of claim 6, wherein the working electrode is obtained by:

s1, mixing the cathode catalyst, the Nafion solution, the organic solvent and water to obtain a mixed solution;

and S2, coating the mixed solution on an electrode substrate and drying to obtain the working electrode.

9. The method according to claim 7, wherein the concentration of the cathode catalyst in the mixed solution is 6-15 mg/mL;

the distribution amount of the cathode catalyst on the electrode substrate is 2-5 mg/cm²；

The organic solvent is selected from one or more of ethanol, methanol and isopropanol.

10. The method of claim 6, wherein the haloantibiotic-containing liquid is a haloantibiotic-containing wastewater;

the halogenated antibiotic is florfenicol and/or chloramphenicol;

in the three-electrode system, platinum is used as a counter electrode, and saturated calomel is used as a reference electrode;

the electrochemical reduction adopts an H-shaped electrolytic cell as a reactor, and the reactor is divided into a cathode chamber and an anode chamber by a proton exchange membrane;

the cathode chamber comprises Na₂SO₄An electrolyte and a halogenated antibiotic solution;

the anode chamber contains Na₂SO₄And (3) an electrolyte.

Technical Field

The invention relates to the field of water pollution control, in particular to a molybdenum disulfide nanosheet, a preparation method and application thereof, and a method for electrochemically reducing and degrading halogenated antibiotics.

Background

Overuse of antibiotics has posed a serious threat to the aquatic environment and human health. Particularly, halogenated antibiotics account for nearly 40 percent of the total amount of the antibiotics used in China, wherein chlorinated antibiotics, including florfenicol, chloramphenicol and the like, are broad-spectrum antibacterial drugs widely used for treating various infections in veterinary medicine, are easy to accumulate in aquatic and sedimentary environments continuously, and cause public attention and worry due to the environmental persistence and serious biological toxicity. However, effective removal of these particular recalcitrant pollutants is difficult to achieve by conventional water treatment methods such as adsorption, catalytic oxidation, biodegradation, fenton's reaction, photocatalytic degradation, biodegradation, etc., and these techniques are inefficient, consume large amounts of energy, and produce toxic by-products. Therefore, it is of great importance to develop efficient and environmentally friendly degradation technology methods to treat these contaminants.

Electrochemical reduction is an environment-friendly and low-cost halogenated antibiotic degradation technology, has low maintenance requirement, does not generate secondary pollution, and can effectively remove halogen atoms playing an important role in the antibacterial activity of halogenated antibiotics. The degradation efficiency of electrochemical reduction mainly depends on the selection of cathode catalysts, noble metals represented by palladium are considered to be ideal electrochemical dechlorination catalysts due to the fact that the noble metals can catalyze and form surface-adsorbed atomic hydrogen (H) with strong reduction capacity, but the high cost and the scarcity of the noble metal catalysts limit the wide application of the noble metal catalysts in the field of water treatment and pollutant degradation. Therefore, the development of low-cost non-noble metal electrochemical reduction cathodes is an ideal development direction.

Disclosure of Invention

In view of the above, the present invention provides a molybdenum disulfide nanosheet, a preparation method and an application thereof, and a method for electrochemically reducing and degrading a halogenated antibiotic. The molybdenum disulfide nanosheet prepared by the invention or the provided method for degrading halogenated antibiotics through electrochemical reduction can effectively degrade halogenated antibiotics in sewage, and is low in cost.

The invention provides a preparation method of molybdenum disulfide nanosheets, which comprises the following steps:

a) mixing ammonium molybdate tetrahydrate, thiourea and water to obtain a mixed solution;

b) and heating the mixed solution for reaction to form the molybdenum disulfide nanosheet.

Preferably, the molar ratio of the ammonium molybdate tetrahydrate to the thiourea is 1: 14.

Preferably, the temperature of the temperature-rising reaction is 200-220 ℃ and the time is 18-24 h.

The invention also provides a molybdenum disulfide nanosheet prepared by the preparation method in the technical scheme.

The invention also provides application of the molybdenum disulfide nanosheet in the technical scheme as a cathode catalyst for electrochemical reduction degradation of halogenated antibiotics.

The invention also provides a method for degrading halogenated antibiotics by electrochemical reduction, which comprises the following steps:

taking an electrode containing a cathode catalyst as a working electrode, taking liquid containing halogenated antibiotics as electrolyte, and carrying out electrochemical reduction in a three-electrode system to degrade the halogenated antibiotics;

the cathode catalyst is the molybdenum disulfide nanosheet in the technical scheme.

Preferably, the electrochemical reduction is carried out under potentiostatic conditions;

the potential of the electrochemical reduction is-0.8V to-1.4V.

Preferably, the working electrode is obtained by:

s1, mixing the cathode catalyst, the Nafion solution, the organic solvent and water to obtain a mixed solution;

and S2, coating the mixed solution on an electrode substrate and drying to obtain the working electrode.

Preferably, in the mixed solution, the concentration of the cathode catalyst is 6-15 mg/mL;

the distribution amount of the cathode catalyst on the electrode substrate is 2-5 mg/cm²；

The organic solvent is selected from one or more of ethanol, methanol and isopropanol.

Preferably, the liquid containing the halogenated antibiotic is sewage containing the halogenated antibiotic;

the halogenated antibiotic is florfenicol and/or chloramphenicol;

in the three-electrode system, platinum is used as a counter electrode, and saturated calomel is used as a reference electrode;

the electrochemical reduction adopts an H-shaped electrolytic cell as a reactor, and the reactor is divided into a cathode chamber and an anode chamber by a proton exchange membrane;

the cathode chamber comprises Na₂SO₄An electrolyte and a halogenated antibiotic solution;

the anode chamber contains Na₂SO₄And (3) an electrolyte.

The synthesized thin-layer molybdenum disulfide nanosheet is used as a cathode catalyst in electrochemical reduction, so that the halogenated antibiotics which are difficult to degrade in the water environment can be efficiently removed, the accumulation of the antibiotics in the water environment is remarkably degraded, an economical and efficient application method is provided for effectively blocking the transfer of drug-resistant genes, and the application prospect is wide. Experimental results show that the thin-layer molybdenum disulfide nanosheet synthesized by the method can be used as a cathode material in electrochemical reduction, and halogenated antibiotics in sewage can be effectively degraded within 4 hours.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is an X-ray crystal diffraction pattern of the molybdenum disulfide catalyst obtained in example 1;

FIG. 2 is a scanning electron micrograph of the molybdenum disulfide catalyst obtained in example 1;

FIG. 3 is a transmission electron micrograph of the molybdenum disulfide catalyst obtained in example 1;

FIG. 4 is a graph showing the effect of degrading florfenicol by electrocatalytic reduction in example 2;

FIG. 5 is a graph showing the effect of degrading chloramphenicol by electrocatalytic reduction in example 3;

FIG. 6 is a graph showing the effect of degrading florfenicol by electrocatalytic reduction at different cathode potentials in example 4;

FIG. 7 is a graph showing the effect of degrading florfenicol by electrocatalytic reduction in comparative example 1;

FIG. 8 is a graph showing the effect of degrading florfenicol by electrocatalytic reduction in comparative example 2.

Detailed Description

The invention provides a preparation method of molybdenum disulfide nanosheets, which comprises the following steps:

a) mixing ammonium molybdate tetrahydrate, thiourea and water to obtain a mixed solution;

b) and heating the mixed solution for reaction to form the molybdenum disulfide nanosheet.

With respect to step a):

according to the method, the specific ammonium molybdate tetrahydrate and thiourea are used as reaction raw materials to synthesize the molybdenum disulfide nanosheet, so that the molybdenum disulfide can be synthesized, the obtained molybdenum disulfide nanosheet is proper in size, the catalytic effect is optimal due to the distribution of catalytic active sites, the halogenated antibiotics can be effectively degraded, and if other raw materials such as sodium molybdate serving as a molybdenum source and cysteine serving as a sulfur source are adopted, the degradation effect of the obtained molybdenum disulfide is poor.

In the invention, the mol ratio of the ammonium molybdate tetrahydrate to the thiourea is preferably 1: 14, the mol ratio of molybdenum to sulfur is 1: 2, the mol ratio is crucial, the formation of flaky molybdenum disulfide is facilitated, if the thiourea is excessive, the synthesized molybdenum disulfide is rich in defects, the nanosheet is thickened, the conductivity is poor, the catalytically active sites are covered, and the degradation effect is poor.

In the present invention, the water is preferably deionized water. The dosage ratio of the ammonium molybdate tetrahydrate to the water is preferably 2mmol to (60-80) mL.

The mixing mode is not particularly limited, and the materials can be uniformly mixed; preferably, the present invention forms a uniform mixed solution by ultrasonic dispersion. In the invention, the ultrasonic time is preferably 15-20 min. After the above treatment, a uniform mixed solution is obtained.

With respect to step b):

in the invention, the temperature rise is preferably raised to 200-220 ℃; more preferably 220 deg.c. In the invention, the reaction time is preferably 18-24 h; in some embodiments of the invention, the reaction is for 18 h.

In the present invention, after the reaction, it is preferable to further include: cooling, washing and drying. The cooling is preferably to room temperature. The detergent used for washing is preferably one or more of an organic solvent and water. The kind of the organic solvent is not particularly limited, and may be a conventional washing organic solvent well known to those skilled in the art, such as ethanol, etc. In the invention, the drying temperature is preferably 70-100 ℃, and the drying time is preferably 12-18 h. After the treatment, a molybdenum disulfide product is obtained, wherein the product is a black powder product on the macroscopic scale and is a thin-layer nanosheet on the microscopic scale.

The preparation method provided by the invention has the advantages of simple synthesis process, one-step hydrothermal synthesis, strong operability, mild reaction process conditions, no secondary pollution, low cost, greenness and economy, and the prepared thin-layer nano flaky molybdenum disulfide has high pollutant degradation efficiency.

The invention also provides a molybdenum disulfide nanosheet prepared by the preparation method in the technical scheme.

The invention also provides application of the molybdenum disulfide nanosheet in the technical scheme as a cathode catalyst for electrochemical reduction and degradation of halogenated antibiotics.

The synthesized thin-layer molybdenum disulfide nanosheet is used as a cathode material in electrochemical reduction, so that the halogenated antibiotics which are difficult to degrade in the water environment can be efficiently removed, the accumulation of the antibiotics in the water environment is remarkably degraded, an economical and efficient application method is provided for effectively blocking the transfer of drug-resistant genes, and the application prospect is wide. According to the invention, the specific nano-flaky molybdenum disulfide can be used for effectively degrading the halogenated antibiotics, and if molybdenum disulfide with other morphological structures such as commercial massive molybdenum disulfide is used, the degradation effect is poor.

The invention provides a method for degrading halogenated antibiotics by electrochemical reduction, which comprises the following steps:

taking an electrode containing a cathode catalyst as a working electrode, taking liquid containing halogenated antibiotics as electrolyte, and carrying out electrochemical reduction in a three-electrode system to degrade the halogenated antibiotics;

the cathode catalyst is the molybdenum disulfide nanosheet in the technical scheme.

According to the invention, the molybdenum disulfide nanosheet obtained by the preparation method is used as a cathode catalyst, an electrode containing the cathode catalyst is used as a working electrode, liquid containing halogenated antibiotics is used as electrolyte, and electrochemical reduction is carried out in a three-electrode system to degrade the halogenated antibiotics.

In the present invention, the working electrode is preferably obtained by:

s1, mixing the cathode catalyst, the Nafion solution, the organic solvent and water to obtain a mixed solution;

and S2, coating the mixed solution on an electrode substrate and drying to obtain the working electrode.

Regarding step S1:

the cathode catalyst is the molybdenum disulfide nanosheet in the technical scheme, and is not described herein again. The organic solvent is preferably one or more of ethanol, methanol and isopropanol.

In the present invention, the amount ratio of the materials in step S1 is preferably such that the concentration of the cathode catalyst in the obtained mixed solution is 6 to 15mg/mL, and more preferably 10 mg/mL. Wherein the volume ratio of the Nafion solution to the organic solvent to the water is preferably 1: 8-12: 8-10, and more preferably 1: 10: 9.

The mixing mode is not particularly limited, and the materials can be uniformly mixed to form uniform mixed liquor.

Regarding step S2:

the kind of the electrode substrate is not particularly limited in the present invention, and the electrode substrate may be prepared by using a conventional electrode substrate for electrochemical reduction degradation, which is well known to those skilled in the artPreferably carbon paper. In the invention, the distribution amount of the cathode catalyst on the electrode substrate in the mixed solution is preferably 2-5 mg/cm²More preferably 3.3mg/cm². In the invention, drying is carried out after coating, the drying temperature is preferably 70-100 ℃, and the drying time is preferably 12-18 h. And (4) obtaining the working electrode after the treatment.

In the present invention, in the three-electrode system, platinum is preferably used as the counter electrode. In the three-electrode system, saturated calomel is preferably used as a reference electrode.

In the present invention, the electrochemical reduction preferably employs an H-type electrolytic cell as a reactor, and the reactor is divided into a cathode chamber and an anode chamber by a proton exchange membrane. Wherein the cathode chamber comprises Na₂SO₄An electrolyte and a halogenated antibiotic solution; in some embodiments of the invention, the cathode compartment contains Na₂SO₄The concentration is 0.1M, and the concentration of the halogenated antibiotic is 20 mg/L. The electrolyte in the electrolyte of the anode chamber comprises Na₂SO₄(ii) a In some embodiments of the invention, Na in the electrolyte₂SO₄The concentration was 0.1M.

In the present invention, the electrochemical reduction is preferably performed in a potentiostatic mode, and the degradation of the halogenated antibiotics in the water is performed by electrocatalytic degradation by providing a constant cathodic potential in the potentiostatic mode of the electrochemical workstation.

In the present invention, the potential of the electrochemical reduction is preferably-0.8V to-1.4V, more preferably-1.0V to-1.4V, and still more preferably-1.0V to-1.2V; in some embodiments of the invention, the potential is-0.8V, -1.0V, -1.2V, or-1.4V.

In the invention, the liquid containing the halogenated antibiotics is preferably sewage containing the halogenated antibiotics, namely, the method is used for degrading the halogenated antibiotics in the sewage, so that the harm of the waste water containing the halogenated antibiotics to the environment is effectively reduced. In the present invention, the halogenated antibiotic is preferably florfenicol and/or chloramphenicol.

According to the method for electrochemically reducing and degrading the halogenated antibiotics, provided by the invention, the molybdenum disulfide nanosheet is used as a cathode catalyst, and under a certain cathode potential, water molecules or protons are activated to generate high-reducing-capability activity H, so that the high-efficiency degradation of the halogenated antibiotics is realized, and the accumulation of the antibiotics in a water environment is remarkably reduced. The method is economical and efficient, does not generate secondary pollution, can efficiently degrade typical halogenated antibiotics, thereby effectively blocking drug-resistant gene transfer, and has wide application prospect.

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

Example 1

2mmol ammonium molybdate tetrahydrate and 28mmol thiourea were dispersed in 70mL deionized water and stirred ultrasonically for 30 minutes to form a homogeneous solution. Thereafter, the solution was transferred to a 100mL autoclave and heated to 220 ℃ for 18 h. After cooling to room temperature, the black suspension was washed with ethanol and water by repeated filtration and dried overnight in a drying oven at 80 ℃. Finally, a black molybdenum disulfide catalyst powder was obtained.

FIG. 1 is an X-ray crystal diffraction pattern of the molybdenum disulfide catalyst obtained in example 1, demonstrating that the resulting product is MoS₂. Fig. 2 is a scanning electron microscope image of the molybdenum disulfide catalyst obtained in example 1, and fig. 3 is a transmission electron microscope image of the molybdenum disulfide catalyst obtained in example 1, which shows that the obtained molybdenum disulfide has a nanosheet-like structure.

Example 2 catalytic degradation of florfenicol solution

S1, 10mg of the molybdenum disulfide catalyst obtained in example 1 is dissolved in a mixed solution containing 50. mu.L of Nafion solution, 450. mu.L of water and 500. mu.L of ethanol, and the solution is sonicated for 1 hour to form a uniform solution. The catalyst solution was then applied dropwise to 1x3cm²The working electrode was obtained by drying overnight at room temperature on a size carbon paper, and was ready for use.

S2, using an H-shaped electrolytic cell as a reactor, dividing the reactor into a cathode chamber and an anode chamber by using a proton exchange membrane, wherein the volume of electrolyte sewage is 80mL, and the volume of cathode electrolyteContaining 0.1M Na₂SO₄Electrolyte solution and 20mg/L florfenicol solution, the anolyte only contains 0.1M Na₂SO₄An electrolyte solution. And the cathode compartment was magnetically stirred at a constant rate.

And S3, performing electrochemical reduction degradation by using a three-electrode system, wherein the electrode obtained in the step S1 is used as a working electrode, a platinum sheet is used as a counter electrode, and a saturated calomel electrode is used as a reference electrode, and the florfenicol is subjected to electrocatalytic reduction degradation by providing a constant cathode potential (the cathode potential in the example is set to-1.2V) in a constant potential mode of an electrochemical workstation. Meanwhile, carbon paper which is not coated with molybdenum disulfide nanosheets is used as a working electrolyte and is used as a blank control sample.

At the same time intervals, 0.6mL of the solution was taken out from the reaction system, and the concentration of the remaining florfenicol in the system was checked using high performance liquid chromatography. Results referring to fig. 4, fig. 4 is a graph showing the effect of degrading florfenicol by electrocatalytic reduction in example 2. It can be seen that the single carbon paper substrate is used as a cathode, which has almost no degradation effect on florfenicol, and when the molybdenum disulfide nanosheet catalyst is coated on the carbon paper substrate and used as a working electrode, almost all florfenicol can be efficiently degraded within 4 hours, because the molybdenum disulfide nanosheet has ultrahigh conductivity and low interfacial charge transfer resistance, the direct electronic reduction of pollutants on the cathode can be promoted, and under the constant cathode potential, water molecules or protons can be activated to generate active H with high reduction capability, so that the efficient degradation of florfenicol is realized.

EXAMPLE 3 catalytic degradation of Chloramphenicol solutions

S1, 10mg of the molybdenum disulfide catalyst obtained in example 1 is dissolved in a mixed solution containing 50. mu.L of Nafion solution, 450. mu.L of water and 500. mu.L of ethanol, and the solution is sonicated for 1 hour to form a uniform solution. The catalyst solution was then applied dropwise to 1x3cm²The working electrode was obtained by drying overnight at room temperature on a size carbon paper, and was ready for use.

S2, using an H-shaped electrolytic cell as a reactor, dividing the reactor into a cathode chamber and an anode chamber by using a proton exchange membrane, wherein the volume of electrolyte sewage is 80mL, and the cathode electrolyte contains 0.1M Na₂SO₄An electrolyte solution and a 20mg/L chloramphenicol solution, the anolyte contained only 0.1M Na₂SO₄An electrolyte solution. And the cathode compartment was magnetically stirred at a constant rate.

And S3, performing electrochemical reduction degradation by using a three-electrode system, wherein the electrode obtained in the step S1 is used as a working electrode, a platinum sheet is used as a counter electrode, and a saturated calomel electrode is used as a reference electrode, and the chloramphenicol is subjected to electrocatalytic reduction degradation by providing a constant cathode potential (the cathode potential in the example is set to-1.2V) in a constant potential mode of an electrochemical workstation. Meanwhile, carbon paper which is not coated with molybdenum disulfide nanosheets is used as a working electrolyte and is used as a blank control sample.

At the same time intervals, 0.6mL of the solution was taken out from the reaction system, and the remaining chloramphenicol concentration in the system was detected by high performance liquid chromatography. Results referring to fig. 5, fig. 5 is a graph showing the effect of degrading chloramphenicol by electrocatalytic reduction in example 3. It can be seen that the single carbon paper substrate is used as a cathode, has almost no degradation effect on chloramphenicol, and when the molybdenum disulfide nanosheet catalyst is coated and used as a working electrode, 90% of chloramphenicol can be efficiently degraded within 4 hours, because the molybdenum disulfide nanosheet has ultrahigh conductivity and low interfacial charge transfer resistance, direct electron reduction of pollutants by the cathode can be promoted, and under a constant cathode potential, water molecules or protons can be activated to generate active H with high reduction capacity, so that efficient degradation of chloramphenicol is realized.

Example 4 electrocatalytic reduction at different cathodic potentials

The procedure for degrading florfenicol by electrochemical reduction in example 2 was followed except that the cathode potentials of the electrochemical workstation were set to-0.8V, -1.0V, -1.2V, -1.4V, respectively. At the same time intervals, 0.6mL of the solution was taken out from the reaction system, and the concentration of the remaining florfenicol in the system was checked using high performance liquid chromatography. Results referring to fig. 6, fig. 6 is a graph showing the effect of electrocatalytic reduction degradation of florfenicol at different cathode potentials in example 4.

As can be seen from FIG. 6, the degradation of florfenicol can be achieved at different potentials. Of these, florfenicol removal is less efficient at-0.8V cathode potential, with only about 30% degradation at 4 hours, since the low potential results in fewer available electrons and limits the molybdenum disulfide to produce more active H for reductive degradation. 80% degradation can be achieved at-1.0V; at-1.2V and-1.4V, the removal efficiency gradually increased with further increase in potential. Therefore, the degradation can be realized under-0.8V to-1.4V, the degradation rate can be further improved under-1.0V to-1.4V, and the selection of a proper cathode potential can ensure the high-efficiency halogenated antibiotic removal efficiency and reduce the cost and select the best-1.0V to-1.2V in consideration of the problem of energy consumption.

Comparative example 1

The entire procedure for establishing an electrochemical reduction system and an electrochemical reduction degradation experiment was performed as in example 2, using commercial molybdenum disulfide bulk (provided by Shandong-Longhui chemical Co., Ltd.) as a cathode catalyst.

Test results referring to fig. 7, fig. 7 is a graph showing the effect of degrading florfenicol by electrocatalytic reduction in comparative example 1. It can be seen that the carbon paper substrate alone is used as the cathode, and has almost no degradation effect on florfenicol, and when the commercial bulk molybdenum disulfide catalyst is used as the working electrode, the degradation effect is only half of that of example 2 within 4 hours, because the commercial bulk molybdenum disulfide components are aggregated and stacked into a bulk, the conductivity is poor, the number of active sites on the edge is small, and the degradation reaction is not facilitated.

Comparative example 2

Molybdenum disulfide nanosheets were synthesized according to the procedure of example 1, except that the synthesis conditions were varied. The method comprises the following specific steps:

1mmol ammonium molybdate tetrahydrate and 35mmol thiourea were dispersed in 70mL deionized water and stirred ultrasonically for 30 minutes to form a homogeneous solution. Thereafter, the solution was transferred to a 100mL autoclave and heated to 220 ℃ for 18 h. After cooling to room temperature, the black suspension was washed with ethanol and water by repeated filtration and dried overnight in a drying oven at 80 ℃. Finally, a black molybdenum disulfide catalyst powder was obtained.

An electrochemical reduction system was established and an electrochemical reduction degradation experiment was performed as in example 2. Results referring to fig. 8, fig. 8 is a graph showing the effect of degrading florfenicol by electrocatalytic reduction in comparative example 2. It can be seen that the single carbon paper substrate is used as a cathode, and has almost no degradation effect on florfenicol, and when the thick molybdenum disulfide catalyst synthesized in comparative example 2 after changing the synthesis conditions is used as a working electrode, the degradation effect is only half of that of the molybdenum disulfide nanosheet synthesized in example 1 within 4 hours, because the thick molybdenum disulfide catalyst components are aggregated and stacked into blocks, the conductivity is poor, the edge active sites are few, and the degradation reaction is not utilized.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.