Schottky heterojunction photocatalyst and preparation method and application thereof

Abstract

The invention provides a Schottky heterojunction photocatalyst as well as a preparation method and application thereof, and belongs to the technical field of photocatalysts. The preparation method of the Schottky heterojunction photocatalyst comprises the following steps: dispersing Ti3C2 nanosheets into water to obtain a dispersion liquid; and adding a Sn source and a sulfur source into the dispersion liquid, uniformly mixing, and reacting to obtain the Schottky heterojunction photocatalyst. C-SnS2 and MXenes are compounded to form a Schottky heterojunction photocatalyst, the Schottky heterojunction photocatalyst is coupled with PMS for activation, separation of charge carriers is promoted through the sub-metallic characteristic of MXenes, and PMS activation is promoted to generate a series of free radicals at the same time, so that the organic matter degradation capacity of a reaction system is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalysts, and particularly relates to a Schottky heterojunction photocatalyst, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, environmental problems caused by the large-scale use and discharge of antibiotics have attracted wide attention. Ciprofloxacin (CIP) is one of the most effective antibiotics in the quinolone class and is widely used due to its broad-spectrum antibacterial properties. However, CIP cannot be completely absorbed by humans or animals, and 40%-50% of CIP is excreted through the kidneys. Since CIP is difficult to degrade in the natural environment, more and more CIP has been detected in water bodies, and the residual CIP will pose a hazard to the aquatic environment and even human health. Therefore, developing a technology for efficiently removing CIP from wastewater will have very important practical significance.

[0003] Among many wastewater treatment technologies, advanced oxidation technologies are widely used to remove various organic pollutants due to their high oxidation ability, mild reaction conditions, good removal effect, and short reaction time. Among them, the advanced oxidation technology using peroxymonosulfate (PMS) as an oxidant has been widely studied and applied due to its good water solubility, convenient storage and transportation, and strong oxidation ability. The ability of PMS itself to oxidize organic pollutants is limited, and it needs to rely on external substances and energy to activate and generate oxidative free radicals to efficiently oxidize and degrade organic pollutants. At present, the main methods for activating PMS are to use external energies such as heat, ultrasound, or light, and to use materials such as transition metals and their oxides as catalysts to activate PMS to generate various free radicals. In recent years, coupling PMS activation with photocatalytic technology has received wide attention due to its high catalytic efficiency and low energy consumption.

[0004] The key to photocatalytic technology is to prepare a photocatalyst with good visible light response. Semiconductor photocatalytic technology has received more and more attention as a reliable, green, and efficient method for solar energy conversion and environmental purification. Traditional TiO 2 catalysts can perform functions such as photocatalytic water splitting for hydrogen production, dye-sensitized solar cells, photocatalytic degradation of pollutants, and conversion of CO 2 into organic fuels. Traditional TiO 2 catalysts have the characteristics of low cost, stable chemical properties, and high oxidation ability. However, the practical application of this traditional photocatalyst is quite limited because it only responds to ultraviolet light, has low visible light utilization rate, a large band gap, and low quantum efficiency. Summary of the Invention

[0005] In order to overcome the problems that traditional photocatalysts only respond to ultraviolet light, have low visible light utilization rate, large band gap, low quantum efficiency, etc., the purpose of the present invention is to provide a Schottky heterojunction photocatalyst, its preparation method and application.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention is a preparation method of a Schottky heterojunction photocatalyst, which includes the following steps:

[0008] Step 1. Disperse Ti 3 C 2 nanosheets in water to obtain a dispersion;

[0009] Step 2. Add an Sn source and a sulfur source to the dispersion, mix evenly and then react to obtain a Schottky heterojunction photocatalyst.

[0010] Another technical solution of the present invention is a Schottky heterojunction photocatalyst prepared by the above preparation method.

[0011] Another technical solution of the present invention is an application of the above Schottky heterojunction photocatalyst in catalyzing the degradation of ciprofloxacin by peroxymonosulfate.

[0012] Another technical solution of the present invention is a method for degrading ciprofloxacin. Add the above Schottky heterojunction photocatalyst and peroxymonosulfate to the ciprofloxacin-containing wastewater and react under visible light.

[0013] The present invention discloses the following technical effects:

[0014] The present invention composes C-SnS 2 and MXenes to form a Schottky heterojunction photocatalyst to couple with PMS activation. Through the sub-metal characteristics of MXenes, the separation of charge carriers is promoted and a series of free radicals are generated by promoting PMS activation, thereby enhancing the degradation ability of the reaction system for organic matter. The removal rate of CIP within 60 minutes can reach 98.2%, and the reaction rate constant k can reach 0.07068 min -1 , which is 5.51 times higher than that of C-SnS 2 . Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 For the catalysts obtained in Examples 1-4 and Ti 3 C 2 , C-SnS 2 , XRD pattern a and infrared spectrum b;

[0017] Figure 2 For the catalysts obtained in Examples 1-4 and C-SnS 2 , nitrogen adsorption-desorption isotherm a and pore size distribution b;

[0018] Figure 3 In which, a is the scanning electron microscopy image of MXene (Ti 3 C 2 ), b is the scanning electron microscopy image of C-SnS 2 , and c is the scanning electron microscopy image of the catalyst obtained in Example 3 (10-MXene / C-SnS 2 );

[0019] Figure 4 Degradation curves a and pseudo-first-order kinetic fitting curves b for the catalytic degradation of CIP in Examples 1-4 and Comparative Examples 1-4;

[0020] Figure 5 For the degradation mechanism diagram of CIP in the MXene / C-SnS 2 / PMS catalytic system. Detailed implementation manners

[0021] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0022] It should be understood that the terms used in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0023] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0024] Without departing from the scope or spirit of the present invention, various modifications and variations can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the present invention specification are obvious to those skilled in the art. The present invention specification and examples are merely exemplary.

[0025] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0026] As a cheap and environmentally friendly visible light photocatalytic material, SnS 2 has been used to remove organic pollutants and heavy metal ions and has received wide attention. However, SnS 2 has a relatively small specific surface area and a slow charge transfer rate, resulting in low photocatalytic activity. Changing the electronic structure by doping heteroatoms is an effective strategy. Compared with S atoms, C atoms with a smaller radius have lower energy and more empty 2p orbitals, which can generate sp2 hybridization sites on the outermost layer. In addition, the electronegativity difference between C and S will cause asymmetric charge distribution, thus generating highly active defects in SnS 2 . Therefore, SnS doped with C 2 (C-SnS 2 ) can significantly improve the photocatalytic activity of SnS 2 .

[0027] MXenes are two-dimensional metal carbides, carbon nitrides or nitrides, with strong carrier mobility, good hydrophilicity and numerous functional groups. MXenes are a potential photocatalytic material that can effectively transfer photo-generated charge carriers and provide a large number of surface active sites for the photocatalytic process. MXenes have sub-metal properties, and combining with semiconductors can generate Schottky junctions. Electrons in the semiconductor transfer to MXenes through the semiconductor / metal interface of the Schottky junction until the Fermi levels of the two materials reach equilibrium, thus generating a space charge region and band bending (Schottky barrier). In addition to suppressing the recombination of electrons and holes in the semiconductor, the Schottky barrier also restricts the backflow of electrons from the metal to the semiconductor. In addition, the Schottky junction usually generates an internal electric field, thus effectively promoting carrier separation. Therefore, it is very feasible to design a Schottky catalyst based on MXene to obtain more effective photocatalytic activity.

[0028] The first aspect of the present invention provides a method for preparing a Schottky heterojunction photocatalyst, comprising the following steps:

[0029] Step 1. Mix Ti 3 C 2The nanosheets are dispersed in water to obtain a dispersion liquid;

[0030] Step 2. Add an Sn source and a sulfur source to the dispersion liquid, mix evenly and then carry out a reaction to obtain a Schottky heterojunction photocatalyst.

[0031] In a preferred embodiment of the present invention, the 3 C 2 preparation method of the Ti 3 AlC 2 nanosheets is: by means of chemical etching, the Al layer in the Ti 3 C 2 is removed to obtain a multi-layer Ti 3 C 2 solid; then the multi-layer Ti 3 C 2 solid is ultrasonically treated to obtain the Ti

[0032] specifically, the preparation method of the Ti 3 C 2 nanosheets includes the following steps: Add LiF to hydrochloric acid and stir vigorously, then add Ti 3 AlC 2 powder, react at 45 °C for 48 h to obtain a black precipitate; dry the obtained black precipitate to obtain a multi-layer Ti 3 C 2 solid; ultrasonically disperse the multi-layer Ti 3 C 2 solid in water, then centrifuge, collect the supernatant, and freeze-dry the supernatant to obtain the Ti 3 C 2 nanosheets.

[0033] In a preferred embodiment of the present invention, the Sn source is SnCl 4 , the sulfur source is L-cysteine; the mass percentage of the Ti 3 C 2 nanosheets and the SnCl 4 is 5%-15%; the mass percentage of the Ti 3 C 2 nanosheets and the L-cysteine is 3%-10%.

[0034] In a preferred embodiment of the present invention, the mass percentage of the Ti 3 C 2 nanosheets and the SnCl 4 is 8%-15%; the mass percentage of the Ti 3 C 2 nanosheets and the L-cysteine is 5%-9%.

[0035] In a preferred embodiment of the present invention, the mass percentage of the Ti 3 C 2 nanosheets and the SnCl 4 is 10%-15%; the mass percentage of the Ti 3 C 2 nanosheets and the L-cysteine is 6%-10%.

[0036] In a preferred embodiment of the present invention, the mass percentage of the Ti 3 C 2 nanosheets and the SnCl 4 is 5%, 8%, 10%, 15%; the mass percentage of the Ti 3 C 2 nanosheets and the L-cysteine is 3%, 5%, 6%, 9%.

[0037] In the present invention, if the ratio of the Ti 3 C 2 nanosheets, SnCl 4 , and L-cysteine is not within the above range, the catalytic effect of the finally obtained catalyst will be reduced.

[0038] In a preferred embodiment of the present invention, the temperature of the reaction is 150-200 °C and the time is 12-36 h.

[0039] In a preferred embodiment of the present invention, the temperature of the reaction is 180-200 °C and the time is 24-36 h.

[0040] In a preferred embodiment of the present invention, the temperature of the reaction is 180 °C and the time is 24 h.

[0041] In a preferred embodiment of the present invention, after the reaction, it further includes the steps of centrifugation, washing, and drying.

[0042] The second aspect of the present invention provides a Schottky heterojunction photocatalyst prepared by the above preparation method.

[0043] The third aspect of the present invention provides an application of the above Schottky heterojunction photocatalyst in catalyzing the degradation of ciprofloxacin (CIP) by peroxymonosulfate (PMS).

[0044] The fourth aspect of the present invention provides a method for degrading ciprofloxacin, adding the above Schottky heterojunction photocatalyst and peroxymonosulfate to the ciprofloxacin-containing wastewater and reacting under visible light. The degradation mechanism of CIP in the MXene / C-SnS 2 / PMS catalytic system is as Figure 5 shown.

[0045] In a preferred embodiment of the present invention, the dosage of the Schottky heterojunction photocatalyst is 0.3 - 0.8 mg / mL; the dosage of the peroxymonosulfate is 0.3 - 0.8 mg / mL.

[0046] In a preferred embodiment of the present invention, the dosage of the Schottky heterojunction photocatalyst is 0.3 - 0.5 mg / mL; the dosage of the peroxymonosulfate is 0.3 - 0.5 mg / mL.

[0047] In a preferred embodiment of the present invention, the dosage of the Schottky heterojunction photocatalyst is 0.5 mg / mL; the dosage of the peroxymonosulfate is 0.4 mg / mL.

[0048] The technical solutions of the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are all purchased from commercial channels or are publicly available.

[0049] To better understand the present invention, the content of the present invention will be further clarified below in conjunction with examples, but the content of the present invention is not limited to the following examples.

[0050] In the example, Ti 3 C 2 MXene nanosheets are prepared by selectively etching Ti 3 AlC 2 , and then ultrasonic treatment is performed on the multi-layer Ti 3 C 2 . Specifically, 800 mg of LiF is added to 10 mL of hydrochloric acid (9 mol / L) and stirred vigorously for 10 min. Then, 500 mg of Ti 3 AlC 2 powder is slowly added, and the reaction is carried out at 45 °C for 48 h to obtain a black precipitate. The prepared black precipitate is vacuum dried at 60 °C for 12 h to obtain a multi-layer Ti 3 C 2 solid. The multi-layer Ti 3 C 2 solid is ultrasonically dispersed in water, and then centrifuged at 3000 rpm for 1 h. After that, the supernatant is freeze-dried to obtain Ti 3 C 2 nanosheets.

[0051] Example 1

[0052] After dispersing 18 mg of Ti 3 C 2 nanosheets into 50 mL of water, 351 mg of SnCl 4And 606 mg of L-cysteine was added and stirred vigorously for 1 h. Subsequently, it was transferred to a reactor and reacted at 180 °C for 24 h. After centrifugation, washing with water and drying, MXene / C-SnS was obtained 2 , and it was labeled as 5-MXene / C-SnS 2 , where 5 represents Ti 3 C 2 and the mass ratio of SnCl 4 was 5%.

[0053] Catalytic degradation of CIP:

[0054] The visible light source was a 500 W xenon lamp with a 420 nm cut-off filter. 25 mg of the catalyst obtained in Example 1 was dispersed in 50 mL of an aqueous CIP solution (20 mg / L) and stirred in the dark for 30 min. Subsequently, the solution was placed under visible light, and 20 mg of PMS was quickly added. At the beginning of the reaction, 2 mL of the reaction solution was taken every 10 min. After centrifuging to remove the catalyst, the concentration of CIP in the solution was measured with a UV-visible spectrophotometer. The removal rate of CIP within 60 min was tested to be 94.5%.

[0055] Example 2

[0056] The difference from Example 1 was only that 18 mg of Ti 3 C 2 nanosheets were replaced with 28 mg of Ti 3 C 2 nanosheets, and the other steps and parameters were the same as those in Example 1, obtaining MXene / C-SnS 2 , labeled as 8-MXene / C-SnS 2 , where 8 represents Ti 3 C 2 and the mass ratio of SnCl 4 was 8%.

[0057] Catalytic degradation of CIP:

[0058] The visible light source was a 500 W xenon lamp with a 420 nm cut-off filter. 25 mg of the catalyst obtained in Example 2 was dispersed in 50 mL of an aqueous CIP solution (20 mg / L) and stirred in the dark for 30 min. Subsequently, the solution was placed under visible light, and 20 mg of PMS was quickly added. At the beginning of the reaction, 2 mL of the reaction solution was taken every 10 min. After centrifuging to remove the catalyst, the concentration of CIP in the solution was measured with a UV-visible spectrophotometer. The removal rate of CIP within 60 min was tested to be 96.5%.

[0059] Example 3

[0060] The difference from Example 1 is only that 18 mg of Ti 3 C 2 nanosheets are replaced with 35 mg of Ti 3 C 2 nanosheets, and the other steps and parameters are the same as those in Example 1, obtaining MXene / C-SnS 2 , labeled as 10-MXene / C-SnS 2 , where 10 represents the mass ratio of Ti 3 C 2 to SnCl 4 is 10%.

[0061] Catalytic degradation of CIP:

[0062] The visible light source is from a 500 W xenon lamp with a 420 nm cut-off filter. 25 mg of the catalyst obtained in Example 3 was dispersed in 50 mL of an aqueous CIP solution (20 mg / L) and stirred in the dark for 30 min. Subsequently, the solution was placed under visible light, and 20 mg of PMS was quickly added. At the beginning of the reaction, 2 mL of the reaction solution was taken every 10 min. After centrifuging to remove the catalyst, the concentration of CIP in the solution was measured with a UV-visible spectrophotometer. The removal rate of CIP within 60 min was tested to be 98.2%.

[0063] Example 4

[0064] The difference from Example 1 is only that 18 mg of Ti 3 C 2 nanosheets are replaced with 52 mg of Ti 3 C 2 nanosheets, and the other steps and parameters are the same as those in Example 1, obtaining MXene / C-SnS 2 , labeled as 15-MXene / C-SnS 2 , where 15 represents the mass ratio of Ti 3 C 2 to SnCl 4 is 15%.

[0065] Catalytic degradation of CIP:

[0066] The visible light source is from a 500 W xenon lamp with a 420 nm cut-off filter. 25 mg of the catalyst obtained in Example 4 was dispersed in 50 mL of an aqueous CIP solution (20 mg / L) and stirred in the dark for 30 min. Subsequently, the solution was placed under visible light, and 20 mg of PMS was quickly added. At the beginning of the reaction, 2 mL of the reaction solution was taken every 10 min. After centrifuging to remove the catalyst, the concentration of CIP in the solution was measured with a UV-visible spectrophotometer. The removal rate of CIP within 60 min was tested to be 96.9%.

[0067] Comparative Example 1

[0068] Catalytic degradation of CIP under visible light + MXene / C - SnS 2 system:

[0069] The visible light source was from a 500W xenon lamp with a 420nm cut - off filter. 25mg of MXene / C - SnS 2 (the catalyst 10 - MXene / C - SnS obtained in Example 3 2 ) was dispersed in 50mL of CIP aqueous solution (20mg / L) and stirred in the dark for 30min. Subsequently, the solution was placed under visible light, and 2mL of the reaction solution was taken every 10min. After centrifuging to remove the catalyst, the concentration of CIP in the solution was measured with a UV - visible spectrophotometer. The removal rate of CIP within 60min was tested to be 59.7%.

[0070] Comparative Example 2

[0071] Preparation of C - SnS 2 :

[0072] 351mg of SnCl was added to 50mL of water 4 and 606mg of L - cysteine and stirred vigorously for 1h. Subsequently, it was transferred to a reactor and reacted at 180°C for 24h. After centrifuging, washing with water and drying, C - SnS 2 was obtained.

[0073] Catalytic degradation of CIP under visible light + C - SnS 2 system:

[0074] The visible light source was from a 500W xenon lamp with a 420nm cut - off filter. 25mg of C - SnS 2 was dispersed in 50mL of CIP aqueous solution (20mg / L) and stirred in the dark for 30min. Subsequently, the solution was placed under visible light, and 2mL of the reaction solution was taken every 10min. After centrifuging to remove the catalyst, the concentration of CIP in the solution was measured with a UV - visible spectrophotometer. The removal rate of CIP within 60min was tested to be 52.6%.

[0075] Comparative Example 3

[0076] Catalytic degradation of CIP under visible light + PMS system:

[0077] The visible light source comes from a 500 W xenon lamp with a 420 nm cut-off filter. 50 mL of CIP aqueous solution (20 mg / L) was stirred in the dark for 30 min. Subsequently, the solution was placed under visible light, and 20 mg of PMS was quickly added. At the beginning of the reaction, 2 mL of the reaction solution was taken every 10 min. After centrifuging to remove the catalyst, the concentration of CIP in the solution was measured using a UV-visible spectrophotometer. The removal rate of CIP within 60 min was tested to be 5.8%.

[0078] Comparative Example 4

[0079] Catalytic degradation of CIP only under the visible light system:

[0080] The visible light source comes from a 500 W xenon lamp with a 420 nm cut-off filter. 50 mL of CIP aqueous solution (20 mg / L) was stirred in the dark for 30 min. Subsequently, the solution was placed under visible light, and 2 mL of the reaction solution was taken every 10 min. After centrifuging to remove the catalyst, the concentration of CIP in the solution was measured using a UV-visible spectrophotometer. The removal rate of CIP within 6 min was tested to be 4.2%.

[0081] Figure 1 The XRD pattern and infrared spectrum of 2 can illustrate that the MXene / C-SnS

[0082] Figure 2 photocatalyst was successfully prepared. The nitrogen adsorption-desorption isotherm and pore size distribution diagram of

[0083] Figure 3 can illustrate the specific surface area and pore size of the material, which have an impact on the catalytic performance of the material. The scanning electron microscopy image of

[0084] Figure 4 can clearly show the microscopic morphology of the material. It shows the degradation performance and degradation kinetics of the prepared catalysts (Examples 1-4 and Comparative Examples 1-4) for CIP.

[0085] Comparative Example 5

[0086] MXene / C-SnS 2 mixture:

[0087] Disperse 35 mg of Ti 3 C 2 nanosheets (obtained in Example 1) into 50 mL of water, and then add 248 mg of C-SnS 2 (obtained in Comparative Example 2). After stirring for 2 h, centrifuge, wash with water and dry to obtain the MXene / C-SnS 2 mixture.

[0088] Catalytic degradation of CIP:

[0089] The visible light source is a 500 W xenon lamp with a 420 nm cut-off filter. 25 mg of the MXene / C-SnS 2 mixture was dispersed in 50 mL of an aqueous CIP solution (20 mg / L) and stirred in the dark for 30 min. Subsequently, the solution was placed under visible light, and 20 mg of PMS was quickly added. At the beginning of the reaction, 2 mL of the reaction solution was withdrawn every 10 min. After centrifuging to remove the catalyst, the concentration of CIP in the solution was measured using a UV-visible spectrophotometer. The removal rate of CIP within 60 min was tested to be 82.6%.

[0090] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a Schottky heterojunction photocatalyst, characterized in that: The following steps are involved: Step 1. Dispersing Ti3C2 nanosheets in water to obtain a dispersion; Step 2. Adding a Sn source and a sulfur source to the dispersion, mixing them evenly and reacting them to obtain a Schottky heterojunction photocatalyst.

2. The method for preparing a Schottky heterojunction photocatalyst according to claim 1, characterized in that: The preparation method of the Ti3C2 nanosheet is as follows: removing the Al layer in Ti3AlC2 by chemical etching to obtain a multilayer Ti3C2 solid; and then ultrasonically treating the multilayer Ti3C2 solid to obtain the Ti3C2 nanosheet.

3. The method for preparing a Schottky heterojunction photocatalyst according to claim 1, characterized in that: The Sn source is SnCl4, and the sulfur source is L-cysteine; the mass percentage of the Ti3C2 nanosheets and the SnCl4 is 5%-15%; the mass percentage of the Ti3C2 nanosheets and the L-cysteine ​​is 3%-10%.

4. The method for preparing a Schottky heterojunction photocatalyst according to claim 1, characterized in that: The reaction temperature is 150-200°C and the reaction time is 12-36h.

5. The method for preparing a Schottky heterojunction photocatalyst according to claim 1, characterized in that: After the reaction is completed, the steps of centrifugation, washing and drying are also included.

6. A Schottky heterojunction photocatalyst prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the Schottky heterojunction photocatalyst according to claim 6 in catalyzing the degradation of ciprofloxacin by peroxymonosulfate.

8. A method for degrading ciprofloxacin, characterized in that: The Schottky heterojunction photocatalyst and peroxymonosulfate according to claim 6 are added to wastewater containing ciprofloxacin, and the reaction is carried out under visible light.

9. The method for degrading ciprofloxacin according to claim 8, characterized in that: The dosage of the Schottky heterojunction photocatalyst is 0.3-0.8 mg / mL; the dosage of the peroxymonosulfate is 0.3-0.8 mg / mL.

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