CN115254186A

CN115254186A - Nano-silver/silver chloride/supermolecule perylene bisimide derivative composite photocatalyst and preparation method and application thereof

Info

Publication number: CN115254186A
Application number: CN202211005053.3A
Authority: CN
Inventors: 徐婧; 王周平; 陈雪
Original assignee: Jiangnan University
Current assignee: Jiangnan University
Priority date: 2022-08-22
Filing date: 2022-08-22
Publication date: 2022-11-01
Anticipated expiration: 2042-08-22
Also published as: CN115254186B

Abstract

The invention discloses a nano-silver/silver chloride/supermolecule perylene bisimide derivative composite photocatalyst and a preparation method and application thereof. The composite photocatalyst is prepared by loading nano silver/silver chloride on a supermolecule perylene bisimide derivative by an in-situ deposition-photoreduction method; the mass ratio of the silver contained in the nano silver/silver chloride to the supermolecule perylene bisimide derivative is 1-1000. Compared with the supramolecular perylene bisimide derivative in the prior art, the composite photocatalyst prepared by the invention has more excellent photocatalytic performance in the aspects of pollutant degradation and drug-resistant bacterium killing, and the preparation method is green and safe, has easily obtained raw materials, simple process, and has higher application prospect and practical value.

Description

Nano-silver/silver chloride/supramolecular perylene imide derivative composite photocatalyst and preparation method and application thereof

Technical Field

The invention relates to the technical field of photocatalyst materials, in particular to a nano-silver/silver chloride/supermolecule perylene bisimide derivative composite photocatalyst and a preparation method and application thereof.

Background

The 3,4,9,10-perylene bisimide (PDI) is composed of a central rigid plane perylene core of a pi electron conjugated system and lactams at two ends, the PDI and derivatives thereof are generally used as photosensitizers in early research to enhance the light absorption capacity of a host material, and recently, the fact that effective overlapping occurs between molecular orbitals of the perylene core through a self-assembly method based on pi-pi stacking action and hydrogen bonding action is discovered, and single molecules of PDI are orderly assembled into supramolecular PDI with a continuous energy level structure and a larger pi electron conjugated system. Meanwhile, a carboxyl group is introduced into an imide position of a PDI molecule to regulate the supermolecule self-assembly process of the PDI, so that the dispersity, the stability and the energy band structure of the supermolecule PDI can be effectively improved, and the photocatalytic performance of the supermolecule PDI is further improved. As a novel organic semiconductor photocatalyst, the supramolecular PDI has the advantages of wide spectral response range, strong photooxidation capability and the like, so that the supramolecular PDI is widely applied to the fields of degrading pollutants, killing pathogenic bacteria, photolyzing aquatic products and the like. However, the current supramolecular PDI has the problems of limited visible light absorption capacity, low separation and migration rate of photogenerated carriers, high recombination probability of photogenerated electron-hole pairs and the like, and the application prospect of the supramolecular PDI is influenced. Therefore, the development of the supermolecule PDI-based photocatalyst with strong visible light absorption capacity, high photogenerated carrier separation and migration rate and low recombination probability of photogenerated electron-hole pairs is significant.

The nano silver (AgNPs) supported photocatalyst is proved to be an effective means for improving the activity of the catalyst, because the nano silver supported photocatalyst can improve the migration rate of photo-generated electrons and can also enhance the absorption of visible light by the material through the Surface Plasmon Resonance (SPR) effect. Nano silver/silver chloride (Ag @ AgCl) as a typical composite plasma photocatalyst can show good photocatalytic activity and stability under the irradiation of visible light. In addition, ag @ AgCl can also be used for modifying other semiconductor materials to construct a heterojunction composite photocatalyst, a new light absorption source can be introduced into the composite material through the SPR effect of AgNPs, the migration efficiency of photon-generated carriers can be improved through a matched energy band structure, and the visible light catalysis performance of the composite material can be obviously improved. At present, no relevant research for improving the performance of the supramolecule PDI by utilizing Ag @ AgCl exists.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a nano-silver/silver chloride/supermolecule perylene bisimide derivative composite photocatalyst and a preparation method and application thereof. Compared with the supermolecule perylene bisimide derivative (SA-PDI) in the prior art, the composite photocatalyst prepared by the invention has more excellent photocatalytic performance in the aspects of degrading pollutants and killing drug-resistant bacteria, and the preparation method is green and safe, has easily obtained raw materials, is simple in process, and has higher application prospect and practical value.

The technical scheme of the invention is as follows:

a nano silver/silver chloride/supermolecule perylene bisimide derivative composite photocatalyst is characterized in that nano silver/silver chloride is loaded on supermolecule perylene bisimide derivative through an in-situ deposition-photoreduction method; the mass ratio of the silver contained in the nano silver/silver chloride to the supermolecule perylene bisimide derivative is 1-1000.

Further, the particle size of the nano silver/silver chloride is 10-100 nm; the supramolecular perylene bisimide derivative is perylene bisimide substituted by supramolecular terminal carboxylic acid straight-chain alkane; the diameter of the supermolecule perylene bisimide derivative is 10-50nm, and the length of the supermolecule perylene bisimide derivative is 100-800 nm.

Furthermore, the mass ratio of the silver contained in the nano silver/silver chloride to the supermolecule perylene bisimide derivative is 1.

Furthermore, the particle size of the composite photocatalyst is 100-800 nm.

The preparation method of the composite photocatalyst comprises the following steps:

(1) Mixing 3,4,9, 10-perylene tetracarboxylic dianhydride, imidazole and beta-aminopropionic acid, heating, stirring, carrying out reflux reaction, cooling to room temperature, adding ethanol and hydrochloric acid, carrying out stirring reaction, centrifuging, collecting precipitate, washing, drying and grinding to obtain a perylene bisimide derivative;

(2) Adding water into the perylene bisimide derivative obtained in the step (1) for dispersion, adding triethylamine for stirring, adding strong acid for stirring reaction, centrifuging, washing, drying and grinding to obtain the supermolecule perylene bisimide derivative;

(3) Adding a dispersing agent into the supramolecular perylene bisimide derivative prepared in the step (2) for ultrasonic dispersion to obtain a supramolecular perylene bisimide derivative dispersion liquid, adding a silver nitrate solution, stirring, adding a chloride solution, and continuously stirring for reaction to obtain a mixed liquid; and then stirring the mixed solution under the irradiation of an LED lamp for reaction, centrifuging, collecting the precipitate, washing, drying and grinding to obtain the nano-silver/silver chloride/supramolecular perylene bisimide derivative composite photocatalyst.

Further, in the step (1), the mass ratio of the 3,4,9, 10-perylenetetracarboxylic dianhydride to the beta-aminopropionic acid is 1 to 5; the mass ratio of the 3,4,9, 10-perylene tetracarboxylic dianhydride to the imidazole is 1-20; the mass volume ratio of the 3,4,9, 10-perylene tetracarboxylic dianhydride to the ethanol is 1; the mass volume ratio of the 3,4,9, 10-perylene tetracarboxylic dianhydride to the hydrochloric acid is 1.

Further, in the step (2), the mass-to-volume ratio of the perylene bisimide derivative to water is 1.1-10 mg/mL, and the mass-to-volume ratio of the perylene bisimide derivative to triethylamine is 1; the mass volume ratio of the perylene bisimide derivative to the strong acid is 1.01-1 mg/mL, the strong acid is hydrochloric acid, sulfuric acid or nitric acid, and the molar concentration of the strong acid is 0.01-10 mol/L.

Further, in the step (3), the mass ratio of silver contained in the silver nitrate solution to the supramolecular perylene diimide derivative in the supramolecular perylene diimide derivative dispersion liquid is 1 to 1000, and the mass-to-volume ratio of the supramolecular perylene diimide derivative in the supramolecular perylene diimide derivative dispersion liquid to the dispersant is 1; the dispersant is water, methanol or ethanol.

Further, in the step (3), the mass-to-volume ratio of silver contained in the silver nitrate solution to the solvent is 1.1 to 10mg/mL, the mass-to-volume ratio of chloride in the chloride solution to the solvent is 1.1 to 100mg/mL, the chloride is sodium chloride, potassium chloride or calcium chloride, and the solvent is water, methanol or ethanol; the molar ratio of silver nitrate in the silver nitrate solution to chloride in the chloride solution is 1.1-10.

The application of the composite photocatalyst is used for degrading pollutants or killing drug-resistant bacteria.

The principle of the invention is as follows: the preparation of the composite photocatalyst by adopting a supramolecular self-assembly-in-situ deposition-photoreduction method specifically comprises the following steps: preparing end-position carboxylic acid straight-chain alkane by using 3,4,9, 10-perylene tetracarboxylic dianhydride to replace perylene bisimide (PDI), dissolving PDI in triethylamine solution by using the end-position carboxylic acid straight-chain alkane as a raw material through a supermolecule self-assembly method, and then adding an acid solution to form supermolecule perylene bisimide derivatives (SA-PDI) by using pi-pi stacking action generated among PDI molecules and hydrogen bonding action generated among carboxylic acid groups, wherein the supermolecule perylene bisimide derivatives (SA-PDI) are used as a main photocatalyst; nano silver/silver chloride (Ag @ AgCl) as a typical composite plasma photocatalyst can be used for modifying other semiconductor materials to improve the visible light catalytic performance of the composite material. Adding nitrate, chloride and Ag into the main catalyst ⁺ And Cl ^- AgCl generated by electrostatic assembly and precipitation reaction is deposited on the surface of SA-PDI, and Ag in part of AgCl is subjected to in-situ photoreduction reaction ⁺ Reduction to Ag ⁰ Finally, the Ag @ AgCl/SA-PDI composite photocatalytic material is formed.

The beneficial technical effects of the invention are as follows:

(1) According to the invention, ag @ AgCl is used as a plasma photocatalyst to be combined with other semiconductor materials to construct a heterojunction composite photocatalyst, the light absorption capacity of a composite photocatalytic system is enhanced through a Surface Plasmon Resonance (SPR) effect, and the recombination probability of a photo-generated electron-hole pair is reduced by accelerating the transfer of photo-generated charges at a heterogeneous interface.

(2) According to the invention, the space and the electronic structure of the SA-PDI for photocatalysis are improved by means of combining with the Ag @ AgCl, and the addition of the Ag @ AgCl serving as a plasma photocatalyst improves the absorption capacity of the SA-PDI for visible light and the separation and migration efficiency of a photon-generated carrier, so that the prepared Ag @ AgCl/SA-PDI composite photocatalyst has excellent pollutant degradation rate and drug-resistant bacterium killing efficiency.

(3) Compared with SA-PDI in the prior art, the Ag @ AgCl/SA-PDI composite photocatalyst has more excellent photocatalytic performance in the aspects of degrading pollutants and killing drug-resistant bacteria, the rate of degrading phenol is improved by 3.8 times after visible light irradiates for 2 hours, the killing rate of sulfonamide-resistant bacteria is close to 100%, and the sterilizing rate of SA-PDI is only 49.4%; the preparation method is green and safe, has easily obtained raw materials, simple process and higher application prospect and practical value.

(4) The invention adopts an in-situ deposition-photoreduction method, and Ag is in the process of combining Ag @ AgCl and SA-PDI ⁺ And Cl ^- AgCl generated by electrostatic assembly and precipitation reaction is deposited on the surface of SA-PDI, and Ag in part of AgCl is subjected to in-situ photoreduction reaction ⁺ Reduction to Ag ⁰ Finally forming the Ag @ AgCl/SA-PDI composite photocatalytic material; in an Ag @ AgCl/SA-PDI system, the SPR effect of nano silver (AgNPs) can enhance the absorption capacity of a composite photocatalytic system to visible light, so that more photon-generated carriers are generated to participate in the reaction; agNPs can play a role of an electron trap, effectively capture photogenerated electrons on an SA-PDI conduction band and prevent the recombination of photogenerated electron-hole pairs; ag ⁰ The formed Schottky barrier enables electrons excited by the SPR effect to be transferred from AgNPs to the AgCl surface through the Ag @ AgCl interface, and the separation and migration rate of photon-generated carriers are further improved. Therefore, compared with SA-PDI, the Ag @ AgCl/SA-PDI composite photocatalyst prepared by the invention has stronger visible light absorption capacity, higher photogenerated carrier separation and migration rate and lower photogenerated electron-hole pair recombination probability, and has important significance for improving the application prospect and the practical value of the SA-PDI-based photocatalyst; in addition, the in-situ deposition-photoreduction method has the characteristics of high efficiency, greenness and mildness.

Drawings

FIG. 1 is a graph showing the degradation performance of the Ag @ AgCl/SA-PDI composite photocatalyst prepared in examples 1-5 of the present invention, the SA-PDI photocatalyst prepared in comparative example 1, the Ag @ AgCl photocatalyst prepared in comparative example 2, the graphite-like carbon nitride photocatalyst prepared in comparative example 3, and the perylene bisimide derivative material prepared in comparative example 4 on phenol under visible light.

In the figure: a. the change curve of the phenol concentration with time is compared with a graph; b. the apparent rate constants (k) for phenol degradation are plotted versus time.

FIG. 2 is a graph comparing the antibacterial performance of Ag @ AgCl/SA-PDI-3% prepared in example 3 with SA-PDI prepared in comparative example 1 and Ag @ AgCl prepared in comparative example 2 under visible light.

FIG. 3 is a TEM comparison of Ag @ AgCl/SA-PDI-3% prepared in example 3 with SA-PDI prepared in comparative example 1.

In the figure: a. TEM image as SA-PDI; b. TEM image at Ag @ AgCl/SA-PDI-3%.

FIG. 4 is an XRD comparison of Ag @ AgCl/SA-PDI prepared in examples 1-5 with SA-PDI prepared in comparative example 1 and Ag @ AgCl prepared in comparative example 2.

FIG. 5 is a graph comparing the Raman spectra of Ag @ AgCl/SA-PDI-3% prepared in example 3 and SA-PDI prepared in comparative example 1.

FIG. 6 is an XPS comparison of Ag @ AgCl/SA-PDI-3% prepared in example 3 and SA-PDI prepared in comparative example 1.

In the figure: a. XPS full spectrum for SA-PDI and Ag @ AgCl/SA-PDI-3%; b. c1s spectra for SA-PDI and Ag @ AgCl/SA-PDI-3%; c. ag3d spectrum of Ag @ AgCl/SA-PDI-3%; d. cl 2p profile of Ag @ AgCl/SA-PDI-3%.

FIG. 7 is a DRS plot of Ag @ AgCl/SA-PDI-3% prepared in example 3 compared to SA-PDI prepared in comparative example 1 and Ag @ AgCl prepared in comparative example 2.

FIG. 8 is a graph comparing the photoelectric properties of Ag @ AgCl/SA-PDI-3% prepared in example 3 and SA-PDI prepared in comparative example 1.

In the figure: a. is a photocurrent response diagram of SA-PDI and Ag @ AgCl/SA-PDI-3% under light-dark alternation; b. electrochemical impedance Nyquist plots for SA-PDI and Ag @ AgCl/SA-PDI-3% under dark and visible light.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings and examples.

Example 1

The supermolecule perylene bisimide derivative is supermolecule end-position carboxylic acid straight-chain alkane substituted perylene bisimide; the preparation method of the composite photocatalyst comprises the following steps:

(1) Preparation of perylene bisimide derivatives

Weighing 1.373g of 3,4,9, 10-perylene tetracarboxylic dianhydride, 2.495g of beta-aminopropionic acid and 18g of imidazole, mixing, heating the mixture to 100 ℃ under the protection of argon, stirring and refluxing at the rotating speed of 500r/min for 4 hours, adding 100mL of anhydrous ethanol and 300mL of 2.0mol/L hydrochloric acid when the product is naturally cooled to room temperature, stirring at the rotating speed of 500r/min for 15h, centrifugally separating and precipitating at the rotating speed of 500r/min, washing the precipitate with water to be neutral, drying at the temperature of 60 ℃ for 24 hours, and grinding the product for 1 hour to obtain a dark red powder product, namely the perylene imide derivative (bulk-PDI).

(2) Preparation of supramolecular perylene bisimide derivatives

Weighing 300mg of bulk-PDI, ultrasonically dispersing (560W, 40kHz) in 109mL of water for 30min, adding 453 mu L of triethylamine, stirring at the rotation speed of 500r/min for 2h to completely dissolve the bulk-PDI to form a dark red bulk-PDI solution, then adding 14.13mL of 4.0mol/L hydrochloric acid, stirring at the rotation speed of 500r/min for reaction for 1h, centrifugally separating and precipitating at the rotation speed of 8000r/min, washing and precipitating with water to be neutral, drying at 60 ℃ for 24h, grinding a product for 1h to obtain the supramolecular perylene imide derivative (SA-PDI); wherein, the diameter of the SA-PDI is 10-50nm, and the length is 100-800 nm.

(3) In-situ deposition-photoreduction method for preparing composite photocatalyst

100mg of SA-PDI powder was weighed out in 46.5mL of methanol and sonicated (560W, 40kHz) for 30min to obtain a SA-PDI dispersion, and then 1mL of 1.574mg/mL of AgNO was added ₃ The solution (methanol was used as a solvent for the silver nitrate solution) was added to the SA-PDI dispersion so that the mass fraction of Ag contained therein relative to the SA-PDI was 1%, and the mixture was stirred at 500r/min for 30min, followed by addition of 2.5mL of a 0.133mg/mL NaCl solution (methanol was used as a solvent for the sodium chloride solution) using a syringe pump (0.5 mL/min), stirring at 500r/min for 30min, and irradiation with an LED lamp (10W, 100mW/cm) ² ) Stirring at 500r/min for 3h, centrifuging at 8000r/min to collect precipitate, and collecting precipitate with methanolWashing the precipitate with alcohol, drying the precipitate for 24h at 60 ℃ in vacuum, manually grinding the product for 1h to obtain powder with the particle size of 100-800 nm, namely the nano-silver/silver chloride/supramolecular perylene bisimide derivative composite photocatalyst or the nano-silver/silver chloride/supramolecular end-position carboxylic acid straight-chain alkane substituted perylene bisimide (Ag @ AgCl/SA-PDI) composite photocatalyst. The particle size of the nano silver/silver chloride in the composite photocatalyst is 10-30 nm; the mass ratio of silver contained in the nano silver/silver chloride to the supermolecule perylene bisimide derivative is 1.

Examples 2 to 5

Examples 2 to 5 substantially the same as example 1, SA-PDI dispersion, agNO ₃ The total volume of the solution (methanol in solvent) and NaCl solution (methanol in solvent) was kept at 50mL ₃ The molar ratio to NaCl was kept constant except that the mass fraction of Ag contained in the silver nitrate solution to SA-PDI was 2%, 3%, 4% and 5% in examples 2 to 5, respectively, and the rest of the steps and raw materials were the same as in example 1.

Example 6

A nanometer silver/silver chloride/supermolecule perylene bisimide derivative composite photocatalyst is characterized in that the supermolecule perylene bisimide derivative is perylene bisimide substituted by supermolecule end-position carboxylic acid straight-chain alkane; the preparation method of the composite photocatalyst comprises the following steps:

(1) Preparation of perylene bisimide derivatives

Weighing 1g of 3,4,9, 10-perylenetetracarboxylic dianhydride, 1g of beta-aminopropionic acid and 1g of imidazole, heating the mixture to 88 ℃ under the protection of argon, stirring and refluxing at the rotating speed of 50r/min for reaction for 0.5h, naturally cooling the product to room temperature, adding 10mL of anhydrous ethanol and 10mL of 0.1mol/L hydrochloric acid, stirring at the rotating speed of 50r/min for 5h, centrifugally separating the precipitate at the rotating speed of 1000r/min, washing the precipitate with water to be neutral, drying at 30 ℃ for 1h, and grinding the product for 0.1h to obtain a dark red powder product, namely the perylene imide derivative (bulk-PDI).

(2) Preparation of supramolecular perylene bisimide derivatives

Weighing 100mg of bulk-PDI in 10mL of water, performing ultrasonic treatment (200W, 10kHz) for 0.1h, adding 10 mu L of triethylamine, stirring for 0.1h at the rotation speed of 50r/min to completely dissolve the bulk-PDI to form a dark red bulk-PDI solution, then adding 1mL of 0.01mol/L sulfuric acid, stirring and reacting for 0.5h at the rotation speed of 50r/min, performing centrifugal separation on precipitate at the rotation speed of 1000r/min, washing the precipitate to be neutral by water, drying for 1h at the temperature of 30 ℃, grinding the product for 0.1h to obtain the supramolecular perylene imide derivative (SA-PDI); wherein, the diameter of the SA-PDI is 10-50nm, and the length is 100-800 nm.

300mg of SA-PDI powder is weighed and ultrasonically treated in 3mL of water (200W, 10kHz) for 0.1h to obtain SA-PDI dispersion liquid, and then 0.03mL of AgNO with the concentration of 15.74mg/mL is added ₃ The aqueous solution was added to the SA-PDI dispersion so that the mass fraction of Ag contained therein was 0.1% relative to the SA-PDI, and the mixture was stirred at 50r/min for 0.1 hour, followed by adding 0.207mL of a 10mg/mL aqueous KCl solution by a syringe pump (0.1 mL/min), stirring at 50r/min for 0.1 hour, and then irradiating with an LED lamp (1W, 10 mW/cm) ² ) Stirring at the rotating speed of 50r/min for 0.1h, centrifugally collecting the precipitate at the rotating speed of 1000r/min, washing the precipitate with water, drying at the temperature of 30 ℃ for 1h in vacuum, and manually grinding the product for 0.1h to obtain powder with the particle size of 100-800 nm, namely the nano silver/silver chloride/supermolecule perylene imide derivative composite photocatalyst or the nano silver/silver chloride/supermolecule end carboxylic acid straight-chain alkane substituted perylene imide (Ag @ AgCl/SA-PDI) composite photocatalyst. The particle size of the nano silver/silver chloride in the composite photocatalyst is 10-100 nm; the mass ratio of silver contained in the nano silver/silver chloride to the supermolecule perylene bisimide derivative is 1.

Example 7

A nano-silver/silver chloride/supramolecular perylene bisimide derivative composite photocatalyst is characterized in that supramolecular perylene bisimide derivatives are perylene bisimide substituted by supramolecular end-position carboxylic acid straight-chain alkanes; the preparation method of the composite photocatalyst comprises the following steps:

(1) Preparation of perylene bisimide derivatives

Weighing 1g of 3,4,9, 10-perylene tetracarboxylic dianhydride, 5g of beta-aminopropionic acid and 20g of imidazole, heating the mixture to 150 ℃ under the protection of argon, stirring and refluxing at the rotating speed of 1500r/min for 10h, adding 150mL of anhydrous ethanol and 500mL of 10.0mol/L hydrochloric acid when the product is naturally cooled to room temperature, stirring at the rotating speed of 1500r/min for 30h, centrifuging at the rotating speed of 15000r/min for separating precipitate, washing the precipitate with water to neutrality, drying at the temperature of 80 ℃ for 48h, and grinding the product for 5h to obtain a dark red powder product, namely the perylene imide derivative (bulk-PDI).

(2) Preparation of supramolecular perylene bisimide derivatives

Weighing 100mg of bulk-PDI, ultrasonically treating the bulk-PDI in 1000mL of water (800W, 50kHz) for 5 hours, adding 1000 mu L of triethylamine, stirring the mixture for 5 hours at the rotating speed of 1500r/min to completely dissolve the bulk-PDI to form a dark red bulk-PDI solution, then adding 100mL of 10mol/L nitric acid, stirring the mixture for 10h at the rotating speed of 1500r/min, centrifugally separating and precipitating the solution at the rotating speed of 15000r/min, washing the precipitate with water to be neutral, drying the precipitate for 48 hours at the temperature of 80 ℃, and grinding the product for 5 hours to obtain a product, namely the supramolecular perylene imide derivative (SA-PDI); wherein, the diameter of the SA-PDI is 10-50nm, and the length is 100-800 nm.

(3) The composite photocatalyst is prepared by an in-situ deposition-photoreduction method

30mg of SA-PDI powder is weighed and ultrasonically treated (800W, 50kHz) in 300mL of ethanol for 5h to obtain SA-PDI dispersion liquid, and then 300mL of AgNO with the concentration of 0.1574mg/mL is added ₃ The ethanol solution is added into the SA-PDI dispersion liquid, so that the mass fraction of Ag contained in the SA-PDI dispersion liquid is 100 percent, the SA-PDI dispersion liquid is stirred for 10 hours at the rotating speed of 1500r/min, and then 308.51mL of 0.01mg/mL CaCl is added into the SA-PDI dispersion liquid by using a syringe pump (50 mL/min) ₂ Stirring the ethanol solution at 1500r/min for 10h, and irradiating with LED lamp (100W, 500mW/cm) ² ) Stirring at 1500r/min for 10h, centrifuging at 15000r/min for collecting precipitate, washing the precipitate with ethanol, vacuum drying at 80 ℃ for 48h, and manually grinding the product for 5h to obtain powder with the particle size of 100-800 nm, namely the nano-silver/silver chloride/supramolecular perylene imide derivative composite photocatalyst or the nano-silver/silver chloride/supramolecular terminal carboxylic acid straight-chain alkane substituted perylene imide (Ag @ AgCl/SA-PDI) composite photocatalyst. The particle size of the nano silver/silver chloride in the composite photocatalyst is 30-100 nm; the mass ratio of silver contained in the nano silver/silver chloride to the supermolecule perylene bisimide derivative is 1.

Comparative example 1

The supermolecule self-assembly method for preparing the supermolecule perylene bisimide derivative comprises the following steps:

(1) Preparing perylene bisimide derivatives: weighing 1.373g of 3,4,9, 10-perylene tetracarboxylic dianhydride, 2.495g of beta-aminopropionic acid and 18g of imidazole, heating the mixture to 100 ℃ under the protection of argon, stirring and refluxing at the rotating speed of 500r/min for 4 hours, naturally cooling the product to room temperature, adding 100mL of anhydrous ethanol and 300mL of 2.0mol/L hydrochloric acid, stirring at the rotating speed of 500r/min for 15h, centrifugally separating the precipitate at the rotating speed of 8000r/min, washing the precipitate with water to neutrality, drying at the temperature of 60 ℃ for 24 hours, and grinding the product for 1 hour to obtain a dark red powder product, namely the perylene imide derivative (bulk-PDI).

(2) Preparing supermolecule perylene imide derivatives (SA-PDI), 300mg of bulk-PDI is weighed and ultrasonically treated (560W, 40kHz) in 109mL of water for 30min, 453 mu L of triethylamine is added, stirring is carried out for 2h at the rotating speed of 500r/min, the bulk-PDI is completely dissolved to form dark red bulk-PDI solution, then 14.13mL of 4.0mol/L hydrochloric acid is added, stirring is carried out at the rotating speed of 500r/min for reaction for 1h, centrifugal separation and precipitation are carried out at the rotating speed of 8000r/min, washing and precipitation are carried out to neutrality by water, drying is carried out for 24h at the temperature of 60 ℃, products are ground for 1h, and powder products with the diameter of 10-50nm and the length of 100-800 nm are obtained, namely the perylene imide derivatives (SA-PDI).

Comparative example 2

The preparation method of the nano silver/silver chloride material by a precipitation reaction-photoreduction method comprises the following steps:

500mg of AgNO ₃ And 105.84mg NaCl were dissolved in 25mL of water, and the NaCl solution was slowly added dropwise to AgNO using a syringe pump (0.5 mL/min) ₃ In solution, then irradiated under an LED lamp (10W, 100mW/cm) ² ) Stirring at 500r/min for 3h, centrifuging at 8000r/min for collecting precipitate, washing the precipitate with water, vacuum drying at 60 deg.C for 24h, and manually grinding the product for 1h to obtain powder, i.e. nano silver/silver chloride material (Ag @ AgCl).

Comparative example 3

The preparation method of the graphite-like phase carbon nitride material by the high-temperature polycondensation method comprises the following steps:

10g of melamine was weighed into a 50mL crucible with a lid and heated to 550 ℃ in a muffle furnace at a heating rate of 2 ℃/minCalcining at constant temperature for 4h, naturally cooling, and manually grinding for 1h to obtain graphite-like carbon nitride (g-C) ₃ N ₄ )。

Comparative example 4

The preparation method of the perylene bisimide derivative comprises the following steps:

weighing 1.373g of 3,4,9, 10-perylene tetracarboxylic dianhydride, 2.495g of beta-aminopropionic acid and 18g of imidazole, heating the mixture to 100 ℃ under the protection of argon, stirring and refluxing at the rotating speed of 500r/min for 4 hours, naturally cooling the product to room temperature, adding 100mL of anhydrous ethanol and 300mL of 2.0mol/L hydrochloric acid, stirring at the rotating speed of 500r/min for 15h, centrifugally separating the precipitate at the rotating speed of 8000r/min, washing the precipitate with water to neutrality, drying at the temperature of 60 ℃ for 24 hours, and grinding the product for 1 hour to obtain a dark red powder product, namely the perylene imide derivative (bulk-PDI).

Test example:

performance tests were conducted on the composite photocatalysts obtained in examples 1 to 5 and the products obtained in comparative examples 1 to 4.

(1) Photocatalytic pollutant degradation performance test

The degradation activities of the composite photocatalysts of examples 1-5 and the products prepared in comparative examples 1-4 were examined under visible light using phenol as the target degradation product. The visible light source adopts a 10W LED lamp (lambda is more than 400 nm); taking 50mL of 5ppm phenol solution, adding 10mg of photocatalyst to obtain a mixed solution, ultrasonically dispersing the mixed solution for 30min, and then stirring the mixed solution for 30min in a dark environment to ensure that the adsorption balance between the photocatalyst and a target pollutant is achieved; turning on a light source to start a photocatalytic reaction, taking 2mL of reaction solution at regular intervals, centrifuging to remove the photocatalyst in the solution, and filtering supernatant by using a 0.22-micron water system filter membrane; the concentration of phenol in the supernatant was measured by High Performance Liquid Chromatography (HPLC) (Waters-C18 column, detection wavelength 270nm, methanol/water volume ratio 60, flow rate 1 mL/min.

FIG. 1 is a graph showing Ag @ AgCl/SA-PDI composite photocatalysts prepared in examples 1-5, SA-PDI photocatalyst prepared in comparative example 1, ag @ -AgCl photocatalyst prepared in comparative example 2, and g-C prepared in comparative example 3 ₃ N ₄ Photocatalyst and bulk-PDI material prepared in comparative example 4 para-phenol under visible lightComparative degradation performance of (c). In the figure: the nano-silver/silver chloride/supramolecular perylene imide derivative composite photocatalyst prepared in the examples 1-5 is named after Ag @ AgCl/SA-PDI, the mass fraction of Ag in the composite photocatalyst relative to SA-PDI is taken as a standard, in the examples 1-5, the samples with the mass ratios of Ag to SA-PDI of 1%, 2%, 3%, 4% and 5% are respectively named as Ag @ AgCl/SA-PDI-1%, ag @ AgCl/SA-PDI-2%, ag @ AgCl/SA-PDI-3%, ag @ AgCl/SA-PDI-4%, ag @ AgCl/SA-5%, the perylene imide derivative prepared in the comparative example 1 is SA-PDI, the nano-silver/silver chloride prepared in the comparative example 2 is Ag AgCl, the graphite-like carbon nitride material prepared in the comparative example 3 is g-C ₃ N ₄ The perylene bisimide derivative prepared in comparative example 4 is abbreviated as bulk-PDI. As can be seen from FIG. 1 (a), in visible light, compared to the Ag @ AgCl/SA-PDI composite photocatalyst prepared in examples 1-5, the SA-PDI prepared in comparative example 1, the Ag @ AgCl prepared in comparative example 2, and the g-C prepared in comparative example 3 ₃ N ₄ While the bulk-PDI prepared in comparative example 4 showed substantially no degradation ability to phenol. From examples 1 to 5, it can be seen that as the mass fraction of Ag in the composite photocatalyst relative to SA-PDI increases from 1% to 5%, the photocatalytic efficiency of the composite compound as a whole tends to increase and then decrease, and the optimum loading amount is 3%, at which time the photocatalytic activity of the composite compound is the highest. By fitting a quasi-first order kinetic equation ln (C/C) ₀ ) = kt apparent rate constant k for photocatalytic degradation (FIG. 1 (b)), and the apparent rate constant k value of Ag @ AgCl/SA-PDI-3% composite photocatalyst prepared in example 3 was 0.49h ^-1 About SA-PDI (k 0.13 h) prepared in comparative example 1 ^-1 ) 3.8 times of that of comparative example 2, about Ag @ AgCl (k 0.12 h) ^-1 ) 4.1 times of (g-C) of comparative example 3 ₃ N ₄ (k is 0.04h ^-1 ) 12.3 times of; the result shows that the SA-PDI prepared in the comparative example 1 and the Ag @ AgCl prepared in the comparative example 2 are combined to really play a role in improving the composite photocatalytic degradation activity, and the improvement of the performance of the photocatalyst is a result of the synergistic effect of the Ag @ AgCl and the SA-PDI and is not the simple addition of the effects of the comparative examples 1-2. Demonstration of the comparison with SA-PDI prepared in comparative example 1, ag @ AgC prepared in comparative example 2l g-C prepared in comparative example 3 ₃ N ₄ Compared with the bulk-PDI prepared in the comparative example 4, the nano silver/silver chloride/supermolecule perylene bisimide derivative composite photocatalyst has excellent pollutant degradation performance, and the silver/silver chloride and SA-PDI in the composite photocatalyst have a synergistic effect.

(2) Photocatalytic antibacterial property test

Sulfonamide drug-resistant bacteria are selected as model bacteria for testing the photocatalytic antibacterial performance of the sample. An environmental water sample of the university of Jiangnan is collected and cultured on Luria Bertani (LB) solid medium containing 512mg/L sulfadimethoxine, and the culture is carried out for 24 hours at 37 ℃. Randomly selecting a single colony, streaking on an LB solid culture medium, culturing for 24h at 37 ℃, and repeatedly purifying the separated strain for 3 times to obtain the sulfonamide-resistant bacteria. The sulfonamide-resistant bacteria isolates were inoculated into LB liquid medium, incubated with shaking at 37 ℃ for 4 hours, the bacterial cells were collected by centrifugation, washed 2 times with sterile 0.9% NaCl solution, and then resuspended in sterile 0.9% NaCl. In the antibacterial experiment, 10mg of sample material is added into 41mL of normal saline for ultrasonic dispersion for 15min, 9mL of bacterial cell sap (OD value is about 0.5) is added for dark reaction for 30min, a 10W LED lamp (lambda is more than 400 nm) is used as a light source in the photocatalysis antibacterial process, 2mL of bacterial liquid is taken every 30min, and the bacterial liquid is diluted by 4 times by using the sterile normal saline. And (3) coating 100 mu L of diluent on an LB solid culture medium, culturing at 37 ℃ for 12h, and counting the number of floras in bacterial liquid after different illumination time by using a plate colony counting method. The light control groups were illuminated without photocatalyst and each experiment was run as triplicate samples. The experimental apparatus used, physiological saline solution, was sterilized at 121 ℃ for 20min under high pressure.

FIG. 2 is a graph showing the comparison of the antibacterial performance of the Ag @ AgCl/SA-PDI-3% composite photocatalyst prepared in example 3, the SA-PDI prepared in comparative example 1 and the Ag @ AgCl prepared in comparative example 2 under visible light. As can be seen from FIG. 2, the sulfonamide-resistant bacteria in the light-controlled group were hardly inactivated, indicating that visible light irradiation had no effect thereon; under the irradiation of visible light, the photocatalytic sterilization efficiency of Ag @ AgCl/SA-PDI-3% is obviously higher than that of SA-PDI, 100% of sulfonamide-resistant bacteria can be killed after 2 hours of illumination, and the sterilization rate of SA-PDI is only 49.4%; the antibacterial effect of Ag @ AgCl under visible light is slightly inferior to that of Ag @ AgCl/SA-PDI-3%, mainly because the Ag @ AgCl/SA-PDI-3% contains high-content AgNPs and only contains a small amount of Ag @ AgCl, the high antibacterial efficiency can still be achieved, and the excellent antibacterial performance of the Ag @ AgCl/SA-PDI composite photocatalyst is mainly the result of the synergistic effect between the Ag @ AgCl and the SA-PDI. Compared with SA-PDI prepared in comparative example 1 and Ag @ AgCl prepared in comparative example 2, the nano silver/silver chloride/supramolecular perylene imide derivative composite photocatalyst is proved to have more excellent drug-resistant bacterium killing performance.

(3) The invention adopts a JEOL JEM-2100 type transmission electron microscope, the accelerating voltage of electron beams is 200kV, and a Transmission Electron Microscope (TEM) image is shot; FIG. 3 is a TEM comparison of the Ag @ AgCl/SA-PDI-3% composite photocatalyst prepared in example 3 with the SA-PDI prepared in comparative example 1. As shown in FIG. 3 (a), SA-PDI has a 1D nanofiber structure, a diameter of 10 to 50nm and a length of 100 to 800nm; FIG. 3 (b) is a graph of Ag @ AgCl/SA-PDI-3% composite photocatalyst prepared in example 3, after Ag @ AgCl is compounded with SA-PDI, ag @ AgCl nanoparticles can be observed to be successfully loaded on the SA-PDI nanofibers, and the particle size of Ag @ AgCl is in the range of 10-50 nm; the result shows that the invention can successfully combine Ag @ AgCl and SA-PDI into the nano silver/silver chloride/supermolecule perylene imide derivative composite photocatalyst with a heterostructure by using an in-situ deposition-photoreduction method.

The X-ray diffraction spectrum (XRD) of the sample was investigated using a Bruker D2-phaseR X-ray diffractometer (CuK α,30kV, 10mA); FIG. 4 is an XRD comparison of the Ag @ AgCl/SA-PDI composite photocatalyst prepared in examples 1-5 with the SA-PDI prepared in comparative example 1 and the Ag @ AgCl prepared in comparative example 2. As can be seen from FIG. 4, the characteristic diffraction peaks of Ag @ AgCl at 27.9 °, 32.4 °, 46.4 °, 55.1 °, 57.6 °, 67.5 °, 74.5 ° and 76.9 ° are attributed to AgCl, while the weak peaks at 38.3 ° and 44.4 ° are strongly attributed to Ag; for SA-PDI, there are multiple diffraction peaks in the range of 5 to 28, where the P0 peak at 26.2 can be attributed to the extent of π - π stacking, typically with the intensity ratio of the P1 peak to the P0 peak (I) at 14.2 ° _P1 /I _P0 ) To evaluate the degree of self-assembly of PDI, I of SA-PDI _P1 /I _P0 More than 1, indicating that the material has an ordered pi-pi stacking structure and is beneficial to interlayer transfer of photogenerated electronsMoving; for the Ag @ AgCl/SA-PDI composite photocatalyst, with the increase of the mass percentage of Ag @ AgCl, the characteristic diffraction peaks of Ag @ AgCl/SA-PDI at 27.9 degrees, 32.4 degrees, 44.4 degrees, 46.4 degrees, 55.1 degrees, 57.6 degrees and 76.9 degrees are gradually enhanced, which indicates the successful load of Ag @ AgCl; in addition, I of Ag @ AgCl/SA-PDI _P1 /I _P0 And the Ag @ AgCl content is increased gradually with the increase of the mass percentage of the Ag @ AgCl, which shows that the Ag @ AgCl load improves the pi-pi accumulation degree of the composite photocatalyst. The in-situ deposition-photoreduction method is proved to be capable of successfully combining Ag @ AgCl and SA-PDI into the nano silver/silver chloride/supermolecule perylene imide derivative composite photocatalyst with a good pi-pi stacking structure.

The Raman spectrum of the sample is measured by a DXR2xi micro-Raman imaging spectrometer, and FIG. 5 is a Raman spectrum comparison graph of the Ag @ AgCl/SA-PDI-3% composite photocatalyst prepared in example 3 and the SA-PDI prepared in comparative example 1. As can be seen from FIG. 5, the SA-PDI is located at 1590cm ^-1 The vibration peak corresponds to the C = C/C-C stretching vibration in the benzene ring, the peak is sensitive to pi-pi accumulation and can change along with the change of a pi-pi accumulation structure, 1302cm ^-1 The peak of vibration corresponds to C-H vibration in plane bending, and the peak is insensitive to pi-pi stacking, so that 1590cm can be calculated ^-1 /1302cm ^-1 The intensity ratio of the two components is used for evaluating the pi-pi accumulation degree of the material; the vibration peak corresponding to SA-PDI in the Ag @ AgCl/SA-PDI-3% composite photocatalyst does not obviously change at the peak position, but 1590cm ^-1 /1302cm ^-1 The intensity ratio (0.733) of (A) is higher than that of (SA-PDI) (0.621), and the result shows that the loading of Ag @ AgCl improves the pi-pi stacking degree of the composite photocatalyst, which is consistent with the result of XRD. The in-situ deposition-photoreduction method is proved to successfully combine Ag @ AgCl and SA-PDI into the nano silver/silver chloride/supermolecule perylene diimide derivative composite photocatalyst with a good pi-pi stacking structure.

Testing the X-ray photoelectron spectroscopy (XPS) of the sample by adopting an EscaLab 250Xi energy spectrometer; FIG. 6 is a graph comparing the Ag @ AgCl/SA-PDI-3% composite photocatalyst prepared in example 3 with the SA-PDI prepared in comparative example 1. As shown in FIG. 6 (a), SA-PDI mainly contains C, N, and O elements, and Ag @ AgCl/SA-PDI-3% mainly contains C, N, O, ag, and Cl elements(ii) a As can be seen from FIG. 6 (b), the C1s spectrum of Ag @ AgCl/SA-PDI-3% shows the presence of 284.8eV, 286.3eV, 287.9eV, 289.2eV peaks corresponding to C-C, C-N, C = O and π -extation bonds, respectively, and the C = O peak in the Ag @ AgCl/SA-PDI-3% composite shifts toward lower binding energy relative to the C = O peak of SA-PDI (288.0 eV), indicating the presence of electron transfer between Ag @ AgCl and SA-PDI at the interface; as can be seen from FIG. 6 (c), the Ag3d spectrum of Ag @ AgCl/SA-PDI-3% has four peaks of 367.4eV, 368.3e V, 373.2eV and 373.7eV, wherein the two peaks of 367.4eV and 373.2eV correspond to Ag of AgCl ⁺ 3d _5/2 And Ag ⁺ 3d _3/2 368.3eV and 373.7eV correspond to Ag for AgNPs ⁰ 3d _5/2 And Ag ⁰ 3d _3/2 (ii) a As shown in FIG. 6 (d), the Cl 2p spectrum of Ag @ AgCl/SA-PDI-3% has two peaks of 197.7eV and 199.2eV, which correspond to Cl 2p _3/2 And Cl 2p _1/2 (ii) a XPS results further indicate that Ag @ AgCl is successfully loaded on SA-PDI. The in-situ deposition-photoreduction method is proved to successfully combine Ag @ AgCl and SA-PDI into the nano silver/silver chloride/supermolecule perylene diimide derivative composite photocatalyst with a heterostructure.

Recording the Diffuse Reflectance Spectrum (DRS) of the sample by using a Shimadzu UV-3600Plus ultraviolet-visible spectrophotometer; FIG. 7 is a DRS comparison of the Ag @ AgCl/SA-PDI-3% composite photocatalyst prepared in example 3 with the SA-PDI prepared in comparative example 1 and the Ag @ AgCl prepared in comparative example 2. As can be seen from FIG. 7, the SA-PDI of comparative example 1 itself exhibited a wide light absorption range, covering almost the entire visible light region; the Ag @ AgCl of comparative example 2 has a larger absorption peak in the range of 400-800nm, indicating the existence of SPR effect; compared with SA-PDI, after Ag @ AgCl is loaded, the light absorption capacity of the Ag @ AgCl/SA-PDI-3% composite material in a region above 700nm is improved, and due to the SPR effect of Ag NPs, more photon-generated carriers can be generated under illumination, and the improvement of the photocatalytic activity is facilitated. The result proves that the light absorption capacity of the nano silver/silver chloride/supramolecular perylene bisimide derivative composite photocatalyst is obviously improved.

(4) Photoelectric performance test

Measurement with CHI 660D electrochemical workstation (Chenhua Instrument)Photoelectric performance, standard three-electrode system includes counter electrode (platinum wire), reference electrode (saturated calomel electrode) and working electrode, and 0.1mol/L Na is added ₂ SO ₄ The solution acts as an electrolyte. The preparation method of the working electrode comprises the following steps: 2mg of the catalyst powder were dispersed in 1mL of ultrapure water, and the suspension was coated on an Indium Tin Oxide (ITO) glass surface, dried at room temperature and heated at 180 ℃ for 5h. A300W xenon lamp with a 400nm cut-off filter was used as the visible light source. The photocurrent response test was performed at 0.0V; alternating impedance spectroscopy (EIS) spectra at 5mV AC voltage and at 0.05Hz to 10 Hz ⁵ Recorded in the range of Hz.

FIG. 8 is a graph comparing the photoelectric properties of the Ag @ AgCl/SA-PDI-3% composite photocatalyst prepared in example 3 and the SA-PDI prepared in comparative example 1. As can be seen from FIG. 8 (a), under visible light, the photocurrent response of Ag @ AgCl/SA-PDI-3% is obviously higher than that of SA-PDI, about 1.9 times of SA-PDI, which indicates that the migration efficiency of the photo-generated carriers of the composite material loaded with Ag @ AgCl is remarkably improved, mainly because the heterogeneous interface formed by the Ag @ AgCl/SA-PDI composite material is favorable for the separation and migration of photo-generated charges, so that the photocatalytic performance of the composite material can be improved; as can be seen from FIG. 8 (b), the arc radius of the EIS map can reflect the reaction rate of the electrode surface, the smaller arc radius means that the resistance of charge transfer is smaller, in the dark and in the visible light, SA-PDI and Ag @ AgCl/SA-PDI-3% both show similar semi-circles, but the radii are different, and the arc radius of Ag @ AgCl/SA-PDI-3% is smaller than that of SA-PDI, which indicates that the charge transfer resistance of the composite photocatalyst is smaller, i.e. the composite photocatalyst has higher photo-generated carrier separation and migration efficiency. The result proves that the photo-generated carrier separation and migration capacity of the nano-silver/silver chloride/supermolecule perylene bisimide derivative composite photocatalyst prepared by the invention is obviously improved, so that the photocatalyst has more excellent visible light catalytic pollutant degradation and drug-resistant bacterium killing performance.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The composite photocatalyst is characterized in that the composite photocatalyst is prepared by loading nano silver/silver chloride on supramolecular perylene imide derivatives through an in-situ deposition-photoreduction method; the mass ratio of silver contained in the nano silver/silver chloride to the supermolecule perylene bisimide derivative is 1-1000.

2. The composite photocatalyst of claim 1, wherein the nano silver/silver chloride has a particle size of 10-100 nm; the supermolecule perylene bisimide derivative is supermolecule end-position carboxylic acid straight-chain alkane substituted perylene bisimide.

3. The composite photocatalyst as claimed in claim 1, wherein the mass ratio of silver contained in the nano silver/silver chloride to supramolecular perylene imide derivatives is 1.

4. The composite photocatalyst of claim 1, wherein the composite photocatalyst has a particle size of 100-800 nm.

5. A process for preparing a composite photocatalyst as claimed in any one of claims 1 to 4, which comprises the steps of:

(1) Mixing 3,4,9, 10-perylene tetracarboxylic dianhydride, imidazole and beta-aminopropionic acid, heating, stirring, refluxing, reacting, cooling to room temperature, adding ethanol and hydrochloric acid, stirring, reacting, centrifuging, collecting precipitate, washing, drying and grinding to obtain perylene imide derivatives;

(2) Adding water into the perylene bisimide derivative obtained in the step (1) for dispersion, adding triethylamine for stirring, adding strong acid for stirring reaction, centrifuging, collecting precipitate, washing, drying and grinding to obtain the supermolecule perylene bisimide derivative;

(3) Adding a dispersing agent into the supramolecular perylene bisimide derivative prepared in the step (2) for ultrasonic dispersion to obtain a supramolecular perylene bisimide derivative dispersion liquid, adding a silver nitrate solution, stirring, adding a chloride solution, and continuously stirring for reaction to obtain a mixed liquid; and (3) stirring the mixed solution under the irradiation of an LED lamp for reaction, centrifuging, collecting the precipitate, washing, drying and grinding to obtain the nano silver/silver chloride/supramolecular perylene imide derivative composite photocatalyst.

6. The preparation method according to claim 5, wherein in the step (1), the mass ratio of the 3,4,9, 10-perylenetetracarboxylic dianhydride to the beta-aminopropionic acid is 1; the mass ratio of the 3,4,9, 10-perylene tetracarboxylic dianhydride to the imidazole is 1-20; the mass volume ratio of the 3,4,9, 10-perylene tetracarboxylic dianhydride to the ethanol is 1; the mass volume ratio of the 3,4,9, 10-perylene tetracarboxylic dianhydride to the hydrochloric acid is 1.

7. The preparation method according to claim 5, wherein in the step (2), the mass-to-volume ratio of the perylene imide derivative to water is 1; the mass volume ratio of the perylene bisimide derivative to the strong acid is 1.01-1 mg/mL, the strong acid is hydrochloric acid, sulfuric acid or nitric acid, and the molar concentration of the strong acid is 0.01-10 mol/L.

8. The preparation method according to claim 5, wherein in the step (3), the mass ratio of silver contained in the silver nitrate solution to the supramolecular perylene imide derivative in the supramolecular perylene imide derivative dispersion is 1 to 1000, and the mass-to-volume ratio of the supramolecular perylene imide derivative in the supramolecular perylene imide derivative dispersion to the dispersant is 1; the dispersant is water, methanol or ethanol.

9. The preparation method according to claim 5, wherein in the step (3), the mass-to-volume ratio of silver contained in the silver nitrate solution to the solvent is 1; the molar ratio of silver nitrate in the silver nitrate solution to chloride in the chloride solution is 1.1-10.

10. Use of a composite photocatalyst as claimed in any one of claims 1 to 4, in the degradation of contaminants or the killing of drug-resistant bacteria.