CN113751009A

CN113751009A - Cu/Cu with core-sheath structure2O-ZnO-Fe3O4Process for preparing nano composite material

Info

Publication number: CN113751009A
Application number: CN202010483159.9A
Authority: CN
Inventors: 温鸣; 傅琳; 周为; 赵龙
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2020-06-01
Filing date: 2020-06-01
Publication date: 2021-12-07

Abstract

Cu/Cu with core-sheath structure₂O‑ZnO‑Fe₃O₄NanocompositeA material comprising a Cu NWs homogeneously loaded with a multilayer oxide comprising Cu₂O, ZnO and Fe₃O₄. The preparation method of the nano composite material comprises the following steps: (1) direct synthesis of Cu/Cu by hydrothermal synthesis₂O one-dimensional linear core-sheath structure nano composite material; (2) one-step preparation of Cu/Cu by constant temperature reaction method₂O‑ZnO‑Fe₃O₄A one-dimensional linear core-sheath structure nano composite material. The method of the invention uniformly loads multilayer oxide (Cu) on Cu NWs₂O, ZnO and Fe₃O₄) The core-sheath structure photocatalyst has stronger visible light absorption capacity, and the photocatalytic performance is enhanced and relatively stable. The method has the advantages of simple process, universal preparation conditions, stable product appearance, high purity and convenient and simple product treatment, and is suitable for medium-scale industrial production.

Description

Cu/Cu with core-sheath structure2O-ZnO-Fe3O4Process for preparing nano composite material

Technical Field

The invention belongs to the technical field of sewage treatment, photocatalytic degradation disinfection by-products and photosensitive disinfection and sterilization, and relates to a one-dimensional nano Cu wire (Cu NWs) loaded multilayer oxide (Cu₂O, ZnO and Fe₃O₄) The preparation method of the core-sheath structure photocatalyst.

Background

The photocatalysis method has the advantages of mild reaction conditions, simple process and good effect of degrading organic matters, and is a hotspot of the current research. The search for highly efficient photocatalysts is a primary task in this field. The core-sheath structure may often impart the material with superior properties in terms of thermal stability, optical characteristics, laser emission of semiconductor nanowires, photoconductivity, characteristics of optical switches, photocatalytic characteristics, and the like, as compared to other nanomaterials.

Cu₂O is an important p-type semiconductor material, the band gap energy is 2.0-2.2 e V, and since the performance of photocatalytic water decomposition hydrogen production under visible light is reported, Cu₂O is considered to be one of the most potential semiconductor photocatalysts, and has a wide application prospect in the aspect of environmental pollution control. However, Cu₂The lower quantum efficiency and photo-corrosivity of O limit its further applications. Under illumination, the active group capturing the photo-generated electrons can absorb the positively charged metal ions and form particles on the surface of the substrate. Cu can act as a highly efficient channel for the transport of electrons between semiconductor materials. Mixing Cu and Cu₂O is compounded into a multi-level heterostructure in a proper mode, so that the effective separation of photogenerated electrons and holes can be realized, and Cu is reduced₂The forbidden band width of O enhances the visible light absorption capability. The one-dimensional metal core composite structure can further improve the separation efficiency of the photo-generated electron and hole of the system, and the large specific surface area can also improve the separation efficiency of the photo-generated electron and holeMore photogenerated electrons are captured, and more active sites are added. Meanwhile, ZnO is introduced, is used as an n-type direct semiconductor, has the band gap energy of about 3.3e V and can be matched with Cu₂O forms a pn-type heterojunction, and under the illumination condition, photo-generated electrons are transferred to a conduction band of ZnO, and holes are transferred to Cu₂And an O valence band, thereby realizing the separation of photon-generated carriers. Fe₃O₄The introduction of the (B) can improve the sterilization and disinfection performance of the system. Further, Fe₃O₄Can be reacted with Cu₂O or ZnO forms a pn-type heterojunction, and the photocatalytic performance of the system is enhanced.

Disclosure of Invention

The invention mainly aims to provide a photoreaction catalyst, a preparation method and application thereof, and a core-sheath structure Cu/Cu₂O-ZnO-Fe₃O₄The nano composite material has stronger visible light absorption capacity, enhanced photocatalytic performance and relative stability.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a photoreaction catalyst for uniformly supporting multiple layers of oxide on Cu NWs, said oxide including Cu₂O, ZnO and Fe₃O₄. The preparation method of the photoreaction catalyst comprises the following steps: (1) direct preparation of Cu/Cu by hydrothermal synthesis₂An O nanocomposite; (2) preparation of Cu/Cu by isothermal reaction method₂O-ZnO-Fe₃O₄A nanocomposite material.

Cu/Cu capable of maintaining one-dimensional core-sheath structure₂O-ZnO-Fe₃O₄The preparation method of the composite nano catalyst comprises the following steps: (1) fully dissolving copper salt, glucose and amine in deionized water, synthesizing for a period of time by a hydrothermal method, (2) adding a proper amount of PTCDA into the solution, continuing the hydrothermal reaction, and synthesizing one-dimensional Cu/Cu₂O-nanocomposite (Cu/Cu)₂O NWs); (3) mixing the Cu/Cu prepared above₂Dispersing the O nano composite material in an aqueous solution consisting of zinc salt and amine salt with equal mole, stirring at room temperature, and preparing Cu/Cu through oil bath constant temperature reaction₂O-ZnO nanocompositeA material; (4) after the reaction is carried out for a period of time, the supernatant is poured off, the ferric salt aqueous solution is added, and the oil bath constant temperature reaction is continued to prepare Cu/Cu₂O-ZnO-Fe₃O₄A nanocomposite material.

Furthermore, the invention provides a Cu/Cu with a core-sheath structure₂O-ZnO-Fe₃O₄The preparation method of the nano composite material comprises the following steps:

(1) mixing water soluble copper salt (such as copper chloride, copper acetate, copper sulfate, copper nitrate, etc.), glucose, amine (such as Hexadecylamine (HDA), ethylenediamine, N₂H₄Etc.) are fully dissolved in deionized water and synthesized for a period of time by a hydrothermal method.

(2) Adding a proper amount of 3,4,9, 10-perylenetetracarboxylic dianhydride (PTCDA) into the solution, and continuing hydrothermal synthesis;

(3) centrifuging the product, dissolving with n-hexane (or toluene or m-xylene or p-xylene), repeatedly washing to remove Cu/Cu₂O NWs; washing the Cu/Cu₂O NWs is stored in an alcoholic solvent (e.g., ethanol, ethylene glycol, etc.);

(4) mixing the Cu/Cu prepared above₂Dispersing the O nano composite material in an aqueous solution consisting of zinc salt and amine salt with equal mole, stirring at room temperature, and preparing Cu/Cu through oil bath constant temperature reaction₂An O-ZnO nanocomposite;

(5) after the reaction is carried out for a period of time, the supernatant is poured off, the ferric salt aqueous solution is added, and the oil bath constant temperature reaction is continued to prepare Cu/Cu₂O-ZnO-Fe₃O₄A nanocomposite;

(6) the reaction system is naturally cooled to room temperature, washed and centrifuged, and the product is stored in an alcohol solvent for further characterization and testing.

The purity of all chemical reagents (copper salt, glucose, amine, n-hexane, alcohol solvents, zinc salt, amine salt and iron salt) is not lower than the chemical purity;

the concentration of the proper amount of copper salt, glucose and amine dissolved in deionized water is 2-10 mg/mL;

the concentration of the zinc salt aqueous solution is 0.005 mol/L-0.03 mol/L, and the concentration of the iron salt aqueous solution is 0.01 mol/L-0.04 mol/L;

the heating rate of the solvothermal reaction is 1-3 ℃/min;

the temperature of the solvothermal is 90-180 ℃;

the solvothermal time is 3-10 h;

the temperature of the oil bath constant temperature reaction is 70-100 ℃;

the washing is to wash the product with deionized water and absolute ethyl alcohol (or n-hexane, etc.) in sequence.

Due to the adoption of the scheme, the invention has the beneficial effects that:

the method has certain universality for preparing the core-sheath structure nano Cu wire (Cu NWs) loaded multilayer metal oxide photocatalyst; simple inorganic salt is adopted as a reactant, the raw materials are easy to obtain, and the price is low; the product prepared by the method has good photocatalytic degradation performance and disinfection and sterilization performance, can be used as a high-performance photocatalytic degradation disinfection and sterilization byproduct and a photosensitive disinfection and sterilization material, and has a wide development prospect and an application space; the method has the advantages of simple process, mild preparation conditions, stable product appearance, high purity and convenient and simple product treatment.

The method loads the multilayer metal oxide on the one-dimensional nano Cu wire, not only can enhance the photocatalytic performance of the one-dimensional nano Cu wire, but also improves the recovery rate and the repeatable utilization rate of the nano composite material, and has important application prospect in the fields of sewage treatment, photocatalytic degradation of disinfection byproducts and disinfection and sterilization environments.

Drawings

In fig. 1: a is an SEM photograph of a product obtained by multiplying the Cu NWs in example 1 by 1 μm;

b is an SEM photograph of a product obtained by multiplying 5 mu m by the Cu NWs in example 1;

c is the SEM photograph of the product obtained by multiplying 500nm of the Cu NWs in example 1.

In fig. 2: a is Cu/Cu in example 1₂SEM photograph of the product obtained by taking O at the multiple of 1 micron;

b isCu/Cu in example 1₂SEM photograph of the product obtained by taking O at the multiple of 500 nm;

c is Cu/Cu in example 1₂SEM photograph of the product obtained by O-ZnO under the multiple of 5 μm;

d is Cu/Cu in example 1₂SEM photograph of the product obtained by O-ZnO under the multiple of 500 nm;

e is Cu/Cu in example 1₂O-ZnO-Fe₃O₄SEM photograph of the product obtained at a magnification of 5 μm;

f is Cu/Cu in example 1₂O-ZnO-Fe₃O₄SEM photograph of the product obtained at a multiple of 500 nm.

In fig. 3: a is Cu NWs, Cu/Cu in example 1₂O,Cu/Cu₂O-ZnO and Cu/Cu₂O-ZnO-Fe₃O₄An XRD pattern of (a);

b is Cu/Cu in example 1₂O-ZnO-Fe₃O₄HRTEM photograph of the product obtained at a magnification of 2nm, and Cu/Cu₂O-ZnO-Fe₃O₄The SAED pattern of (A).

Detailed Description

The present invention will be described in further detail with reference to the following examples, which are illustrated in the accompanying drawings.

Example 1

1)Cu/Cu₂Preparation of ONWs

(1) 0.5525g of CuCl₂·2H₂O, 1.3g glucose and 3.8g HDA were dissolved in 260ml deionized water and magnetically stirred overnight at room temperature.

(2) The suspension was poured into an average of 12 Teflon-lined autoclaves of 30 ml. The autoclave was heated at 150 ℃ for 4 hours.

(3) Adding 6mg of 3,4,9, 10-perylenetetracarboxylic dianhydride (PTCDA) into each autoclave solution, continuing the hydrothermal reaction, and heating at 150 ℃ for 4 hours;

(4) centrifuging at high speed to separate the product, dissolving with n-hexane, and precipitating Cu/Cu with ethanol₂ONWs, centrifuging the product, washing with anhydrous ethanol and deionized water three times, and washing with Cu/Cu₂ONWs stored in BIn alcohol.

2)Cu/Cu₂O-ZnO-Fe₃O₄Preparation of

(1) 20mL of Cu/Cu with a concentration of 0.1g/mL was taken₂100mL of zinc nitrate (2.5X 10) was added to an aqueous solution of ONWs in an equimolar amount^-5mol) and Hexamethylenetetramine (HMT) (2.5X 10)^-5mol) water solution, stirring at room temperature, and carrying out oil bath constant-temperature reaction at 100 ℃;

(2) after the reaction is carried out for 4 hours, the supernatant is poured off, 100mL of 0.01mol/L ferric nitrate aqueous solution is added, the oil bath constant temperature reaction at 100 ℃ is continued for 2 hours to prepare Cu/Cu₂O-ZnO-Fe₃O₄A nanocomposite;

(3) the reaction was cooled to room temperature, washed and centrifuged, and the product was stored in an alcoholic solvent for further characterization.

As shown in the figure, FIG. 1(A-C) is SEM photograph of one-dimensional nano Cu wire obtained under different magnifications in example 1, and the prepared Cu NWs, Cu/Cu are shown in FIG. 2(A, B, C, D, E, F)₂O,Cu/Cu₂O-ZnO and Cu/Cu₂O-ZnO-Fe₃O₄SEM image of (d). As can be seen, Cu was produced₂O nano particles are tightly attached to the nano Cu wires, ZnO is tightly coated on Cu/Cu wires₂On O, Fe₃O₄Closely adhered to Cu/Cu₂O-ZnO.

By the pair of Cu/Cu₂X-ray diffraction analysis (XRD), high-resolution transmission electron microscope (HRTEM), and selected-area electron diffraction (SAED) of O, as shown in fig. 3(a), (B), and 3(B), it can be observed that the (111), (200), and (220) plane diffraction peaks corresponding to the face-centered-cubic (fcc) lattice of Cu, and JCPDF No.65-9026 cards corresponding to Cu appear at 43.35 °, 50.44 °, and 74.14 °, respectively. 36.40 DEG appears corresponding to Cu₂Diffraction peak of (111) plane of O corresponding to Cu₂JCPDF No.05-3288 card of O, further proving the heterostructure Cu/Cu₂And forming O. Cu/Cu₂XRD, HRTEM and SAED of O-ZnO composite nanomaterial as shown in FIGS. 3(A) (c) and 3(B) show hexagonal close-packed (hcp) lattice of ZnO (JCPDF No.65-0682), corresponding peaks (100) at 31.83 deg., (002) at 34.53 deg., (101) at 36.31 deg. ° C(110) at 56.58 °, (103) at 62.94 °, (112) at 67.10 °. Due to the introduction of ZnO, part of Cu₂O is converted to CuO. Cu/Cu₂O-ZnO-Fe₃O₄As shown in fig. 3(a) (d) and 3(B), two additional peaks are shown at 35.74 ° and 62.22 °, corresponding to the (200) diffraction peak in the (110) crystal plane. All peaks correspond to the original peak diffraction pattern Cu (JCPDS No.65-9026) of each component, Cu₂O (JCPDF No.05-0667), ZnO (JCPDF No.65-3411) and Fe₃O₄(JCPDF No.65-3107) confirmed Cu, Cu₂O, ZnO and Fe₃O₄Is present.

Example 2

1)Cu/Cu₂Preparation of ONWs

(1) 0.5525g of CuCl₂·2H₂O, 1.0g glucose and 3.8g HDA were dissolved in 260ml deionized water and magnetically stirred overnight at room temperature.

(2) The suspension was poured into an average of 12 Teflon-lined autoclaves of 30 ml. The autoclave was heated at 110 ℃ for 6 hours.

(3) Adding 5mg of 3,4,9, 10-perylenetetracarboxylic dianhydride (PTCDA) into the solution, continuing hydrothermal synthesis, and heating at 110 ℃ for 4 hours;

(4) centrifuging at high speed to separate the product, dissolving with n-hexane, and precipitating Cu/Cu with ethanol₂ONWs, centrifuging the product, washing with anhydrous ethanol and deionized water three times, and washing with Cu/Cu₂ONWs were stored in ethanol.

2)Cu/Cu₂O-ZnO-Fe₃O₄Preparation of

(1) 20mL of Cu/Cu with a concentration of 0.1g/mL was taken₂100mL of zinc nitrate (2.5X 10) was added to an aqueous solution of ONWs in an equimolar amount^-5mol) and Hexamethylenetetramine (HMT) (2.5X 10)^-5mol) of an aqueous solution;

(2) the suspension was poured into 6 Teflon-lined autoclaves of 30ml on average. The autoclave was heated at 110 ℃ for 2 h.

(3) Pouring out the supernatant after the reaction, adding 20mL of 0.01mol/L ferric nitrate aqueous solution into each autoclave, and continuing the hydrothermal reaction at 110 ℃ for 2hCu/Cu₂O-ZnO-Fe₃O₄A nanocomposite;

(4) the reaction system is naturally cooled to room temperature, washed and centrifuged, and the product is stored in an alcohol solvent for further characterization and testing.

Example 3

1)Cu/Cu₂Preparation of ONWs

0.5525g of CuCl₂·2H₂O, 1.0g glucose, 3.8g HDA and 0.06g PTCDA were dissolved in 260ml deionized water and magnetically stirred overnight at room temperature. The suspension was poured into an average of 12 Teflon-lined autoclaves of 30 ml. The autoclave was heated at 110 ℃ for 6 hours. Centrifuging at high speed to separate the product, dissolving with n-hexane, and precipitating Cu/Cu with ethanol₂ONWs, centrifuging the product, washing with anhydrous ethanol and deionized water three times, and washing with Cu/Cu₂ONWs were stored in ethanol.

2)Cu/Cu₂O-ZnO-Fe₃O₄Preparation of

20mL of Cu/Cu with a concentration of 0.1g/mL was taken₂100mL of zinc nitrate (2.5X 10) was added to an aqueous solution of ONWs in an equimolar amount^-5mol) and Hexamethylenetetramine (HMT) (2.5X 10)^-5mol) of the aqueous solution, and then adding 10mL of 0.12mol/L ferric nitrate aqueous solution; the suspension was poured into an average of 7 Teflon-lined autoclaves of 30 ml; the autoclave was heated at 140 ℃ for 5 h. The reaction system is naturally cooled to room temperature, washed and centrifuged, and the product is stored in an alcohol solvent for further characterization and testing.

Example 4

1)Cu/Cu₂And O synthesis:

mixing 3mmol/L copper sulfate, 2g glucose, 0.15mol/L o-anisidine and 2.4mmol/L N₂H₄Dissolved in 260ml of deionized water and magnetically stirred overnight at room temperature. The suspension was poured into an autoclave on average, heated at 180 ℃ for 4 hours, and then cooled to room temperature. Centrifuging to separate the product, dissolving with m-xylene, precipitating Cu NWs with ethanol, centrifuging to separate the product, washing with deionized anhydrous ethanol and water respectively for three times, and storing the washed CuNWs in ethanolIn alcohol.

6mmol/L copper sulfate ethanol solution is dissolved in a conical flask uniformly, prepared nano copper wires are added into the solution, the system is magnetically stirred for 0.5 hour, and then the solution is put into an oil bath at 50 ℃. Before the reaction started, 4mL of 40mg/L NaOH was added and stirred for 1 minute, followed by 4mL of 50mg/L glucose. The system is reacted in an oil bath at 50 ℃ for 60 minutes, cooled to room temperature, centrifuged at low speed to separate the product, and washed with deionized water and absolute ethyl alcohol three times respectively. The product was stored in ethanol for further characterization of the test;

2)Cu/Cu₂O-ZnO-Fe₃O₄the synthesis steps are as follows:

dissolving the mixture in 0.05mol/L zinc nitrate ethanol solution at 60 ℃ by vigorous stirring. 0.01mol/L NaOH ethanol solution was dropwise added to the above solution. The system is continuously heated and stirred for 2.5 hours at the temperature of 60 ℃ to obtain ZnO seed crystal sol-gel solution.

The obtained Cu/Cu₂O is dispersed in the prepared ZnO seed crystal solution and stirred for 2 hours to obtain the Cu/Cu coated by the ZnO seed crystal₂And O. Dispersing the centrifuged product in 300mL of an aqueous solution consisting of zinc nitrate and Hexamethylenetetramine (HMT) in equal moles, carrying out oil bath reaction at 80 ℃ for 2 hours, cooling the system to room temperature, and washing the system with deionized water and absolute ethyl alcohol respectively for three times. The product was stored in ethanol for further characterization of the test.

5mL of Cu/Cu with a concentration of 1.0423g/mL were taken₂Adding 5mmol/L ferric acetate water solution into ethanol solution of O-ZnO, stirring with a glass rod, and heating to viscous state. 50mg of NaBH was added₄Reducing, adding 2-3 ml of absolute ethyl alcohol, and sealing and storing at room temperature. Multiple washes with deionized water were used before use.

Example 5

Cu/Cu₂And O synthesis:

2.0mmol of copper acetate, 2.4mL of oleic acid, 2.4g of Hexadecylamine (HDA) and 1.3g of glucose were dissolved in 260mL of deionized water and magnetically stirred at room temperature overnight. The suspension was poured on average into a three-hole round-bottom flask, heated at 120 ℃ for 4 hours, and then cooled to room temperature. And (3) centrifugally separating the product, dissolving the product by using toluene, adding ethanol to separate out Cu NWs, centrifugally separating the product, respectively washing the product by using deionized absolute ethanol and water for three times, and then storing the washed Cu NWs in the ethanol.

6mmol/L copper nitrate ethanol solution is dissolved evenly in a conical flask, prepared nano copper wires are added into the solution, the system is magnetically stirred for 0.5 hour, and then the solution is put into 50 ℃ oil bath. Before the reaction started, 4mL of 50mg/L NaOH was added and stirred for 1 minute, followed by 4mL of 70mg/L glucose. The system is reacted in an oil bath at 50 ℃ for 40 minutes, cooled to room temperature, centrifuged at low speed to separate the product, and washed with deionized water and absolute ethyl alcohol three times respectively. The product was stored in ethanol for further characterization of the test;

2)Cu/Cu₂O-ZnO-Fe₃O₄the synthesis steps are as follows:

dissolving the mixture in 0.03mol/L zinc chloride ethanol solution at 60 ℃ by vigorous stirring. 0.01mol/L NaOH ethanol solution was dropwise added to the above solution. The system is continuously heated and stirred for 3 hours at the temperature of 60 ℃ to obtain ZnO seed crystal sol-gel solution.

The obtained Cu/Cu₂O is dispersed in the prepared ZnO seed crystal solution and stirred for 2 hours to obtain the Cu/Cu coated by the ZnO seed crystal₂And O. Dispersing the centrifuged product in 300mL of an aqueous solution consisting of zinc nitrate and Hexamethylenetetramine (HMT) in equal moles, carrying out oil bath reaction at 80 ℃ for 1 hour, cooling the system to room temperature, and washing the system with deionized water and absolute ethyl alcohol respectively for three times. The product Cu/Cu₂O-ZnO was stored in ethanol for further characterization of the test. 5mL of Cu/Cu with a concentration of 1.0423g/mL were taken₂Adding 5mmol/L FeCl into ethanol solution of O-ZnO₃Stirring the aqueous solution with a glass rod and heating to a viscous state. And adding 50mg of NaBH4 for reduction, adding 2-3 ml of absolute ethyl alcohol, and sealing and storing at room temperature. Multiple washes with deionized water were used before use.

The invention adopts copper salt as a copper source, zinc salt as a zinc source and iron salt as an iron source, and successfully prepares the Cu/Cu with the core-sheath structure by combining a hydrothermal method and high-temperature reflux₂O-ZnO-Fe₃O₄A nanocomposite material. The photoreaction catalystHas excellent photocatalytic performance. The method has the advantages of simple process, universal preparation conditions, stable product appearance, high purity and convenient and simple product treatment, and is suitable for medium-scale industrial production.

The embodiments described above are intended to facilitate one of ordinary skill in the art in understanding and using the present invention. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the embodiments herein, and modifications made without departing from the scope of the present invention are within the scope of the present invention.

Claims

1. Cu/Cu with core-sheath structure₂O-ZnO-Fe₃O₄A nanocomposite characterized by: uniformly supporting a multilayer oxide on Cu NWs, the oxide comprising Cu₂O, ZnO and Fe₃O₄。

2. The method for preparing a photocatalyst as set forth in claim 1, characterized by comprising the steps of:

(1) preparation of Cu/Cu by hydrothermal synthesis₂An O nanocomposite;

(2) preparation of Cu/Cu by isothermal reaction method₂O-ZnO-Fe₃O₄A nanocomposite material.

3. The method for preparing a photocatalyst as claimed in claim 2, wherein Cu/Cu is prepared₂The O nanocomposite comprises the steps of:

(1) weighing a proper amount of copper salt, glucose and amine, fully dissolving in a solvent, and synthesizing for a period of time by a hydrothermal method;

(3) centrifuging the above product, dissolving with n-hexane (or toluene or m-xylene or p-xylene), repeatedly washing with the solution,washing out Cu/Cu₂O NWs; washing the Cu/Cu₂The O NWs are stored in alcoholic solvents.

4. The method for preparing a photocatalyst as claimed in claim 3, wherein said Cu/Cu is₂The preparation method of the O nano composite material comprises the following steps of (1) using deionized water as a solvent; all of the chemical agents described are not less pure than chemically pure.

5. The method for preparing a photocatalyst as claimed in claim 3, wherein said Cu/Cu is₂The preparation method of the O nanocomposite comprises the steps of (1) dissolving a proper amount of copper salt, glucose and amine in deionized water to obtain a concentration of 2-10 mg/mL; the hydrothermal synthesis time is 3-10 h; the hydrothermal synthesis temperature is 90-180 ℃.

6. The method for preparing a photocatalyst as claimed in claim 3, wherein said Cu/Cu is₂The preparation method of the O nanocomposite comprises the following steps of (2) dissolving PTCDA in deionized water at a concentration of 0.02-0.04 mg/mL; the ratio of PTCDA to copper salt is 1: (70-100).

7. The method for preparing a photocatalyst as claimed in claim 3, wherein said Cu/Cu is₂The preparation method of the O nanocomposite comprises the following steps of (3) controlling the rotating speed of a centrifugal machine to be 1000-3000 rpm; in the step (3), the purity of the n-hexane, the toluene, the m-xylene or the p-xylene is not lower than the chemical purity; the washing solution in the step (3) is a solution with the ratio of ethanol to water being 1: 1; the purity of the alcohol solvent in the step (3) is analytical purity.

8. The method for preparing a photocatalyst as claimed in claim 2, wherein said Cu/Cu is₂O-ZnO-Fe₃O₄The preparation of the nano composite material comprises the following steps:

(1) mixing the Cu/Cu prepared above₂O nano composite material is dispersed in equimolar zinc salt and amine salt to form waterIn the solution, stirring at room temperature, and carrying out oil bath constant temperature reaction to prepare Cu/Cu₂An O-ZnO nanocomposite;

(2) after the reaction is carried out for a period of time, the supernatant is poured off, the ferric salt aqueous solution is added, and the oil bath constant temperature reaction is continued to prepare Cu/Cu₂O-ZnO-Fe₃O₄A nanocomposite;

(3) the reaction system is naturally cooled to room temperature, washed and centrifuged, and the product is stored in an alcohol solvent for further characterization and testing.

9. The method for preparing a photocatalyst in accordance with claim 9, wherein: the purity of the zinc salt in the step (1) is analytical purity; the molar weight of the zinc salt and the amine salt with the same mole in the step (1) is 0.005 mol/L-0.03 mol/L; in the step (1), the heating rate is 1-3 ℃/min; the heat preservation temperature in the step (1) is 70-100 ℃; the heat preservation time in the step (1) is 3-8 h.

10. The method for preparing a photocatalyst in accordance with claim 9, wherein: the molar weight of the ferric salt in the step (2) is 0.01-0.04 mol/L; in the step (2), the heating rate is 1-3 ℃/min; the heat preservation temperature in the step (2) is 70-100 ℃; the heat preservation time in the step (2) is 3-8 h.

11. The method for preparing a photocatalyst in accordance with claim 9, wherein: the rotating speed of the centrifugal machine in the step (3) is 5000-7000 rpm; the washing solution in the step (3) is a solution with the ratio of ethanol to water being 1: 1; the purity of the alcohol solvent in the step (3) is analytical purity.

12. Use of the photoreaction catalyst of claim 1 for photocatalytic degradation.