Preparation method of magnetic Cu2O / Cu heterojunction material

Abstract

The application relates to the field of composite nanomaterials, in particular to a preparation method of a magnetic Cu2O / Cu heterojunction material. The application discloses a preparation method of a magnetic Cu2O / Cu heterojunction material, which comprises the following steps: firstly, loading magnetic Fe3O4 on mesoporous silica microspheres by a solvothermal method, so that the material has magnetism; and secondly, continuously loading Cu2O / Cu heterojunction on the surface of Fe3O4@mSiO2 by controlling reaction conditions through the solvothermal method. According to the application, a layer of Cu2O / Cu heterojunction is loaded on the surface of Fe3O4@mSiO2 through a simple solvothermal method, the Cu2O / Cu heterojunction has a unique flower cluster shape, the preparation method is simple, production is convenient, and the Cu2O / Cu heterojunction shows excellent stability and pollutant photocatalytic degradation performance.

Description

Technical Field

[0001] This invention relates to the field of composite nanomaterials, and in particular to a method for preparing a magnetic Cu2O / Cu heterojunction material. Background Technology

[0002] With the rapid development of human technology, environmental pollution and its control have become a major global concern, with water pollution being the most severe. Therefore, wastewater treatment is a topic of widespread interest to researchers worldwide. Traditional wastewater treatment methods generally include adsorption, filtration, sedimentation, and electrochemical methods. These traditional methods all suffer from slow processing speeds, incomplete purification, high costs, and secondary pollution problems. Therefore, exploring and researching more economical and effective methods for controlling environmental pollution is essential. As research has deepened, photocatalytic oxidation technology has been found to be one of the most promising methods for treating wastewater pollution. In the presence of a semiconductor photocatalyst, many biodegradable organic pollutants can be directly oxidized and decomposed into smaller molecules such as H2O and CO2 using ultraviolet or visible light and air.

[0003] Current photocatalytic technologies suffer from challenges such as difficult recycling and low visible light utilization. While titanium dioxide is the most researched semiconductor photocatalyst, its application in degrading organic pollutants has limitations. Its band gap energy level is 3.2 eV, requiring ultraviolet light for catalytic reaction, resulting in a utilization rate of less than 5% of sunlight. Therefore, many researchers have begun studying visible light-responsive semiconductor photocatalysts. Cuprous oxide (Cu₂O) has emerged as a novel photocatalyst. A novel semiconductor with a band gap energy of 2.0–2.2 eV, it can complete photodegradation under visible light. However, reports on using nanoscale Cu₂O to degrade domestic wastewater are rare. This is because while small-particle-size Cu₂O has a large specific surface area and high photocatalytic efficiency, it is difficult to separate from wastewater, easily causing secondary pollution. Furthermore, Cu₂O's low quantum efficiency and photocorrosion limit its further application.

[0004] Iron(III) oxide (Fe3O4) is an anti-spinel ferrite material. When combined with paramagnetic iron(III) oxide, an external magnetic field can be used to separate the catalyst from wastewater. This allows for the recycling and reuse of the composite photocatalyst, achieving the goal of degrading harmful substances without causing secondary pollution. Semiconductor photocatalysis technology is a relatively new environmental purification technology with significant advantages in environmental protection, and has gained widespread attention.

[0005] CN 113751009 A discloses a core-sheath structure Cu / Cu2O-ZnO-Fe3O4 nanocomposite material, which is a core-sheath structure photocatalyst with multiple layers of oxides (Cu2O, ZnO, and Fe3O4) uniformly loaded on Cu nanowires. It utilizes Cu nanowires as an efficient channel for electron transport between semiconductor materials, and introduces ZnO and Cu2O to form a pn-type heterojunction, achieving separation of photogenerated carriers. The introduction of Fe3O4 improves the system's bactericidal and disinfection performance. Its drawback lies in the complexity of the structure due to the multi-layered loading of copper nanowires, cuprous oxide, zinc oxide, and finally iron(III) oxide, resulting in an unclear photocatalytic mechanism. Furthermore, covering cuprous oxide, which has visible light photocatalytic properties, with Fe3O4 being an insulator or semiconductor material, lacks the good electrical conductivity of pure copper (Cu). Loading Fe3O4 on the material surface may limit electron transport efficiency and reduce its response range to visible light, affecting its visible light degradation performance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for preparing magnetic Cu2O / Cu heterojunction materials.

[0007] A method for preparing a magnetic Cu₂O / Cu heterojunction material includes the following steps:

[0008] (1) Preparation of Fe3O4@mSiO2 microspheres;

[0009] (2) Cu / Cu2O heterojunction was loaded on the surface of Fe3O4@mSiO2 microspheres to obtain Cu / Cu2O@Fe3O4@mSiO2.

[0010] Preferably, the preparation method of the magnetic Cu2O / Cu heterojunction material includes the following steps:

[0011] (1) Preparation of Fe3O4@mSiO2 microspheres;

[0012] (2) The Fe3O4@mSiO2 microspheres obtained in step (1) are loaded with Cu / Cu2O heterojunctions to obtain Cu / Cu2O@Fe3O4@mSiO2;

[0013] The steps for preparing Fe3O4@mSiO2 microspheres are as follows: Fe(NO3)3·9H2O and mesoporous silica microspheres are placed in a beaker with a mass ratio of (1-4):1. An organic solvent is then added, followed by magnetic stirring for 10-20 min and ultrasonic dispersion for 20-30 min. The dispersed mixture is then transferred to the liner of a para-polystyrene reactor and reacted at 220-260℃ for 18-30 h. After cooling to room temperature, the solid matter is separated by magnetic separation. The obtained product is washed 5-6 times with anhydrous ethanol. The sample is then transferred to a vacuum drying oven and dried at 50-70℃ for 8-12 h to collect Fe3O4@mSiO2.

[0014] Preferably, the preparation method of the magnetic Cu2O / Cu heterojunction material includes the following steps:

[0015] (1) Preparation of Fe3O4@mSiO2 microspheres;

[0016] (2) Cu / Cu2O heterojunctions were loaded on the surface of Fe3O4@mSiO2 microspheres to obtain Cu / Cu2O@Fe3O4@mSiO2;

[0017] The step of loading Cu / Cu2O heterojunctions on the surface of Fe3O4@mSiO2 microspheres obtained in step (1) is as follows: Weigh Cu(NO3)3·3H2O and Fe3O4@mSiO2 prepared in step (1) into a beaker. The mass ratio of Cu(NO3)3·3H2O to Fe3O4@mSiO2 is (9.5-10):1. Then add it into an organic mixed solvent and ultrasonically disperse it at room temperature for 20-30 min. Transfer the dispersed mixture to the liner of a para-polystyrene reactor and react it at 180-220℃ for 55-65 min. After cooling to room temperature, separate the solid substances by magnetic separation. Wash the obtained product with anhydrous ethanol 5-6 times. Transfer the sample to a vacuum drying oven and dry it at 50-70℃ for 8-12 h before collecting it to obtain Cu / Cu2O@Fe3O4@mSiO2.

[0018] Most preferably, the preparation method of the magnetic Cu2O / Cu heterojunction material includes the following steps:

[0019] (1) Preparation of Fe3O4@mSiO2: Fe(NO3)3·9H2O and mesoporous silica microspheres were placed in a beaker with a mass ratio of (1-4):1. Organic solvent was then added, followed by magnetic stirring for 10-20 min and ultrasonic dispersion for 20-30 min. The dispersed mixture was then transferred to the liner of a para-polystyrene reactor and reacted at 220-260℃ for 18-30 h. After cooling to room temperature, the solid matter was separated by magnetic separation. The product was washed with anhydrous ethanol 5-6 times and then transferred to a vacuum drying oven and dried at 50-70℃ for 8-12 h. Fe3O4@mSiO2 was collected.

[0020] (2) Preparation of Cu / Cu2O@Fe3O4@mSiO2: Weigh Cu(NO3)3·3H2O and Fe3O4@mSiO2 prepared in step (1) into a beaker. The mass ratio of Cu(NO3)3·3H2O to Fe3O4@mSiO2 is (9.5-10):1. Then add it into an organic mixed solvent and ultrasonically disperse it at room temperature for 20-30 min. Transfer the dispersed mixture to the liner of the para-polystyrene reactor and react it at 180-220℃ for 55-65 min. After cooling to room temperature, separate the solid substances by magnetic separation. Wash the obtained product with anhydrous ethanol 5-6 times. Transfer the sample to a vacuum drying oven and dry it at 50-70℃ for 8-12 h before collecting it to obtain Cu / Cu2O@Fe3O4@mSiO2.

[0021] Preferably, in step (1), the mass-to-volume ratio of Fe(NO3)3·9H2O to the organic solvent is [value missing].

[0022] Preferably, the organic solvent in step (1) is selected from diethylene glycol, ethanol, or ethylene glycol.

[0023] Preferably, the organic mixed solvent in step (2) is a mixture of ethanol and ethylene glycol, wherein the volume ratio of ethanol to ethylene glycol is (1.5-2):1.

[0024] Preferably, the mass-to-volume ratio of Fe3O4@mSiO2 to the organic solvent in (2) is 1g:(1-1.2)L.

[0025] This invention first loads magnetic Fe3O4 onto mesoporous silica microspheres using a solvothermal method to make the material magnetic. Then, Cu2O / Cu heterojunctions are loaded onto the Fe3O4@mSiO2 surface by controlling the reaction conditions using a solvothermal method. By loading Fe and Cu elements sequentially onto the mesoporous silica microspheres using a solvothermal method, a Cu / Cu2O@Fe3O4@mSiO2 magnetic heterojunction material with a flower-like surface is obtained.

[0026] Mesoporous silica has a large number of micropores and mesoporous structures, resulting in a high surface area. This provides more loading sites, improves the dispersion and uniformity of the supported material, and increases the contact area between the supported material and the contaminants, which is beneficial for improving the efficiency of catalytic reactions.

[0027] The introduction of magnetic Fe3O4 enables the magnetic Cu2O / Cu heterojunction material to be separated from wastewater, thus avoiding secondary pollution.

[0028] Cu₂O / Cu heterojunction materials are sensitive to visible and near-infrared light, which enables them to exhibit catalytic activity under visible light irradiation, making them suitable for many photocatalytic applications. Cu, as a material with good electrical conductivity, facilitates rapid electron transport and separation, improving catalytic efficiency. The unique electronic structure and charge distribution at the Cu₂O / Cu interface promote the reaction and enhance catalytic activity.

[0029] However, Cu2O / Cu heterojunction materials also have significant drawbacks. Cu2O may undergo redox reactions during catalytic processes, leading to decreased material stability. This may necessitate measures to improve stability in applications. The catalytic selectivity of Cu2O / Cu heterojunctions is limited by their electronic structure, and therefore may not be suitable for all types of catalytic reactions.

[0030] This invention utilizes a solvothermal method to load magnetic Fe3O4 onto mesoporous silica microspheres, followed by a solvothermal method to load Cu2O / Cu heterojunctions onto the Fe3O4@mSiO2 surface under controlled reaction conditions, resulting in a Cu / Cu2O@Fe3O4@mSiO2 magnetic heterojunction material with a flower-like surface. This invention uses Fe3O4@mSiO2 as a carrier to load Cu / Cu2O on its surface, resulting in a unique flower-like morphology for the Cu / Cu2O@Fe3O4@mSiO2 magnetic heterojunction material. Furthermore, the use of iron(III) oxide as a carrier does not affect the light absorption of Cu / Cu2O. In addition, iron(III) oxide is a relatively stable material that can improve the overall stability of cuprous oxide, reduce the photocorrosion of Cu2O, and can also form a synergistic effect with Cu2O / Cu, improving catalytic performance.

[0031] The beneficial effects of this invention are as follows:

[0032] In existing technologies, copper is often used as a substrate to load cuprous oxide and iron oxide on its surface. However, it is rare to load Cu2O / Cu heterojunctions on the surface of iron oxide. This invention loads a Cu2O / Cu heterojunction on the surface of Fe3O4@mSiO2 using a simple solvothermal method. It has a unique flower-like morphology. The preparation method is simple and easy to produce. It also shows excellent stability and photocatalytic degradation performance of pollutants. Attached Figure Description

[0033] Figure 1 SEM images of Cu / Cu2O@Fe3O4@mSiO2 prepared in Example 1: (a) 2.00 μm; (b) 1.00 μm.

[0034] Figure 2 Degradation curve of tetracycline hydrochloride by Cu / Cu2O@Fe3O4@mSiO2 prepared in Example 1. Detailed Implementation

[0035] Mesoporous silica microspheres:

[0036] Example 1

[0037] A method for preparing a magnetic Cu₂O / Cu heterojunction material includes the following steps:

[0038] (1) Preparation of Fe3O4@mSiO2: Weigh 0.8g of Fe(NO3)3·9H2O and 0.2g of mesoporous silica microspheres into a beaker, then add 60mL of diethylene glycol, stir magnetically for 15min, and then ultrasonically disperse for 20min. Transfer the dispersed mixture to the liner of a para-polystyrene reactor and react at 220℃ for 24h. After cooling to room temperature, separate the solid material by magnetic separation. The obtained product is washed 6 times with anhydrous ethanol. Transfer the sample to a vacuum drying oven and dry at 50℃ for 12h to obtain Fe3O4@mSiO2.

[0039] (2) Preparation of Cu / Cu2O@Fe3O4@mSiO2: Weigh 0.245g of Fe3O4@mSiO2 and 0.025g of Cu(NO3)3·3H2O into a beaker, then add 10mL of ethylene glycol and 20mL of ethanol, and disperse by ultrasonication at room temperature for 30min. Transfer the dispersed mixture to the liner of the para-polystyrene reactor and react at 180℃ for 55min. After cooling to room temperature, separate the solid substances by magnetic separation. Wash the obtained product with anhydrous ethanol 6 times, transfer the sample to a vacuum drying oven and dry at 60℃ for 12h before collecting to obtain Cu / Cu2O@Fe3O4@mSiO2.

[0040] Example 2

[0041] A method for preparing a magnetic Cu₂O / Cu heterojunction material includes the following steps:

[0042] (1) Preparation of Fe3O4@mSiO2: To prepare Fe3O4@mSiO2, 0.8 g of Fe(NO3)3·9H2O and 0.2 g of mesoporous silica microspheres were weighed into a beaker, and then 60 mL of methanol was added. After stirring magnetically for 15 min, the mixture was ultrasonically dispersed for 20 min. The dispersed mixture was transferred to the liner of a para-polystyrene reactor and reacted at 220 °C for 24 h. After cooling to room temperature, the solid matter was separated by magnetic separation. The obtained product was washed 6 times with anhydrous ethanol. The sample was transferred to a vacuum drying oven and dried at 50 °C for 12 h to obtain Fe3O4@mSiO2.

[0043] (2) Preparation of Cu / Cu2O@Fe3O4@mSiO2: To prepare Cu / Cu2O@Fe3O4@mSiO2, 0.245 g of Cu(NO3)3·3H2O and 0.025 g of Fe3O4@mSiO2 were weighed into a beaker, and then 10 mL of ethylene glycol and 20 mL of ethanol were added. The mixture was ultrasonically dispersed at room temperature for 30 min. The dispersed mixture was then transferred to the liner of a para-polystyrene reactor and reacted at 180 °C for 55 min. After cooling to room temperature, the solid matter was separated by magnetic separation. The product was washed 6 times with anhydrous ethanol. The sample was then transferred to a vacuum drying oven and dried at 60 °C for 12 h before being collected to obtain Cu / Cu2O@Fe3O4@mSiO2.

[0044] Example 3

[0045] A method for preparing a magnetic Cu₂O / Cu heterojunction material includes the following steps:

[0046] (1) Preparation of Fe3O4@mSiO2: To prepare Fe3O4@mSiO2, 0.8 g of Fe(NO3)3·9H2O and 0.2 g of mesoporous silica microspheres were weighed into a beaker, and then 60 mL of ethylene glycol was added. After stirring magnetically for 15 min, the mixture was ultrasonically dispersed for 20 min. The dispersed mixture was transferred to the liner of a para-polystyrene reactor and reacted at 220 °C for 24 h. After cooling to room temperature, the solid matter was separated by magnetic separation. The obtained product was washed 6 times with anhydrous ethanol. The sample was transferred to a vacuum drying oven and dried at 50 °C for 12 h to obtain Fe3O4@mSiO2.

[0047] (2) Preparation of Cu / Cu2O@Fe3O4@mSiO2: To prepare Cu / Cu2O@Fe3O4@mSiO2, 0.245 g of Cu(NO3)3·3H2O and 0.025 g of Fe3O4@mSiO2 were weighed into a beaker, and then 10 mL of ethylene glycol and 20 mL of ethanol were added. The mixture was ultrasonically dispersed at room temperature for 30 min. The dispersed mixture was then transferred to the liner of a para-polystyrene reactor and reacted at 180 °C for 55 min. After cooling to room temperature, the solid matter was separated by magnetic separation. The product was washed 6 times with anhydrous ethanol. The sample was then transferred to a vacuum drying oven and dried at 60 °C for 12 h before being collected to obtain Cu / Cu2O@Fe3O4@mSiO2.

[0048] The products obtained in Examples 1-3 above were subjected to performance tests. It can be seen that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within the scope of its essence and protection. Such modifications or equivalent substitutions should also be considered to fall within the protection scope of the technical solution of the present invention.

[0049] Comparative Example 1

[0050] A method for preparing a magnetic Cu₂O / Cu heterojunction material includes the following steps:

[0051] (1) Preparation of Fe3O4: Weigh 0.8g of Fe(NO3)3·9H2O into a beaker, then add 60mL of diethylene glycol, then stir magnetically for 15min, then ultrasonically disperse for 20min, transfer the dispersed mixture to the liner of the para-polystyrene reactor, react at 220℃ for 24h, cool to room temperature and then separate the solid matter by magnetic separation. The obtained product is washed 6 times with anhydrous ethanol, and the sample is transferred to a vacuum drying oven and dried at 50℃ for 12h to obtain Fe3O4;

[0052] (2) Preparation of Cu / Cu2O@Fe3O4: Weigh 0.245g of Fe3O4 and 0.025g of Cu(NO3)3·3H2O into a beaker, then add 10mL of ethylene glycol and 20mL of ethanol, and sonicate at room temperature for 30min. Transfer the dispersed mixture to the liner of the para-polystyrene reactor and react at 180℃ for 55min. After cooling to room temperature, separate the solid substances by magnetic separation. Wash the obtained product with anhydrous ethanol 6 times, transfer the sample to a vacuum drying oven and dry at 60℃ for 12h before collecting to obtain Cu / Cu2O@Fe3O4.

[0053] Comparative Example 2

[0054] A method for preparing a Cu2O / Cu heterojunction material includes the following steps:

[0055] (1) Preparation of Cu / Cu2O: Weigh 0.025g of Cu(NO3)3·3H2O into a beaker, then add 10mL of ethylene glycol and 20mL of ethanol, and sonicate at room temperature for 30min. Transfer the dispersed mixture to the liner of the para-polystyrene reactor and react at 180℃ for 55min. After cooling to room temperature, separate the solid substances by magnetic separation. Wash the obtained product with anhydrous ethanol 6 times, transfer the sample to a vacuum drying oven and dry at 60℃ for 12h before collecting to obtain Cu / Cu2O.

[0056] Test Example 1

[0057] The degradation performance of the magnetic Cu₂O / Cu heterojunction materials prepared in Examples 1-3, the magnetic Cu₂O / Cu heterojunction material of Comparative Example 1, and the Cu₂O / Cu heterojunction material prepared in Comparative Example 2 on tetracycline hydrochloride was tested. The light intensity was 500W visible light, and the concentration of tetracycline hydrochloride in the tetracycline hydrochloride solution was 50 mg / L. The mass-to-volume ratio of the magnetic Cu₂O / Cu heterojunction material or Cu₂O / Cu heterojunction material to the tetracycline hydrochloride solution was 0.1 g: 200 mL.

[0058] Table 1: Degradation performance test results of tetracycline hydrochloride

[0059]

[0060]

[0061] As shown in Table 1, the magnetic Cu2O / Cu heterojunction material prepared in Example 1 exhibits the best degradation effect on tetracycline hydrochloride under visible light. Examples 2 and 3 show slightly weaker degradation than Example 1. This is due to the different solvents used in the preparation of Fe3O4@mSiO2. This invention suggests that the solvent can affect the loading of Fe3O4 on the surface of mesoporous SiO2 microspheres. Using diethylene glycol as a solvent provides the best loading effect, and the iron(III) oxide exhibits the most uniform loading on the surface of mesoporous SiO2 microspheres. This is beneficial for the loading of Cu2O / Cu heterojunction on the Fe3O4@mSiO2 surface, and facilitates the formation of a synergistic effect with Cu2O / Cu, improving catalytic performance while enhancing the stability of cuprous oxide and reducing the photocorrosion of Cu2O.

[0062] The comparison between Comparative Example 1, Comparative Example 2 and Example 1 shows that the product obtained by using Fe3O4@mSiO2 as a support has the best photocatalytic degradation performance of tetracycline hydrochloride. This indicates that the Fe3O4@mSiO2 support can significantly improve the photocatalytic performance of Cu2O / Cu heterojunction.

Claims

1. A method for preparing a magnetic Cu₂O / Cu heterojunction material, characterized in that, Includes the following steps: (1) Take Fe(NO3)3·9H2O and mesoporous silica microspheres in a beaker, the mass ratio of Fe(NO3)3·9H2O and mesoporous silica microspheres is (1-4):1, then add organic solvent, then stir magnetically for 10-20 min, then disperse ultrasonically for 20-30 min, transfer the dispersed mixture to the liner of the para-polystyrene reactor, react at 220-260℃ for 18-30 h, cool to room temperature, and then separate the solid matter by magnetic separation. The obtained product is washed with anhydrous ethanol 5-6 times, and then the sample is transferred to a vacuum drying oven and dried at 50-70℃ for 8-12 h to collect Fe3O4@mSiO2; (2) Weigh Cu(NO3)3·3H2O and Fe3O4@mSiO2 prepared in step (1) into a beaker. The mass ratio of Cu(NO3)3·3H2O to Fe3O4@mSiO2 is (9.5-10):

1. Then add it into an organic mixed solvent and ultrasonically disperse it at room temperature for 20-30 min. Transfer the dispersed mixture to the liner of the para-polystyrene reactor and react it at 180-220℃ for 55-65 min. After cooling to room temperature, separate the solid substances by magnetic separation. Wash the obtained product with anhydrous ethanol 5-6 times. Transfer the sample to a vacuum drying oven and dry it at 50-70℃ for 8-12 h before collecting it to obtain Cu / Cu2O@Fe3O4@mSiO2.

2. The method for preparing the magnetic Cu₂O / Cu heterojunction material as described in claim 1, characterized in that, The organic solvent in step (1) is one of diethylene glycol, ethanol, or ethylene glycol.

3. The method for preparing the magnetic Cu₂O / Cu heterojunction material as described in claim 1, characterized in that, In step (2), the organic mixed solvent is a mixture of ethanol and ethylene glycol, and the volume ratio of ethanol to ethylene glycol is (1.5-2):

1.

4. The method for preparing the magnetic Cu₂O / Cu heterojunction material as described in claim 1, characterized in that, In step (2), the mass-to-volume ratio of Fe3O4@mSiO2 to the organic mixed solvent is 1g:(1-1.2)L.

5. A magnetic Cu₂O / Cu heterojunction material, characterized in that, It is prepared by the method for preparing magnetic Cu2O / Cu heterojunction material according to any one of claims 1-4.

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