A porous CuSe / Cu 2-X Method for preparing Se composite nanosheet photocatalyst

Abstract

The application discloses a porous CuSe / Cu 2‑X The application discloses a porous CuSe / Cu 2‑X The porous CuSe / Cu

Description

Technical Field

[0001] The present invention belongs to the field of inorganic materials, environmental protection and photocatalysis, and specifically relates to a porous CuSe / Cu 2-X Preparation method of Se composite nanosheet photocatalyst. Background Art

[0002] Printing and dyeing wastewater often contains large amounts of organic dyes, characterized by large volumes of water, dark colors, and high organic content. Modern industrial development has driven advancements in printing and dyeing processing technologies, leading to the widespread use of a large number of new, high-efficiency dyes, dyeing auxiliaries, slurries, and other non-biodegradable organic compounds within the printing and dyeing industry. This has directly resulted in a significant increase in dye wastewater, with its organic components becoming increasingly complex and diverse. Therefore, eliminating high chroma and high COD values ​​in dye wastewater are two key challenges in current printing and dyeing wastewater treatment. These dye wastewaters seriously impact the ecological environment and human health. Printing and dyeing wastewater is one of the most challenging types of industrial wastewater to treat. Due to technical and economic constraints, most currently used biological-physical treatment methods can only meet basic discharge requirements. While they can slightly reduce chroma, they only break down organic matter into smaller components. The properties of these decomposition products are difficult to control and understand, and there is no guarantee that they will not harm the environment.

[0003] Photocatalytic oxidation, an emerging water treatment technology developed in the 1980s, can typically completely mineralize organic matter into simple inorganic compounds such as CO2 and H2O within a sufficient reaction time, avoiding secondary pollution. Compared to traditional water treatment technologies, it offers significant advantages in energy conservation, high efficiency, and thorough pollutant degradation. Photocatalysis utilizes naturally occurring light energy to convert it into the energy required for chemical reactions, generating a catalytic effect and achieving catalytic degradation. Under illumination, photocatalysts generate highly oxidizing free radicals, which can completely degrade organic matter and ultimately produce small inorganic molecules such as CO2 and H2O. Currently, the most studied semiconductor catalysts are n-type wide-bandgap semiconductor compounds, such as TiO2, ZnO, and ZnS. However, these compounds are only excited by ultraviolet light, which accounts for only 3–5% of sunlight, limiting their practical applications.

[0004] Nanoselenides are semiconductor materials formed between II-VI group elements with unique physical and chemical properties and some potential application prospects. In recent years, they have attracted more and more attention from scientists. Copper selenide compounds include a series of ideal ratio compounds (CuSe, CuSe2, Cu2Se, Cu3Se2, Cu7Se4, etc.) and non-ideal ratio compounds (Cu 2-xSe). Due to the special composition and properties of copper selenide compounds, they have become a hot topic of research. Among them, CuSe (band gap is 1.7eV) and Cu 2-x Selenium (band gap 2.2 eV) is effectively excited by visible light and exhibits good photocatalytic activity, leading to its increasing application in photocatalytic wastewater treatment. Currently, most synthesized products are thin films or nanoparticles, with few reports on porous copper selenide nanosheets. Furthermore, the synthesis of copper selenide compounds often requires high temperatures or the addition of surfactants. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a porous CuSe / Cu 2-X Se composite nanosheet photocatalyst and its preparation method. The method uses less chemical reagents, has a simple preparation process, low reaction temperature, does not require any surfactant, does not require complex and expensive equipment, and has mild synthesis conditions. 2-X The synthesis of Se composite nanosheet photocatalysts does not introduce impurities, has high purity, and has high photocatalytic activity.

[0006] The porous CuSe / Cu 2-X CuSe / CuSe composite nanosheet photocatalyst 2-X The Se complex is a porous nanosheet structure with a nanosheet dimension (length or width) of 15 to 20 μm, an average thickness of 100 nm, and a pore size distribution range of 1 to 80 nm.

[0007] The present invention provides a preparation method, the specific steps are as follows:

[0008] 1) Dissolve zinc nitrate and selenium powder in 10 mL of ethylenediamine, and transfer the solution to a 20 mL reaction kettle; the molar ratio of zinc nitrate to selenium powder is (1:3) to (3:1);

[0009] 2) Keep the reactor at 140-220°C for 8-24 hours. After cooling, wash the precipitate with deionized water and anhydrous ethanol respectively;

[0010] 3) dissolving the precipitate obtained in step 2) in 10 mL of 0.2-2.0 mol / L copper nitrate solution, and transferring the solution to a 20 mL reaction kettle;

[0011] 4) The reactor of step 3) was kept at 120-180°C for 8-24 hours, and after cooling, the precipitate was washed with deionized water and anhydrous ethanol respectively to obtain CuSe / Cu 2-X Se composite nanosheet photocatalyst.

[0012] The preferred conditions of the above preparation method are as follows:

[0013] The molar ratio of zinc nitrate to selenium powder in step 1) is preferably (1:2) to (2:1);

[0014] In step 2), the reaction vessel is reacted at 160-200° C. for 10-18 hours;

[0015] Step 3) the solubility of copper nitrate is 0.4-1.0 mol / L

[0016] In step 4), the reaction vessel is reacted at 140-160° C. for 10-20 hours.

[0017] Beneficial effects of the present invention:

[0018] 1. The present invention adopts a two-step solvent thermal method to prepare porous CuSe / Cu with zinc nitrate, selenium powder, copper nitrate and ethylenediamine. 2-X The Se composite nanosheet photocatalyst has a simple preparation process, convenient operation, low production cost, and is easy to obtain cheap raw materials and industrial production.

[0019] 2. The present invention has few raw materials and simple process, which reduces the adverse factors in the reaction process, so the product will not introduce impurities and has high purity.

[0020] 3. The porous CuSe / Cu obtained by the present invention 2-X Se composite nanosheet photocatalyst has high activity under sunlight irradiation and has the advantages of being easy to use, easy to recycle, and reusable when photocatalytically degrading organic dyes. The degradation rate of rhodamine-B can reach more than 99.1% in 45 minutes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The X-ray diffraction (XRD) spectra of the products obtained in Examples 1 to 3 of the present invention are shown.

[0022] Figure 2 This is a scanning electron microscope (SEM) image of the product obtained in Example 1 of the present invention.

[0023] Figure 3 This is a scanning electron microscope (SEM) image of the product obtained in Example 1 of the present invention.

[0024] Figure 4 This is the N2 adsorption-desorption isotherm of the product obtained in Example 1 of the present invention.

[0025] Figure 5 This is the pore size distribution diagram of the product obtained in Example 1 of the present invention.

[0026] Figure 6 The degradation rate curves of the products obtained in Examples 1 to 3 of the present invention vary with reaction time. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further explained and illustrated in the following in the form of specific embodiments.

[0028] Example 1

[0029] In the first step of the solvothermal reaction, 2 mmol of zinc nitrate and 2 mmol of selenium powder were first dissolved in 10 mL of ethylenediamine, and the solution was transferred to a 20 mL reactor. The reactor was then kept at 180° C. for 16 h. After cooling, the precipitate was washed with deionized water and anhydrous ethanol, respectively.

[0030] In the second step, the precipitate obtained from the first step was dissolved in 10 mL of 1.1 mol / L copper nitrate solution, and the solution was transferred to a 20 mL reactor. The reactor was kept at 120°C for 24 h. After cooling, the precipitate was washed with deionized water and anhydrous ethanol, respectively, to obtain CuSe / Cu 2-X Se composite nanosheet photocatalyst.

[0031] Effect verification: Figure 1 Curve 1 in the figure is the X-ray diffraction curve of the obtained product. Figure 1 As shown, the diffraction peaks of the obtained products are consistent with those of CuSe (JCPDS No. 27-0184) and Cu 2-X The diffraction peaks on the standard card of Se (JCPDS No.06-0680) are consistent, and no impurity peaks appear, indicating that the product is CuSe / Cu 2-X Se complex. Figure 2 and Figure 3 : is the SEM picture of the product obtained in this embodiment. Figure 2 As shown, the product obtained in this embodiment is a sheet-like structure with irregular shape and rough surface, and its dimension is about 10-15 μm. Figure 3 As shown, the surface of the product obtained in this embodiment is relatively rough, and its average thickness is about 100 nm. Figure 4 is the N2 adsorption-desorption isotherm of the product obtained in this embodiment. Figure 4 The specific surface area of ​​the product is calculated to be 9.64 m 2 / g. Figure 5 The pore size distribution diagram of the product obtained in the embodiment of the present invention is shown in FIG. Figure 5 As can be seen in the figure, the pore size distribution is between 1-80 nm. Figure 6 Curve 1 in FIG is the degradation rate curve of Rhodamine-B catalyzed by sunlight of the product obtained in this embodiment. Figure 6 As shown, when the concentration of Rhodamine-B solution is 10 mg / L, the power of the xenon lamp is 250 W, and the reaction time is 45 minutes, the degradation rate reaches 99.1%.

[0032] Example 2

[0033] The first step of the solvothermal reaction, first, 3 mmol of zinc nitrate and 1 mmol of selenium powder were dissolved in 10 mL of ethylenediamine, and the solution was transferred to a 20 mL reaction kettle; then the reaction kettle was incubated at 140°C for 24 h, and after cooling, the precipitate was washed with deionized water and anhydrous ethanol, respectively.

[0034] The second step of the solvothermal reaction, the precipitate obtained in the first step of the solvothermal reaction was dissolved in 10 mL of 0.2 mol / L copper nitrate solution, and the solution was transferred to a 20 mL reaction kettle; the reaction kettle was incubated at 180°C for 8 h, and after cooling, the precipitate was washed with deionized water and anhydrous ethanol, respectively, to obtain CuSe / Cu 2-X Se composite nanosheet photocatalyst.

[0035] Effect verification: Figure 1 Curve 2 in the middle is the X-ray diffraction curve of the obtained product. As Figure 1 shown, the diffraction peaks of the obtained product are consistent with the diffraction peak positions on the standard cards of CuSe (JCPDS No. 27-0184) and Cu 2-X Se (JCPDS No. 06-0680), and no impurity peaks appear, indicating that the product is a CuSe / Cu 2-X Se composite. Figure 6 Curve 2 in the middle is the solar light catalytic rhodamine-B degradation rate curve of the product obtained in this example. As Figure 6 shown, the rhodamine-B solution concentration is 10 mg / L; the xenon lamp power is 250 W, and the reaction time is 45 minutes, and the degradation rate reaches 93.4%.

[0036] Example 3

[0037] The first step of the solvothermal reaction, first, 1 mmol of zinc nitrate and 3 mmol of selenium powder were dissolved in 10 mL of ethylenediamine, and the solution was transferred to a 20 mL reaction kettle; then the reaction kettle was incubated at 220°C for 8 h, and after cooling, the precipitate was washed with deionized water and anhydrous ethanol, respectively.

[0038] The second step of the solvothermal reaction, the precipitate obtained in the first step of the solvothermal reaction was dissolved in 10 mL of 2.0 mol / L copper nitrate solution, and the solution was transferred to a 20 mL reaction kettle; the reaction kettle was incubated at 120°C for 24 h, and after cooling, the precipitate was washed with deionized water and anhydrous ethanol, respectively, to obtain CuSe / Cu 2-X Se composite nanosheet photocatalyst.

[0039] Effect verification: Figure 1 Curve 3 in the middle is the X-ray diffraction curve of the obtained product, as Figure 1As shown, the diffraction peaks of the obtained products are consistent with those of CuSe (JCPDS No. 27-0184) and Cu 2-X The diffraction peaks on the standard card of Se (JCPDS No.06-0680) are consistent, and no impurity peaks appear, indicating that the product is CuSe / Cu 2-X Se complex. Figure 6 Curve 3 in FIG is the degradation rate curve of Rhodamine-B catalyzed by sunlight of the product obtained in this embodiment. Figure 6 As shown, when the concentration of Rhodamine-B solution is 10 mg / L, the power of the xenon lamp is 250 W, and the reaction time is 45 minutes, the degradation rate reaches 89.2%.

[0040] In the embodiment, the first step of the reaction generates a nanosheet-like structure of ZnSe(en) 0.5 Precursor complex. The second step reaction mainly uses the cation exchange method. On the one hand, the precursor ZnSe(en) 0.5 The Zn ions in the solution are replaced by Cu ions, and the precursor ZnSe(en) 0.5 becomes CuSe(en) 0.5 , while CuSe(en) 0.5 Further decomposition produces CuSe / Cu 2-X Se complex; on the other hand, ZnSe(en) 0.5 Directly decompose to form ZnO, and the Cu ions in the solution replace the Zn ions in ZnSe to form CuSe. Since all the reactions in the second step occur simultaneously, CuSe / Cu is finally formed. 2-X Se complex, while the product retains the morphology and size of the precursor. In this embodiment, the reaction reagents are relatively few, which reduces the production cost, and the product does not introduce impurities and has a high purity; the obtained catalyst has high performance, and the method has the advantages of cheap raw materials and a simple preparation process.

Claims

1. A porous CuSe / Cu 2-X Se composite nanosheet photocatalyst, characterized in that CuSe / Cu 2-X The Se complex is a porous nanosheet structure with a length or width of 15-20 μm, an average thickness of 100 nm, and a pore size distribution range of 1-80 nm. The specific steps of its preparation method are as follows: 1) Dissolve zinc nitrate and selenium powder in 10 mL of ethylenediamine and transfer the resulting solution to a 20 mL reactor. The molar ratio of zinc nitrate to selenium powder should be (1:3) to (3:1). 2) Keep the reactor at 140-220°C for 8-24 hours. After cooling, wash the precipitate with deionized water and anhydrous ethanol respectively. 3) Dissolve the precipitate obtained in step 2) in 10 mL of 0.2-2.0 mol / L copper nitrate solution and transfer the resulting solution to a 20 mL reaction vessel; 4) The reactor of step 3) was kept at 120-180°C for 8-24 hours. After cooling, the precipitate was washed with deionized water and anhydrous ethanol respectively to obtain CuSe / Cu 2-X Se composite nanosheet photocatalyst.

2. The porous CuSe / Cu according to claim 1 2-X Se composite nanosheet photocatalyst, characterized in that The molar ratio of zinc nitrate to selenium powder in step 1) is (1:2) to (2:1).

3. The porous CuSe / Cu according to claim 1 2-X Se composite nanosheet photocatalyst, characterized in that In step 2), the reactor is placed in a constant temperature box at 160-200° C. for 10-18 hours.

4. The porous CuSe / Cu according to claim 1 2-X Se composite nanosheet photocatalyst, characterized in that In step 4), the reactor is kept in a constant temperature box at 140-160° C. for 10-20 hours.

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